HVAC Water Treatment
Neutrality remake campaign: from-scratch field derivation per authoring cheatsheet; project parameters and derived dispositions
Showing changes from Rev 8
to Rev 9
in HVAC Water Treatment.
−---
−title: HVAC Water Treatment
−category: Mechanical / Piping & Pumps
−toc_depth: 3
−description: >
− When to use: Chemical and physical water treatment for HVAC water systems in commercial, institutional, and industrial buildings. Covers closed hydronic loops (heating hot water, chilled water, dual-temperature, water-source heat pump, ground source loop), open recirculating condenser-water systems serving cooling towers and evaporative condensers, glycol-protected closed loops at any concentration, and low-pressure steam and condensate-return systems up to 150 psig. Scope includes pre-operational cleaning and flushing, alkaline degreasing and acid passivation where required, initial inhibitor charge, ongoing inhibitor and biocide dosing, side-stream filtration, automatic chemical feed and bleed control, conductivity- and corrosion-coupon-based monitoring, sample-port provisions, service contract requirements, and the documentation package needed to support a building water management plan under ASHRAE Standard 188.
−
− Not intended for: Domestic potable hot and cold water (see [[sync/domestic-water-piping]]); pure-water and reverse-osmosis loops serving humidifiers, laboratory equipment, or process; high-pressure steam systems above 150 psig (governed by ASME B31.1 and a process-grade boiler water program); fire protection sprinkler piping (see [[sync/wet-pipe-fire-sprinkler-systems]]); refrigerant circuits (governed by refrigerant equipment standards); fuel oil; or municipal water mains upstream of the building water service. The pumps, piping, expansion devices, and air separators that this treatment program protects are covered in companion standards [[sync/hydronic-piping]] and [[sync/hvac-pumps]]; air-handler cooling coils that share the same chilled water are covered in [[sync/air-handling-units]]; chemical-feed pumps, conductivity controllers, and metering devices that integrate with the building automation system are coordinated through [[sync/building-automation-system]].
−---
−
−# Scope {toc}
−
−## This standard covers the design, equipment, materials, and ongoing program for chemical and physical treatment of water and water-glycol fluids in HVAC service. {note}
−## The systems addressed are closed hydronic loops (heating hot water, chilled water, dual-temperature, water-source heat pump and ground-source heat pump loops, and any closed loop protected with propylene or ethylene glycol), open recirculating condenser-water systems serving open- and closed-circuit cooling towers and evaporative condensers, and low-pressure steam and condensate-return systems serving humidifiers, sterilizers, and heating boilers. {note}
−## The work includes initial inspection and analysis of make-up water and any existing system water; the pre-operational cleaning and flushing of new piping, vessels, and equipment; pre-passivation of clean metal surfaces before the system is placed in service; the initial chemical charge that establishes baseline corrosion-inhibitor, scale-inhibitor, and biocide levels; the equipment that doses, monitors, bleeds, and filters the circulating fluid; and the service program that maintains chemistry within control ranges throughout the system's life. {note}
−## The standard also defines the documentation that the design team and the Owner need to satisfy ASHRAE Standard 188's requirements for a building water management program where open recirculating systems are present. {note}
−
−## Water treatment is the single most important determinant of long-term hydronic system reliability. {note}
−
−## A closed loop with disciplined inhibitor maintenance can run for thirty years with the original pipe and pump internals intact, while a closed loop run on raw fill water with no inhibitor program loses its first heat exchanger to oxygen pitting within two years and accumulates iron-oxide sludge that disables the coldest, slowest-velocity branches first. {note}
−
−## An open condenser water system without effective scale, corrosion, and biological control will scale a cooling tower fill in a single hot-weather season, accelerate condenser-tube failures, and — in the case of biological control failure — present a documented Legionellosis transmission risk that has produced both fatalities and litigation. {note}
−
−## The treatment program described here is the operational layer that determines whether the hydronic and refrigeration equipment specified elsewhere in these documents will reach the end of its design life; it is not a discretionary refinement. {note}
−
−## The boundary of work under this standard begins at the make-up water connection to each treated system, continues through all chemical feed, monitoring, bleed-off, and filtration equipment, and includes the chemical reservoirs, day-tanks, and chemical-storage room provisions located in the central plant.
−
−## The interconnecting piping that carries treated water through the building — the hydronic distribution mains, branch piping, expansion devices, and air separators that the program protects — is covered in [[sync/hydronic-piping]]; pumps that circulate the treated fluid are covered in [[sync/hvac-pumps]]; cooling coils and heat exchangers exposed to the treated fluid are covered in the respective equipment standards including [[sync/air-handling-units]]; and the conductivity controllers, chemical-feed pumps, and metering devices that report to the BAS are coordinated through [[sync/building-automation-system]]. {note}
−
−## Where open recirculating systems are present, the building's overall water management plan, prepared in accordance with ASHRAE Standard 188 and the local public health authority's requirements, shall integrate this standard's monitoring data, control set points, and corrective-action procedures into a single facility document maintained by the Owner.
−
−# Referenced Standards {toc}
−
−## Equipment, materials, treatment programs, and installation shall comply with the latest adopted edition of the following standards and guidelines unless a specific edition is cited.
−
−| Standard | Title |
−|----------|-------|
−| ANSI/ASHRAE 188 | Legionellosis: Risk Management for Building Water Systems |
−| ASHRAE Guideline 12 | Managing the Risk of Legionellosis Associated with Building Water Systems |
−| ASHRAE Handbook — HVAC Applications | Chapter on Water Treatment: Deposition, Corrosion, and Biological Control |
−| ASHRAE Handbook — HVAC Systems and Equipment | Chapters on Hydronic Heating and Cooling and on Cooling Towers |
−| ANSI/ASHRAE/IES 90.1 | Energy Standard for Buildings Except Low-Rise Residential Buildings |
−| CTI STD-159 | Acceptable Water for Cooling Tower Make-Up |
−| CTI WTP-148 | Legionellosis Guideline: Best Practices for Control of Legionella |
−| AWT Technical Reference and Training Manual | Association of Water Technologies — recommended practice for industrial water treatment programs |
−| ASTM D1141 | Standard Practice for the Preparation of Substitute Ocean Water (reference for chloride aggressiveness comparisons) |
−| ASTM D1193 | Standard Specification for Reagent Water (laboratory test water purity grades) |
−| ASTM D596 | Standard Guide for Reporting Results of Analysis of Water |
−| ASTM D2688 | Standard Test Methods for Corrosivity of Water in the Absence of Heat Transfer (Weight Loss Methods) — corrosion coupon practice |
−| ASTM D3370 | Standard Practices for Sampling Water from Closed Conduits |
−| ASTM D4012 | Standard Test Method for Adenosine Triphosphate (ATP) Content of Microorganisms in Water — rapid microbiological screening |
−| AWWA C651 | Disinfecting Water Mains (reference for chlorination procedure) |
−| AWWA B100 | Granular Filter Material |
−| NACE SP0189 (now AMPP) | On-Line Monitoring of Cooling Waters |
−| NACE SP0775 (now AMPP) | Preparation, Installation, Analysis, and Interpretation of Corrosion Coupons in Oilfield Operations (adapted to HVAC) |
−| ASME B31.9 | Building Services Piping |
−| NSF/ANSI 60 | Drinking Water Treatment Chemicals — Health Effects (where treated water may contact potable systems) |
−| NSF/ANSI 50 | Equipment and Chemicals for Swimming Pools, Spas, Hot Tubs, and Other Recreational Water Facilities (reference for biocide handling) |
−| FDA 21 CFR 173.310 | Boiler Water Additives (where steam contacts food) |
−| EPA FIFRA | Federal Insecticide, Fungicide, and Rodenticide Act — registration of biocidal products |
−| OSHA 29 CFR 1910.1200 | Hazard Communication Standard (chemical container labeling, SDS) |
−| OSHA 29 CFR 1910.119 | Process Safety Management (where bulk chemical thresholds are exceeded) |
−| DOT 49 CFR | Hazardous Materials Regulations (chemical shipment) |
−| IBC | International Building Code (chemical storage room rating and ventilation) |
−| IFC | International Fire Code (hazardous materials storage and signage) |
−| IPC / UPC | International Plumbing Code or Uniform Plumbing Code as adopted (cross-connection control, make-up backflow prevention) |
−| ASSE 1013 | Performance Requirements for Reduced Pressure Principle Backflow Prevention Assemblies |
−
−## Where the contract documents, the adopted building or mechanical code, the local public health authority's water-management requirements, or a referenced standard impose conflicting requirements, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
−
−## The Owner's local public health authority — typically a state department of health or a state department of environmental services — may publish additional requirements for cooling tower registration, Legionella sampling, and water management plan content. {note}
−
−## Public health authority requirements take precedence within their jurisdiction and shall be incorporated into the program by the design team and the water treatment service provider.
−
−# Submittals {toc}
−
−## Action Submittals {toc}
−
−### The Contractor and the water treatment service provider shall submit the following for the Engineer's review and return before procurement, before the initial chemical charge, and before any acid or alkaline cleaning operation begins:
−
−- A pre-design water analysis for the project's intended make-up water source, including total hardness as CaCO3, calcium hardness, total alkalinity, chloride, sulfate, silica, total dissolved solids (TDS) or conductivity, pH, iron, manganese, and total organic carbon. The analysis shall be performed by an independent laboratory using current ASTM methods and shall be no more than twelve months old. Where the building draws from a well, an analysis from each well shall be submitted; where the building draws from a municipal supply, the most recent annual Consumer Confidence Report from the supplier shall accompany the laboratory analysis.
−- A written treatment design for each system — closed HHW, closed CHW, condenser-water, glycol loop, steam — identifying the proposed inhibitor chemistry, scale inhibitor where applicable, biocide types and rotation, expected control ranges for each parameter, target cycles of concentration for open systems, and the conductivity, oxidation-reduction potential (ORP), or other set point on which automatic feed and bleed are based.
−- Product data sheets and Safety Data Sheets (SDS) for every chemical product proposed for use on the project, including initial cleaner, passivator, inhibitor, biocide, and any specialty products. The SDS shall be the current version published within the last three years.
−- EPA registration documentation for every biocidal product, demonstrating the product is registered under FIFRA for the use proposed. Non-registered or off-label use of biocides shall not be permitted.
−- Compatibility statement confirming that each treatment chemical is compatible with the materials of construction in each system — copper, copper alloys, carbon steel, stainless steel, galvanized steel where present, cast iron, aluminum where present, EPDM, NBR, and the gasket materials used in grooved couplings, flanges, and pump seals. Where galvanized steel cooling towers are present, the compatibility statement shall specifically address white-rust prevention chemistry. Where aluminum components are present (some pump impellers, some heat exchangers, some humidifier cylinders), the compatibility statement shall confirm that the proposed chemistry maintains pH and inhibitor levels within the narrow window aluminum tolerates.
−- Pre-operational cleaning plan for each system, including the sequence of fill, circulation, drain, flush, and refill operations; the cleaner concentration, temperature, and circulation time; the velocity that will be maintained during flushing; the temporary piping, bypasses, and strainers required to protect coils and small-bore equipment; and the acceptance criteria for flush completion.
−- Pre-passivation plan for each closed system, identifying the passivator chemistry, dosage, circulation time, and temperature, and the corrosion-coupon installation that will document the passivation result.
−- Chemical feed and control equipment shop drawings, showing each chemical feed pump, day-tank or bulk tank, feed line routing, isolation valves, calibration columns, conductivity probe location, ORP probe location (open systems), flow switch location, bleed-off solenoid and metering equipment, side-stream filter, and sample-port locations. Locations shall be coordinated with chemical-storage room layout, structural housekeeping pads, BAS conduit, and clearance to permit chemical drum changeout without disassembly.
−- Side-stream filter product data including filtration micron rating, design flow, design pressure drop clean and dirty, backwash or change-out interval and method, and connection details.
−- Sample-port locations and details for each system, showing port type, isolation valve, drain, and the sequence in which the port will be used during sampling.
−- Cooling tower drift-eliminator data confirming maximum drift loss of 0.005% of recirculating flow or less for any open tower as required by ASHRAE 188 risk management.
−- A draft Water Management Plan template (open systems only) prepared in accordance with ASHRAE Standard 188 and the local public health authority's requirements, identifying the building water systems within scope, the control measures for each system, the control limits, the monitoring schedule, and the documentation and corrective-action procedures. Final plan content depends on Owner inputs and shall be completed before substantial completion.
−- Service contract proposal identifying the scope of routine service, the frequency of visits, the parameters tested at each visit, the third-party laboratory used for any off-site analysis, the corrosion-coupon installation and reading schedule, the cooling tower Legionella sampling schedule (where applicable), the after-hours response commitment, and the chemical-supply replenishment basis.
−
−```datasheet
−label: Action Submittals Required
−type: checkbox
−options:
− - "Pre-design make-up water analysis (independent laboratory)"
− - "Treatment design narrative per system"
− - "Chemical product data and Safety Data Sheets"
− - "EPA FIFRA registration for each biocidal product"
− - "Materials compatibility statement"
− - "Pre-operational cleaning plan per system"
− - "Pre-passivation plan per closed system"
− - "Chemical feed and control equipment shop drawings"
− - "Side-stream filter product data"
− - "Sample-port locations and details"
− - "Drift-eliminator data (open systems)"
− - "Draft ASHRAE 188 Water Management Plan template"
− - "Service contract proposal"
−default: "Pre-design make-up water analysis (independent laboratory)"
−```
−
−### Cleaning and chemical addition shall not start on any system until the corresponding submittals are reviewed and returned.
−
−### Submittal review precedes chemical addition because the consequences of using the wrong chemistry or the wrong sequence are typically irreversible — passivation cannot be undone, and chemistry compatibility errors can scrap a coil run or strip a galvanized cooling tower of its protective coating. {note}
−
−## Closeout Submittals {toc}
−
−### At substantial completion, before each treated system is accepted by the Owner, the following shall be delivered:
−
−- Signed and dated cleaning and flushing reports for each system, documenting cleaner used and concentration, circulation time and temperature, the flushed water clarity at acceptance, the iron and total suspended solids measured in the final flush, and the sign-off of both the installing contractor and the water treatment service provider.
−- Signed and dated pre-passivation reports for each closed system, with the inhibitor concentration achieved, the circulation time and temperature, and any corrosion-coupon weight-loss result available at the time of acceptance.
−- Initial water analysis reports for each system showing the system filled with treated water and within all control ranges before the system was placed into operating service.
−- Operation and maintenance manuals for all treatment equipment — chemical feed pumps, conductivity and ORP controllers, side-stream filters, sample ports, bleed-off equipment — including manufacturer's parts lists, replacement schedules, and calibration procedures.
−- BAS point list and control narratives for all chemical-feed-related signals (conductivity, ORP, make-up flow, bleed-off flow, chemical-day-tank level alarms, side-stream filter differential pressure) integrated with [[sync/building-automation-system]].
−- A printed Water Management Plan binder (open systems) that includes the system descriptions, control measures, control limits, monitoring procedures, corrective-action procedures, communication and documentation procedures, the names and contact information of the water management team, and signature pages for the building owner, the operating engineer, and the water treatment service provider.
−- A Chemical Inventory List with the SDS for each chemical present on site, the location of each chemical, the maximum quantity stored, and the spill-response procedure.
−- The first six months of the service contract, with a documented service-visit schedule and a defined point of contact, included in the base bid.
−
−```datasheet
−label: Closeout Submittals Required
−type: checkbox
−options:
− - "Cleaning and flushing reports (signed) per system"
− - "Pre-passivation reports (signed) per closed system"
− - "Initial treated-water analysis reports per system"
− - "Operation and maintenance manuals for treatment equipment"
− - "BAS point list and control narratives"
− - "Printed Water Management Plan binder (open systems)"
− - "Chemical Inventory List with SDS"
− - "First six months of service contract (in base bid)"
−default: "Cleaning and flushing reports (signed) per system"
−```
−
−### The closeout package is the document trail that lets the Owner's service provider take over the program, that the Owner's facility staff need to operate the system, and that the Owner needs to demonstrate compliance with ASHRAE 188 and any state cooling tower registration requirement. {note}
−
−# Quality Assurance {toc}
−
−## Service Provider Qualifications {toc}
−
−### The water treatment service provider shall be a firm whose primary business is industrial water treatment, with a minimum of five years of continuous experience treating commercial HVAC water systems of comparable size and complexity.
−
−### The provider shall employ certified water technologists.
−
−### Certification by the Association of Water Technologies (AWT Certified Water Technologist, CWT) or an equivalent third-party credential shall be held by at least one technician assigned to the project.
−
−### The provider shall maintain product liability and professional liability insurance appropriate to the scope of work.
−
−### The provider shall maintain an EPA establishment number where any treatment product is repackaged or blended at the provider's facility.
−
−## Manufacturer-Independent Selection {toc}
−
−### Proposed inhibitors and biocides shall be selected because they suit the project's make-up water, materials of construction, and operating regime, not because they are part of a vendor's exclusive product line.
−
−### Where a project has multiple bidders, each bidder shall propose chemistry meeting the same performance criteria, evaluated on cost-per-treatment-cycle and program completeness rather than on brand.
−
−### The program description shall be specific enough that a successor provider can match chemistry parameters, so that the Owner is free to change service providers without re-cleaning the system.
−
−## Materials Compatibility Verification {toc}
−
−### Before initial chemical charge, the service provider's written compatibility verification governs whether chemistry may be added.
−
−```datasheet
−label: Materials Compatibility Verification — Signed by Service Provider
−type: radio
−options:
− - "Required and on file before initial chemical charge"
− - "Required at every chemistry change, not only initial fill"
− - "Both — initial and on every product substitution"
−default: "Both — initial and on every product substitution"
−```
−
−### Before initial chemical charge, the service provider shall verify in writing that the proposed chemistry is compatible with every material in the wetted path: pipe metallurgy at every section (carbon steel, copper, stainless steel, galvanized where present), pump and valve bodies, mechanical seal faces and elastomers, gasket compounds at flanges and grooved couplings, heat exchanger tube and shell materials, expansion-tank diaphragm material, and any aluminum component such as aluminum cylinders in steam humidifiers or aluminum impellers in light-duty pumps.
−
−### The verification shall identify any incompatibility and propose a substitute chemistry or a control measure such as pH window narrowing.
−
−### The verification shall be signed by the service provider's technical authority before chemistry is added.
−
−## Cross-Connection Control {toc}
−
−### For chemically treated systems, the minimum backflow protection device is typically a reduced-pressure principle backflow prevention assembly (RPBA) conforming to ASSE 1013; many jurisdictions specifically require RPBA on open cooling tower make-up because the chemistry contains biocides registered under FIFRA. {note}
−
−### Make-up water connections to all treated systems shall be protected by backflow prevention assemblies of the type and rating required by the adopted plumbing code and the local cross-connection control authority.
−
−```datasheet
−label: Make-up Water Backflow Prevention
−type: radio
−options:
− - "Reduced Pressure Principle Assembly (RPBA), ASSE 1013 — standard for all chemically treated systems"
− - "Air Gap (AG) — where physical separation is feasible and acceptable to AHJ"
− - "Double Check Backflow Assembly (DCBA), ASSE 1015 — closed loops only, where AHJ accepts"
−default: "Reduced Pressure Principle Assembly (RPBA), ASSE 1013 — standard for all chemically treated systems"
−```
−
−### Treated water shall not be permitted to flow back into the domestic supply at any operating condition.
−
−### The Contractor shall confirm the specific device type with the local cross-connection control authority before procurement.
−
−### The Contractor shall install the assembly in a location accessible for the annual test required by the cross-connection program.
−
−## Chemical Storage Room {toc}
−
−### A dedicated chemical storage room or area shall be provided for the treatment program's bulk chemistry, with the minimum provisions below.
−
−```datasheet
−label: Chemical Storage Room — Secondary Containment Capacity
−type: radio
−options:
− - "110% of largest single tank (code minimum)"
− - "150% of largest single tank (recommended where multiple bulk tanks present)"
− - "Sum of all stored chemical volumes (worst-case complete-failure containment)"
−default: "110% of largest single tank (code minimum)"
−```
−
−### A chemical-resistant floor coating shall be provided.
−
−### Secondary containment sized for at least 110% of the largest tank in the room shall be provided.
−
−### A floor drain shall be provided that does not directly connect to a storm sewer or sanitary sewer without spill-isolation provisions.
−
−### Eyewash and emergency shower meeting ANSI Z358.1 shall be provided.
−
−### Mechanical ventilation that meets the IBC and IFC requirements for the chemical hazard class present shall be provided.
−
−### Chemical-compatible separation between incompatible products shall be provided, with acids separated from oxidizers and oxidizers separated from organic biocides.
−
−### Spill response materials, including absorbent and containment booms, shall be provided.
−
−### Posted Safety Data Sheets in a weatherproof binder shall be provided at the room entry.
−
−### Where bulk chemistry quantities exceed the IFC thresholds for hazardous occupancy classification, the room shall be classified and constructed accordingly.
−
−# Water Analysis — Pre-Design {toc}
−
−## Significance of Make-Up Water Quality {toc}
−
−### Every treatment program is built on the chemistry of the make-up water available at the project site, because make-up water continuously refreshes the system either through evaporation (open systems) or through small steady losses to leakage, drain-down, and routine venting (closed systems). {note}
−
−### The hardness, alkalinity, chloride, silica, and conductivity of the make-up water determine the cycles of concentration achievable in an open tower, the scaling potential at evaporator surfaces, the corrosion aggressiveness of the resulting concentrated water, and the inhibitor consumption rate. {note}
−
−### A program designed for soft, low-conductivity municipal water will fail on a project that draws from a hard well, while a program designed for hard well water will over-treat soft city water at unnecessary cost. {note}
−
−### The pre-design water analysis is the foundation of program design and shall not be omitted.
−
−## Required Make-Up Water Parameters {toc}
−
−### The pre-design water analysis shall report at minimum the parameters listed below.
−
−```datasheet
−label: Required Pre-Design Water Analysis Parameters
−type: checkbox
−options:
− - "pH"
− - "Total hardness as CaCO3"
− - "Calcium hardness as CaCO3"
− - "Magnesium hardness as CaCO3"
− - "Total alkalinity as CaCO3"
− - "Chloride as Cl-"
− - "Sulfate as SO4-2"
− - "Silica as SiO2"
− - "Total dissolved solids (TDS) or conductivity"
− - "Iron, total"
− - "Manganese"
− - "Total organic carbon (TOC)"
− - "Free chlorine residual (municipal supplies)"
− - "Monochloramine residual (chloraminated supplies)"
−default: "pH"
−```
−
−```datasheet
−label: Make-Up Water Source
−type: select
−options:
− - "Municipal potable supply (treated city water)"
− - "On-site well — single well"
− - "On-site well — multiple wells with blended draw"
− - "Reclaimed water (purple-pipe non-potable supply)"
− - "Captured rainwater or condensate"
− - "Mixed sources — primary and bypass"
−drawing_ref: true
−default: "Municipal potable supply (treated city water)"
−```
−
−### The pre-design water analysis shall be performed by an independent laboratory using current ASTM or Standard Methods procedures.
