Hydronic System Cleaning and Flushing
Remake batch 22: rewritten from scratch under the authoring cheatsheet with datasheet constraints; scope boundaries restated against the remade neighbors
Showing changes from Rev 3
to Rev 4
in Hydronic System Cleaning and Flushing.
---
title: Hydronic System Cleaning and Flushing
category: Mechanical / Controls & Testing
−toc_depth: 3
description: >
− When to use: The construction-phase procedure the installing mechanical
− contractor follows to clean, flush, and passivate closed hydronic
− distribution systems (heating hot water, chilled water, dual-temperature,
− condenser water, and glycol-protected loops) before TAB begins and before
− the ongoing water treatment program is placed online. Covers system filling
− and fill-pressure verification, temporary flush bypasses around sensitive
− equipment, external flush-pump connection, alkaline or TSP cleaning
− circulation, high-velocity mechanical flushing, flush-water disposal
− coordination, acceptance testing (turbidity, iron, TSS, pH, conductivity),
− corrosion-inhibitor start charge and passivation circulation, corrosion
− coupon installation, and the signed cleaning, flushing, and passivation
− report that hands off to the water treatment provider and TAB contractor.
− Applies to new construction and to renovation or retro-commissioning where
− existing systems are re-entered or extended, at any size and in any pipe
− material.
− Not intended for: the ongoing chemical water treatment program, inhibitor
− dosing, side-stream filtration, and ASHRAE 188 water management planning
− (use [[sync/hvac-water-treatment]]); hydronic pipe material selection,
− joining, supports, and structural pressure testing per ASME B31.9 (use
− [[sync/hydronic-piping]]); third-party air and water balancing (use
− [[sync/testing-adjusting-and-balancing]]); functional performance testing
− and controls checkout (use [[sync/commissioning]]); domestic water
− disinfection (use [[sync/domestic-water-piping]]); fire sprinkler flushing
− and hydrostatic testing (use [[sync/common-work-results-fire-suppression]]);
− steam boiler waterside cleaning and layup (governed by ASME BPVC Section I);
− and pump selection and trim (use [[sync/hvac-pumps]]).
+ When to use: The one-time preparation of a hydronic system's wetted interior between the piping pressure test and the start of the ongoing water treatment program, performed by the installing contractor on new systems and on extensions of existing systems in commercial, institutional, and industrial buildings. Covers the fill and the fill water baseline, the chemical cleaning step where one is selected, high-velocity flushing with its velocity calculation, flush pump, passes, and sampling, the protection and bypassing of coils, control valves, heat exchangers, and plant equipment during the flush, flush acceptance by measurement (clarity, turbidity, pH, conductivity, iron, suspended solids), disposal of the flush water and spent cleaner, passivation of the cleaned metal with the inhibitor chemistry of the ongoing program, installation of the corrosion coupon rack, the initial glycol charge where the system carries glycol, the signed cleaning, flushing, and passivation report that releases the system to balancing, startup, and treatment, and the flushing of the field piping of open condenser water systems. Applies to heating hot water, chilled water, dual-temperature, water-source and ground-source heat pump, closed-circuit condenser, inhibited-glycol, snow melt, and runaround loops in any pipe material and at any size.
+
+ Not intended for: The ongoing chemical treatment program, its inhibitor control ranges and monitoring, the ASTM D2688 weight-loss readings through the life of the program, the start-up disinfection and the pH-controlled conditioning of new galvanized surfaces in open recirculating systems, and the disposal of fluid drained from a system in service (see [[sync/hvac-water-treatment]]); the pipe, joints, and the piping pressure test, the selection of glycol type and concentration, the fill, drain, and temporary connection points, cleanliness of the pipe interior during installation, and the re-flush after a leak repair (see [[sync/hydronic-piping]]); strainers, temporary startup screens, chemical bypass feeders, fill assemblies, and makeup packages as devices, and the cleaning of permanent strainer screens after flushing (see [[sync/hydronic-specialties]]); testing, adjusting, and balancing (see [[sync/testing-adjusting-and-balancing]]); functional performance testing (see [[sync/commissioning]]); flushing and disinfection of potable water piping (see [[sync/domestic-water-piping]]); flushing of fire protection piping (see [[sync/common-work-results-fire-suppression]]); the suitability of the circulating pumps for flushing duty and the compatibility of their seals with cleaning chemistry (see [[sync/hvac-pumps]]); cleaning of the cooling tower basin and fill (see [[sync/cooling-towers]]); waterbox and tube cleaning of chillers and heat exchangers (see [[sync/chillers]] and [[sync/heat-exchangers]]); the boiler's own fill, venting, and pre-startup verification (see [[sync/boilers]]); and the boil-out of steam boilers, which follows the boiler manufacturer's procedure under ASME BPVC Section VII.
---
# Scope {toc}
−## This standard governs the construction-phase cleaning, high-velocity flushing, and chemical passivation of closed hydronic distribution systems, performed by the installing mechanical contractor after the piping passes its hydrostatic pressure test and before the system is balanced or placed in chemical service. {note}
+## This standard governs the one-time preparation of a hydronic system's wetted interior between the piping pressure test and the start of the ongoing water treatment program: the fill, the removal of construction debris and residue by chemical cleaning and high-velocity flushing, the acceptance of the flush by measurement, the passivation of the cleaned metal, the installation of the corrosion coupon rack, the initial glycol charge where the system carries glycol, and the disposal of the water the work produces. {note}
−## Closed hydronic systems within scope include heating hot water (HHW), chilled water (CHW), dual-temperature, condenser water, and inhibited-glycol loops, in carbon steel, copper, or grooved-mechanical piping, at any system size. {note}
+## The systems in scope are closed hydronic loops of every service, including heating hot water, chilled water, dual-temperature, water-source and ground-source heat pump loops, closed-circuit condenser and fluid cooler loops, inhibited-glycol loops, snow melt loops, and runaround heat-recovery loops, together with the field piping of open condenser water systems between the tower and the plant. {note}
−## The work of this standard ends at acceptance of passivation and delivery of the signed cleaning, flushing, and passivation report; the ongoing chemical treatment program described in [[sync/hvac-water-treatment]] takes over from that point. {note}
+## The standard applies to new systems, to new piping that extends an existing system, and to any pipe material and system size. {note}
−## This standard owns the construction-phase execution sequence the piping contractor works to. The pre-operational cleaning rationale and the long-term chemistry are owned by [[sync/hvac-water-treatment]]; the two are complementary and shall be read together.