−
−### Where multiple make-up sources are possible (municipal supply normally, well water on bypass), each source shall be analyzed.
−
−## Suitability for Cooling Tower Make-Up {toc}
−
−### A make-up water with high chloride (typically above approximately 250 mg/L) or high conductivity (typically above approximately 1,000 µS/cm) limits the achievable cycles of concentration and may require softening, partial reverse osmosis, or another pretreatment before the make-up enters the tower.
−
−```datasheet
−label: Pre-Treatment of Make-Up Water (Open Systems)
−type: select
−options:
− - "None — make-up water suitable as-is per CTI STD-159"
− - "Softening — ion exchange for hardness reduction"
− - "Reverse osmosis (RO) — partial or full"
− - "Filtration — particle removal at make-up only"
− - "Multiple — softening plus RO blend per design"
−drawing_ref: true
−default: "None — make-up water suitable as-is per CTI STD-159"
−```
−
−### For projects with open cooling tower service, the make-up water shall be evaluated against CTI STD-159 acceptable limits.
−
−### Where the analysis indicates the raw supply does not meet CTI STD-159 without pretreatment, the Engineer shall coordinate pretreatment equipment selection with the architectural and plumbing scope before tower selection is finalized.
−
−## Reagent and Test Water for the Service Program {toc}
−
−### Test reagents and laboratory water used for in-house analysis at the project site shall meet ASTM D1193 Type II or better for general chemistry.
−
−### The service provider's test kits shall use reagents traceable to recognized standards, with documented expiration dates, stored in conditions matching the manufacturer's requirements.
−
−### Expired reagents shall not be used.
−
−### Expired reagents are a common cause of misleading low or high test results that, in turn, drive incorrect chemistry adjustments. {note}
−
−# Pre-Operational Cleaning and Flushing {toc}
−
−## Why Pre-Operational Cleaning is Mandatory {toc}
−
−### A new hydronic or condenser-water system, as installed, contains construction debris that no amount of inhibitor chemistry can remove or tolerate: cutting oils on the inside of carbon steel pipe, mill scale, weld spatter, pipe joint compound that has leached into the bore, slag and oxide from brazing, dust, drywall mud splatters, and the occasional rag or tool left in a pipe section. {note}
−
−### If these contaminants are left in the system at start-up, they migrate to the points of lowest velocity — terminal coil tubes, control valve seats, pump suction strainers, balancing valve cones — and accumulate, and the inhibitor cannot establish a stable film on a metal surface that is intermittently covered by sliding debris. {note}
−
−### Pre-operational cleaning shall be performed for every new closed and open system covered by this standard, regardless of the construction quality of the piping installation.
−
−### Failure to clean a system before placing it in service shall be cause for rejection of the system commissioning.
−
−### The cost of subsequent clean-out, which is significantly higher than pre-operational cleaning because the system must be disassembled in places, coils back-flushed individually, and the chemistry made more aggressive, shall fall to the responsible party.
−
−## Cleaning Method Selection {toc}
−
−### Two broad approaches are used: a chemical cleaning that combines a degreasing surfactant with an alkaline builder (and, where construction debris includes mill scale or weld discoloration, an acid passivation step after the alkaline degrease), and a mechanical flushing approach that relies on high-velocity recirculation through temporary bypasses. {note}
−### Most projects use an alkaline degreasing circulation followed by extended high-velocity mechanical flushing. {note}
−
−### The cleaning method shall be selected based on the predominant material of construction, the system's geometry, and the anticipated nature and quantity of construction debris.
−
−```datasheet
−label: Pre-Operational Cleaning Method — Closed Systems
−type: select
−options:
− - "Alkaline degreaser circulation followed by high-velocity flush (standard for new closed systems)"
− - "Alkaline degreaser, acid clean for mill scale/weld discoloration, high-velocity flush (high-debris steel systems)"
− - "Trisodium phosphate (TSP) flush — economical alternative for small or all-copper systems"
− - "Mechanical flushing only — small all-copper systems where degreasing not warranted"
−default: "Alkaline degreaser circulation followed by high-velocity flush (standard for new closed systems)"
−```
−
−### The historical method using trisodium phosphate (TSP) at approximately 0.5% by weight, circulated at operating temperature, remains acceptable for small systems and for all-copper systems where cutting oil and brazing flux residue are the only significant contaminants. {note}
−
−### TSP discharge into a municipal sanitary sewer is restricted or prohibited in many jurisdictions because of phosphate nutrient loading. {note}
−
−### Where TSP is selected, the Contractor shall confirm discharge acceptance with the local sewer authority before circulation.
−
−### Open systems are exposed to airborne contamination during construction (dust, bird debris, vegetation), and biological growth can establish itself in a cooling tower basin during the period between tower set and start-up if water has accumulated in the basin from rainfall or test water. {note}
−
−### A new open system shall receive both a chemical degreasing step for construction oils and dust and an oxidizing biocide pre-treatment for biological knockdown before the system is placed in service with its long-term chemistry.
−
−```datasheet
−label: Pre-Operational Cleaning Method — Open Condenser Water Systems
−type: select
−options:
− - "Alkaline degreaser circulation through cooling tower basin and piping, high-velocity flush"
− - "Alkaline degreaser plus oxidizing biocide (initial microbial knockdown) followed by flush"
− - "Mechanical flushing followed by direct online passivation (small towers with clean piping)"
−default: "Alkaline degreaser plus oxidizing biocide (initial microbial knockdown) followed by flush"
−```
−
−### Pre-operational biocide treatment shall be timed so that any chlorine or bromine residual is dissipated before the long-term inhibitor and biocide program begins, to avoid chemistry interference.
−
−## Flushing Velocity and Duration {toc}
−
−### The flushing operation removes loosened debris by hydraulic sweeping. {note}
−### Debris that settles in a corner at 3 ft/s requires 6 to 8 ft/s to lift and carry, achieved either by running the system pumps with all balancing and control valves wide open and temporary bypasses around coils, or by using a temporary high-volume flush pump connected at the central plant. {note}
−
−### The Contractor shall demonstrate by calculation that the planned flush arrangement produces a minimum velocity of 5 ft/s in every pipe section to be flushed, with 6 to 8 ft/s preferred where attainable.
−
−```datasheet
−label: Minimum Flushing Velocity
−type: range
−unit: ft/s
−options:
− min: 3
− max: 10
− setpoints: [3, 4, 5, 6, 7, 8, 10]
−default: 5
−```
−
−### The flush shall continue until the water at the system's lowest point (the drain valve or designated sample port) runs visibly clear and the suspended solids and iron measurements are within the acceptance criteria.
−
−```datasheet
−label: Flush Acceptance Criteria
−type: checkbox
−options:
− - "Total iron below 1 mg/L at lowest sample point"
− - "Total suspended solids below 5 mg/L"
− - "Visible clarity equivalent to tap water"
− - "pH within 0.5 units of make-up water pH (cleaner residue removed)"
− - "Conductivity within 200 µS/cm of make-up (cleaner residue removed)"
−default: "Total iron below 1 mg/L at lowest sample point"
−```
−
−### A flush that does not reach the acceptance criteria after a full circulation pattern shall be repeated.
−
−### Persistent high iron after multiple flushes shall be investigated rather than addressed by further flushing, because it typically indicates either an active corrosion source (uncleaned mill scale, a damaged surface) or a low-velocity zone the planned flush pattern is not reaching.
−
−## Bypassing Sensitive Equipment {toc}
−
−### Coils, plate heat exchangers, control valves, and balancing valves cannot tolerate the velocity required for effective sweeping, and the small flow paths in these components are precisely the locations where mobilized debris will lodge if allowed to pass through. {note}
−
−### Coils, plate heat exchangers, control valves, and balancing valves shall be bypassed during the high-velocity flush phase.
−
−### The Contractor shall install temporary spool pieces or flush jumpers across each coil and across each major heat exchanger before the flush begins.
−
−### These temporary connections shall be removed and the equipment reconnected to the system only after the flush is complete and accepted.
−
−### Control valves and balancing valves at terminal units in branch piping shall be bypassed by temporary jumpers or removed entirely during the branch flush.
−
−### Where the project budget or schedule does not allow individual coil bypasses, a temporary fine-mesh strainer (typically 100 mesh or finer) shall be installed immediately upstream of each coil bank and cleaned on a programmed interval during the flush.
−
−### Strainer protection is materially better than no precaution but less effective than full bypass, because debris still reaches the strainer at coil-inlet velocity with some passing through. {note}
−
−## Discharge of Flush Water {toc}
−
−### Flush water carries cleaner chemistry, mobilized debris, and possibly elevated iron and copper. {note}
−
−### The Contractor shall coordinate discharge with the local sanitary sewer authority and shall obtain any required discharge permit before flushing.
−
−```datasheet
−label: Flush Water Discharge Route
−type: select
−options:
− - "Sanitary sewer per local authority acceptance (typical)"
− - "Sanitary sewer after neutralization to pH 6–9"
− - "Off-site disposal as regulated waste (acid cleaner residue, biocide residue)"
− - "On-site evaporation pond (rare, project-specific)"
−drawing_ref: true
−default: "Sanitary sewer per local authority acceptance (typical)"
−```
−
−### Discharge directly to storm sewer is generally prohibited because of the cleaner chemistry and metals content. {note}
−
−### Discharge to a sanitary sewer is usually acceptable for diluted alkaline cleaners but may be restricted for acid cleaners, phosphate-based cleaners, or where biocide residual is present. {note}
−
−### Where a project has large cleaning volumes, neutralization or sequestration of the flush water in a temporary tank before discharge shall be provided where required by the local authority.
−
−# Pre-Passivation {toc}
−
−## Once the system has been cleaned of construction debris and flushed clear, the metal surfaces are bright and active — chemically reactive and ready to either form a stable protective oxide layer (passivation) or to begin corroding. {note}
−
−## The window between completion of flushing and the establishment of a stable passive layer is short — within hours, freshly exposed carbon steel begins to flash-rust if exposed to oxygen-bearing water without inhibitor present. {note}
−
−## Pre-passivation establishes the protective oxide layer under controlled conditions, with the system intentionally dosed at higher inhibitor concentration than the long-term operating level, circulating at a specific temperature for a specific time. {note}
−
−## Done well, pre-passivation creates a uniform, dense protective film that resists oxygen corrosion for the life of the system; done badly or omitted, the system establishes a partial, irregular film whose unprotected zones become initiation sites for pitting that persists despite a correct long-term inhibitor concentration. {note}
−
−## Pre-Passivation Procedure — Closed Hydronic Systems {toc}
−
−### The pre-passivation chemistry dose, circulation time, and circulation temperature are set per the datasheets below. {note}
−
−### After flushing acceptance and immediately before placing the system into operating service, the system shall be refilled with treated make-up water and dosed with the pre-passivation chemistry at typically 2 to 3 times the long-term operating inhibitor level.
−
−```datasheet
−label: Pre-Passivation Inhibitor Dose Multiplier (vs. Long-Term Operating Concentration)
−type: range
−unit: × operating level
−options:
− min: 1.5
− max: 5
− setpoints: [1.5, 2, 2.5, 3, 4, 5]
−default: 2.5
−```
−
−### The system shall be circulated continuously at near operating temperature — typically 100°F to 140°F for HHW systems, or ambient with circulation pumps running for CHW systems — for a minimum of 24 hours, with 48 to 72 hours preferred where carbon steel is the predominant material.
−
−```datasheet
−label: Pre-Passivation Circulation Time
−type: range
−unit: hours
−options:
− min: 12
− max: 168
− setpoints: [12, 24, 36, 48, 72, 96, 168]
−default: 48
−```
−
−```datasheet
−label: Pre-Passivation Circulation Temperature — HHW
−type: range
−unit: °F
−options:
− min: 70
− max: 180
− setpoints: [70, 100, 120, 140, 160, 180]
−default: 120
−```
−
−### During passivation, sample-port readings shall confirm that inhibitor concentration remains within the design range across the entire system, with no zones short on inhibitor due to high consumption from un-passivated surfaces.
−
−### During passivation, pH shall remain within the design range.
−
−### After the passivation period, the system inhibitor level shall be drawn down to the long-term operating concentration by a controlled drain-and-replace or by allowing system make-up to dilute over the first weeks of operation.
−
−### The corrosion coupons installed at the start of passivation shall be left in place during the long-term operation and removed at the first scheduled inspection — typically 90 days — to verify passivation success.
−
−## Pre-Passivation — Open Condenser Water Systems {toc}
−
−### Open systems are passivated more rapidly than closed systems because the higher dissolved oxygen content and the higher inhibitor circulation rate establish the protective film quickly. {note}
−
−### A typical open-tower passivation shall run at 1.5 to 2 times the long-term inhibitor level for 24 to 48 hours of circulation with the tower fan off or running on minimum speed to limit evaporation during passivation.
−
−### The cycles of concentration during passivation shall be intentionally held low — close to 1.5 — by elevated bleed-off, so that the passivation chemistry remains close to the dosed level and is not concentrated to a damaging level.
−
−```datasheet
−label: Pre-Passivation — Open System Bleed Strategy
−type: radio
−options:
− - "Manual bleed to hold conductivity near make-up + 200 µS/cm during passivation"
− - "Conductivity controller set to 1.5 COC during passivation, then reset to operating COC"
− - "No bleed during passivation, accept rising cycles for shortened passivation period"
−default: "Conductivity controller set to 1.5 COC during passivation, then reset to operating COC"
−```
−
−# Closed System Chemical Treatment {toc}
−
−## Inhibitor Chemistry Selection {toc}
−
−### The most common chemistries are molybdate, nitrite, and combinations of these with azole copper-corrosion inhibitor and polymer dispersant. {note}
−
−### The inhibitor program for a closed hydronic system shall be selected to match the predominant metallurgy, the operating temperature, and the Owner's preferences regarding monitoring complexity, ecological discharge concerns, and cost.
−
−```datasheet
−label: Closed System Primary Corrosion Inhibitor
−type: select
−options:
− - "Molybdate — non-oxidizing, broad metallurgy, low toxicity, easy to test (preferred for most new closed systems)"
− - "Nitrite — well-established, lower cost, but bacteria-mediated depletion possible"
− - "Molybdate + nitrite blend — synergistic, lower total concentration than either alone"
− - "Phosphonate + azole + polymer — for systems with aluminum or mixed metallurgy"
− - "Silicate — historical, used primarily in glycol systems"
−default: "Molybdate — non-oxidizing, broad metallurgy, low toxicity, easy to test (preferred for most new closed systems)"
−```
−
−### Molybdate-based inhibitors form a passive film on carbon steel through an oxidative mechanism that does not depend on oxygen scavenging, are stable across a wide pH and temperature range, are non-toxic at use concentrations, and are not affected by chloride to the same extent nitrite is; their disadvantages are higher unit cost, the requirement for higher pH (typically 8.5 to 10.5) to protect copper, and a long-term ecological concern with molybdate discharge to surface waters in some jurisdictions. {note}
−
−### Nitrite-based inhibitors are the historical standard, effective on carbon steel at 500 to 1,000 mg/L as NO2-, inexpensive, and easily tested, but their principal vulnerability is biological: certain bacteria (Pseudomonas, Nitrosomonas, Nitrobacter) consume nitrite and can deplete it from 800 mg/L to below 50 mg/L within weeks, leaving the system without effective corrosion protection. {note}
−
−### Where nitrite is selected, the program shall include routine microbial monitoring and a non-oxidizing biocide rotation to suppress nitrite-consuming organisms.
−
−### Phosphonate-and-polymer chemistries are the appropriate choice where aluminum cylinders, aluminum-cored heat exchangers, or aluminum impellers contact the treated water: the phosphonate provides primary corrosion inhibition, an azole (tolyltriazole or benzotriazole) protects copper and copper alloys, and the polymer dispersant prevents scale precipitation in localized hot zones. {note}
−
−## Copper Corrosion Inhibitor (Azole) {toc}
−
−### The azole forms a chemisorbed film on copper surfaces that inhibits both copper dissolution and the redeposition of copper ions on carbon steel (where they would act as cathodes and accelerate steel corrosion). {note}
−
−### Where the system contains copper or copper-alloy components, an azole copper inhibitor shall be added regardless of the primary chemistry, with tolyltriazole (TT) the standard at 5 to 15 mg/L and benzotriazole (BZT) or mercaptobenzothiazole (MBT) as alternatives.
−
−```datasheet
−label: Copper Corrosion Inhibitor (Azole)
−type: radio
−options:
− - "Tolyltriazole (TT) — standard, 5–15 mg/L"
− - "Benzotriazole (BZT) — alternative where TT availability is limited"
− - "Halogen-stable azole — required where oxidizing biocides are used"
− - "Not required — system contains no copper or copper alloys (rare)"
−default: "Tolyltriazole (TT) — standard, 5–15 mg/L"
−```
−
−### In any closed system where an oxidizing biocide rotation is part of the program, azole feed shall be timed to follow the biocide treatment, because azole is consumed by oxidizing biocides.
−
−### Azole concentration shall be tested before and after biocide events.
−
−## Polymer Dispersant {toc}
−
−### The polymer keeps suspended iron oxide, scale particles, and microbial debris in suspension so the side-stream filter can capture them rather than allowing settled deposit at low-velocity zones, and provides crystal-modification action on incipient scale so that scale does not adhere to heat-transfer surfaces. {note}
−
−### A polymer dispersant — typically a polyacrylate, polymethacrylate, or polymaleic acid copolymer — shall be included in the closed-system program at 5 to 20 mg/L.
−
−## Control Ranges — Closed System {toc}
−
−### The long-term operating control ranges depend on the chemistry selected; the service provider's recommendation governs the project-specific control range. {note}
−
−### The closed system inhibitor concentration control range shall be specified for the chemistry selected, and used as the basis for field test comparison at each service visit.
−
−```datasheet
−label: Closed System Control Range — Inhibitor Concentration
−type: select
−options:
− - "Molybdate — 200–400 mg/L as MoO4-2"
− - "Nitrite — 700–1,200 mg/L as NO2-"
− - "Molybdate + Nitrite — 100 mg/L Mo + 400 mg/L NO2 minimum"
− - "Phosphonate — 5–15 mg/L as PO4 active phosphonate"
− - "Per service provider's design"
−default: "Molybdate — 200–400 mg/L as MoO4-2"
−```
−
−### The closed system pH control range shall be specified for the chemistry selected, and used as the basis for field test comparison at each service visit.
−
−```datasheet
−label: Closed System pH Range
−type: select
−options:
− - "8.5–10.5 (molybdate or nitrite chemistry, no aluminum present)"
− - "8.0–9.0 (phosphonate chemistry, mixed metallurgy or aluminum)"
− - "9.0–10.0 (nitrite chemistry, biological inhibition support)"
−default: "8.5–10.5 (molybdate or nitrite chemistry, no aluminum present)"
−```
−
−### Whether closed system conductivity is used as a trending control parameter shall be specified.
−
−```datasheet
−label: Closed System Conductivity Tracking
−type: radio
−options:
− - "Tracked at each service visit; trend used to detect leaks (rising) or dilution (falling)"
− - "Not tracked as a control parameter (chemistry tested directly)"
−default: "Tracked at each service visit; trend used to detect leaks (rising) or dilution (falling)"
−```
−
−### Field test results shall be compared against the project-specific control range at each service visit.
−
−## Closed-Loop Biocide {toc}
−
−### Closed systems are not free of biological activity, particularly when nitrite chemistry is in use. {note}
−### Oxidizing biocides (chlorine, bromine) are generally not used in closed systems because of their interaction with corrosion inhibitors and elastomer attack at the concentrations needed. {note}
−
−### A non-oxidizing biocide — typically isothiazolone, glutaraldehyde, or a quaternary ammonium compound — shall be added on a programmed rotation (typically every 90 to 180 days) where biological inhibition is required.
−
−```datasheet
−label: Closed System Biocide Program
−type: select
−options:
− - "Isothiazolone rotation (every 120 days)"
− - "Glutaraldehyde rotation (every 90 days)"
− - "Two-product rotation (isothiazolone alternating with glutaraldehyde)"
− - "Not required — system shows no microbial activity history and is fully closed"
−default: "Two-product rotation (isothiazolone alternating with glutaraldehyde)"
−```
−
−### The biocide rotation shall use at least two different active ingredients on alternating cycles, to suppress development of resistant organisms.
−
−# Open System Chemical Treatment {toc}
−
−## Why Open Systems Are Different {toc}
−
−### An open recirculating condenser water system loses water continuously by evaporation through the cooling tower fill, leaving dissolved solids behind in the remaining inventory. {note}
−
−### Without bleed-off, dissolved solids concentrate without limit, scaling and corroding rapidly; with controlled bleed-off, the system reaches a stable cycles of concentration — typically 3 to 6 cycles for most projects, with up to 10 cycles achievable when make-up quality and tower design permit. {note}
−
−### The treatment program for an open system comprises four interlocking elements: a scale inhibitor, a corrosion inhibitor maintaining protection of carbon steel, copper, and galvanized surfaces, a biocide program preventing biological growth in the tower fill, basin, and piping, and a conductivity-controlled bleed system maintaining cycles of concentration at the design point. {note}
−
−### Open systems are subject to ASHRAE Standard 188's Legionellosis risk management requirements, so the treatment program is both an asset-protection program and a public-health control measure. {note}
−
−### Treatment parameters, sampling protocols, and corrective actions shall be incorporated into the building's Water Management Plan, and the documentation supporting them shall be maintained as part of building records.
−
−## Scale Inhibitor {toc}
−
−### Open system scale inhibition is typically based on phosphonate chemistry (HEDP — 1-hydroxyethylidene-1,1-diphosphonic acid; PBTC — phosphonobutane tricarboxylic acid; ATMP — amino tris methylene phosphonic acid) combined with a polymer dispersant. {note}
−### The phosphonate provides threshold inhibition while the polymer modifies crystal habit and keeps suspended solids dispersed. {note}
−
−### The open system scale inhibitor formulation shall be specified, consistent with the make-up water silica content and any jurisdictional restriction on phosphate discharge.
−
−```datasheet
−label: Open System Scale Inhibitor
−type: select
−options:
− - "Phosphonate (HEDP or PBTC) plus polymer dispersant (standard for most open systems)"
− - "Phosphonate plus polymer plus silica inhibitor (high-silica make-up, > 100 mg/L SiO2)"
− - "All-organic (polymer-only) — phosphate-discharge-restricted jurisdictions"
−default: "Phosphonate (HEDP or PBTC) plus polymer dispersant (standard for most open systems)"
−```
−
−### At higher cycles of concentration (typically above 5 cycles) or with high-silica make-up water, supplemental silica scale inhibitor shall be provided where required by the design conditions.