+## A new hydronic system contains mill scale, weld spatter, cutting oil, thread-cutting lubricant, jointing compound, flux, sand, and whatever fell into an open pipe end during construction. Left in the water, that material lodges in the first coil, control valve seat, strainer, or heat exchanger passage it reaches, and the loss of flow it causes is discovered as a comfort complaint months later rather than as a construction defect. Cleaning and flushing exist to remove the material while it is still cheap to remove, and passivation exists because freshly cleaned steel begins to rust again within hours in untreated water. {note}
−## The Contractor shall not begin cleaning operations until the hydronic piping has passed and the Engineer of Record has witnessed the hydrostatic pressure test required by [[sync/hydronic-piping]] and ASME B31.9.
+## The work of this standard ends with the delivery of the signed cleaning, flushing, and passivation report for each system. The ongoing program under [[sync/hvac-water-treatment]] begins at that hand-off. {note}
−## Cleaning, flushing, and passivation shall be complete and accepted before the testing, adjusting, and balancing (TAB) contractor begins balancing under [[sync/testing-adjusting-and-balancing]].
+## The following are outside this scope and are governed by the companion standards named. {note}
+- The ongoing chemical treatment program, its inhibitor control ranges and monitoring, the ASTM D2688 weight-loss readings through the life of the program, the start-up disinfection and the pH-controlled conditioning of new galvanized surfaces in open recirculating systems, and the disposal of fluid drained from a system in service: [[sync/hvac-water-treatment]].
+- The pipe, joints, and the piping pressure test, the selection of glycol type and concentration, the fill, drain, and temporary connection points, cleanliness of the pipe interior during installation, and the re-flush after a leak repair: [[sync/hydronic-piping]].
+- Strainers, temporary startup screens, chemical bypass feeders, fill assemblies, and makeup packages as devices, and the cleaning of permanent strainer screens after flushing: [[sync/hydronic-specialties]].
+- Testing, adjusting, and balancing: [[sync/testing-adjusting-and-balancing]].
+- Functional performance testing and systems checkout: [[sync/commissioning]].
+- Flushing and disinfection of potable water piping: [[sync/domestic-water-piping]].
+- Flushing of fire protection piping: [[sync/common-work-results-fire-suppression]].
+- The suitability of the circulating pumps for flushing duty and the compatibility of their seals with cleaning chemistry: [[sync/hvac-pumps]].
+- Cleaning of the cooling tower basin and fill: [[sync/cooling-towers]].
+- Waterbox and tube cleaning of chillers and heat exchangers: [[sync/chillers]] and [[sync/heat-exchangers]].
+- The boiler's own fill, venting, and pre-startup verification: [[sync/boilers]].
+- The boil-out of steam boilers, which follows the boiler manufacturer's procedure under ASME BPVC Section VII.
−## Cleaning, flushing, and passivation acceptance shall be a documented prerequisite to functional performance testing under [[sync/commissioning]].
+## Cleaning and flushing of a system shall begin only after the piping within the boundary has passed the pressure test required under [[sync/hydronic-piping]] and the test report has been signed.
+## Cleaning, flushing, and passivation of a system shall be accepted and the signed report delivered before the balancing agency begins work on that system under [[sync/testing-adjusting-and-balancing]].
+
+## Cleaning, flushing, and passivation of a system shall be accepted and the signed report delivered before functional performance testing of that system begins under [[sync/commissioning]].
+
+## The ongoing treatment program shall be placed online on a system only after the signed report for that system has been delivered to the water treatment service provider under [[sync/hvac-water-treatment]].
+
+## Where temporary use of permanent equipment during construction is permitted under [[sync/common-work-results-mechanical]], the hydronic system serving that equipment shall be cleaned, flushed, and passivated under this standard before temporary use begins.