−
−## Corrosion Inhibitor — Open Systems {toc}
−
−### Open system corrosion control uses lower inhibitor concentrations than closed systems because the inhibitors are continuously lost to bleed-off. {note}
−
−### The standard approach shall combine a phosphate or zinc-phosphate steel inhibitor at 2 to 6 mg/L (as PO4) with an azole copper inhibitor at 1 to 3 mg/L (as TT) and the polymer dispersant that supports the scale inhibitor.
−
−```datasheet
−label: Open System Corrosion Inhibitor
−type: select
−options:
− - "Phosphate plus azole plus polymer (standard mild-steel-and-copper towers)"
− - "Zinc-phosphate plus azole plus polymer (galvanized towers, white-rust prevention)"
− - "All-organic phosphate-free formulation (phosphate-discharge-restricted jurisdictions)"
−default: "Phosphate plus azole plus polymer (standard mild-steel-and-copper towers)"
−```
−
−### Where galvanized steel cooling towers are present, the pH shall be held between 7.0 and 8.0 during the first three to six months of operation while the zinc surface develops its protective patina, after which the pH range may rise to 8.0 to 9.0 for long-term operation.
−
−```datasheet
−label: New Galvanized Tower — Initial Operation pH (Months 1–3)
−type: range
−unit: pH units
−options:
− min: 7.0
− max: 9.0
− setpoints: [7.0, 7.2, 7.5, 7.8, 8.0, 8.2, 8.5, 9.0]
−default: 7.5
−```
−
−### Aggressive pH excursions above 9.5 in the first weeks of operation cause rapid loss of the zinc coating and shall be prevented.
−
−## Biocide Program — Open Systems {toc}
−
−### Open system biocide programs combine an oxidizing biocide (continuous low-dose or periodic shock) with a non-oxidizing biocide on a rotational schedule. {note}
−### The biocide program is the primary engineering control for Legionella in the cooling tower water, and its proper design and documentation is the principal mechanism by which the project demonstrates compliance with ASHRAE 188 for the open system. {note}
−
−### The oxidizing biocide shall be chlorine (sodium hypochlorite) or bromine (sodium bromide activated by hypochlorite, or stabilized bromine donor), and the non-oxidizing biocide shall be selected from isothiazolone, glutaraldehyde, dibromonitrilopropionamide (DBNPA), or quaternary ammonium compounds.
−
−```datasheet
−label: Open System Biocide Program
−type: select
−options:
− - "Continuous low-dose halogen (chlorine or bromine) plus non-oxidizing rotation"
− - "Slug-dose halogen on schedule plus non-oxidizing rotation"
− - "ORP-controlled halogen plus non-oxidizing rotation (preferred — feedback control)"
− - "Stabilized bromine donor plus non-oxidizing rotation"
−drawing_ref: "ASHRAE 188 Water Management Plan"
−default: "ORP-controlled halogen plus non-oxidizing rotation (preferred — feedback control)"
−```
−
−```datasheet
−label: Oxidizing Biocide Selection
−type: radio
−options:
− - "Sodium hypochlorite (chlorine) — economical, broad-spectrum"
− - "Activated sodium bromide (bromine) — better performance at high pH"
− - "Stabilized halogen donor (chlorinated or brominated hydantoin) — slug or feeder-tablet"
− - "Chlorine dioxide — high-biofilm-penetration applications"
−default: "Activated sodium bromide (bromine) — better performance at high pH"
−```
−
−### The two biocide classes shall be alternated to suppress development of resistant organisms and to maintain biocide effectiveness against the broadest range of microbial species.
−
−```datasheet
−label: Non-Oxidizing Biocide Rotation
−type: checkbox
−options:
− - "Isothiazolone (broad-spectrum, low pH dependence)"
− - "Glutaraldehyde (effective against sulfate-reducing bacteria)"
− - "DBNPA (rapid-acting, short half-life, low residual)"
− - "Quaternary ammonium compound (surfactant action, biofilm penetration)"
− - "THPS — tetrakis(hydroxymethyl)phosphonium sulfate (anaerobe control)"
−default: "Isothiazolone (broad-spectrum, low pH dependence)"
−```
−
−### Bromine is generally preferred over chlorine for open cooling towers operating in the typical alkaline pH range (8.0 to 9.0) because hypobromous acid (HOBr) is the dominant species at these pH values and is a more effective biocide than hypochlorous acid (HOCl), which dissociates to less-active hypochlorite (OCl-) at higher pH; chlorine remains effective and economical below pH 8.0 or where pH is intentionally controlled lower for galvanized tower protection. {note}
−
−## Cycles of Concentration and Conductivity Control {toc}
−
−### Higher cycles save make-up water and reduce blowdown discharge volume but concentrate dissolved solids and increase the burden on scale and corrosion inhibitors. {note}
−### For typical municipal make-up water of moderate hardness, target cycles of 4 to 6 are common; for soft, low-conductivity make-up water, cycles of 6 to 10 are achievable; for hard well water, cycles may be limited to 2 to 3 before scale or chloride control becomes the constraint.
−
−```datasheet
−label: Target Cycles of Concentration
−type: range
−unit: cycles
−options:
− min: 2
− max: 10
− setpoints: [2, 3, 4, 5, 6, 7, 8, 10]
−default: 5
−```
−
−```datasheet
−label: Conductivity Controller Configuration
−type: select
−options:
− - "Standalone controller with conductivity setpoint and bleed solenoid output"
− - "Combined conductivity/ORP/pH controller (multi-parameter integrated)"
− - "BAS-integrated multi-parameter controller with remote access and trending"
−default: "BAS-integrated multi-parameter controller with remote access and trending"
−```
−
−```datasheet
−label: Chemical Feed Pacing
−type: radio
−options:
− - "Make-up water meter pulse — chemicals dosed proportional to make-up volume"
− - "Bleed event paced — chemicals dosed when bleed solenoid energizes"
− - "Continuous feed at fixed rate — least preferred, manual chemistry adjustment required"
−default: "Make-up water meter pulse — chemicals dosed proportional to make-up volume"
−```
−
−### The target cycles of concentration shall be established by the service provider based on make-up water quality, the most limiting scale-or-corrosion control parameter (typically calcium hardness × alkalinity product, or chloride concentration at concentrated conditions), and the Owner's water-conservation goals.
−
−### Conductivity control is the operational mechanism that maintains cycles of concentration: a conductivity probe immersed in the recirculating water signals the controller, which energizes a bleed-off solenoid when conductivity rises above the set point and closes the bleed valve when conductivity falls below it, while make-up water flows in automatically through the float-controlled make-up valve. {note}
−
−### The conductivity controller and the chemical feed pumps shall be integrated so that chemical addition is proportional to make-up water flow (water-meter pulse signal) or proportional to bleed events, maintaining inhibitor and biocide concentration despite the continuous loss to bleed.
−
−## ORP (Oxidation-Reduction Potential) Control of Oxidizing Biocide {toc}
−
−### ORP correlates well with the biocidal effectiveness of free halogen residual, integrates the effect of pH on halogen species, and responds rapidly to demand changes. {note}
−### Typical control ranges are 600 to 750 mV for active biocidal residual in the recirculating water. {note}
−
−### Where oxidizing biocide feed is automatically controlled, the preferred control parameter shall be oxidation-reduction potential (ORP), measured in millivolts by an in-line ORP probe.
−
−### The ORP set point shall be established by the service provider based on the specific oxidizing chemistry and verified by free halogen residual measurement at the corresponding ORP reading.
−
−```datasheet
−label: ORP Control Setpoint Range
−type: range
−unit: mV
−options:
− min: 400
− max: 900
− setpoints: [400, 500, 550, 600, 650, 700, 750, 800, 900]
−default: 650
−```
−
−### A calibration curve relating ORP to free halogen residual shall be established and verified at least quarterly.
−
−# Glycol Systems {toc}
−
−## When Glycol is Used {toc}
−
−### Glycol — propylene glycol (PG) or ethylene glycol (EG) — is added to closed hydronic loops to provide freeze protection in piping or equipment that may experience temperatures below 32°F.
−### Typical applications include rooftop and outdoor piping in cold climates, ground-source heat pump loops, and snowmelt loops by design. {note}
−
−### The glycol concentration shall be selected by the design freeze temperature with a safety margin, where 30% PG provides protection to approximately 0°F, 40% PG to approximately -15°F, and 50% PG to approximately -30°F.
−
−### The concentration shall be selected on the basis of burst protection (lowest concentration at which the fluid does not split a pipe even if it gels) for systems that can tolerate intermittent gelling but not pipe damage, or flow protection (higher concentration at which the fluid remains pumpable at the cold temperature) for systems that must continue operating at the cold extreme.
−
−## Glycol Selection — Propylene vs. Ethylene {toc}
−
−### Most commercial HVAC projects use PG; EG is reserved for industrial process loops, district energy plants, and snowmelt systems where toxicity hazard is managed by the system design. {note}
−
−### The glycol type, propylene or ethylene, shall be specified, consistent with the toxicity hazard and heat-transfer performance required by the application.
−
−```datasheet
−label: Glycol Type
−type: radio
−options:
− - "Propylene glycol (PG) — preferred for HVAC service, low toxicity"
− - "Ethylene glycol (EG) — high-performance heat transfer, restricted by some codes"
−default: "Propylene glycol (PG) — preferred for HVAC service, low toxicity"
−```
−
−### Propylene glycol (PG) is preferred for HVAC service because of its lower toxicity profile, which simplifies storage, spill response, and accidental cross-connection consequences. {note}
−
−### Ethylene glycol (EG) has slightly better heat-transfer properties — lower viscosity at low temperatures — but is toxic if ingested and is restricted by many plumbing codes from use in any building where any cross-connection to potable water is possible. {note}
−
−## Glycol Quality — Inhibited Industrial Grade {toc}
−
−### Automotive glycol contains inhibitors selected for automotive cooling systems (copper, brass, aluminum, frequent fluid replacement) that are not optimal for a building hydronic system (carbon steel, copper, multi-year service life), and its dyes and bittering agents can interfere with field testing. {note}
−
−### The glycol concentration, by percent volume, shall be specified for this system, based on the freeze protection level required by the design conditions.
−
−```datasheet
−label: Glycol Concentration
−type: range
−unit: '% by volume'
−options:
− min: 20
− max: 50
− setpoints: [20, 25, 30, 35, 40, 45, 50]
−drawing_ref: true
−default: 30
−```
−
−### Glycol for HVAC service shall be inhibited industrial grade — pre-formulated with corrosion inhibitors selected for hydronic service.
−
−```datasheet
−label: Glycol Product Grade
−type: radio
−options:
− - "Inhibited industrial grade — pre-formulated with HVAC-appropriate inhibitors"
− - "Inhibited industrial grade plus supplemental azole and biocide rotation"
− - "Uninhibited grade — separate inhibitor program required (rare, project-specific)"
−default: "Inhibited industrial grade — pre-formulated with HVAC-appropriate inhibitors"
−```
−
−### Uninhibited or automotive glycol shall not be used.
−
−### The glycol product shall be confirmed compatible with all wetted materials including the system's primary inhibitor chemistry if one is also present.
−
−## Glycol Degradation and Testing {toc}
−
−### Glycol degrades slowly under hydronic service conditions, particularly at the elevated temperatures typical of HHW operation. {note}
−### The degradation produces organic acids that lower system pH and increase corrosion aggressiveness; the reserve alkalinity buffer in inhibited industrial glycol neutralizes these acids until it is consumed and the inhibitor package depletes. {note}
−
−### Glycol systems shall be tested at each service visit for pH, inhibitor reserve, and glycol concentration by refractometer.
−
−```datasheet
−label: Glycol System Test Parameters at Each Service Visit
−type: checkbox
−options:
− - "pH"
− - "Glycol concentration (refractometer)"
− - "Inhibitor reserve (per glycol manufacturer's test method)"
− - "Conductivity (trend for leak detection)"
− - "Total iron, total copper (annual)"
− - "Biological activity (annual, where applicable)"
−default: "pH"
−```
−
−### When inhibitor reserve is depleted (indicated by pH drift below the design range despite stable glycol concentration), the system shall be either fully recharged with fresh inhibited glycol or supplemented with concentrated inhibitor package, per the glycol manufacturer's recommendation.
−
−# Steam and Condensate Treatment {toc}
−
−## Steam and Condensate Program Boundaries {toc}
−
−### The program addresses three regions of the system: the boiler water, where dissolved solids concentrate and where scale, corrosion, and carryover are controlled; the steam itself, where amines and neutralizers control condensate-line corrosion; and the condensate return, where carbonic acid attack of carbon steel return piping is the principal corrosion mechanism. {note}
−
−### The steam and condensate treatment program covered here applies to low-pressure (15 psig) and medium-pressure (up to 150 psig) steam systems serving humidifiers, sterilizers, kitchen equipment, and heating boilers.
−
−### High-pressure steam systems above 150 psig are outside the scope of this standard and shall use a process-grade boiler water program designed under separate cover.
−
−## Boiler Water — Pre-Boiler and Internal Treatment {toc}
−
−### Steam boilers concentrate dissolved solids similarly to open cooling towers: water enters as feed, steam exits as vapor, and dissolved solids remain in the boiler. {note}
−### Cycles of concentration are managed by blowdown, either continuous (a small bleed from the surface of the boiler water) or intermittent (manual blow from the mud drum). {note}
−
−### The boiler feedwater pretreatment method shall be specified, consistent with the boiler operating pressure and the makeup water quality and cycles of concentration required.
−
−```datasheet
−label: Boiler Feedwater Pretreatment
−type: select
−options:
− - "Softening (ion exchange) — standard for boilers above 15 psig"
− - "Softening plus deaeration (mechanical oxygen removal)"
− - "Softening plus reverse osmosis (low-conductivity makeup, high cycles)"
− - "None — small low-pressure heating boilers only"
−default: "Softening (ion exchange) — standard for boilers above 15 psig"
−```
−
−```datasheet
−label: Boiler Water Oxygen Scavenger
−type: radio
−options:
− - "Sulfite — economical, suited to non-food-contact steam"
− - "DEHA — diethyl hydroxylamine, food-grade per FDA 21 CFR 173.310"
− - "Erythorbic acid — food-grade alternative"
−default: "Sulfite — economical, suited to non-food-contact steam"
−```
−
−```datasheet
−label: Boiler Internal Treatment
−type: select
−options:
− - "Phosphate program — chelant or coordinated phosphate for hardness conditioning"
− - "All-polymer program — polymeric dispersant only, for soft-water boilers"
− - "Phosphate plus polymer — combined hardness conditioning and sludge dispersion"
−default: "Phosphate plus polymer — combined hardness conditioning and sludge dispersion"
−```
−
−### The boiler water program shall include a pre-boiler oxygen scavenger that removes residual dissolved oxygen from the feedwater, typically sulfite or DEHA (diethyl hydroxylamine).
−
−### The boiler water program shall include an internal phosphate or polymer treatment that conditions any remaining hardness and prevents scale on heating surfaces.
−
−### The boiler water program shall include an alkalinity builder (typically caustic) that maintains boiler water pH in the protective range, typically 10.5 to 11.5.
−
−## Steam Line Amines {toc}
−
−### The principal aggressor in condensate is carbonic acid (H2CO3), formed when carbon dioxide released from carbonate alkalinity in the boiler water dissolves in the condensate; carbonic acid lowers condensate pH to as low as 5.0 to 5.5, aggressively attacking carbon steel condensate return piping and causing grooving corrosion at the bottom of horizontal returns where condensate collects. {note}
−
−### A volatile amine — typically morpholine, cyclohexylamine, or DEAE (diethylaminoethanol) — shall be added to the boiler water so that the amine volatilizes with the steam, condenses with the water, and neutralizes the carbonic acid to maintain condensate pH at 8.5 to 9.0.
−
−```datasheet
−label: Steam Line Amine
−type: select
−options:
− - "Cyclohexylamine — broad distribution, standard non-food steam"
− - "Morpholine — concentrates at first condensing point, suited to short-distribution systems"
− - "DEAE — diethylaminoethanol, broad distribution"
− - "Blend of two amines — tailored distribution across long steam mains"
− - "Per FDA 21 CFR 173.310 list — food-contact steam"
−default: "Cyclohexylamine — broad distribution, standard non-food steam"
−```
−
−### The selection of amine shall account for its distribution ratio (the proportion that ends up at the first vs. last condensing point) and, where the steam contacts food, for the amines allowed by FDA 21 CFR 173.310.
−
−## Condensate Sampling {toc}
−
−### Test parameters include pH (control range 8.5 to 9.0), conductivity (trend), and total iron (high iron indicates active return-line corrosion). {note}
−
−### The condensate quality control range shall be specified, consistent with the system's service application, including any food-contact steam requirement limiting amine use.
−
−```datasheet
−label: Condensate Quality Control Range
−type: select
−options:
− - "pH 8.5–9.0, iron < 1 mg/L (standard heating and humidification)"
− - "pH 8.0–8.5, iron < 0.5 mg/L (food-contact steam, where amine is limited)"
−default: "pH 8.5–9.0, iron < 1 mg/L (standard heating and humidification)"
−```
−
−### Condensate quality shall be tested at the condensate receiver and at any sampling point representative of the longest return-line distance.
−
−### Where condensate iron exceeds 1 mg/L, the amine dose shall be increased and the distribution of amine reviewed.
−
−### Persistently high iron despite correct pH indicates either dissolved-oxygen ingress at the receiver (correctable by venting and air-tightness) or under-amination at the most distant returns, and shall be investigated accordingly.
−
−# Equipment — Feeders, Controllers, Filtration {toc}
−
−## Chemical Feed Pumps {toc}
−
−### The standard pump for HVAC water treatment service is a peristaltic, diaphragm, or solenoid-actuated metering pump with adjustable stroke length, adjustable stroke frequency, and a pulse input for pacing by water meter or controller signal. {note}
−
−### The chemical feed pump type shall be specified for each chemical product, consistent with the chemical's compatibility, dosing accuracy, and off-gassing characteristics.
−
−```datasheet
−label: Chemical Feed Pump Type
−type: select
−options:
− - "Diaphragm metering pump (standard, broad chemical compatibility)"
− - "Peristaltic pump (preferred for low-flow accurate dosing and chemicals that gas off)"
− - "Solenoid-actuated metering pump (economical, suited to small systems)"
− - "Pneumatically operated drum pump (large-volume bulk feed)"
−default: "Diaphragm metering pump (standard, broad chemical compatibility)"
−```
−
−### The pacing signal source for each chemical feed pump shall be specified, consistent with the parameter the dose is intended to track.
−
−```datasheet
−label: Chemical Feed Pacing Signal Source
−type: select
−options:
− - "Make-up water meter contact-pulse output (volumetric pacing)"
− - "Conductivity or ORP controller proportional output (residual pacing)"
− - "Manual rate, set during commissioning and adjusted during service visits"
− - "BAS-controlled pulse via [[sync/building-automation-system]]"
−default: "Make-up water meter contact-pulse output (volumetric pacing)"
−```
−
−### Each chemical product shall have its own dedicated feed pump and feed line, because chemicals shall not share feed lines due to cross-contamination risk in the suction tube and incompatibility between products (acid and oxidizer, oxidizer and reducing agent).
−
−### Feed pumps shall be located within secondary containment, with feed lines routed in plain view and labeled at each end with the chemical product, the feeding pump tag, and the receiving system tag.
−
−### Calibration columns shall be provided on each feed pump suction to verify dose volume against expected delivery.
−
−## Solid Chemical Feeders {toc}
−
−### Solid (puck, tablet, briquette) chemical feeders eliminate the need for a chemical-storage room with bulk tanks and provide longer service intervals between chemical replenishment, but they offer less precise dose control and require manual top-up rather than automatic bulk-tank refilling. {note}
−
−### The chemical feed equipment configuration, bulk liquid or solid, shall be specified for each chemical product, consistent with the dose-control precision and service-interval needs of the project.
−
−```datasheet
−label: Chemical Feed Equipment — Bulk vs. Solid
−type: radio
−options:
− - "Bulk liquid feed with metering pumps (standard for medium and large projects)"
− - "Solid feeders (pucks, tablets) for inhibitor and halogen donor"
− - "Combination — bulk inhibitor with solid halogen donor (common compromise)"
−default: "Bulk liquid feed with metering pumps (standard for medium and large projects)"
−```
−
−### Solid chemical feeders are an alternative to liquid bulk feed for some chemistries, particularly for low-cycle stabilized halogen donors in small open systems and for inhibitor pucks in some closed systems. {note}
−
−### Solid feeders are appropriate for small projects, for projects in space-constrained mechanical rooms, and for Owners who prefer the simpler service model. {note}
−
−## Conductivity and ORP Controllers {toc}
−
−### Modern controllers integrate conductivity measurement, ORP measurement, pH measurement (where required), water-meter pulse counting, multiple chemical-feed pump outputs, bleed-off solenoid output, alarm contacts, and a communication port (typically Modbus RTU or BACnet) to the building automation system. {note}
−
−### The measurement, feed-pacing, and communication capabilities required of the conductivity and ORP controller shall be specified for this installation.
−
−```datasheet
−label: Controller Capabilities Required
−type: checkbox
−options:
− - "Conductivity measurement with isolated probe"
− - "ORP measurement (open systems with oxidizing biocide)"
− - "pH measurement"
− - "Make-up water meter pulse input"
− - "Bleed-off solenoid output with flow verification"
− - "Multiple chemical pump pacing outputs"
− - "Alarm output for parameter excursion"
− - "BAS communication (BACnet, Modbus, or LonWorks)"
− - "Local 30-day data logging"
− - "Remote web-based access for service provider"
−default: "Conductivity measurement with isolated probe"
−```
−
−### The controller shall provide local display of all measured parameters and recent trend data.
−
−### The controller shall provide remote alarm output for any critical parameter excursion.
−
−### The controller shall provide a logging function that retains parameter history for at least 30 days locally and longer via BAS integration.
−
−### Controller probes — conductivity, ORP, pH — shall be calibrated against reference solutions on routine intervals, typically 30 days for ORP and pH probes and 90 days for conductivity probes.
−
−### Calibration solutions, calibration logs, and probe replacement records shall be maintained as part of the service contract.
−
−### Probes that fail to hold calibration shall be replaced rather than re-calibrated repeatedly, because an out-of-calibration probe drives wrong chemistry adjustments that, in turn, damage the system.
−
−## Side-Stream Filtration {toc}
−
−### A filter is side-stream because it processes a fraction of the recirculation flow (typically 5% to 10%) rather than the full flow, achieving effective particle removal over time without the pressure drop and equipment size penalty of full-flow filtration. {note}
−
−### The side-stream filtration type shall be specified for open systems, consistent with the particle size range and density expected in the recirculating water.