+
+## The sequence runs in one direction. The pressure test proves the pipe before the water is prepared, the flush removes the debris before the balancing agency sets flows that a fouled screen would later change, and the passivation charge is in the water before any plant equipment runs on it. Each later stage assumes the earlier one has already happened, which is why each is a stated prerequisite rather than a coordination item. {note}
+
# Referenced Standards {toc}
−## Equipment, materials, and execution shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
+## Chemistry, equipment, and execution shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
−## BSRIA BG 29 is cited as an industry reference guide for velocity selection, method-statement content, and acceptance criteria; it is not a mandatory compliance document on US projects. {note}
−
| Standard | Title |
|----------|-------|
| ASME B31.9 | Building Services Piping |
−| ANSI/ASHRAE Standard 188 | Legionellosis: Risk Management for Building Water Systems |
−| ASHRAE Guideline 12 | Managing the Risk of Legionellosis Associated with Building Water Systems |
−| ASHRAE Guideline 0 | The Commissioning Process |
−| ASHRAE Handbook | HVAC Systems and Equipment (Hydronic Heating and Cooling) |
+| ASHRAE Handbook, HVAC Systems and Equipment | Hydronic Heating and Cooling System Design |
+| ASHRAE Handbook, HVAC Applications | Water Treatment: Deposition, Corrosion, and Biological Control |
+| ASTM D1193 | Reagent Water |
+| ASTM D1293 | pH of Water |
+| ASTM D1125 | Electrical Conductivity and Resistivity of Water |
+| ASTM D1068 | Iron in Water |
+| ASTM D7315 | Determination of Turbidity Above 1 Turbidity Unit (TU) in Static Mode |
+| ASTM D5907 | Filterable Matter (Total Dissolved Solids) and Nonfilterable Matter (Total Suspended Solids) in Water |
| ASTM D3370 | Sampling Water from Closed Conduits |
| ASTM D2688 | Corrosivity of Water in the Absence of Heat Transfer (Weight Loss Methods) |
−| ASTM D1193 | Reagent Water |
−| ASTM D4012 | Adenosine Triphosphate (ATP) Content of Microorganisms in Water |
−| NFPA 13 | Installation of Sprinkler Systems |
−| NSF/ANSI 60 | Drinking Water Treatment Chemicals - Health Effects |
+| ASTM D3321 | Use of the Refractometer for Field Test Determination of the Glycol-Base Concentration of Engine Coolant |
+| ASTM D1177 | Freezing Point of Aqueous Engine Coolants |
+| NSF/ANSI 60 | Drinking Water Treatment Chemicals: Health Effects |
| OSHA 29 CFR 1910.1200 | Hazard Communication Standard |
−| EPA FIFRA | Federal Insecticide, Fungicide, and Rodenticide Act |
−| IMC Chapter 12 | International Mechanical Code - Hydronic Piping |
+| EPA 40 CFR Part 403 | General Pretreatment Regulations for Existing and New Sources of Pollution |
+| DOT 49 CFR | Hazardous Materials Regulations |
| BSRIA BG 29 | Pre-Commission Cleaning of Pipework Systems |
+## BSRIA BG 29 is a United Kingdom industry guide cited for its treatment of flush velocity selection, method statement content, and sample-based acceptance. It is a reference for method, not an adopted code, and the values in this standard's datasheets govern where the two differ. {note}
+
# Submittals {toc}
−## Action Submittals {note}
+## Action Submittals {toc}
−### Action submittals establish the planned method before any chemical is brought to site, so the Owner and Engineer can confirm velocity feasibility, chemical compatibility, bypass arrangement, and discharge route in advance of the work. {note}
+### The Contractor shall submit the following for the Engineer of Record's review and return before any cleaning chemical, passivation inhibitor, or glycol is brought to the site:
−### Specifying the cleaning scope only as a line item inside the piping section, with no method statement or acceptance criteria, lets subcontractors price the work without planning it. This standard requires a dedicated, reviewed method statement. {note}
+- A cleaning and flushing method statement for each system, describing the boundary, the fill, the cleaning chemistry and its circulation, the flush sequence section by section, the sample points, the acceptance values, the passivation, the glycol charge where one is made, the hold points, and the reinstatement of the permanent piping
+- A flush velocity and flow calculation listing every pipe section in the system with its size, its flow at the flush velocity, and the pump that will deliver that flow, identifying the sections that the main flush cannot reach
+- A temporary bypass, isolation, and screen schedule listing every coil, heat exchanger, control valve, pressure-independent control valve, flow meter, flow-limiting cartridge, and item of plant equipment, and stating how each is protected during the flush
+- Product data and Safety Data Sheets for the cleaner, the passivation inhibitor, and the glycol, with the supplier's published dosing, circulation, neutralization, and disposal procedure for each
+- A materials compatibility statement confirming the cleaner and the passivation inhibitor against every wetted material in the system, signed by the chemical supplier's technical authority
+- A flush water discharge plan with the receiving authority's written acceptance of the discharge, the neutralization method where one is used, and the haul and disposal arrangement where one is used
+- Where the system carries glycol, the glycol charge calculation stating the system fluid volume, the residual water volume after drain-down, the quantity of concentrate or premixed solution required, the dilution water source, and the expected makeup rate
+- The qualifications of the party performing the cleaning and of the chemical supplier
−### The Contractor shall submit the following action items for review before mobilizing the cleaning operation:
−
−- Cleaning and flushing method statement describing fill, cleaning chemistry, flush sequence, bypass arrangement, and reinstatement
−- Velocity calculation demonstrating that every pipe section reaches the minimum flush velocity, identifying sections that require an external flush pump or targeted jumpers
−- Flush-pump plan identifying system pumps versus external flush pump, with flow and head for the section being flushed
−- Temporary bypass and strainer schedule listing every coil, plate heat exchanger, control valve, and balancing valve to be bypassed or strainer-protected
−- Chemical product data and Safety Data Sheets for cleaner, passivation inhibitor, and glycol, with NSF/ANSI 60 status where make-up water contact is possible
−- Flush-water discharge plan with the local sewer authority's written acceptance, neutralization method, and any off-site disposal manifest
−
```datasheet
−label: Action submittals required before mobilization
+label: Action Submittals Required
type: checkbox
options:
− - Cleaning and flushing method statement
− - Flush velocity calculation (all sections)
− - Flush-pump plan (system vs. external)
− - Temporary bypass and strainer schedule
− - Chemical product data and SDS
− - Flush-water discharge plan with authority acceptance
+ - "Cleaning and flushing method statement per system"
+ - "Flush velocity and flow calculation per section"
+ - "Temporary bypass, isolation, and screen schedule"
+ - "Chemical product data, Safety Data Sheets, and supplier procedures"
+ - "Materials compatibility statement"
+ - "Flush water discharge plan with authority acceptance"
+ - "Glycol charge calculation"
+ - "Cleaning party and chemical supplier qualifications"
default:
− - Cleaning and flushing method statement
− - Flush velocity calculation (all sections)
− - Flush-pump plan (system vs. external)
− - Temporary bypass and strainer schedule
− - Chemical product data and SDS
− - Flush-water discharge plan with authority acceptance
+ - "Cleaning and flushing method statement per system"
+ - "Flush velocity and flow calculation per section"
+ - "Temporary bypass, isolation, and screen schedule"
+ - "Chemical product data, Safety Data Sheets, and supplier procedures"
+ - "Materials compatibility statement"
+ - "Flush water discharge plan with authority acceptance"
+ - "Glycol charge calculation"
+ - "Cleaning party and chemical supplier qualifications"
+constraint: all_of
```
−## Closeout Submittals {note}
+### Cleaning chemistry shall not be added to any system until the submittals covering that system have been returned by the Engineer of Record.