−
−```datasheet
−label: Side-Stream Filtration Type — Open Systems
−type: select
−options:
− - "Sand filter — 5 to 15 micron nominal (broad particle range, backwashable)"
− - "Centrifugal separator — 30+ micron (high-density particles, no media replacement)"
− - "Bag filter — 5 to 25 micron (economical, manual change-out)"
− - "Cartridge filter — 5 to 10 micron (fine filtration, manual change-out)"
− - "Disk filter — 10 to 100 micron (backwashable, intermediate performance)"
−default: "Sand filter — 5 to 15 micron nominal (broad particle range, backwashable)"
−```
−
−### Where side-stream filtration is provided on a closed system, the filtration type shall be specified, consistent with the particulate load and fineness of filtration required.
−
−```datasheet
−label: Side-Stream Filtration Type — Closed Systems (Where Provided)
−type: select
−options:
− - "Bag filter — 5 to 25 micron (standard, easy change-out)"
− - "Cartridge filter — 1 to 10 micron (fine filtration where required)"
− - "Centrifugal separator — 30+ micron (high iron-oxide load)"
− - "Not provided — system small enough that combination air/dirt separator suffices"
−default: "Bag filter — 5 to 25 micron (standard, easy change-out)"
−```
−
−### The side-stream filter flow rate, as a percent of total system recirculation flow, shall be specified.
−
−```datasheet
−label: Side-Stream Flow Rate as Percent of System Flow
−type: range
−unit: '%'
−options:
− min: 1
− max: 15
− setpoints: [1, 3, 5, 7, 10, 12, 15]
−default: 5
−```
−
−### Side-stream filtration shall be provided for all open systems under this standard and is strongly recommended for large closed systems.
−
−### Side-stream flow shall be drawn from a location with representative particle loading — typically immediately downstream of the system's lowest-velocity zone where particles are most likely to settle — and returned to a different location to encourage circulation through the filter rather than direct recycle.
−
−### For open systems, the side-stream filter shall draw from the tower basin or the condenser water return main and discharge to the basin or to the return main upstream of the chiller.
−
−### For closed systems, the side-stream shall draw from the return main downstream of the air/dirt separator and discharge to the return main downstream of the side-stream loop.
−
−# Monitoring and Sampling {toc}
−
−## Sample Ports {toc}
−
−### Sample ports shall be provided at locations that allow representative water sampling without disturbing equipment operation.
−
−```datasheet
−label: Sample Port Configuration
−type: select
−options:
− - "Full-port ball valve, 1/4 in., with hose-bib outlet and cap"
− - "Full-port ball valve, 1/2 in., with quick-connect outlet"
− - "Sample cooler with isolation valve (steam and high-temperature systems)"
−default: "Full-port ball valve, 1/4 in., with hose-bib outlet and cap"
−```
−
−### For closed systems, the minimum sample-port set shall be one port on the supply main downstream of the air/dirt separator and one port on the return main upstream of the chiller or boiler, with additional ports at each riser and at each major terminal-equipment branch to allow zone-specific sampling.
−
−### For open systems, sample ports shall be provided on the tower basin, on the condenser water supply to the chiller, and on the condenser water return from the chiller.
−
−### Each port shall be a full-port ball valve in 1/4 in. or 1/2 in. line size, with a hose-bib outlet or a quick-connect fitting compatible with the service provider's sampling equipment, located at hand height (approximately 4 ft above the floor) in an accessible position with a permanent label identifying the system and the port location.
−
−## Test Frequency {toc}
−
−### The frequencies shown in the datasheets below are minimums. {note}
−
−### The service provider shall test the systems at the frequency below, with results recorded in the service log.
−
−```datasheet
−label: Service Visit Frequency — Open Systems
−type: select
−options:
− - "Weekly during cooling season, monthly during off-season"
− - "Bi-weekly year-round"
− - "Monthly year-round"
−drawing_ref: "ASHRAE 188 Water Management Plan"
−default: "Weekly during cooling season, monthly during off-season"
−```
−
−```datasheet
−label: Service Visit Frequency — Closed Systems
−type: select
−options:
− - "Monthly"
− - "Quarterly"
− - "Bi-annually"
−default: "Quarterly"
−```
−
−```datasheet
−label: Service Visit Frequency — Steam Systems
−type: select
−options:
− - "Weekly during heating season, monthly off-season"
− - "Monthly year-round"
−drawing_ref: "boiler operator schedule"
−default: "Monthly year-round"
−```
−
−### More frequent testing shall be performed during start-up, after any chemistry change, after any major system upset (leak, equipment failure, repair), and during the first six months after a new system is commissioned.
−
−## Corrosion Coupons {toc}
−
−### Corrosion coupons are weighed, pre-cleaned metal samples installed in a coupon rack — a small parallel side-stream loop — exposed to system water at a controlled flow rate for a defined period (typically 90 days), then removed, cleaned, re-weighed, and analyzed for weight loss, pitting, deposit type, and surface appearance. {note}
−### Weight loss is reported as mils per year (mpy) and compared against acceptance criteria. {note}
−
−### Whether a corrosion coupon rack is installed shall be specified for each treated system, consistent with the system type, size, and open or closed configuration.
−
−```datasheet
−label: Corrosion Coupon Rack Installation
−type: radio
−options:
− - "Required on every treated system, both closed and open"
− - "Required on open systems and large closed systems; optional on small closed systems"
− - "Not required (chemistry-only monitoring) — acceptable only for very small systems"
−default: "Required on every treated system, both closed and open"
−```
−
−### The corrosion coupon metallurgy shall be specified for the closed system, representative of the metals and specialty equipment present in the system.
−
−```datasheet
−label: Coupon Metallurgy — Closed System
−type: checkbox
−options:
− - "Carbon steel (primary structural metal)"
− - "Copper (representative of coil tubes and small-bore piping)"
− - "Admiralty brass (where condensers or specialty equipment use admiralty)"
− - "Galvanized steel (where present, typically not used in closed systems)"
−default: "Carbon steel (primary structural metal)"
−```
−
−### The corrosion coupon exposure period shall be specified, consistent with the monitoring purpose, whether start-up evaluation or long-term trending.
−
−```datasheet
−label: Coupon Exposure Period
−type: select
−options:
− - "90 days standard (industry norm)"
− - "60 days (faster turnaround during start-up evaluation)"
− - "180 days (extended exposure for slow-corroding closed systems)"
− - "Continuous rotating coupon set (always one coupon at 30, 60, 90 days)"
−default: "90 days standard (industry norm)"
−```
−
−### Acceptable corrosion rates per the AWT recommendations shall be below 1 mpy for carbon steel and below 0.2 mpy for copper in closed systems, and below 3 mpy carbon steel and below 0.2 mpy copper in open systems.
−
−## Microbiological Monitoring {toc}
−
−### ATP testing per ASTM D4012 provides a rapid screening for total microbial load and is increasingly used as the primary in-field microbial test method because results are available in minutes rather than the 48-hour incubation required for dip slides. {note}
−
−### Open systems shall be monitored for microbial activity, with the minimum monitoring being dip-slide testing at each service visit for total aerobic bacteria (TAB) and action levels defined in the Water Management Plan.
−
−```datasheet
−label: Microbial Monitoring at Routine Service
−type: checkbox
−options:
− - "Dip-slide for total aerobic bacteria (TAB)"
− - "ATP test per ASTM D4012 (rapid screening)"
− - "Sulfate-reducing bacteria (SRB) test (anaerobe sentinel)"
− - "Nitrifying bacteria test (where nitrite chemistry is in use)"
−default: "Dip-slide for total aerobic bacteria (TAB)"
−```
−
−### Routine Legionella sampling (culture method per ISO 11731 or qPCR molecular method) shall be performed at intervals specified in the Water Management Plan, with the typical interval being quarterly for non-healthcare facilities and monthly for healthcare and high-risk facilities.
−
−```datasheet
−label: Legionella Sampling Frequency — Open Cooling Towers
−type: select
−options:
− - "Quarterly culture (ISO 11731) — typical commercial baseline"
− - "Monthly culture — healthcare and high-risk facilities"
− - "Quarterly culture plus quarterly qPCR — accelerated trend response"
− - "Per local public health authority requirement (where stricter)"
−default: "Quarterly culture (ISO 11731) — typical commercial baseline"
−```
−
−### The local public health authority may require more frequent Legionella sampling.
−
−### A positive Legionella culture above the Water Management Plan's action threshold shall trigger the corrective-action procedure documented in the plan — typically immediate hyperchlorination or hyperbromination of the affected system, intensified flushing, sample re-testing at 48 to 72 hours, and notification of building management and, depending on counts and jurisdiction, the local public health authority.
−
−### Corrective-action procedures shall be developed by the design team and the service provider before the system is commissioned and shall be included in the closeout Water Management Plan binder.
−
−## BAS Integration of Treatment Data {toc}
−
−### Treatment data — conductivity, ORP, pH, make-up flow, bleed flow, side-stream filter differential pressure, chemical-day-tank levels, alarm states — supports operation and recordkeeping when reported to the building automation system. {note}
−
−### Treatment data shall be reported to the building automation system through the controller's communication port, with the points listed below provided as a minimum, and point configuration coordinated with [[sync/building-automation-system]].
−
−```datasheet
−label: BAS Points from Water Treatment Controllers
−type: checkbox
−options:
− - "Conductivity (4–20 mA or Modbus value)"
− - "ORP (open systems, 4–20 mA or Modbus value)"
− - "pH (where measured, 4–20 mA or Modbus value)"
− - "Make-up water flow rate and cumulative make-up volume"
− - "Bleed-off flow rate and cumulative bleed volume"
− - "Side-stream filter differential pressure"
− - "Chemical day-tank low-level alarm (each chemical)"
− - "Bleed solenoid command and verification status"
− - "Controller general fault / no-flow alarm"
− - "Cycles of concentration (calculated, open systems)"
−default: "Conductivity (4–20 mA or Modbus value)"
−```
−
−# Service Contract {toc}
−
−## Scope of Routine Service {toc}
−
−### Each service visit produces the deliverables in the datasheet below. {note}
−
−### The water treatment service contract shall provide for routine on-site service at the frequencies established above.
−
−### Each service visit shall include a visual inspection of system conditions (sight glasses, sample-port samples, cooling tower basin condition, side-stream filter condition); a calibration check of conductivity, ORP, and pH probes; collection of water samples and field testing for the required parameters; calibration check and dose adjustment of chemical feed pumps; visual inspection of corrosion coupons in-place; microbiological testing per the program; review of the controller's data log for any trend indicating an issue; and a written service report uploaded to the Owner's records, the service provider's records, and the BAS as a service log point.
−
−```datasheet
−label: Routine Service Visit Deliverable
−type: checkbox
−options:
− - "Written service report with all field test results"
− - "Photographs of system condition (tower basin, sample appearance, equipment condition)"
− - "Probe calibration records"
− - "Pump calibration records"
− - "Chemistry trend chart vs. control range"
− - "Recommendations for chemistry adjustment or system action"
− - "Upload to Owner's records system within 24 hours"
−default: "Written service report with all field test results"
−```
−
−## After-Hours Response {toc}
−
−### The standard commitment is on-site response within 4 hours during the cooling season and within 24 hours otherwise; healthcare facilities and other high-risk facilities require shorter response intervals. {note}
−
−### The service contract shall include a defined after-hours response commitment for emergency situations — significant chemistry excursion, suspected biological event, chemical spill, feed equipment failure during cooling-season operation.
−
−```datasheet
−label: After-Hours Response Commitment
−type: select
−options:
− - "On-site within 4 hours, cooling season; 24 hours otherwise (standard commercial)"
− - "On-site within 2 hours, year-round (healthcare and high-risk)"
− - "Phone support within 1 hour; on-site within 8 hours (small projects)"
−default: "On-site within 4 hours, cooling season; 24 hours otherwise (standard commercial)"
−```
−
−## Annual Comprehensive Review {toc}
−
−### The annual review is the formal touch-point at which the program is recalibrated against actual experience and at which the Owner has the opportunity to direct any change in priorities or scope. {note}
−
−### In addition to routine service visits, the service contract shall include an annual comprehensive review for each system, comprising a complete water analysis at an independent laboratory (the make-up water analysis parameters plus the inhibitor concentrations and microbial counts for the system in question), a corrosion coupon analysis, a review of the year's trend data, a re-evaluation of the chemistry program against the year's experience, a written annual report with recommendations for the upcoming year, and an in-person review meeting with the Owner's facility staff.
−
−# Documentation — Water Management Plan (ASHRAE 188) {toc}
−
−## Applicability {toc}
−
−### The plan is a written document — typically a binder, increasingly supplemented by a digital records system — that identifies the building's water systems within scope, describes the control measures for each system, sets control limits, defines a monitoring schedule, defines corrective-action procedures, defines communication and documentation procedures, and names the people responsible for the program. {note}
−
−### Where the project includes any open cooling tower, evaporative condenser, decorative fountain, or other open recirculating water system, ASHRAE Standard 188 requires the Owner to establish and maintain a Water Management Plan for the building.
−
−### The water treatment program described in this standard provides the control measures, control limits, monitoring schedule, and corrective-action procedures for the open systems under treatment. {note}
−
−### Other building water systems within ASHRAE 188 scope — domestic hot water, decorative fountains, humidifiers, certain medical equipment — have their own plan sections developed under the respective project scope. {note}
−
−## Plan Content — Treatment-Related Sections {toc}
−
−### The treatment-related sections of the Water Management Plan shall include the following at minimum:
−
−- System descriptions for each open recirculating system: equipment summary, recirculation flow, drift loss specification, make-up source, normal cycles of concentration, normal operating temperature range, occupancy and use of the surrounding building areas.
−- Control measures for each system: the chemistry program (inhibitor, biocide, scale inhibitor), the conductivity- and ORP-based control configuration, the side-stream filtration, the drift eliminators, the equipment shutdown and re-start procedures, and the seasonal lay-up procedure.
−- Control limits for each measured parameter: the upper and lower bounds within which the parameter must be maintained for the control measure to remain effective.
−- Monitoring procedures: the testing performed at each service visit, the testing frequency, the personnel performing each test, the records kept.
−- Corrective-action procedures: the specific steps to be taken when each control limit is exceeded, the personnel responsible for each step, the timing of each step, the notification procedure, the re-monitoring procedure to verify resolution.
−- Verification procedures: how the program's effectiveness is confirmed — corrosion coupon analysis, microbial trending, equipment condition inspection at scheduled intervals.
−- Documentation procedures: what records are kept, where they are kept, how long they are retained, who has access.
−- Roles and responsibilities: named individuals or positions responsible for each aspect of the program, including the Owner's representative, the operating engineer, the water treatment service provider, and the Owner's risk management or infection control representative where applicable.
−
−```datasheet
−label: Water Management Plan Format
−type: select
−options:
− - "Printed binder maintained on-site, with digital backup"
− - "Digital records system with controlled access, printed quick-reference posted at mechanical rooms"
− - "Combined — full binder plus digital data system integrated with BAS"
−default: "Combined — full binder plus digital data system integrated with BAS"
−```
−
−```datasheet
−label: Water Management Plan Annual Review
−type: radio
−options:
− - "Required — formal annual review and update by water management team"
− - "Required — annual review plus event-driven review after any significant change"
−default: "Required — annual review plus event-driven review after any significant change"
−```
−
−## Plan Maintenance and Audit {toc}
−
−### The Water Management Plan is a living document. {note}
−
−### The Water Management Plan shall be reviewed and updated at least annually, and after any of the following: change in chemistry program, change in service provider, change in building occupancy or operating hours that affect water system use, addition or removal of equipment, corrective-action event that revealed a procedural gap, or change in applicable regulation.
−
−### The Owner shall maintain records demonstrating that the plan has been followed — service visit reports, chemistry results, corrosion coupon results, microbiological results, training records for the operating staff — for the retention period specified in the plan, typically a minimum of five years.
−
−### External audit of the Water Management Plan relies on these records being available, organized, and complete; the closeout submittals establish the plan, the service contract maintains it, and the Owner's facility staff own it. {note}
−
−# Pipe and Equipment Identification {toc}
−
−## The intent of identification is that any service provider new to the site can identify each connection unambiguously and that an emergency responder can identify each chemical without requiring access to the SDS binder. {note}
−
−## All chemical feed lines, sample-port lines, and treated-water sample piping shall be labeled with the chemical name, the direction of flow, and any hazard warnings appropriate to the contents in accordance with ASME A13.1 and OSHA 29 CFR 1910.1200.
−
−## Labels shall be permanent (engraved, adhesive vinyl, or wraparound printed sleeves) and shall be replaced when faded or damaged.
−
−## Chemical day tanks and bulk tanks shall bear the chemical name, the SDS reference number, the maximum capacity, and a tank identification number consistent with the controller's chemical-feed pump number.
−
−## Sample ports shall be labeled with the system and location (for example, "CHW Return Sample, Riser 3, Floor 4 Return Main").
−
−## Chemical Feed Line Labeling Datasheet {toc}
−
−```datasheet
−label: Chemical Feed Line Labeling
−type: radio
−options:
− - "Permanent adhesive labels per ASME A13.1 at intervals not exceeding 25 ft and at each end"
− - "Wraparound printed sleeves at each end, fittings, and valve"
− - "Both — permanent labels plus printed sleeves at fittings"
−default: "Both — permanent labels plus printed sleeves at fittings"
−```
−
−# System Lay-Up and Decommissioning {toc}
−
−## Seasonal Lay-Up {toc}
−
−### Lay-up methods are wet (system kept full of treated water with inhibitor concentration boosted, typically with slow or periodic recirculation, ideally with nitrogen blanketing where practical) and dry (system drained, blown dry with compressed air, sealed against air ingress, sometimes with desiccant cartridges in the equipment). {note}
−
−### Systems that are taken out of service for a season shall be laid up in a manner that protects the metal surfaces during the off-season.
−
−```datasheet
−label: Seasonal Lay-Up Method — Cooling Tower (Cold-Climate Winter)
−type: select
−options:
− - "Dry lay-up — drain, blow dry, seal basin and piping; restart procedure includes refill, biocide pre-treatment, chemistry charge"
− - "Wet lay-up — basin heater on, recirculation continuous, inhibitor and biocide maintained"
− - "Partial dry — basin and fill drained, tower piping drained to lowest point, mechanical room piping kept warm"
−default: "Dry lay-up — drain, blow dry, seal basin and piping; restart procedure includes refill, biocide pre-treatment, chemistry charge"
−```
−
−```datasheet
−label: Seasonal Lay-Up Method — Chilled Water System (Winter)
−type: select
−options:
− - "Wet lay-up with elevated inhibitor concentration (1.5× operating level)"
− - "Wet lay-up with nitrogen blanketing of expansion tank"
− - "Continuous pump circulation 1 hour per week minimum"
− - "Drained — only where the system has glycol protection or freeze risk drives drain"
−default: "Wet lay-up with elevated inhibitor concentration (1.5× operating level)"
−```
−
−### Wet lay-up is generally preferred for closed systems because the protective inhibitor film is maintained; dry lay-up is generally preferred for outdoor cooling towers in freezing climates and for any system where there is significant risk of freeze damage. {note}
−
−## Restart from Lay-Up {toc}
−
−### When a system is returned to service from lay-up, the program shall confirm that the protective chemistry is intact (wet lay-up) or that the system has been properly recommissioned (dry lay-up — repeated flush, biocide pre-treatment for open systems, re-passivation as needed for steel systems dry more than a few weeks).
−
−### The restart procedure shall be documented in the Water Management Plan or in the service contract and shall be executed by qualified personnel.
−
−## End-of-Life Decommissioning {toc}
−
−### Treated water typically contains corrosion inhibitor, biocide residue, and dissolved metals (iron, copper) at concentrations that may exceed sewer discharge limits, particularly for open systems with concentrated chemistry.
−
−### When a system is decommissioned at end of life, the treated water shall be drained and disposed of in accordance with applicable environmental regulations.
−
−### The service provider shall characterize the drained water for parameters of concern and arrange compliant disposal — typically sanitary sewer with prior coordination, or off-site disposal as regulated industrial waste for chemistry that cannot be discharged to sewer.
−
−# Coordination with Other Standards {toc}
−
−## The treatment program established by this standard depends on the physical systems built per [[sync/hydronic-piping]] and [[sync/hvac-pumps]]: the cleanliness of the system at start-up determines whether the chemistry can establish effective control, the velocity profile determines whether side-stream filtration reaches all zones, and the placement of sample ports and chemical-feed connections affects whether the program can be operated and monitored without disassembly. {note}
−
−## The Engineer shall coordinate the treatment design with the piping and pump design early, at the schematic phase, so that sample-port and feed-connection locations are integrated with the piping layout rather than added afterward as field modifications.
−
−## The chemistry shall be confirmed compatible with the cooling coil construction in [[sync/air-handling-units]] (copper tube, aluminum fin where present, gasketed or brazed headers), since those coils are direct beneficiaries of the chilled water treatment program.
−
−## The chemical-feed controllers and the BAS integration described here interface with the building automation system per [[sync/building-automation-system]], with the controller's communication protocol, point list, alarm priority, and trend logging configuration agreed at the BAS submittal stage.
+---
+title: HVAC Water Treatment
+category: Mechanical / Piping & Pumps
+description: >
+ When to use: The ongoing chemical and physical water treatment program for HVAC water systems in commercial, institutional, and industrial buildings. Covers closed hydronic loops (heating hot water, chilled water, dual-temperature, water-source and ground-source heat pump loops, and inhibited-glycol loops), open recirculating condenser water systems served by cooling towers and evaporative condensers, and steam and condensate systems at or below 150 psig. Addresses make-up water characterization, corrosion and scale inhibitor chemistry, biocide programs, cycles of concentration and bleed control, chemical feed and controller equipment, side-stream filtration, sample ports and routine monitoring, corrosion coupon reading, the Legionella risk-management documentation required under ANSI/ASHRAE 188, the service contract that sustains the program, and seasonal lay-up.
+
+ Not intended for: Construction-phase cleaning, high-velocity flushing, passivation, corrosion coupon installation, and the initial glycol charge of closed systems, which are the installing contractor's work under [[sync/hydronic-cleaning-and-flushing]]. Domestic potable water treatment, softening, and filtration (see [[sync/domestic-water-softeners-and-filtration]] and [[sync/domestic-water-piping]]); disinfection and bacteriological clearance of new potable piping (see [[sync/disinfection-of-water-systems]]); the cooling tower, fluid cooler, or evaporative condenser as equipment (see [[sync/cooling-towers]]); boiler pressure vessels, trim, and combustion controls (see [[sync/boilers]]); steam and condensate distribution piping (see [[sync/steam-and-condensate-piping]]); backflow assembly installation and annual certification (see [[sync/backflow-prevention]]); pure-water, reverse-osmosis, and deionized loops serving laboratory or process equipment; fire protection piping; refrigerant circuits (see [[sync/refrigerant-piping]]); fuel oil; and steam systems above 150 psig, which require a process-grade boiler water program designed under separate cover.