−### The closeout submittals are the documentation baseline the Owner relies on for the water treatment program and for any future coil warranty claim; without them there is no evidence that cleaning was performed. {note}
+### The velocity calculation is the submittal that decides whether the flush will work. A system pump sized for design flow against design head rarely moves water fast enough through the mains to lift settled debris with every valve open, and the calculation is where that shortfall is found while a temporary pump can still be arranged. A method statement without a section-by-section calculation is a plan to flush the parts of the system that happen to be easy. {note}
−### The Contractor shall submit the following closeout items before final acceptance:
+## Closeout Submittals {toc}
−- Signed cleaning and flushing report including flush start and finish, velocity achieved, and number of passes
−- Flush acceptance test results for turbidity, total iron, TSS, pH, and conductivity at each sample point
−- Signed passivation report including inhibitor type, dose multiplier, circulation temperature, and circulation duration
−- Corrosion coupon installation record listing coupon metallurgy and rack locations
−- Photographic flush-color log at the defined sampling intervals
−- Glycol charge record (glycol systems only) with pre-charge water chemistry and post-charge concentration
+### The Contractor shall submit the following for each system before the system is released to balancing and before substantial completion:
+- The signed cleaning, flushing, and passivation report required under Acceptance and Hand-Off
+- Flush acceptance test results for every sample point and every pass, with the fill water baseline they are compared against
+- The flush sample photograph log
+- The passivation record, stating the chemistry, the dose, the inhibitor residual at the start and end of circulation, the circulation duration and temperature, and the end-of-passivation water analysis
+- The corrosion coupon installation record, stating the rack location, each coupon's metallurgy, serial number, initial weight, and installation date
+- Where the system carries glycol, the glycol charge record
+- The flush water disposal record, stating the volumes discharged, the neutralization readings, and any haul manifests
+- The reinstatement record, listing every temporary jumper, screen, hose, blind, and connection installed and the date each was removed
+
```datasheet
−label: Closeout submittals required for final acceptance
+label: Closeout Submittals Required
type: checkbox
options:
− - Signed cleaning and flushing report
− - Flush acceptance test results (turbidity, iron, TSS, pH, conductivity)
− - Signed passivation report
− - Corrosion coupon installation record
− - Photographic flush-color log
− - Glycol charge record (glycol systems)
+ - "Signed cleaning, flushing, and passivation report"
+ - "Flush acceptance test results per sample point and pass"
+ - "Flush sample photograph log"
+ - "Passivation record"
+ - "Corrosion coupon installation record"
+ - "Glycol charge record"
+ - "Flush water disposal record"
+ - "Reinstatement record"
default:
− - Signed cleaning and flushing report
− - Flush acceptance test results (turbidity, iron, TSS, pH, conductivity)
− - Signed passivation report
− - Corrosion coupon installation record
− - Photographic flush-color log
+ - "Signed cleaning, flushing, and passivation report"
+ - "Flush acceptance test results per sample point and pass"
+ - "Flush sample photograph log"
+ - "Passivation record"
+ - "Corrosion coupon installation record"
+ - "Glycol charge record"
+ - "Flush water disposal record"
+ - "Reinstatement record"
+constraint: all_of
```
−## Informational Submittals {note}
+### The closeout package is the only evidence that the cleaning happened. A coil that fouls in the second year is either a construction defect or a treatment failure, and the flush results, the passivation residuals, and the coupon baseline are what let the Engineer of Record tell which. Without them the argument is settled by whoever is more persuasive. {note}
−### The Contractor shall submit the following informational items:
+# Quality Assurance {toc}
−- Qualifications of the specialty cleaning subcontractor or water treatment service provider performing or witnessing the work
−- Rental flush-pump skid data sheet where an external pump is used
−- Laboratory certification for any off-site flush-water analysis
+## Responsibility {toc}
+### The party performing the cleaning, flushing, and passivation shall be as indicated in the datasheet.
+
```datasheet
−label: Informational submittals
−type: checkbox
+label: Party Performing Cleaning, Flushing, and Passivation
+type: radio
options:
− - Cleaning subcontractor / treatment provider qualifications
− - External flush-pump skid data sheet
− - Laboratory certification for flush-water analysis
−default:
− - Cleaning subcontractor / treatment provider qualifications
+ - "Installing mechanical contractor"
+ - "Specialty cleaning contractor engaged by the installing mechanical contractor"
+ - "Water treatment service provider engaged for the ongoing program"
+default: "Installing mechanical contractor"
```
−# Quality Assurance {toc}
+### The party supplying and dosing the cleaning and passivation chemistry shall be as indicated in the datasheet.
−## Responsibility Assignment {note}
+```datasheet
+label: Party Supplying and Dosing the Chemistry
+type: radio
+options:
+ - "Water treatment service provider engaged for the ongoing program"
+ - "Chemical supplier engaged by the installing mechanical contractor"
+ - "Specialty cleaning contractor"
+default: "Water treatment service provider engaged for the ongoing program"
+```
−### Ambiguity over who performs the cleaning - the piping contractor, an Owner-furnished water treatment provider, or a specialty cleaning subcontractor - creates responsibility gaps and schedule conflicts with TAB and commissioning. The responsible party shall be named before the work begins.