+---
+
+# Scope {toc}
+
+## This standard covers the ongoing chemical and physical treatment program that protects HVAC water systems from corrosion, scale, deposition, and microbiological growth for the operating life of the building. {note}
+
+## The systems in scope are closed hydronic loops (heating hot water, chilled water, dual-temperature, water-source and ground-source heat pump loops, and inhibited-glycol loops), open recirculating condenser water systems served by cooling towers and evaporative condensers, and steam and condensate systems operating at or below 150 psig. {note}
+
+## The work comprises the treatment design, the chemistry, the equipment that doses and controls it, the monitoring that proves it is working, the documentation the Owner needs to operate it, and the service program that sustains it. {note}
+
+## The program begins where construction-phase cleaning ends. Pre-operational cleaning, high-velocity flushing, passivation, corrosion coupon installation, and the initial glycol charge of closed systems are the installing contractor's work under [[sync/hydronic-cleaning-and-flushing]], which hands off with a signed report. This standard governs everything after that hand-off, plus the start-up disinfection of open recirculating systems, which that standard does not cover. {note}
+
+## The long-term treatment program shall not be placed online on a closed system until the signed cleaning, flushing, and passivation report required by [[sync/hydronic-cleaning-and-flushing]] has been delivered for that system.
+
+## Water treatment decides whether the equipment specified elsewhere in these documents reaches its design life. A closed loop held at its inhibitor control range runs for decades on its original pipe and pump internals; the same loop run on untreated fill water loses heat-transfer surface to oxygen pitting within a few years and accumulates iron oxide that disables the lowest-velocity branches first. {note}
+
+## An open condenser water system without effective scale, corrosion, and biological control fouls tower fill within a single hot-weather season, and on the biological side becomes a documented Legionellosis exposure pathway rather than an asset-protection problem alone. {note}
+
+## The systems to be treated under this standard shall be as indicated on [[drawing: the mechanical drawings and equipment schedules]].
+
+## The following are outside this scope and are governed by the companion standards named. {note}
+- Construction-phase cleaning, flushing, passivation, coupon installation, and glycol charging of closed systems - [[sync/hydronic-cleaning-and-flushing]].
+- Domestic potable hot and cold water, including its own treatment equipment and its own Legionella controls - [[sync/domestic-water-piping]] and [[sync/domestic-water-softeners-and-filtration]].
+- Disinfection and bacteriological clearance of newly constructed potable piping - [[sync/disinfection-of-water-systems]].
+- The cooling tower, fluid cooler, and evaporative condenser as equipment, including drift eliminators, basin construction, and basin heaters - [[sync/cooling-towers]].
+- Backflow prevention assembly installation detail and annual certification testing - [[sync/backflow-prevention]].
+- Hydronic distribution piping, valves, air separators, and expansion devices - [[sync/hydronic-piping]] and [[sync/expansion-tanks-and-air-separators]].
+- Steam and condensate distribution piping, traps, and receivers - [[sync/steam-and-condensate-piping]].
+- Boiler pressure vessels, trim, safety devices, and combustion controls - [[sync/boilers]].
+- Humidifier fill water quality and steam dispersion assemblies - [[sync/humidifiers]].
+- Chiller evaporator and condenser waterboxes and tube cleaning - [[sync/chillers]] and [[sync/heat-exchangers]].
+- Circulating pumps and their seals - [[sync/hvac-pumps]].
+- Controller point mapping, trending, and alarm integration - [[sync/building-automation-system]].
+- Functional performance testing and systems checkout - [[sync/commissioning]].
+
+## Where an open recirculating water system is present, the treatment program shall be documented within the building water management program required by ANSI/ASHRAE 188.
+
+# Referenced Standards {toc}
+
+## Equipment, chemistry, and the treatment program shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
+
+## Where the contract documents, the adopted code, the local public health authority's water management requirements, or a referenced standard impose conflicting requirements on the same subject, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
+
+| Standard | Title |
+|----------|-------|
+| ANSI/ASHRAE 188 | Legionellosis: Risk Management for Building Water Systems |
+| ASHRAE Guideline 12 | Managing the Risk of Legionellosis Associated with Building Water Systems |
+| ASHRAE Handbook — HVAC Applications | Water Treatment: Deposition, Corrosion, and Biological Control |
+| ANSI/ASHRAE/IES 90.1 | Energy Standard for Buildings Except Low-Rise Residential Buildings |
+| CTI STD-159 | Acceptable Water for Cooling Tower Make-Up |
+| CTI WTP-148 | Legionellosis Guideline: Best Practices for Control of Legionella in Cooling Water Systems |
+| AWT Technical Reference and Training Manual | Association of Water Technologies reference for industrial water treatment programs |
+| ABMA Boiler Water Limits | Recommended Boiler Water Limits and Steam Purity for Watertube and Firetube Boilers |
+| ASME BPVC Section VII | Recommended Guidelines for the Care of Power Boilers |
+| ASME B31.9 | Building Services Piping |
+| ASME A13.1 | Scheme for the Identification of Piping Systems |
+| ASTM D596 | Reporting Results of Analysis of Water |
+| ASTM D1193 | Reagent Water |
+| ASTM D2688 | Corrosivity of Water in the Absence of Heat Transfer (Weight Loss Methods) |
+| ASTM D3370 | Sampling Water from Closed Conduits |
+| ASTM D4012 | Adenosine Triphosphate (ATP) Content of Microorganisms in Water |
+| ASTM D5391 | Electrical Conductivity and Resistivity of a Flowing High Purity Water Sample |
+| ASTM D6161 | Terminology Applied to Membrane Processes |
+| ISO 11731 | Water Quality — Enumeration of Legionella |
+| AWWA C651 | Disinfecting Water Mains |
+| ANSI Z358.1 | Emergency Eyewash and Shower Equipment |
+| ASSE 1013 | Reduced Pressure Principle Backflow Prevention Assemblies |
+| ASSE 1015 | Double Check Backflow Prevention Assemblies |
+| ASSE 1047 | Reduced Pressure Detector Fire Protection Backflow Prevention Assemblies |
+| NSF/ANSI 60 | Drinking Water Treatment Chemicals — Health Effects |
+| FDA 21 CFR 173.310 | Boiler Water Additives Permitted in Food-Contact Steam |
+| EPA FIFRA | Federal Insecticide, Fungicide, and Rodenticide Act — registration of biocidal products |
+| OSHA 29 CFR 1910.1200 | Hazard Communication Standard |
+| OSHA 29 CFR 1910.119 | Process Safety Management of Highly Hazardous Chemicals |
+| DOT 49 CFR | Hazardous Materials Regulations |
+| IBC | International Building Code — chemical storage occupancy and construction |
+| IFC | International Fire Code — hazardous materials storage, containment, and signage |
+| IPC / UPC | International Plumbing Code or Uniform Plumbing Code as adopted — cross-connection control |
+
+## Many local public health authorities publish their own requirements for cooling tower registration, Legionella sampling, and water management plan content that go beyond the consensus standards above. {note}
+
+## Requirements published by the local public health authority shall be incorporated into the program by the design team and the water treatment service provider.
+
+# Submittals {toc}
+
+## Action Submittals {toc}
+
+### The Contractor and the water treatment service provider shall submit the following for the Engineer of Record's review and return before treatment equipment is procured and before any chemistry is added to any system:
+
+- A make-up water analysis for the project's water supply, performed by an independent laboratory using current ASTM or Standard Methods procedures, reporting each analyte required by this standard
+- A written treatment design for each system in scope, identifying the proposed chemistry, the control range for each measured parameter, the target cycles of concentration for open systems, and the control parameter on which automatic feed and bleed act
+- Product data and Safety Data Sheets for every chemical product proposed for the project
+- EPA FIFRA registration documentation for every biocidal product, showing the product is registered for the use proposed
+- A materials compatibility statement covering every wetted material in each treated system
+- Chemical feed and control equipment shop drawings, showing feed pumps, tanks, feed line routing, isolation and calibration provisions, probe locations, bleed equipment, side-stream filtration, and sample ports
+- Side-stream filter product data, including nominal rating, design flow, clean and fouled pressure drop, and the backwash or change-out method
+- Sample port details and a port location list for each system
+- A draft water management program document for the open recirculating systems, prepared in accordance with ANSI/ASHRAE 188
+- A service contract proposal identifying visit frequency, parameters tested, laboratory used, coupon reading schedule, emergency response commitment, and the chemical replenishment basis
+
+```datasheet
+label: Action Submittals Required
+type: checkbox
+options:
+ - "Independent laboratory make-up water analysis"
+ - "Written treatment design per system"
+ - "Chemical product data and Safety Data Sheets"
+ - "EPA FIFRA registration for each biocidal product"
+ - "Materials compatibility statement"
+ - "Chemical feed and control equipment shop drawings"
+ - "Side-stream filter product data"
+ - "Sample port details and location list"
+ - "Draft ANSI/ASHRAE 188 water management program document"
+ - "Service contract proposal"
+default:
+ - "Independent laboratory make-up water analysis"
+ - "Written treatment design per system"
+ - "Chemical product data and Safety Data Sheets"
+ - "EPA FIFRA registration for each biocidal product"
+ - "Materials compatibility statement"
+ - "Chemical feed and control equipment shop drawings"
+ - "Sample port details and location list"
+ - "Service contract proposal"
+```
+
+### Chemistry shall not be added to any system until the submittals covering that system have been returned by the Engineer of Record.
+
+### A chemistry compatibility error is usually irreversible. The wrong pH window strips zinc from a galvanized tower in weeks, and an inhibitor incompatible with a gasket compound is discovered as a leak rather than as a test result. Review before dosing is what makes those errors correctable on paper instead of in the field. {note}
+
+## Closeout Submittals {toc}
+
+### The Contractor shall submit the following at substantial completion, before each treated system is accepted by the Owner:
+
+- The initial treated-water analysis for each system, showing every measured parameter within its control range before the system entered normal operating service
+- Start-up disinfection records for each open recirculating system, with the halogen residual achieved, the contact time held, and the post-disinfection microbiological result
+- Operation and maintenance manuals for all treatment equipment, including parts lists, replacement intervals, and calibration procedures
+- The controller point list and control narrative for every treatment signal reported to the building automation system
+- The completed water management program document for the open recirculating systems, with signature pages for the Owner, the operating engineer, and the service provider
+- A chemical inventory list with the Safety Data Sheet, storage location, maximum stored quantity, and spill response procedure for each chemical present on site
+- The executed service contract for the term included in the base bid, with the visit schedule and a named point of contact
+
+```datasheet
+label: Closeout Submittals Required
+type: checkbox
+options:
+ - "Initial treated-water analysis per system"
+ - "Start-up disinfection records for open systems"
+ - "Operation and maintenance manuals for treatment equipment"
+ - "Controller point list and control narrative"
+ - "Completed water management program document"
+ - "Chemical inventory list with Safety Data Sheets"
+ - "Executed service contract for the base-bid term"
+default:
+ - "Initial treated-water analysis per system"
+ - "Start-up disinfection records for open systems"
+ - "Operation and maintenance manuals for treatment equipment"
+ - "Controller point list and control narrative"
+ - "Chemical inventory list with Safety Data Sheets"
+ - "Executed service contract for the base-bid term"
+```
+
+### The closeout package is what lets a successor service provider take over the program without re-establishing it, and what the Owner produces when a public health authority audits the water management program. {note}
+
+# Quality Assurance {toc}
+
+## Service Provider Qualifications {toc}
+
+### The water treatment service provider shall be a firm whose principal business is water treatment and shall have treated commercial HVAC water systems comparable to this project in size and system mix for not less than the period indicated in the datasheet.
+
+```datasheet
+label: Minimum Service Provider Experience
+type: range
+unit: years
+options:
+ min: 0
+ max: 15
+ setpoints: [0, 2, 3, 5, 10, 15]
+default: 5
+```
+
+### The technician credentials required of personnel assigned to this project shall be as indicated in the datasheet.
+
+```datasheet
+label: Technician Credential Required
+type: checkbox
+options:
+ - "Association of Water Technologies Certified Water Technologist (CWT)"
+ - "Manufacturer certification for the chemistry program supplied"
+ - "State-licensed water treatment or boiler water operator where the jurisdiction licenses the trade"
+ - "Documented in-house training program with records available for review"
+default:
+ - "Association of Water Technologies Certified Water Technologist (CWT)"
+```
+
+### The service provider shall maintain product liability and professional liability insurance covering the chemistry and the recommendations it supplies.
+
+### The service provider shall hold a current EPA establishment number where any treatment product supplied to the project is blended or repackaged at the provider's facility.
+
+## Chemistry Selection Independence {toc}
+
+### The treatment design shall be described in performance terms — active chemistry, control ranges, dosing basis, and monitoring method — rather than by product name, so that a successor provider can match the program without draining or re-passivating the system.
+
+### Where the project is competitively bid, each bidder shall propose chemistry meeting the same performance criteria stated in the treatment design.
+
+### A program described only by a vendor's product names becomes a switching cost. The Owner discovers at the first re-bid that changing providers means changing chemistry, and changing chemistry on an established system means a transition period during which the passive film is neither the old one nor the new one. {note}
+
+## Materials Compatibility Verification {toc}
+
+### Before chemistry is added to a system, the service provider shall verify in writing that the proposed chemistry is compatible with every wetted material in that system, including pipe metallurgy at each section, pump and valve bodies, mechanical seal faces and elastomers, gasket compounds at flanges and grooved couplings, heat exchanger tube and shell materials, expansion device diaphragms, and any aluminum component.
+
+### The compatibility verification shall identify each incompatibility found and shall propose either a substitute chemistry or a control measure such as a narrowed pH window.
+
+### The compatibility verification shall be signed by the service provider's technical authority.
+
+### The occasions on which compatibility verification is required shall be as indicated in the datasheet.
+
+```datasheet
+label: Materials Compatibility Verification Occasions
+type: checkbox
+options:
+ - "Before the initial chemical charge"
+ - "Before any change of chemistry program"
+ - "Before any single product substitution within an established program"
+ - "Before any equipment addition that introduces a new wetted material"
+default:
+ - "Before the initial chemical charge"
+ - "Before any change of chemistry program"
+ - "Before any single product substitution within an established program"
+ - "Before any equipment addition that introduces a new wetted material"
+```
+
+### Aluminum is the material that most often defeats an otherwise sound program. Aluminum humidifier cylinders, aluminum-cored coils, and light-duty aluminum impellers corrode rapidly above roughly pH 9, which is inside the normal control band for molybdate and nitrite chemistries. Where aluminum is in the wetted path the pH window narrows, and the chemistry has to be chosen for that window rather than adjusted into it later. {note}
+
+# Make-Up Water Supply {toc}
+
+## Design Basis Water Supply {toc}
+
+### Every treatment program is built on the water available at the site, because make-up water continuously refreshes each system — through evaporation on open systems, and through leakage, drain-down, and venting losses on closed systems. {note}
+
+### The treatment design shall be based on [[parameter: site-water-supply-source]] and [[parameter: site-water-supply-hardness]], and where more than one supply can serve the building, on the most aggressive of them.
+
+### A program designed for soft, low-conductivity municipal water fails on a project drawing hard well water, and a program designed for hard well water over-treats soft city water for the life of the building. The supply is not a preference; it is a measured fact that the design either accounts for or does not. {note}
+
+## Pre-Design Water Analysis {toc}
+
+### An independent laboratory analysis of the make-up water shall be obtained and shall report each analyte indicated in the datasheet.
+
+```datasheet
+label: Make-Up Water Analysis Parameters
+type: checkbox
+options:
+ - "pH"
+ - "Total hardness as CaCO3"
+ - "Calcium hardness as CaCO3"
+ - "Magnesium hardness as CaCO3"
+ - "Total alkalinity as CaCO3"
+ - "Chloride"
+ - "Sulfate"
+ - "Silica"
+ - "Total dissolved solids or specific conductance"
+ - "Total iron"
+ - "Manganese"
+ - "Total organic carbon"
+ - "Free chlorine residual"
+ - "Monochloramine residual"
+ - "Total phosphorus"
+default:
+ - "pH"
+ - "Total hardness as CaCO3"
+ - "Calcium hardness as CaCO3"
+ - "Total alkalinity as CaCO3"
+ - "Chloride"
+ - "Sulfate"
+ - "Silica"
+ - "Total dissolved solids or specific conductance"
+ - "Total iron"
+ - "Free chlorine residual"
+```
+
+### The analysis used for the treatment design shall be no older at the time of submittal than the age indicated in the datasheet.
+
+```datasheet
+label: Maximum Age of Make-Up Water Analysis at Submittal
+type: range
+unit: months
+options:
+ min: 0
+ max: 60
+ setpoints: [0, 6, 12, 24, 36, 60]
+default: 12
+```
+
+### Where the building can draw from more than one source, each source shall be analyzed separately rather than as a blend.
+
+### Monochloramine consumes oxidizing biocide demand in an open system without contributing the free halogen residual the program controls to, so a supply reported only as total chlorine hides a demand the biocide program has to carry. {note}
+
+### Where the supply is chloraminated, the analysis shall report monochloramine separately from free chlorine.
+
+## Make-Up Water Pretreatment {toc}
+
+### The make-up water pretreatment provided for each open recirculating system shall be as indicated in the datasheet.
+
+```datasheet
+label: Make-Up Water Pretreatment for Open Systems
+type: select
+options:
+ - "None"
+ - "Particulate filtration"
+ - "Softening by ion exchange"
+ - "Dealkalization"
+ - "Partial reverse osmosis blended with raw make-up"
+ - "Full reverse osmosis"
+ - "Softening combined with partial reverse osmosis"
+default: "None"
+```
+
+### Where the make-up water does not meet the CTI STD-159 limits at the cycles of concentration the design requires, the Engineer of Record shall resolve the conflict by adding pretreatment, by lowering the target cycles, or by both, before the tower selection is fixed.
+
+### Pretreatment buys cycles. Softening removes the hardness that limits scaling and lets a system run at higher cycles on the same tower, at the cost of the softener, its salt, and its regeneration discharge; reverse osmosis removes conductivity as well and lets cycles rise further, at higher capital and reject-water cost. Where make-up water is inexpensive and sewer discharge is unrestricted, neither is likely to repay its cost; where the utility meters both directions and restricts discharge volume, both often do. {note}
+
+### Softened make-up removes hardness but not alkalinity, so the concentrated water becomes more alkaline and more corrosive to galvanized surfaces than raw make-up at the same cycles. A tower with galvanized construction placed on softened make-up needs its corrosion program set for that condition rather than for the raw supply. {note}
+
+## Cross-Connection Control {toc}
+
+### Every treated system carries FIFRA-registered biocide and other chemistry whose entry into the potable supply is precisely the hazard cross-connection control exists to prevent, which is what makes a make-up connection a cross-connection control matter rather than a piping detail. {note}
+
+### Each make-up water connection to a treated system shall be protected by a backflow prevention assembly of the type required by the adopted plumbing code and the local cross-connection control authority for the degree of hazard the treated system presents.
+
+```datasheet
+label: Make-Up Water Backflow Prevention Assembly
+type: select
+derived: "the degree-of-hazard classification the adopted plumbing code assigns to a chemically treated system, and the assembly type the local cross-connection control authority accepts for that classification"
+options:
+ - "Air gap"
+ - "Reduced pressure principle assembly"
+ - "Reduced pressure principle detector assembly"
+ - "Double check valve assembly"
+ - "Double check detector assembly"
+default: derived
+```
+
+### Treated water shall not be permitted to return to the potable supply under any operating or failure condition, including make-up line depressurization.
+
+### The assembly shall be installed in a position accessible for the annual certification test required by the cross-connection control program, and its installation and testing shall comply with [[sync/backflow-prevention]].
+
+### The Contractor shall confirm the assembly type with the local cross-connection control authority before procurement, because acceptance of a double check assembly on an inhibited closed loop varies between jurisdictions that otherwise adopt the same model code.
+
+# Chemical Storage, Containment, and Handling {toc}
+
+## Storage Arrangement {toc}
+
+### The chemical storage arrangement serving the treatment program shall be as indicated in the datasheet.
+
+```datasheet
+label: Chemical Storage Arrangement
+type: select
+options:
+ - "Dedicated chemical storage room"
+ - "Enclosed chemical storage cabinet within the mechanical room"
+ - "Containment pallets and drum stations within the mechanical room"
+ - "Exterior chemical storage enclosure"
+ - "Day tanks at the feed skid replenished from off-site bulk supply"
+```
+
+### The chemical storage area shall be located as indicated on [[drawing: the mechanical drawings]], with clearance to change containers without disassembling feed equipment.
+
+### No arrangement is the norm across projects, because the answer follows the chemical quantity the program consumes and the space the plant has. A single tower on solid feed needs no more than a shelf and a containment pallet, while a campus central plant on bulk liquid feed needs a rated room with its own ventilation. {note}
+
+## Secondary Containment {toc}
+
+### Secondary containment shall be provided at every chemical storage and feed location, sized not less than the capacity indicated in the datasheet and in no case less than the capacity required by the adopted fire code.
+
+```datasheet
+label: Secondary Containment Capacity as Percent of Largest Container
+type: range
+unit: '%'
+options:
+ min: 100
+ max: 300
+ setpoints: [100, 110, 125, 150, 200, 300]
+default: 110
+```
+
+### Containment sized to the largest single container assumes one container fails at a time. Where incompatible products share a containment area, sizing to the sum of the stored volumes is what prevents a single failure from mixing an acid with an oxidizer inside the containment itself. {note}
+
+### Chemical feed pumps and their suction connections shall be located within secondary containment.
+
+### A chemical-resistant floor coating shall be provided throughout the containment area.
+
+### Where a floor drain is provided in the containment area, it shall be arranged so that a spill cannot reach a storm or sanitary sewer without passing through a spill isolation provision.
+
+## Life Safety and Segregation Provisions {toc}
+
+### Emergency eyewash and shower equipment meeting ANSI Z358.1 shall be provided within the travel distance that standard requires of every chemical handling position.
+
+### Mechanical ventilation meeting the IBC and IFC requirements for the hazard class of the chemicals stored shall be provided.
+
+### Incompatible products shall be physically separated in storage, with acids separated from oxidizers and oxidizers separated from organic biocides and reducing agents.
+
+### Spill response materials sized for the largest single container shall be provided at the storage area.
+
+### Safety Data Sheets for every chemical present shall be posted at the entry to the storage area in a weatherproof enclosure, in addition to the chemical inventory list delivered at closeout.
+
+### Where the stored quantity of any chemical exceeds the IFC threshold for hazardous material occupancy classification, the storage area shall be classified and constructed accordingly.