+### The installing mechanical contractor installed the pipe, owns the temporary connections, and runs the pumps, which is why that contractor performs the flush on most projects and is the default. A specialty cleaning contractor brings its own flush pumps, filtration, and sampling equipment and is engaged where the system is large, the schedule is short, or the installing contractor has no flushing experience. The water treatment service provider performs the whole operation where the Owner wants one party accountable for the water from the first fill onward, at the cost of a contractor on site who does not control the piping work. The chemistry is supplied by the service provider on most projects because the passivation chemistry has to match the ongoing program, and a cleaner the provider did not select is one the provider will later blame. The installing contractor's own supplier is chosen where no ongoing program has been let at the time of cleaning. {note}
−### The Contract Documents shall name a single party responsible for cleaning, flushing, and passivation, with the witnessing party identified separately.
+### Whichever party performs the work, the installing mechanical contractor shall remain responsible for the sequence, for the protection of equipment during the flush, and for the delivery of the signed report.
+### Flush acceptance sampling and the start of passivation circulation shall be witnessed by the party indicated in the datasheet.
+
```datasheet
−label: Party responsible for cleaning, flushing, and passivation
−type: radio
+label: Witness for Flush Acceptance and Passivation
+type: select
options:
− - Installing mechanical (piping) contractor
− - Specialty cleaning subcontractor to the mechanical contractor
− - Owner-furnished water treatment service provider
−default: Installing mechanical (piping) contractor
+ - "Engineer of Record or the Engineer's representative"
+ - "Owner's commissioning authority"
+ - "Water treatment service provider engaged for the ongoing program"
+ - "Owner's representative"
```
+### No witness is the norm across projects. The commissioning authority witnesses where the project is commissioned, because the flush report is a prerequisite the authority has to accept anyway. The Engineer of Record witnesses where there is no commissioning authority and the Engineer wrote the acceptance values. The water treatment service provider witnesses where the provider will inherit the system and wants its own sample at hand-off, and is a poor choice as the sole witness where the provider also performed the work. The Owner's representative witnesses where the Owner operates its own plant and has staff able to read the results. {note}
+
+### The Contractor shall give the witnessing party not less than three business days notice of each witnessed event.
+
+### The hold points at which work shall stop until the witnessing party has observed the event or has released it in writing shall be as indicated in the datasheet.
+
```datasheet
−label: Party witnessing flush and passivation acceptance
−type: radio
+label: Witnessed Hold Points
+type: checkbox
options:
− - Engineer of Record
− - Commissioning authority
− - Owner's water treatment service provider
− - Owner's representative
−default: Commissioning authority
+ - "Fill water baseline sampling"
+ - "Start of cleaning circulation"
+ - "Flush acceptance sampling"
+ - "Passivation charge and start of circulation"
+ - "Corrosion coupon rack installation"
+ - "Glycol charge and concentration verification"
+default:
+ - "Flush acceptance sampling"
+ - "Passivation charge and start of circulation"
+constraint: all_of
```
−## Coordination {note}
+### Where the parties disagree whether a hold point was observed or properly released, the Engineer of Record shall make the initial determination.
−### The flushing operation sits between three other trades, and the most common project failure is starting TAB or commissioning before flushing is accepted, which fouls coils that then must be back-flushed after balancing. {note}
+## Qualifications and Instruments {toc}
−### The Contractor shall coordinate the cleaning sequence so that flush acceptance precedes TAB mobilization and so that passivation completion precedes placing the chemical program online.
+### The party performing the cleaning shall have cleaned, flushed, and passivated not less than three closed hydronic systems comparable to this project in fluid volume and metallurgy within the preceding five years, and shall submit those project references on request.
−### The TAB contractor shall refuse to begin balancing until the signed flushing report is in hand.
+### Where the parties disagree whether a reference project is comparable in fluid volume and metallurgy, the Engineer of Record shall make the initial determination.
−### Flushing operations shall not pressurize, cross-connect, or contaminate adjacent fire sprinkler piping, consistent with the separation principles of NFPA 13.
+### Field test instruments for pH, conductivity, and turbidity shall be calibrated against reference standards on each day they are used, and the calibration shall be recorded on the flush report.
−## Chemical Handling {note}
+### Field test reagents shall be within their stated expiration date, and reagent water used for field chemistry shall meet ASTM D1193 Type II.
−### All cleaning chemicals, degreasers, acid cleaners, and passivation inhibitors brought to site shall be labeled and accompanied by Safety Data Sheets in accordance with OSHA 29 CFR 1910.1200.
+### Laboratory analyses for total iron and total suspended solids shall be performed by a laboratory accredited for those methods, or by a field photometric method whose published detection limit is below the acceptance value indicated in the datasheet.
−### Any biocidal product used for biological knockdown of an open condenser water system shall be EPA-registered under FIFRA for the intended use.
+## Pre-Cleaning Conference {toc}
−### Where a cleaning or passivation chemical may contact domestic make-up water, the chemical shall be certified to NSF/ANSI 60 or the make-up connection shall be physically isolated during the operation.
+### Before any cleaning chemical is brought to the site, the Contractor shall convene a conference attended by the party performing the cleaning, the chemical supplier, the balancing agency, the commissioning authority where one is engaged, the water treatment service provider where one has been engaged, and the Engineer of Record.
−# Environmental and Service Conditions {toc}
+### The conference agenda shall cover the system boundaries, the sequence and schedule by system, the bypass and isolation arrangement, the pump source and the velocity calculation, the sample points and acceptance values, the discharge route and its authority conditions, the hold points, the passivation chemistry and its match to the ongoing program, and the glycol charge where one is made.
−## Pre-Cleaning System Condition {note}
+### The decisions settled at the conference shall be recorded in the minutes and incorporated into the method statement before cleaning begins.