+
+### Hypochlorite and acid together produce chlorine gas within seconds. Segregation and containment sizing are the two provisions that keep an ordinary drum failure from becoming an evacuation, and both are decided at layout rather than corrected later. {note}
+
+# Closed System Treatment Program {toc}
+
+## Corrosion Inhibitor Chemistry {toc}
+
+### The primary corrosion inhibitor chemistry for each closed hydronic system shall be as indicated in the datasheet.
+
+```datasheet
+label: Closed System Corrosion Inhibitor Chemistry
+type: select
+options:
+ - "Molybdate"
+ - "Nitrite"
+ - "Molybdate and nitrite blend"
+ - "Phosphonate with azole and polymer"
+ - "Silicate"
+ - "Borate and nitrite"
+```
+
+### No chemistry is the norm across closed hydronic projects, so this field asserts no default. The choice turns on the system metallurgy, the operating temperature, the Owner's tolerance for monitoring effort, and the local discharge rules — inputs that differ from project to project rather than settling on one answer. {note}
+
+### Molybdate forms a passive film on carbon steel through an oxidative mechanism that does not consume dissolved oxygen, holds across a wide pH and temperature range, and is unaffected by chloride at the concentrations found in closed loops. It costs more per treated gallon than nitrite, needs a pH near the upper end of the common band to protect copper alongside the steel, and faces discharge restrictions on molybdenum in some jurisdictions. {note}
+
+### Nitrite protects carbon steel at several hundred milligrams per litre, tests easily in the field, and is the least expensive of the common chemistries. Its exposure is biological: Nitrosomonas, Nitrobacter, and Pseudomonas species metabolize nitrite and can strip a loop from a protective residual to an unprotected one within weeks, so where nitrite is selected the program depends on microbial control to hold the inhibitor rather than on the inhibitor alone. {note}
+
+### Where nitrite is the primary inhibitor, the program shall include microbial monitoring at every service visit and a non-oxidizing biocide rotation.
+
+### A blend of molybdate and nitrite protects at a lower total concentration than either chemistry alone, which reduces chemical cost relative to straight molybdate while reducing the depth of the loss if nitrite-consuming organisms establish. {note}
+
+### Phosphonate with an azole and a polymer inhibits at a lower pH than molybdate or nitrite chemistry, which is what makes it usable where aluminum or other amphoteric metals are in the wetted path. {note}
+
+### Silicate forms a protective film on steel, copper, and aluminum simultaneously and is the inhibitor package used in most inhibited glycol formulations, which is why it appears in loops that were charged as glycol systems rather than converted to one. {note}
+
+## Copper Corrosion Inhibitor {toc}
+
+### An azole copper inhibitor shall be maintained in every treated system containing copper or copper-alloy surfaces, in addition to the primary corrosion inhibitor.
+
+### The azole selected shall be as indicated in the datasheet.
+
+```datasheet
+label: Copper Corrosion Inhibitor Azole
+type: select
+options:
+ - "Tolyltriazole"
+ - "Halogen-stable tolyltriazole"
+ - "Benzotriazole"
+ - "Mercaptobenzothiazole"
+ - "None"
+default: "Tolyltriazole"
+```
+
+### The minimum azole residual maintained in each closed system shall be as indicated in the datasheet.
+
+```datasheet
+label: Closed System Copper Inhibitor Residual
+type: range
+unit: mg/L
+options:
+ min: 0
+ max: 25
+ setpoints: [0, 2, 5, 10, 15, 20, 25]
+default: 5
+```
+
+### An azole chemisorbs onto copper and stops two things at once: the copper dissolving, and the dissolved copper ions plating out on carbon steel downstream, where each deposit becomes a cathode driving localized attack on the steel. The second mechanism is why a loop with very little copper in it still benefits from azole. {note}
+
+### Where an oxidizing biocide is used in a system carrying azole, the azole feed shall follow the biocide event rather than precede it, and the azole residual shall be measured before and after each event.
+
+### Oxidizing biocides consume azole. Halogen-stable azoles resist that consumption but do not eliminate it, so the ordering of the two feeds is what decides whether the copper film survives the biocide event. {note}
+
+## Polymer Dispersant {toc}
+
+### Whether a polymer dispersant is included in the closed-system program shall be as indicated in the datasheet.
+
+```datasheet
+label: Closed System Polymer Dispersant
+type: radio
+options:
+ - "Included in the closed-system program"
+ - "Not included"
+default: "Included in the closed-system program"
+```
+
+### The dispersant does two jobs. It holds iron oxide, scale particles, and microbial debris in suspension so a side-stream filter or a dirt separator can remove them rather than letting them settle in the slowest branches, and it modifies crystal habit on incipient scale so what does form stays loose instead of adhering to heat-transfer surfaces. {note}
+
+## Closed System Control Ranges {toc}
+
+### The inhibitor control range for each closed system shall be as indicated in the datasheet, and shall be the basis against which every field test result is compared.
+
+```datasheet
+label: Closed System Inhibitor Control Range
+type: text
+derived: "the closed-system inhibitor chemistry selected for this system and the published protective band for that chemistry at the system metallurgy"
+default: derived
+```
+
+### The pH control range for each closed system shall be as indicated in the datasheet.
+
+```datasheet
+label: Closed System pH Control Range
+type: text
+derived: "the closed-system inhibitor chemistry selected and the presence of aluminum or other amphoteric metals in the wetted path"
+default: derived
+```
+
+### Control ranges are not free selections. Once the chemistry and the metallurgy are stated, the protective band follows from published data for that chemistry, and two competent providers given the same two inputs arrive at the same numbers. Recording them as derived keeps the datasheet from offering a choice the chemistry has already made. {note}
+
+### Whether conductivity is measured and trended on each closed system shall be as indicated in the datasheet.
+
+```datasheet
+label: Closed System Conductivity Trending
+type: radio
+options:
+ - "Measured and trended at every service visit"
+ - "Not measured"
+default: "Measured and trended at every service visit"
+```
+
+### Conductivity on a closed loop is a leak detector, not a control parameter. A steady rise means make-up water is entering and concentrating; a fall means the loop is being diluted faster than the inhibitor is being replaced. Either direction shows up in the trend before it shows up as a chemistry excursion. {note}
+
+### A closed system whose measured inhibitor concentration falls below its control range shall be brought back within range and the cause of the loss identified before the next scheduled visit.
+
+## Microbiological Control in Closed Loops {toc}
+
+### A closed loop is not a sterile one. Fill water carries organisms, low-velocity branches and dead legs give them somewhere to settle, and a nitrite residual gives some of them something to eat. {note}
+
+### Oxidizing biocides are not used in closed loops at the concentrations that would be required, because they attack elastomers and consume the corrosion inhibitor faster than they suppress the organisms. {note}
+
+### The non-oxidizing biocide program for each closed system shall be as indicated in the datasheet.
+
+```datasheet
+label: Closed System Biocide Program
+type: select
+options:
+ - "Isothiazolone"
+ - "Glutaraldehyde"
+ - "Quaternary ammonium compound"
+ - "Tetrakis hydroxymethyl phosphonium sulfate"
+ - "Two-product alternating rotation"
+ - "None"
+```
+
+### Where a biocide rotation is specified, the rotation shall use at least two active ingredients from different chemical families on alternating cycles.
+
+### The biocide dosing interval for each closed system on a biocide program shall be as indicated in the datasheet.
+
+```datasheet
+label: Closed System Biocide Dosing Interval
+type: range
+unit: days
+options:
+ min: 30
+ max: 365
+ setpoints: [30, 60, 90, 120, 180, 365]
+```
+
+### Rotating actives suppresses the resistant subpopulation that a single active selects for over repeated doses. A single-product program often reads clean for a year and then stops working, and the reading that shows it is the microbial count rather than the corrosion rate. {note}
+
+# Open Recirculating System Treatment Program {toc}
+
+## Why Open Systems Concentrate {toc}
+
+### An open recirculating system loses water as vapor through the tower fill and leaves every dissolved solid behind in the remaining inventory. Without bleed the inventory concentrates without limit; with controlled bleed it settles at a stable ratio of recirculating water quality to make-up water quality, which is the cycles of concentration. {note}
+
+### An open system's program has four interlocking parts: scale control, corrosion control across carbon steel, copper, and galvanized surfaces, biological control in the fill, basin, and piping, and the bleed control that holds the concentration where the first three were designed to work. {note}
+
+### Open systems fall within the scope of ANSI/ASHRAE 188, so the biological part of the program is a public health control measure with documentation obligations, not only an equipment protection measure. {note}
+
+## Start-Up Disinfection of Open Systems {toc}
+
+### A tower set months before start-up collects rainwater, dust, vegetation, bird debris, and construction dirt in its basin, and biological growth establishes in that standing water long before the system is commissioned. {note}
+
+### Each open recirculating system shall be disinfected before it is placed in service, by the method indicated in the datasheet.
+
+```datasheet
+label: Open System Start-Up Disinfection Method
+type: select
+options:
+ - "Mechanical cleaning of basin and fill followed by hyperhalogenation"
+ - "Hyperhalogenation without mechanical cleaning"
+ - "Chlorine dioxide disinfection"
+ - "Mechanical cleaning without chemical disinfection"
+default: "Mechanical cleaning of basin and fill followed by hyperhalogenation"
+```
+
+### The free halogen residual and contact time achieved during start-up disinfection shall be recorded, and a post-disinfection microbiological sample shall be taken before the long-term program is placed online.
+
+### The oxidant residual from start-up disinfection shall be allowed to fall to the program's normal operating residual before the corrosion inhibitor and azole are charged, so that the inhibitor package is not consumed by the disinfection chemistry.
+
+## Scale Control {toc}
+
+### The scale inhibitor for each open recirculating system shall be as indicated in the datasheet.
+
+```datasheet
+label: Open System Scale Inhibitor
+type: select
+options:
+ - "Phosphonate with polymer dispersant"
+ - "Polyphosphate with polymer dispersant"
+ - "All-organic polymer, phosphorus-free"
+ - "Chelant with polymer dispersant"
+default: "Phosphonate with polymer dispersant"
+```
+
+### A phosphonate works by threshold inhibition — a few milligrams per litre disrupt crystal nucleation far below the concentration that would be needed to sequester the hardness stoichiometrically — while the polymer modifies the crystal habit of whatever does nucleate and keeps the resulting particles dispersed. {note}
+
+### Where the jurisdiction restricts phosphorus discharge to the sanitary sewer or to surface water, a phosphorus-free program removes the discharge exposure at the cost of a narrower operating window, because all-organic chemistry generally tolerates less scaling potential before it stops holding. {note}
+
+### Whether a supplemental silica scale inhibitor is included shall be as indicated in the datasheet.
+
+```datasheet
+label: Supplemental Silica Scale Inhibitor
+type: radio
+derived: "the make-up water silica concentration multiplied by the target cycles of concentration, measured against the silica solubility limit at the system's operating pH and temperature"
+options:
+ - "Included in the open-system program"
+ - "Not included"
+default: derived
+```
+
+### Silica scale is the one deposit that ordinary acid cleaning does not remove, which is why silica rather than calcium sets the cycles ceiling on high-silica make-up water. The threshold is a calculation on the analysis, not a judgment call. {note}
+
+## Corrosion Control in Open Systems {toc}
+
+### Open system corrosion inhibitor concentrations are lower than closed system concentrations because bleed continuously removes inhibitor along with the dissolved solids, so the program feeds continuously to hold a residual rather than charging once and maintaining it. {note}
+
+### The steel corrosion inhibitor for each open recirculating system shall be as indicated in the datasheet.
+
+```datasheet
+label: Open System Steel Corrosion Inhibitor
+type: select
+options:
+ - "Orthophosphate"
+ - "Zinc and orthophosphate"
+ - "Molybdate"
+ - "All-organic, phosphorus-free"
+ - "Alkaline passivation program with no metallic inhibitor"
+default: "Orthophosphate"
+```
+
+### The minimum azole residual maintained in each open recirculating system shall be as indicated in the datasheet.
+
+```datasheet
+label: Open System Copper Inhibitor Residual
+type: range
+unit: mg/L
+options:
+ min: 0
+ max: 10
+ setpoints: [0, 0.5, 1, 2, 3, 5, 10]
+default: 1
+```
+
+### The inhibitor control range for each open recirculating system shall be as indicated in the datasheet, and shall be the basis against which every field test result is compared.
+
+```datasheet
+label: Open System Inhibitor Control Range
+type: text
+derived: "the open-system scale and steel corrosion inhibitors selected, the make-up water analysis, and the target cycles of concentration at which those inhibitors must hold"
+default: derived
+```
+
+## Galvanized Surface Passivation {toc}
+
+### New galvanized steel in a cooling tower needs a controlled period at reduced pH before it carries a stable zinc carbonate patina. Run alkaline from the first fill and the zinc converts instead to loose white zinc hydroxide, which sheds rather than protects and does not re-form once lost. {note}
+
+### Where a system includes new galvanized steel surfaces, the recirculating water pH shall be held at or below the value indicated in the datasheet through the initial passivation period.
+
+```datasheet
+label: Galvanized Surface Passivation pH Ceiling
+type: range
+unit: pH units
+options:
+ min: 6.5
+ max: 9.0
+ setpoints: [6.5, 7.0, 7.2, 7.5, 7.8, 8.0, 8.5, 9.0]
+default: 8.0
+```
+
+### The initial passivation period for new galvanized surfaces shall be as indicated in the datasheet, measured from the date the system enters continuous operating service.
+
+```datasheet
+label: Galvanized Surface Passivation Period
+type: range
+unit: days
+options:
+ min: 0
+ max: 180
+ setpoints: [0, 30, 45, 60, 90, 120, 180]
+default: 60
+```
+
+### After the passivation period, the pH control range for the system reverts to the range established for the selected chemistry.
+
+## Biocide Program for Open Systems {toc}
+
+### The biocide program is the primary engineering control for Legionella in the recirculating water, and its design, dosing, and documentation are the mechanism by which the project demonstrates the control measure required under ANSI/ASHRAE 188. {note}
+
+### The open system biocide program shall combine an oxidizing biocide with a non-oxidizing biocide rotation, unless the datasheet indicates that no oxidizing biocide is used.
+
+### The oxidizing biocide for each open recirculating system shall be as indicated in the datasheet.
+
+```datasheet
+label: Open System Oxidizing Biocide
+type: select
+options:
+ - "Sodium hypochlorite"
+ - "Calcium hypochlorite"
+ - "Activated sodium bromide"
+ - "Stabilized bromine donor"
+ - "Chlorine dioxide"
+ - "None"
+```
+
+### Halogen chemistry is pH-dependent in a way that decides which oxidant holds at a given operating band. Hypochlorous acid dissociates to the far less active hypochlorite ion as pH rises, so a chlorine program loses effectiveness across the alkaline band many open systems run in, while hypobromous acid remains largely undissociated across that same band. Below roughly pH 8, and on systems held low for galvanized passivation, chlorine retains its activity and costs less per pound of available halogen. {note}
+
+### Chlorine dioxide does not hydrolyze with pH and penetrates established biofilm more effectively than either halogen, which is what recommends it where biofilm rather than planktonic count is the controlling problem. It is generated on site rather than delivered, so it adds a generator, its feedstocks, and their own storage and monitoring obligations. {note}
+
+### The non-oxidizing biocides in the rotation shall be as indicated in the datasheet.
+
+```datasheet
+label: Open System Non-Oxidizing Biocide Rotation
+type: checkbox
+options:
+ - "Isothiazolone"
+ - "Glutaraldehyde"
+ - "Dibromonitrilopropionamide"
+ - "Quaternary ammonium compound"
+ - "Tetrakis hydroxymethyl phosphonium sulfate"
+ - "Carbamate"
+ - "Bronopol"
+default:
+ - "Isothiazolone"
+ - "Glutaraldehyde"
+```
+
+### The rotation shall use at least two active ingredients from different chemical families on alternating cycles.
+
+### The non-oxidizing biocide dosing interval shall be as indicated in the datasheet.
+
+```datasheet
+label: Open System Non-Oxidizing Biocide Dosing Interval
+type: range
+unit: days
+options:
+ min: 7
+ max: 90
+ setpoints: [7, 14, 21, 30, 45, 60, 90]
+default: 14
+```
+
+### Every biocidal product used shall be registered under FIFRA for the application in which it is used, and shall be dosed within the concentrations and intervals stated on its registered label.
+
+### Off-label dosing of a registered biocide is a federal violation independent of whether it works, and label rates are also what the water management program cites as its control limits. A dose outside the label leaves the program without a defensible control measure. {note}
+
+## Cycles of Concentration and Bleed Control {toc}
+
+### Higher cycles reduce make-up volume and bleed discharge volume, and concentrate every dissolved solid the scale and corrosion inhibitors have to hold in solution. The ceiling is set by whichever species reaches its limit first — calcium carbonate on hard water, silica on high-silica water, chloride on brackish or reclaimed water. {note}
+
+### The target cycles of concentration for each open recirculating system shall be as indicated in the datasheet.
+
+```datasheet
+label: Target Cycles of Concentration
+type: range
+unit: cycles
+derived: "the make-up water analysis for the project including [[parameter: site-water-supply-hardness]], evaluated against whichever scale or corrosion limit is reached first at concentration"
+options:
+ min: 1.5
+ max: 20
+ setpoints: [1.5, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20]
+default: derived
+```
+
+### Cycles of concentration is not a preference and has no norm across projects. Given the analysis and the limiting species, the achievable ceiling is a calculation, and the target sits below that ceiling by whatever margin the program's control tolerance requires. {note}
+
+### Bleed shall be controlled automatically on conductivity, with the bleed valve opening above the set point and closing below it, and make-up entering under level control as the inventory falls.
+
+### The conductivity set point at which bleed is initiated shall be as indicated in the datasheet.
+
+```datasheet
+label: Bleed Control Conductivity Set Point
+type: range
+unit: µS/cm
+derived: "the target cycles of concentration applied to the measured specific conductance of the project's make-up water"
+options:
+ min: 200
+ max: 6000
+ setpoints: [200, 500, 750, 1000, 1500, 2000, 2500, 3000, 4000, 5000, 6000]
+default: derived
+```
+
+### Chemical feed shall be paced so that inhibitor and biocide concentrations are maintained against continuous bleed loss, on the basis indicated in the datasheet.
+
+```datasheet
+label: Open System Chemical Feed Pacing Basis
+type: select
+options:
+ - "Make-up water meter contact pulse"
+ - "Bleed valve event pacing"
+ - "Controller residual feedback"
+ - "Continuous proportional feed"
+ - "Timer-based feed"
+ - "Manual dosing at service visits"
+default: "Make-up water meter contact pulse"
+```
+
+### Meter pacing doses in proportion to the water actually entering the system, which tracks evaporation load rather than clock time. Timer pacing runs the same dose on a mild day as on a design day, which either under-treats the peak or wastes chemical through the shoulder seasons. {note}
+
+## Oxidant Residual Control {toc}
+
+### The free halogen residual maintained in the recirculating water shall be as indicated in the datasheet.
+
+```datasheet
+label: Free Halogen Residual Target
+type: range
+unit: mg/L
+options:
+ min: 0.1
+ max: 5
+ setpoints: [0.1, 0.2, 0.5, 1, 1.5, 2, 3, 5]
+default: 0.5
+```
+
+### Where oxidizing biocide feed is controlled automatically, oxidation-reduction potential shall be the control parameter, and the set point shall be established by correlating measured potential against the free halogen residual target in the recirculating water of this system.
+
+```datasheet
+label: Oxidation-Reduction Potential Control Set Point
+type: range
+unit: mV
+derived: "the free halogen residual target for this system correlated against measured potential in its own recirculating water at operating pH"
+options:
+ min: 300
+ max: 900
+ setpoints: [300, 400, 450, 500, 550, 600, 650, 700, 750, 800, 900]
+default: derived
+```
+
+### Oxidation-reduction potential measures oxidizing power rather than halogen concentration, so it already accounts for the pH-driven shift between active and inactive halogen species and responds within seconds to a demand change. What it does not do is transfer between systems: the same potential corresponds to different residuals in different waters, which is why the correlation is established on the installed system rather than taken from a table. {note}
+
+### The correlation between potential and free halogen residual shall be re-verified at the interval indicated in the datasheet.
+
+```datasheet
+label: Oxidant Correlation Re-Verification Interval
+type: range
+unit: days
+options:
+ min: 30
+ max: 365
+ setpoints: [30, 60, 90, 180, 365]
+default: 90
+```
+
+# Glycol Loop Chemistry Maintenance {toc}
+
+## Glycol Program Boundary {toc}
+
+### The glycol fluid itself — its type, its design concentration, and its initial charge — is selected and charged under [[sync/hydronic-cleaning-and-flushing]]. This standard governs what happens to that fluid afterward. {note}
+
+### Inhibited industrial glycol arrives with its own corrosion inhibitor package and a reserve alkalinity buffer, so a glycol loop is not dosed with a separate closed-system inhibitor unless the compatibility verification establishes that the two packages coexist. {note}
+
+### Supplemental inhibitor, azole, or biocide shall not be added to an inhibited glycol loop unless the compatibility verification required by this standard covers the combination.
+
+## Glycol Degradation {toc}
+
+### Glycol oxidizes slowly in service, faster at heating hot water temperatures than at chilled water temperatures, and the oxidation products are organic acids. The reserve alkalinity in the fluid neutralizes those acids until it is consumed, after which pH falls, the inhibitor package depletes, and the degraded fluid becomes more aggressive to carbon steel than plain water would have been. {note}
+
+### Falling pH at a stable glycol concentration is the signature of a depleted buffer rather than of dilution, which is why the two parameters are read together rather than separately. {note}
+
+### The lower pH action limit for each glycol loop shall be as indicated in the datasheet.
+
+```datasheet
+label: Glycol Loop Lower pH Action Limit
+type: range
+unit: pH units
+options:
+ min: 6.5
+ max: 9.5
+ setpoints: [6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5]
+default: 8.0
+```
+
+## Routine Glycol Testing {toc}
+
+### Each glycol loop shall be tested at every service visit for the parameters indicated in the datasheet.
+
+```datasheet
+label: Glycol Loop Test Parameters
+type: checkbox
+options:
+ - "pH"
+ - "Glycol concentration by refractometer"
+ - "Inhibitor reserve by the fluid supplier's test method"
+ - "Reserve alkalinity"
+ - "Conductivity"
+ - "Total iron and total copper"
+ - "Microbial activity"
+ - "Degradation acids by chromatography"
+default:
+ - "pH"
+ - "Glycol concentration by refractometer"
+ - "Inhibitor reserve by the fluid supplier's test method"
+ - "Reserve alkalinity"
+ - "Conductivity"
+```
+
+### Glycol concentration shall be measured by refractometer rather than by hydrometer, because a hydrometer reading shifts with temperature and with the dissolved solids a service loop accumulates.
+
+### A concentration that has fallen since the previous visit indicates make-up water entering the loop, and shall be investigated as a leak or an unrecorded drain-down rather than corrected by adding concentrate alone.