−### Construction debris in a new hydronic system includes mill scale, weld spatter, cutting oils, thread-cutting lubricant, jointing compound, and general trash; the purpose of cleaning and flushing is to remove this material before it lodges in coils, exchangers, and valve seats. {note}
+# Environmental and Service Conditions {toc}
−### Copper oxide scale formed inside brazed joints made without a nitrogen purge flakes off during high-velocity flushing and recirculates into finned coil tubes, where it cannot be flushed out and causes sustained heat-transfer loss. {note}
+## Systems and Boundaries {toc}
−### Brazed copper joints shall have been made with a nitrogen purge per [[sync/hydronic-piping]]; joints made without a purge shall be reported to the Engineer before flushing.
+### The systems to be cleaned, flushed, and passivated under this standard shall be as indicated on [[drawing: the mechanical equipment schedules and piping plans]].
−## System Type {note}
+### Each system shall be cleaned and flushed as one interconnected loop, including every main, riser, branch, and dead leg within the pressure-tested boundary, so that no section remains unflushed that later opens to the flushed system.
−### The cleaning chemistry, flush velocity target, and passivation temperature all depend on the system type and dominant metallurgy, which shall be identified before selecting the method.
+### Where new piping extends an existing system, the extent of the cleaning shall be as indicated in the datasheet.
```datasheet
−label: Hydronic system type
+label: Cleaning Extent at an Existing System Tie-In
type: radio
options:
− - Heating hot water (HHW)
− - Chilled water (CHW)
− - Dual-temperature
− - Condenser water (closed)
− - Inhibited-glycol loop
−default: Chilled water (CHW)
+ - "New piping only, cleaned and flushed in isolation before the tie-in is opened"
+ - "Combined existing and new system, cleaned and flushed together after the tie-in"
```
+### No extent is the norm, because the answer follows the condition of the existing water. Cleaning the new piping in isolation keeps the existing treated water in service and keeps new debris out of existing coils, and it requires a temporary circulation loop and a fill point on the new section. Cleaning the combined system removes the existing deposits at the same time and resets the whole loop to one baseline, at the cost of draining treated water, disposing of it, re-passivating existing steel, and an outage the Owner has to accept. {note}
+
+### Where the combined system is to be cleaned, the existing system water shall be sampled for pH, conductivity, total iron, inhibitor residual, and glycol concentration before the method statement is finalized, and the result shall be reported to the Engineer of Record.
+
+### Existing treated water drained for a combined cleaning shall be disposed of by the route the discharge plan provides, and where it contains glycol, as [[sync/hvac-water-treatment]] requires for drained glycol.
+
+## Fill Water {toc}
+
+### The water used to fill, clean, and flush the system shall be from the source indicated in the datasheet.
+
```datasheet
−label: Dominant system metallurgy
+label: Fill and Flush Water Source
type: radio
options:
− - Carbon steel
− - Copper
− - Mixed carbon steel and copper
−default: Mixed carbon steel and copper
+ - "Building make-up water through the system fill assembly"
+ - "Softened water from the building softener or a temporary softener"
+ - "Temporary supply from a hydrant, standpipe, or tanker"
+default: "Building make-up water through the system fill assembly"
```
−# System Filling and Pressure Verification {toc}
+### The building make-up water is already connected, already protected by the backflow assembly on the fill connection, and is the water the ongoing program was designed around, which is why it is the default. Softened water is chosen where the supply is hard enough that a phosphate cleaner or an inhibited glycol would precipitate calcium in the system, and it costs a softener and its regeneration. A temporary supply is chosen where the building service is not yet live or where the fill assembly cannot deliver flush volumes in a useful time, and it brings water of a quality nobody has characterized unless it is sampled. {note}
−## Filling {note}
+### The fill water baseline shall be established against [[parameter: site-water-supply-source]] and [[parameter: site-water-supply-hardness]], and a baseline sample drawn at the first fill of each system shall report the parameters indicated in the datasheet.
−### The system is filled with clean make-up water and brought to fill pressure so that the pre-cleaning condition - leak-free and at a known baseline chemistry - is confirmed before any chemical is added. {note}
+```datasheet
+label: Fill Water Baseline Parameters
+type: checkbox
+options:
+ - "pH"
+ - "Conductivity"
+ - "Total hardness"
+ - "Chloride"
+ - "Total iron"
+ - "Turbidity"
+default:
+ - "pH"
+ - "Conductivity"
+ - "Total hardness"
+ - "Total iron"
+ - "Turbidity"
+constraint: all_of
+```
−### The system shall be filled with potable or treated make-up water and vented at all high points until air-free.
+### Every flush acceptance comparison in this standard is made against the fill water baseline, so a baseline drawn from a different source than the flush water, or not drawn at all, leaves the acceptance values with nothing to be compared to. {note}
−### Fill water chemistry (pH and conductivity) shall be recorded at filling to serve as the baseline against which flush acceptance is judged.
+### Where a temporary supply is used, the sample drawn at the first fill shall be taken from that supply, and the supply connection shall be protected against backflow into the building water system.
−### Initial fill pressure shall be verified and recorded after venting and confirmed stable before cleaning chemistry is introduced.
+### The make-up water connection shall be closed while cleaner is in the system, and cleaning chemistry shall not be introduced at any point upstream of the backflow protection on the make-up connection.
−```datasheet
−label: System design working pressure
−type: range
−unit: psig
−min: 50
−max: 300
−step: 5
−default: 125
−```
+## Wetted Materials {toc}
−```datasheet
−label: Hydrostatic test pressure (1.5x design, witnessed before cleaning)
−type: range
−unit: psig
−min: 75
−max: 450
−step: 5
−default: 190
−```
+### Before the cleaner is selected, the Contractor shall list every wetted material in the system, including the pipe metallurgy of each section, gasket and sealing element compounds, mechanical seal faces and elastomers, aluminum, galvanized, stainless steel, brass, and plastic components, and the materials of the coils, heat exchangers, and plant equipment connected to the loop.
−```datasheet
−label: Hydrostatic test hold duration
−type: range
−unit: min
−min: 30
−max: 240
−step: 30
−default: 30
−```
+### The cleaner and the passivation inhibitor shall be compatible with every material on that list, as confirmed in the materials compatibility statement.
−# Temporary Bypasses and Equipment Protection {toc}
+### Where aluminum is in the wetted path, the pH of the cleaning solution shall be held at or below the limit published by the manufacturer of the aluminum component throughout circulation.
−## Sensitive Equipment Isolation {note}
+### Aluminum is the material that most often turns a routine clean into a damage claim. An alkaline cleaner at the concentration that lifts cutting oil from steel sits above the pH at which aluminum corrodes, and an aluminum boiler heat exchanger or an aluminum-cored coil connected during the clean is etched before the flush ends. Galvanized components lose zinc to the same chemistry. A solvent degreaser attacks EPDM gaskets and seals that a water-based alkaline cleaner leaves alone. The compatibility statement is where each of these is caught on paper. {note}
−### Debris mobilized at flushing velocity damages coil tubes, scores control valve seats, and clogs plate heat exchanger channels. Routing flush flow through this equipment is the second most common cleaning failure, after premature TAB. {note}
+# Cleaning Method {toc}
−### Coils, plate heat exchangers, control valves, and balancing valves shall be isolated from the flush stream by spool-piece jumper bypasses or by fine-mesh temporary strainers installed immediately upstream, before high-velocity flushing begins.
+## Method Selection {toc}
−### Spool-piece jumpers shall be fabricated from the same pipe material as the run they replace and fitted with isolation valves at each end.
+### The cleaning method for each system shall be as indicated in the datasheet.
−### Where temporary strainers are used instead of jumpers, they shall be 100 mesh or finer stainless steel and shall be inspected and cleaned between flush passes.
−
```datasheet
−label: Sensitive-equipment protection method
+label: Cleaning Method
type: radio
options:
− - Spool-piece jumper bypass (most thorough)
− - Temporary fine-mesh strainer upstream (100 mesh or finer)
− - Combination by equipment type
−default: Spool-piece jumper bypass (most thorough)
+ - "Water flush only, no chemical cleaner"
+ - "Alkaline detergent and dispersant cleaner, then flush"
+ - "Trisodium phosphate cleaner, then flush"
+ - "Inhibited acid or chelant descaler, then flush"
+default: "Alkaline detergent and dispersant cleaner, then flush"
```
−```datasheet
−label: Temporary strainer mesh (where strainers used)
−type: select
−options:
− - 100 mesh
− - 150 mesh
− - 200 mesh
−default: 100 mesh
−unit: mesh
−```
+### A water flush alone removes loose debris and is chosen on a small system of copper or press-joined pipe assembled without cutting oil, where there is nothing for a cleaner to dissolve and the discharge needs no authority coordination. An alkaline detergent with a dispersant lifts cutting oil, thread lubricant, and jointing compound from carbon steel and holds the fines in suspension so the flush carries them out, which is the condition most new systems with steel mains are in and is why it is the default. Trisodium phosphate is a commodity alkaline cleaner that does the same job at lower material cost and adds a phosphate load that many receiving authorities limit. An inhibited acid or chelant descaler dissolves mill scale and rust rather than lifting oil, and is chosen where the system stood wet through a long construction period, was used for temporary heating before cleaning, or carries heavy mill scale. It requires an inhibited formulation, continuous monitoring, neutralization, and passivation on the same day, because the metal it leaves behind is bare. {note}
−## Dead Legs and Branch Ends {note}
+### Where an inhibited acid or chelant descaler is selected, the circulating solution shall be sampled for pH and total iron at intervals not exceeding one hour, and the system shall be drained, neutralized, rinsed, and passivated within the same working day the descaler circulation ends.
−### Debris accumulates in uncirculated sections and migrates back into the cleaned system once interconnecting valves are opened for service. Every dead leg and branch-end service needs a temporary jumper or end-of-line flush connection. {note}
+### Where a trisodium phosphate cleaner is selected, the discharge plan shall record the receiving authority's acceptance of the phosphate load before the cleaner is added.
−### Every dead leg and branch-end service shall be provided with a temporary drain-and-fill jumper or an end-of-line flush connection so it is circulated during flushing.
+### Where a water flush alone is selected and the flush fails to reach the acceptance values of this standard after three passes at the flush velocity, the Contractor shall report the result to the Engineer of Record, who shall determine whether a chemical cleaning step is added.
−### The complete interconnected loop, including both carbon steel and copper sections, shall be flushed as one system; sections shall not be flushed in permanently isolated groups.
+## Cleaner Dosing and Circulation {toc}
−# Cleaning Chemistry and Circulation {toc}
+### The cleaner shall be dosed at the cleaner manufacturer's published concentration for the cleaning of new hydronic systems, and that concentration shall be stated in the method statement and recorded on the flush report.
−## Cleaning Method Selection {note}
+### The cleaner shall be introduced through the chemical bypass feeder furnished under [[sync/hydronic-specialties]] or through a temporary injection connection, with the system full and vented at every high point.
−### The cleaning method is selected from the dominant contamination: an alkaline degreaser handles cutting oils and general construction soil on most new systems; trisodium phosphate (TSP) is a commodity alternative; an acid clean is reserved for heavy mill scale or weld discoloration; and a mechanical-only flush is acceptable for small all-copper systems. {note}
+### Every isolation valve and balancing valve in the piping shall be fully open during cleaning circulation so that the solution reaches every section of the loop.