+
+## Inhibitor Replenishment and Fluid Replacement {toc}
+
+### Where the inhibitor reserve or the pH of a glycol loop falls below its action limit, the corrective action shall be as indicated in the datasheet.
+
+```datasheet
+label: Glycol Inhibitor Depletion Corrective Action
+type: select
+options:
+ - "Supplement with the fluid supplier's concentrated inhibitor package"
+ - "Partial fluid replacement to restore reserve"
+ - "Complete fluid replacement and recharge"
+ - "Complete fluid replacement preceded by flushing"
+```
+
+### No corrective action is the norm, because the right answer depends on how far the fluid has degraded and on what the replacement fluid costs relative to the loop volume. Supplementing restores the inhibitor but not the fluid, and a loop whose glycol has broken down to organic acids will consume a supplemental package as quickly as the last one. {note}
+
+### Drained glycol shall be disposed of in accordance with applicable environmental regulations and shall not be discharged to a storm sewer.
+
+# Steam and Condensate Treatment {toc}
+
+## Steam Program Boundaries {toc}
+
+### A steam program addresses three regions with three different failure modes: the boiler water, where solids concentrate and scale, corrode, and carry over; the steam, where a neutralizing agent has to travel with the vapor to reach the condensate; and the condensate return, where carbonic acid grooves the bottom of horizontal carbon steel runs. {note}
+
+### This standard's steam program applies to systems operating at or below 150 psig serving humidifiers, sterilizers, kitchen equipment, and heating loads.
+
+### Steam systems above 150 psig shall be treated under a process-grade boiler water program designed under separate cover.
+
+### The boiler pressure vessel, its trim, and its safety devices are governed by [[sync/boilers]], and the distribution piping, traps, and receivers by [[sync/steam-and-condensate-piping]]. {note}
+
+## Boiler Feedwater Pretreatment {toc}
+
+### The boiler feedwater pretreatment shall be as indicated in the datasheet.
+
+```datasheet
+label: Boiler Feedwater Pretreatment
+type: select
+options:
+ - "None"
+ - "Softening by ion exchange"
+ - "Softening with dealkalization"
+ - "Softening with mechanical deaeration"
+ - "Softening with reverse osmosis"
+ - "Demineralization"
+default: "Softening by ion exchange"
+```
+
+### Hardness entering a boiler precipitates on the hottest surface it reaches, and a scale layer measured in thousandths of an inch raises tube metal temperature enough to matter. Removing hardness ahead of the boiler is cheaper than conditioning it inside the boiler, and it is what allows the boiler to run at useful cycles. {note}
+
+### The oxygen scavenger for the boiler feedwater shall be as indicated in the datasheet.
+
+```datasheet
+label: Boiler Water Oxygen Scavenger
+type: select
+options:
+ - "Sodium sulfite"
+ - "Catalyzed sodium sulfite"
+ - "Diethylhydroxylamine"
+ - "Erythorbate"
+ - "Carbohydrazide"
+ - "Mechanical deaeration without a chemical scavenger"
+default: "Catalyzed sodium sulfite"
+```
+
+### Sulfite adds dissolved solids to the boiler water in proportion to the oxygen it removes, which matters on a system already near its solids limit; the volatile scavengers add none and carry into the steam, which is what makes them the usable choice where the steam contacts food or where the solids budget is tight. {note}
+
+### Where steam contacts food, the scavenger and every other boiler additive shall appear on the FDA 21 CFR 173.310 list.
+
+## Boiler Internal Treatment {toc}
+
+### The boiler internal treatment shall be as indicated in the datasheet.
+
+```datasheet
+label: Boiler Internal Treatment
+type: select
+options:
+ - "Coordinated phosphate"
+ - "Phosphate with polymer"
+ - "Chelant"
+ - "All-polymer"
+ - "Chelant with polymer"
+default: "Phosphate with polymer"
+```
+
+### An alkalinity builder shall be fed to hold the boiler water pH within the program's control range.
+
+### Internal treatment is the second line behind pretreatment, conditioning whatever hardness gets past the softener into a sludge the blowdown can carry out rather than a scale bonded to the tube. A chelant program does that by sequestering hardness in solution, which works well on consistently soft feedwater and attacks boiler metal where feedwater hardness swings and the chelant runs in excess. {note}
+
+## Boiler Cycles and Blowdown {toc}
+
+### The boiler water cycles of concentration shall be as indicated in the datasheet, and blowdown shall be controlled to hold them.
+
+```datasheet
+label: Boiler Water Cycles of Concentration
+type: range
+unit: cycles
+derived: "the feedwater analysis after the selected pretreatment, evaluated against the ABMA boiler water and steam purity limits for this boiler's operating pressure"
+options:
+ min: 2
+ max: 60
+ setpoints: [2, 5, 10, 15, 20, 25, 30, 40, 50, 60]
+default: derived
+```
+
+### Boiler cycles are bounded by published limits rather than by preference. The ABMA tables state maximum total dissolved solids, alkalinity, and silica for each pressure band, and the achievable cycles follow from dividing those limits by the feedwater analysis. {note}
+
+### Continuous surface blowdown shall be provided where the boiler is equipped for it, with intermittent bottom blowdown used to remove settled sludge rather than to control dissolved solids.
+
+### Surface blowdown removes water from where the solids are most concentrated and can run continuously against a conductivity signal; bottom blowdown removes sludge from the mud drum in short bursts and controls solids only crudely. Using bottom blowdown for solids control swings the boiler water between over-concentrated and over-diluted at every blow. {note}
+
+## Condensate Corrosion Control {toc}
+
+### Carbon dioxide released from feedwater alkalinity travels with the steam, dissolves in the condensate as carbonic acid, and drives condensate pH down toward 5. The attack that follows concentrates at the bottom of horizontal returns, where the condensate runs, and produces the characteristic longitudinal groove rather than general thinning. {note}
+
+### A neutralizing amine shall be fed so that it volatilizes with the steam, condenses with the water, and holds the condensate above its lower pH limit.
+
+```datasheet
+label: Steam Neutralizing Amine
+type: select
+derived: "the distribution ratio required by this system's steam main length and its condensing profile from the first to the last condensing point, and the FDA 21 CFR 173.310 list where the steam contacts food"
+options:
+ - "Cyclohexylamine"
+ - "Morpholine"
+ - "Diethylaminoethanol"
+ - "Blended amine"
+ - "Filming amine"
+default: derived
+```
+
+### Amines differ in how far they travel before condensing. A low-distribution-ratio amine concentrates at the first condensing point and leaves the far end of a long main unprotected; a high-distribution-ratio amine reaches the far end and under-protects the near end. Which one a system needs follows from the geometry of its distribution rather than from a preference, and long mains are commonly protected by a blend chosen to cover both ends. {note}
+
+### A filming amine protects by laying a hydrophobic barrier on the metal rather than by neutralizing acid, so it does not raise condensate pH and its performance is not verified by a pH reading. {note}
+
+## Condensate Quality Limits {toc}
+
+### The lower pH limit for returned condensate shall be as indicated in the datasheet.
+
+```datasheet
+label: Condensate Return Lower pH Limit
+type: range
+unit: pH units
+options:
+ min: 7.0
+ max: 9.5
+ setpoints: [7.0, 7.5, 8.0, 8.2, 8.5, 8.8, 9.0, 9.5]
+default: 8.2
+```
+
+### The maximum total iron in returned condensate shall be as indicated in the datasheet.
+
+```datasheet
+label: Condensate Maximum Total Iron
+type: range
+unit: mg/L
+options:
+ min: 0.1
+ max: 3
+ setpoints: [0.1, 0.2, 0.5, 1, 1.5, 2, 3]
+default: 1
+```
+
+### Condensate shall be sampled at the receiver and at a point representative of the longest return run.
+
+### Where condensate iron exceeds its limit while pH is within range, the cause shall be investigated as oxygen ingress at the receiver or as under-protection of the most distant returns, rather than corrected by increasing the amine dose alone.
+
+### Iron in the condensate is the boiler's own return piping arriving in solution. It is the earliest quantitative warning that the return system is being consumed, and it usually appears a year or more before the first pinhole. {note}
+
+# Chemical Feed Equipment {toc}
+
+## Feed Form {toc}
+
+### The feed form for the inhibitor and scale chemistry shall be as indicated in the datasheet.
+
+```datasheet
+label: Inhibitor and Scale Chemistry Feed Form
+type: radio
+options:
+ - "Bulk liquid with metering pump"
+ - "Solid tablet or briquette feeder"
+default: "Bulk liquid with metering pump"
+```
+
+### The feed form for the oxidizing halogen shall be as indicated in the datasheet.
+
+```datasheet
+label: Oxidizing Halogen Feed Form
+type: radio
+options:
+ - "Bulk liquid with metering pump"
+ - "Solid tablet or briquette feeder"
+ - "On-site electrochemical generation"
+ - "Gas chlorination"
+```
+
+### Solid feeders remove the bulk tank, the containment volume that goes with it, and much of the spill exposure, and they extend the interval between replenishment visits. What they give up is dose resolution: a feeder erodes product at a rate set by flow and water temperature rather than at a rate a controller commands, so the residual moves with conditions instead of being held. Where mechanical room space or spill exposure is the binding constraint, that trade often favors solids; where a tight residual band is the binding constraint, it does not. {note}
+
+## Metering Pumps {toc}
+
+### The metering pump type for each chemical product shall be as indicated in the datasheet.
+
+```datasheet
+label: Chemical Metering Pump Type
+type: select
+options:
+ - "Solenoid-driven diaphragm"
+ - "Motor-driven diaphragm"
+ - "Peristaltic"
+ - "Pneumatic drum pump"
+```
+
+### Sodium hypochlorite and some other products release gas in the pump head. A diaphragm pump loses prime when that gas collects and can run for days delivering nothing while its stroke counter says otherwise; a peristaltic pump displaces the tube volume regardless of what is in it, so it keeps metering. Where an off-gassing product is fed, that difference decides whether a missed dose is visible. {note}
+
+### Each metering pump shall be capable of pacing from the pulse or analog signal that the treatment controller provides for that product.
+
+### Each chemical product shall have its own dedicated metering pump and its own dedicated feed line.
+
+### Feed lines shall not be shared between chemical products, because residual product in a shared suction or discharge line mixes with the next product fed and can react in the tubing.
+
+### A calibration column shall be provided on the suction of each metering pump so that delivered volume can be verified against commanded volume.
+
+## Feed Line Integrity {toc}
+
+### Feed lines shall be routed in full view along their length rather than concealed, and shall be supported so that a failure discharges into containment.
+
+### Each feed line shall be labeled at both ends and at each intermediate fitting with the chemical product, the pump identification, and the receiving system.
+
+### An injection quill or corporation stop shall be provided at each injection point so that the feed line can be isolated and withdrawn without draining the system.
+
+### A feed line that fails between the pump and the injection point discharges concentrated chemical continuously until someone notices. Full-view routing and containment turn that from a discovery-by-damage event into a discovery-by-inspection event. {note}
+
+# Treatment Controllers and BAS Integration {toc}
+
+## Controller Capabilities {toc}
+
+### A treatment controller shall be provided for each open recirculating system and for each system whose feed is paced automatically, with the capabilities indicated in the datasheet.
+
+```datasheet
+label: Treatment Controller Capabilities Required
+type: checkbox
+options:
+ - "Conductivity measurement with an isolated probe"
+ - "Oxidation-reduction potential measurement"
+ - "pH measurement"
+ - "Make-up water meter pulse input"
+ - "Bleed valve output with flow verification"
+ - "Independent pacing output for each chemical feed pump"
+ - "No-flow interlock that inhibits feed when recirculation stops"
+ - "Alarm output on any control parameter excursion"
+ - "Local display of every measured parameter with recent trend"
+ - "Local data logging"
+ - "Building automation system communication"
+ - "Remote access for the service provider"
+default:
+ - "Conductivity measurement with an isolated probe"
+ - "Oxidation-reduction potential measurement"
+ - "Make-up water meter pulse input"
+ - "Bleed valve output with flow verification"
+ - "Independent pacing output for each chemical feed pump"
+ - "No-flow interlock that inhibits feed when recirculation stops"
+ - "Alarm output on any control parameter excursion"
+ - "Local display of every measured parameter with recent trend"
+ - "Local data logging"
+ - "Building automation system communication"
+```
+
+### The local data retention period of the controller shall be not less than the period indicated in the datasheet.
+
+```datasheet
+label: Controller Local Data Retention Period
+type: range
+unit: days
+options:
+ min: 0
+ max: 730
+ setpoints: [0, 7, 30, 90, 180, 365, 730]
+default: 30
+```
+
+### The no-flow interlock is the provision that prevents a controller from dosing into a stopped system. Without it, a pump failure produces a slug of undiluted chemical sitting against the nearest metal surface until circulation resumes. {note}
+
+## Probe Calibration {toc}
+
+### Controller probes shall be calibrated against reference solutions at the intervals indicated in the datasheets, with calibration records retained as part of the service documentation.
+
+```datasheet
+label: pH and Oxidation-Reduction Potential Probe Calibration Interval
+type: range
+unit: days
+options:
+ min: 7
+ max: 365
+ setpoints: [7, 14, 30, 60, 90, 180, 365]
+default: 30
+```
+
+```datasheet
+label: Conductivity Probe Calibration Interval
+type: range
+unit: days
+options:
+ min: 30
+ max: 365
+ setpoints: [30, 60, 90, 180, 365]
+default: 90
+```
+
+### A probe that fails to hold calibration between two consecutive scheduled calibrations shall be replaced rather than recalibrated again.
+
+### An out-of-calibration probe is worse than no probe, because the controller acts on its reading. A drifting conductivity probe holds a system at twice or half its intended cycles while the log shows the set point being met. {note}
+
+## Building Automation System Integration {toc}
+
+### Treatment data shall be reported to the building automation system through the controller's communication port, with the points indicated in the datasheet, configured in coordination with [[sync/building-automation-system]].
+
+```datasheet
+label: Treatment Points Reported to the Building Automation System
+type: checkbox
+options:
+ - "Conductivity"
+ - "Oxidation-reduction potential"
+ - "pH"
+ - "Make-up water flow rate and cumulative volume"
+ - "Bleed flow rate and cumulative volume"
+ - "Calculated cycles of concentration"
+ - "Side-stream filter differential pressure"
+ - "Chemical container low-level alarm for each product"
+ - "Bleed valve command and verified position"
+ - "Controller fault and no-flow alarm"
+default:
+ - "Conductivity"
+ - "Oxidation-reduction potential"
+ - "Make-up water flow rate and cumulative volume"
+ - "Bleed flow rate and cumulative volume"
+ - "Calculated cycles of concentration"
+ - "Chemical container low-level alarm for each product"
+ - "Controller fault and no-flow alarm"
+```
+
+### Cumulative make-up and bleed volumes reported to the building automation system let the Owner verify achieved cycles against target cycles continuously, which is a check the service report cannot provide between visits. {note}
+
+# Side-Stream Filtration {toc}
+
+## Filtration on Open Systems {toc}
+
+### An open tower is an air washer. It scrubs the airstream it draws and deposits everything the air carried into the basin, so the particulate load on an open system is continuous and independent of the piping. {note}
+
+### The side-stream filtration provided for each open recirculating system shall be as indicated in the datasheet.
+
+```datasheet
+label: Side-Stream Filtration for Open Systems
+type: select
+options:
+ - "Sand or multimedia filter"
+ - "Centrifugal separator"
+ - "Bag filter"
+ - "Cartridge filter"
+ - "Disc filter"
+ - "Not provided"
+default: "Sand or multimedia filter"
+```
+
+### Media filters and separators differ in what they remove and in what they cost to keep running. A centrifugal separator removes dense particles above roughly 40 µm with no media to replace and no consumable, and passes the fine organic solids that feed biofilm; a sand or multimedia filter reaches the low tens of microns across a wider particle density range and needs backwash water and a backwash discharge path. {note}
+
+## Filtration on Closed Systems {toc}
+
+### The side-stream filtration provided for each closed system shall be as indicated in the datasheet.
+
+```datasheet
+label: Side-Stream Filtration for Closed Systems
+type: select
+options:
+ - "Bag filter"
+ - "Cartridge filter"
+ - "Centrifugal separator"
+ - "Magnetic separator"
+ - "Magnetic separator with bag filter"
+ - "Not provided"
+```
+
+### No arrangement is the norm on closed loops. A small loop with a properly sized dirt separator needs nothing more, while a large steel loop generates magnetite continuously and benefits from a magnetic element that captures it before it settles in the slowest branches. {note}
+
+### The particulate a closed loop generates is mostly iron oxide from its own surfaces, so a magnetic element captures a large fraction of it with no consumable, while non-magnetic debris still requires a filter element. {note}
+
+## Side-Stream Flow and Connection {toc}
+
+### The side-stream flow rate shall be as indicated in the datasheet, expressed as a percentage of the system's total recirculation flow.
+
+```datasheet
+label: Side-Stream Flow Rate as Percent of System Flow
+type: range
+unit: '%'
+options:
+ min: 1
+ max: 20
+ setpoints: [1, 2, 3, 5, 7, 10, 15, 20]
+default: 5
+```
+
+### The side-stream nominal filtration rating shall be as indicated in the datasheet.
+
+```datasheet
+label: Side-Stream Nominal Filtration Rating
+type: range
+unit: µm
+options:
+ min: 1
+ max: 100
+ setpoints: [1, 5, 10, 25, 40, 50, 100]
+```
+
+### A side-stream filter processes a fraction of the flow continuously and reaches an effective removal over hours rather than in one pass, which is what lets it use a fine rating without imposing the pressure drop and the equipment size that full-flow filtration at the same rating would require. {note}
+
+### On open systems the side-stream shall draw from the tower basin or from the condenser water return main and shall discharge at a point that does not short-circuit back to the draw.
+
+### On closed systems the side-stream shall draw from the return main downstream of the air and dirt separator and shall discharge to the return main downstream of the draw connection.
+
+### Side-stream filter differential pressure shall be monitored, and the element or media shall be serviced on differential pressure rather than on elapsed time alone.
+
+# Sample Ports {toc}
+
+## Port Locations {toc}
+
+### Sample ports shall be provided so that representative water can be drawn from each treated system without interrupting its operation.
+
+### Each closed system shall have, at minimum, one port on the supply main downstream of the air and dirt separator and one port on the return main upstream of the chiller or boiler.
+
+### Each open recirculating system shall have, at minimum, one port on the tower basin, one on the condenser water supply to the chiller, and one on the condenser water return from the chiller.
+
+### Additional ports at risers and at major terminal branches shall be provided where indicated on [[drawing: the contract drawings]].
+
+### A sample drawn from a stagnant leg reads the leg rather than the system, and a program corrected against that reading moves the whole system to fix a local condition. Port placement in flowing water is what makes every subsequent test result mean what it appears to mean. {note}
+
+## Port Construction {toc}
+
+### The sample port configuration shall be as indicated in the datasheet.
+
+```datasheet
+label: Sample Port Configuration
+type: select
+options:
+ - "Full-port ball valve with hose-bib outlet and cap"
+ - "Full-port ball valve with quick-connect coupling"
+ - "Full-port ball valve with hose-bib outlet and sample cooler"
+ - "Dedicated sample panel with isolation and flow control"
+default: "Full-port ball valve with hose-bib outlet and cap"
+```
+
+### Each port shall be a full-port valve, so that the port itself does not collect the particulate the sample is meant to measure.
+
+### Each port shall be located within reach from the floor or from a permanent working surface, in a position accessible without moving equipment or removing insulation.
+
+### Each port shall carry a permanent label identifying the system and the port location.
+
+### Ports on steam and high-temperature systems shall discharge through a sample cooler, and shall not be arranged so that a sample can be drawn as flashing steam.
+
+# Routine Monitoring and Testing {toc}
+
+## Service Visit Intervals {toc}
+
+### The intervals indicated in the datasheets below are the minimum frequency of routine service, and shall be increased during start-up, after any chemistry change, after any system upset, and through the first operating season of a new system.
+
+```datasheet
+label: Service Visit Interval — Open Systems, Cooling Season
+type: range
+unit: days
+options:
+ min: 1
+ max: 90
+ setpoints: [1, 3, 7, 14, 30, 60, 90]
+default: 7
+```
+
+```datasheet
+label: Service Visit Interval — Open Systems, Off-Season
+type: range
+unit: days
+options:
+ min: 7
+ max: 180
+ setpoints: [7, 14, 30, 60, 90, 180]
+default: 30
+```
+
+```datasheet
+label: Service Visit Interval — Closed Systems
+type: range
+unit: days
+options:
+ min: 30
+ max: 365
+ setpoints: [30, 60, 90, 180, 365]
+default: 90
+```
+
+```datasheet
+label: Service Visit Interval — Steam Systems
+type: range
+unit: days
+options:
+ min: 1
+ max: 180
+ setpoints: [1, 7, 14, 30, 60, 90, 180]
+default: 30
+```
+
+### Open systems are tested far more often than closed ones because they change far faster. An open system's chemistry moves with weather, load, and make-up quality between one visit and the next; a closed system that is not leaking is close to the same water it held a quarter ago. {note}
+
+## Field Test Parameters {toc}
+
+### Each closed system shall be tested at every service visit for the parameters indicated in the datasheet.
+
+```datasheet
+label: Closed System Field Test Parameters
+type: checkbox
+options:
+ - "Primary inhibitor concentration"
+ - "Azole residual"
+ - "pH"
+ - "Conductivity"
+ - "Total iron"
+ - "Total copper"
+ - "Microbial activity"
+ - "Suspended solids or visual clarity"
+default:
+ - "Primary inhibitor concentration"
+ - "Azole residual"
+ - "pH"
+ - "Conductivity"
+ - "Total iron"
+```
+
+### Each open recirculating system shall be tested at every service visit for the parameters indicated in the datasheet.
+
+```datasheet
+label: Open System Field Test Parameters
+type: checkbox
+options:
+ - "Conductivity of recirculating water and of make-up water"
+ - "Calculated cycles of concentration"
+ - "Free halogen residual"
+ - "Oxidation-reduction potential"
+ - "pH"
+ - "Total and calcium hardness"
+ - "Total alkalinity"
+ - "Scale inhibitor residual"
+ - "Steel corrosion inhibitor residual"
+ - "Azole residual"
+ - "Total iron"
+ - "Microbial activity"
+default:
+ - "Conductivity of recirculating water and of make-up water"
+ - "Calculated cycles of concentration"
+ - "Free halogen residual"
+ - "Oxidation-reduction potential"
+ - "pH"
+ - "Total and calcium hardness"
+ - "Total alkalinity"
+ - "Scale inhibitor residual"
+ - "Steel corrosion inhibitor residual"
+ - "Azole residual"
+ - "Microbial activity"
+```
+
+### Each steam system shall be tested at every service visit for the parameters indicated in the datasheet.
+
+```datasheet
+label: Steam System Field Test Parameters
+type: checkbox
+options:
+ - "Boiler water conductivity"
+ - "Boiler water pH"
+ - "Boiler water alkalinity"
+ - "Sulfite or scavenger residual"
+ - "Boiler water phosphate or polymer residual"
+ - "Feedwater hardness"
+ - "Condensate pH"
+ - "Condensate conductivity"
+ - "Condensate total iron"
+default:
+ - "Boiler water conductivity"
+ - "Boiler water pH"
+ - "Boiler water alkalinity"
+ - "Sulfite or scavenger residual"
+ - "Feedwater hardness"
+ - "Condensate pH"
+ - "Condensate total iron"
+```
+
+### Test reagents shall meet the reagent grade required by the test method, shall be within their stated expiration date, and shall be stored as the reagent supplier requires.
+
+### Expired reagents shall not be used.
+
+### An expired reagent does not fail visibly. It returns a plausible number that is wrong in a consistent direction, and the chemistry adjustment made against it moves the system away from its control range rather than toward it. {note}
+
+## Corrosion Coupon Reading {toc}
+
+### Corrosion coupon racks are installed at passivation under [[sync/hydronic-cleaning-and-flushing]]; this standard governs the reading of those coupons through the life of the program. {note}
+
+### Coupons shall be removed, cleaned, weighed, and analyzed per ASTM D2688 at the intervals indicated in the datasheets, and shall be replaced with fresh coupons at each removal.
+
+```datasheet
+label: Corrosion Coupon Read Interval — Open Systems
+type: range
+unit: days
+options:
+ min: 30
+ max: 365
+ setpoints: [30, 60, 90, 180, 365]
+default: 90
+```
+
+```datasheet
+label: Corrosion Coupon Read Interval — Closed Systems
+type: range
+unit: days
+options:
+ min: 90
+ max: 730
+ setpoints: [90, 180, 365, 730]
+default: 365
+```
+
+### Each coupon analysis shall report weight-loss corrosion rate, pitting depth or a pitting index, deposit character, and surface appearance, rather than corrosion rate alone.
+
+### The acceptance criteria for coupon corrosion rate shall be as indicated in the datasheets.
+
+```datasheet
+label: Maximum Corrosion Rate — Carbon Steel, Closed Systems
+type: range
+unit: mpy
+options:
+ min: 0.1
+ max: 5
+ setpoints: [0.1, 0.2, 0.5, 1, 2, 3, 5]
+default: 1
+```
+
+```datasheet
+label: Maximum Corrosion Rate — Carbon Steel, Open Systems
+type: range
+unit: mpy
+options:
+ min: 0.5
+ max: 10
+ setpoints: [0.5, 1, 2, 3, 5, 10]
+default: 3
+```
+
+```datasheet
+label: Maximum Corrosion Rate — Copper
+type: range
+unit: mpy
+options:
+ min: 0.05
+ max: 1
+ setpoints: [0.05, 0.1, 0.2, 0.5, 1]
+default: 0.2
+```
+
+### Where a coupon result exceeds its acceptance criterion, the service provider shall report the exceedance with a proposed corrective action within the reporting interval for that visit, and shall reduce the coupon interval until two consecutive results fall within criteria.
+
+### A general corrosion rate within criteria alongside visible pitting is the result that matters most and the one a rate-only report hides. Uniform loss consumes wall slowly and predictably; a pit consumes it in one place and produces the leak. {note}
+
+## Microbiological Monitoring {toc}
+
+### Each open recirculating system shall be monitored for microbial activity at every service visit by the methods indicated in the datasheet.
+
+```datasheet
+label: Microbiological Monitoring Methods
+type: checkbox
+options:
+ - "Dip slide for total aerobic bacteria"
+ - "Adenosine triphosphate test per ASTM D4012"
+ - "Sulfate-reducing bacteria test"
+ - "Nitrifying bacteria test"
+ - "Fungal and yeast dip slide"
+ - "Laboratory heterotrophic plate count"
+default:
+ - "Dip slide for total aerobic bacteria"
+ - "Adenosine triphosphate test per ASTM D4012"
+```
+
+### Each closed system on nitrite chemistry shall be monitored for nitrifying bacteria at every service visit.
+
+### Action levels for each microbiological method shall be recorded in the water management program document and shall be the basis for corrective action.
+
+### A dip slide incubates for a day or two before it reads, and it counts only organisms that grow on its medium. An adenosine triphosphate test reads in minutes and measures total living biomass including organisms that never culture, so the two answer different questions and are commonly run together rather than one instead of the other. {note}
+
+### Planktonic counts describe the water, not the surfaces. A system with a clean count and an established biofilm is the common presentation, which is why deposit character on the coupons and visual inspection of the basin and fill carry weight alongside the count. {note}
+
+# Legionella Risk Management {toc}
+
+## Applicability of the Water Management Program {toc}
+
+### Where the project includes an open cooling tower, an evaporative condenser, a decorative fountain, or any other open recirculating water system, ANSI/ASHRAE 188 obligates the Owner to establish and maintain a water management program for the building.
+
+### The treatment program in this standard supplies the control measures, control limits, monitoring, and corrective actions for the open recirculating systems within that program. {note}
+
+### Other building water systems within the ANSI/ASHRAE 188 boundary, including domestic hot water and humidification, are covered by their own program sections developed under their own scopes. {note}
+
+### ANSI/ASHRAE 188 sets out a management process rather than a numerical limit. It does not tell an Owner what count is acceptable; it obligates the Owner to identify the hazard, state a control measure, set a control limit, monitor against it, act when it is exceeded, and document all of it. {note}
+
+## Program Content for Treated Systems {toc}
+
+### The treatment-related sections of the water management program document shall include, at minimum, the following:
+
+- A description of each open recirculating system, with recirculation rate, drift loss rating, make-up source, normal cycles of concentration, normal operating temperature range, and the occupancy of the areas surrounding the tower and its air intake path
+- The control measures for each system, being the chemistry program, the automatic control configuration, the side-stream filtration, the drift eliminators, and the shutdown, restart, and lay-up procedures
+- The control limit for each measured parameter, stated as the bound within which the control measure remains effective
+- The monitoring procedures, being the tests performed, their frequency, who performs them, and the records kept
+- The corrective action for each control limit, stating the steps, who performs each, the timing, the notification path, and the re-monitoring that confirms resolution
+- The verification procedures that confirm the program is working, being coupon analysis, microbial trending, and scheduled physical inspection
+- The documentation procedures, being what records are kept, where, for how long, and who has access
+- The roles and responsibilities of each member of the water management team by name or position
+
+```datasheet
+label: Water Management Program Document Format
+type: select
+options:
+ - "Printed binder maintained on site"
+ - "Digital records system with controlled access"
+ - "Printed binder with a digital records system"
+default: "Printed binder with a digital records system"
+```
+
+### The events that trigger a review and update of the water management program shall be as indicated in the datasheet.
+
+```datasheet
+label: Water Management Program Review Triggers
+type: checkbox
+options:
+ - "Scheduled annual review"
+ - "Change to the chemistry program"
+ - "Change of water treatment service provider"
+ - "Addition or removal of water system equipment"
+ - "Change in building occupancy or operating hours affecting water use"
+ - "Any corrective-action event"
+ - "Change in applicable regulation or public health authority requirement"
+default:
+ - "Scheduled annual review"
+ - "Change to the chemistry program"
+ - "Change of water treatment service provider"
+ - "Addition or removal of water system equipment"
+ - "Change in building occupancy or operating hours affecting water use"
+ - "Any corrective-action event"
+ - "Change in applicable regulation or public health authority requirement"
+```
+
+## Legionella Sampling {toc}
+
+### The Legionella sampling method for each open recirculating system shall be as indicated in the datasheet.
+
+```datasheet
+label: Legionella Sampling Method
+type: select
+options:
+ - "Culture per ISO 11731"
+ - "Quantitative polymerase chain reaction"
+ - "Culture per ISO 11731 with confirmatory polymerase chain reaction"
+ - "Not sampled routinely"
+default: "Culture per ISO 11731"
+```
+
+### The Legionella sampling interval shall be as indicated in the datasheet, and shall be shortened where the local public health authority requires a shorter interval.
+
+```datasheet
+label: Legionella Sampling Interval
+type: range
+unit: days
+options:
+ min: 7
+ max: 365
+ setpoints: [7, 14, 30, 60, 90, 180, 365]
+default: 90
+```
+
+### Culture takes days to return and counts only what grows, which understates the population but produces the viable count that action levels are written against. Molecular methods return in hours and detect genetic material from organisms that are dead or unculturable, so they trend faster and read higher. A program that changes methods mid-stream loses its baseline. {note}
+
+### The Legionella corrective-action threshold shall be as indicated in the datasheet, established with the local public health authority and recorded in the water management program document.
+
+```datasheet
+label: Legionella Corrective-Action Threshold
+type: range
+unit: CFU/mL
+options:
+ min: 0.1
+ max: 1000
+ setpoints: [0.1, 1, 10, 100, 1000]
+```
+
+### No threshold is the norm, because jurisdictions and facility types set different action levels for the same organism and a healthcare facility's threshold is not a commercial office building's. The threshold is a decision the Owner makes with the public health authority, which is why the template asks for it rather than asserting one. {note}
+
+## Corrective Action for a Positive Result {toc}
+
+### A result above the corrective-action threshold shall trigger the corrective-action procedure recorded in the water management program document, and the procedure shall be executed within the time the document states.
+
+### The corrective-action procedure shall be developed by the design team and the service provider before the system is commissioned, and shall be included in the closeout water management program document.
+
+### The corrective-action procedure shall identify who notifies building management, and shall state the conditions under which the local public health authority is notified.
+
+### The corrective-action procedure shall require re-sampling after remediation and shall state the result that closes the event.
+
+### The one thing a corrective-action procedure cannot be written during is the event itself. Deciding who calls the health department, and at what count, while a positive result sits on the desk is how a manageable exposure becomes an unmanaged one. {note}
+
+# Service Contract {toc}
+
+## Routine Service Scope {toc}
+
+### The service contract shall provide routine on-site service at the intervals established in this standard for each system in scope.
+
+### Each routine service visit shall include a visual inspection of system condition, a calibration check of every controller probe, collection and field testing of water samples, a calibration check and dose adjustment of every chemical feed pump, inspection of installed corrosion coupons, microbiological testing where the program requires it, and review of the controller data log for trends.
+
+### Each routine service visit shall produce the deliverables indicated in the datasheet.
+
+```datasheet
+label: Routine Service Visit Deliverables
+type: checkbox
+options:
+ - "Written service report with every field test result against its control range"
+ - "Photographs of system condition"
+ - "Probe calibration record"
+ - "Feed pump calibration record"
+ - "Chemistry trend chart against control ranges"
+ - "Written recommendations for chemistry or system action"
+ - "Chemical inventory and consumption record"
+ - "Upload to the Owner's records system"
+default:
+ - "Written service report with every field test result against its control range"
+ - "Probe calibration record"
+ - "Feed pump calibration record"
+ - "Chemistry trend chart against control ranges"
+ - "Written recommendations for chemistry or system action"
+ - "Upload to the Owner's records system"
+```
+
+### The service report for each visit shall be delivered within the interval indicated in the datasheet, measured from the end of the visit.
+
+```datasheet
+label: Service Report Delivery Interval
+type: range
+unit: days
+options:
+ min: 0
+ max: 30
+ setpoints: [0, 1, 2, 3, 5, 7, 14, 30]
+default: 3
+```
+
+### A service report that arrives a month after the visit documents history rather than enabling action, and it arrives after the next visit has already been performed against conditions nobody reviewed. {note}
+
+## Emergency Response {toc}
+
+### The service contract shall define an emergency response commitment covering chemistry excursion beyond control limits, a suspected biological event, a chemical spill, and feed or control equipment failure while the system is in operating service.
+
+### The emergency telephone response time shall be as indicated in the datasheet, measured from the Owner's notification.
+
+```datasheet
+label: Emergency Telephone Response Time
+type: range
+unit: hours
+options:
+ min: 0.25
+ max: 24
+ setpoints: [0.25, 0.5, 1, 2, 4, 8, 24]
+default: 1
+```
+
+### The emergency on-site response time shall be as indicated in the datasheet, measured from the Owner's notification.
+
+```datasheet
+label: Emergency On-Site Response Time
+type: range
+unit: hours
+options:
+ min: 1
+ max: 72
+ setpoints: [1, 2, 4, 8, 12, 24, 48, 72]
+default: 4
+```
+
+### Response time is priced. A commitment that a healthcare campus needs is not one a single-tower office building will pay for, which is why the two intervals are stated as project values rather than assumed. {note}
+
+## Annual Comprehensive Review {toc}
+
+### The service contract shall include an annual comprehensive review for each treated system, in addition to routine service visits.
+
+### The annual comprehensive review shall include a complete independent laboratory analysis of each system, a coupon analysis, a review of the year's trend data, a re-evaluation of the chemistry program against that data, a written annual report with recommendations, and a review meeting with the Owner's facility staff.
+
+### The annual review is the one scheduled occasion on which the program is measured against a year of evidence rather than against the last reading. It is also where a program that has quietly stopped fitting the building — after an occupancy change, an equipment addition, or a shift in make-up water quality — is identified. {note}
+
+## Contract Term and Transfer {toc}
+
+### The service contract term included in the base bid shall be as indicated in the datasheet, beginning at substantial completion of the last treated system.
+
+```datasheet
+label: Service Contract Term Included in the Base Bid
+type: range
+unit: months
+options:
+ min: 0
+ max: 60
+ setpoints: [0, 3, 6, 12, 24, 36, 60]
+default: 12
+```
+
+### At the end of the base-bid term, the service provider shall deliver the complete program record — chemistry history, trend data, coupon results, microbiological results, and calibration records — to the Owner in a form a successor provider can use without re-establishing a baseline.
+
+### A base-bid term that covers a full annual cycle carries the program through one complete cooling season and one complete heating season, which is the shortest interval over which the trend data shows how the systems actually behave. {note}
+
+# Identification and Labeling {toc}
+
+## Chemical Container and Feed Identification {toc}
+
+### Every chemical container, day tank, and bulk tank shall be labeled with the chemical name, the hazard information required by OSHA 29 CFR 1910.1200, the maximum capacity, and an identification number matching the feed pump that draws from it.
+
+### Every chemical feed line shall be labeled with the chemical name, the direction of flow, and the hazard warnings appropriate to its contents, in accordance with ASME A13.1 and OSHA 29 CFR 1910.1200.
+
+### The feed line labeling method shall be as indicated in the datasheet.
+
+```datasheet
+label: Chemical Feed Line Labeling Method
+type: select
+options:
+ - "Adhesive markers at each end and at intervals along the run"
+ - "Wraparound printed sleeves at each end and at each fitting"
+ - "Adhesive markers along the run with printed sleeves at fittings"
+ - "Engraved permanent tags at each end and at each fitting"
+default: "Adhesive markers along the run with printed sleeves at fittings"
+```
+
+### The maximum spacing of feed line markers along a run shall be as indicated in the datasheet.
+
+```datasheet
+label: Maximum Feed Line Marker Spacing
+type: range
+unit: ft
+options:
+ min: 5
+ max: 50
+ setpoints: [5, 10, 15, 20, 25, 30, 50]
+default: 25
+```
+
+### Labels shall be replaced when faded, damaged, or made illegible by chemical contact.
+
+## Sample Port and Equipment Identification {toc}
+
+### Every sample port shall be labeled with the system it serves and its location within that system.
+
+### Every treatment controller, feed pump, side-stream filter, and coupon rack shall be labeled with an identification consistent with the equipment identification convention in [[sync/mechanical-identification]].
+
+### The identification exists so that a service technician new to the site can tell which pump feeds which product into which system without tracing tubing, and so that an emergency responder can identify a container without finding the Safety Data Sheet binder first. {note}
+
+# Seasonal Lay-Up and Restart {toc}
+
+## Lay-Up Method {toc}
+
+### A system taken out of service for a season shall be laid up so that its metal surfaces remain protected through the out-of-service period.
+
+### The lay-up method for each cooling tower and open recirculating system shall be as indicated in the datasheet.
+
+```datasheet
+label: Lay-Up Method — Open Recirculating Systems
+type: select
+options:
+ - "Dry lay-up with basin and piping drained, dried, and sealed"
+ - "Partial dry lay-up with basin and fill drained and interior piping kept wet"
+ - "Wet lay-up with basin heater energized and circulation maintained"
+ - "No lay-up, system remains in continuous service"
+```
+
+### The lay-up method for each closed system taken out of service shall be as indicated in the datasheet.
+
+```datasheet
+label: Lay-Up Method — Closed Systems
+type: select
+options:
+ - "Wet lay-up at elevated inhibitor concentration"
+ - "Wet lay-up at elevated inhibitor concentration with periodic circulation"
+ - "Wet lay-up with an inert gas blanket on the expansion tank"
+ - "Drained lay-up"
+ - "No lay-up, system remains in continuous service"
+```
+
+### Wet lay-up keeps the passive film wet and intact and keeps oxygen out by filling the volume, and it exposes the system to freeze damage wherever any part of it sits below freezing. Dry lay-up removes the freeze exposure and leaves bare metal in contact with humid air, which flash-rusts unless the system is genuinely dried and sealed rather than merely drained. {note}
+
+### A partially drained system is the worst of both. It holds water where the drain did not reach, at the air-water interface where corrosion runs fastest, with no inhibitor circulating to protect it. {note}
+
+### The elevated inhibitor concentration held during wet lay-up shall be as indicated in the datasheet, expressed as a multiple of the system's normal operating concentration.
+
+```datasheet
+label: Wet Lay-Up Inhibitor Concentration Multiplier
+type: range
+unit: '× operating concentration'
+options:
+ min: 1
+ max: 3
+ setpoints: [1, 1.25, 1.5, 2, 2.5, 3]
+default: 1.5
+```
+
+### Chemistry shall be tested during lay-up at the interval indicated in the datasheet, and shall be corrected where it falls outside the lay-up control range.
+
+```datasheet
+label: Lay-Up Chemistry Test Interval
+type: range
+unit: days
+options:
+ min: 7
+ max: 180
+ setpoints: [7, 14, 30, 60, 90, 180]
+default: 30
+```
+
+## Restart from Lay-Up {toc}
+
+### The restart procedure shall be documented in the water management program document or in the service contract, and shall be executed by qualified personnel.
+
+### A system restarted from wet lay-up shall have its chemistry verified within its operating control range before the system is returned to occupied service.
+
+### A system restarted from dry lay-up shall be flushed, refilled, and re-dosed, and shall be re-passivated where carbon steel surfaces were dry for longer than the period the program's restart procedure states.
+
+### An open recirculating system restarted from any lay-up shall receive a start-up disinfection before it is returned to service, by the same method the datasheet specifies for initial start-up.
+
+### Restarting an open tower is the highest-risk moment in its annual cycle. A basin that has stood warm and stagnant grows what a full-year of controlled operation was designed to prevent, and the first minutes of fan operation aerosolize it. {note}
+
+# Decommissioning and Chemical Disposal {toc}
+
+## Fluid Disposal {toc}
+
+### Treated water at the end of a system's life carries corrosion inhibitor, biocide residue, and dissolved iron and copper, at concentrations that on a concentrated open system commonly exceed sewer discharge limits. {note}
+
+### Before a treated system is drained for decommissioning, the service provider shall characterize the fluid for the parameters of concern to the receiving authority.
+
+### The drained fluid shall be disposed of in accordance with applicable environmental regulations, by the route indicated in the datasheet.
+
+```datasheet
+label: Decommissioning Fluid Disposal Route
+type: select
+options:
+ - "Sanitary sewer with prior authority coordination"
+ - "Sanitary sewer after neutralization and dilution"
+ - "Off-site disposal as regulated industrial waste"
+ - "Recovery and reprocessing by the fluid supplier"
+```
+
+### The Contractor shall obtain any discharge authorization the receiving authority requires before draining begins.
+
+### Discharge of treated system water to a storm sewer shall not be permitted.
+
+## Chemical Removal {toc}
+
+### Remaining chemical inventory shall be removed from the site by the service provider at the close of the program, in original labeled containers, transported in accordance with DOT 49 CFR.
+
+### Empty chemical containers shall be triple-rinsed or disposed of as the product label directs, and shall not be reused for another product.
+
+# Warranty and Program Performance {toc}
+
+## Treatment Equipment Warranty {toc}
+
+### Treatment equipment furnished under this standard shall be warranted against defects in material and workmanship for the period indicated in the datasheet, from the date of substantial completion.
+
+```datasheet
+label: Treatment Equipment Warranty Period
+type: range
+unit: months
+options:
+ min: 12
+ max: 60
+ setpoints: [12, 18, 24, 36, 60]
+default: 12
+```
+
+### The warranty shall cover the labor to remove and replace a failed component in addition to the component itself.
+
+### Probes, reagents, filter media and elements, and pump tubing are consumables and are excluded from the equipment warranty, and are covered instead by the service contract. {note}
+
+## Program Performance {toc}
+
+### The service provider shall correct, at its own cost, any chemistry excursion beyond a control limit that results from its own dosing, calibration, or program design, including the cost of the corrective chemistry and of the additional visits required to return the system to its control range.
+
+### Where a coupon corrosion rate exceeds its acceptance criterion for two consecutive readings on a system operated within the program's control limits, the service provider shall revise the treatment design at its own cost.
+
+### Where the parties disagree whether a corrosion result or a chemistry excursion arose from the treatment program or from a condition outside the provider's control, the Engineer of Record shall make the initial determination.
+
+### Splitting responsibility this way is what keeps the coupon result meaningful. A provider that owns the corrosion outcome only when the system was operated as the program required has an incentive to state the operating requirement clearly and to report an excursion when it happens. {note}
+
+## Spare Parts and Consumables {toc}
+
+### The spare parts and consumables indicated in the datasheet shall be turned over to the Owner at substantial completion.
+
+```datasheet
+label: Spare Parts and Consumables Turned Over
+type: checkbox
+options:
+ - "One spare probe of each type installed"
+ - "Calibration solutions for each probe type"
+ - "One complete field test reagent kit for each system type"
+ - "One spare pump head, diaphragm, or tube set for each metering pump"
+ - "One set of spare filter elements, bags, or media charge"
+ - "One spare set of corrosion coupons for each rack"
+ - "Spare feed line tubing and injection fittings"
+default:
+ - "Calibration solutions for each probe type"
+ - "One complete field test reagent kit for each system type"
+ - "One spare pump head, diaphragm, or tube set for each metering pump"
+ - "One set of spare filter elements, bags, or media charge"
+ - "One spare set of corrosion coupons for each rack"
+```
+
+### Spare probes and reagents are what let a service visit correct a problem on the day it is found rather than on the day a part arrives. {note}