−### Acid cleaning shall be used only where heavy mill scale or weld discoloration is present in the piping.
+### Cleaning circulation shall continue for the duration indicated in the datasheet.
−### Acid-cleaner spent solution shall be neutralized on site or removed off-site for disposal.
+```datasheet
+label: Cleaning Circulation Duration
+type: range
+unit: h
+options:
+ min: 2
+ max: 72
+ setpoints: [2, 4, 8, 12, 24, 48, 72]
+default: 24
+constraint: min
+```
+### The cleaning circulation temperature shall be as indicated in the datasheet.
+
```datasheet
−label: Cleaning method
+label: Cleaning Circulation Temperature
type: radio
options:
− - Alkaline degreaser circulation
− - Trisodium phosphate (TSP) flush
− - Acid clean (heavy mill scale only)
− - Mechanical-only flush (small all-copper systems)
−default: Alkaline degreaser circulation
+ - "Ambient, unheated"
+ - "Heated to the cleaner manufacturer's recommended temperature"
+default: "Ambient, unheated"
```
−## Alkaline Degreaser Parameters {note}
+### An alkaline cleaner works faster warm, and a 24 hour circulation at ambient temperature is the duration that lets it work at the temperature most systems are cleaned at, which is why the two defaults go together. Heated circulation shortens the clean and improves oil removal on a heating system, and it needs a heat source: the system boiler cannot be fired on cleaner-bearing water without its manufacturer's written acceptance, and [[sync/boilers]] requires the boiler to be placed on treated water, so heated cleaning usually means a temporary heater. A chilled water system is cleaned at ambient because nothing on it heats water. {note}
−### The alkaline degreaser is dosed into the filled system and circulated warm to lift cutting oils and construction soil into suspension before the mechanical flush carries them out. {note}
+### Where heated circulation is selected, the heat shall be supplied by a temporary heater, or by the system heat source only with the equipment manufacturer's written acceptance of operation on the cleaning solution.
−### The alkaline degreaser shall be circulated at the concentration, temperature, and duration scheduled below, with all valves open to circulate the full loop.
+### The cleaning solution shall be sampled at the start and at the end of circulation, and the pH, conductivity, and total iron of each sample shall be recorded on the flush report.
−```datasheet
−label: Alkaline degreaser concentration (by volume in fill water)
−type: range
−unit: '%'
−min: 2
−max: 5
−step: 0.5
−default: 3
−```
+### At the end of cleaning circulation the solution shall be drained completely from every low point and the system refilled for flushing without the cleaner being allowed to dry on the pipe wall.
−```datasheet
−label: Cleaning circulation temperature
−type: range
−unit: °F
−min: 70
−max: 140
−step: 5
−default: 70
−```
+### A cleaner that dries on the pipe leaves a film that the flush water does not dissolve and that the passivation inhibitor has to form its film through. Draining and refilling in one operation is what keeps the wall wet between the clean and the flush. {note}
+# High-Velocity Flushing {toc}
+
+## Flush Velocity {toc}
+
+### The flush velocity reached in every section of pipe shall be as indicated in the datasheet, and shall be demonstrated section by section in the velocity calculation.
+
```datasheet
−label: Cleaning circulation duration
+label: Flush Velocity in Every Section
type: range
−unit: h
−min: 12
−max: 48
−step: 12
−default: 24
+unit: ft/s
+options:
+ min: 2
+ max: 10
+ setpoints: [2, 3, 4, 5, 6, 7, 8, 10]
+constraint: min
```
−## TSP Alternative Parameters {note}
+### No flush velocity is the norm across projects, because the value trades debris removal against the pump needed to reach it. Settled sand, scale, and weld slag begin to move in a horizontal pipe at roughly 3 ft/s, and are carried reliably through fittings and risers at 5 ft/s and above, which is the band most method statements aim for. A velocity above the design velocity of the section is only reachable with a temporary pump or by flushing the section alone, and the calculation shows which sections that applies to. A low value makes the flush achievable with the system pumps on a small system and leaves the heavier debris where it lies. {note}
−### Trisodium phosphate is restricted for sanitary discharge in some jurisdictions; where TSP is used, the discharge plan shall confirm acceptance before the clean begins. {note}
+### Sections that cannot reach the flush velocity under the main flush flow shall be flushed individually through temporary connections until the velocity is reached in each.
−### The TSP concentration by weight shall be specified, and its use shall be confirmed against the jurisdiction's sanitary discharge restrictions before the clean begins.
+### The flush shall proceed from the plant outward, mains first, then risers, then branches, with each section discharged to the drain nearest its far end rather than through the next section.
−```datasheet
−label: TSP concentration (by weight)
−type: range
−unit: '%'
−min: 0.3
−max: 0.7
−step: 0.1
−default: 0.5
−```
+### Embedded tubing circuits served from a manifold, including snow melt and radiant circuits, shall be flushed circuit by circuit through the manifold isolation valves to a drain until each circuit runs clear and air-free.
−### The TSP circulation duration shall be specified, coordinated with the discharge plan confirming acceptance of the chemistry before the clean begins.
+### Dead legs, capped future connections, and branch ends shall be fitted with a temporary drain connection and flushed, and where no drain connection can be made, the leg shall be drained, inspected, and recorded as inspected before the flush is accepted.
+### A dead leg is a settling basin. Debris that the main flush lifts drops out where the water stops moving, and it migrates back into the cleaned system the first time the isolation valve on that leg is opened for service. Every leg either gets flow during the flush or gets looked at. {note}
+
+## Flush Pump {toc}
+
+### The pump used to produce the flush flow shall be as indicated in the datasheet.
+
```datasheet
−label: TSP circulation duration
−type: range
−unit: h
−min: 12
−max: 24
−step: 6
−default: 18
+label: Flush Pump Source
+type: radio
+options:
+ - "System circulating pumps"
+ - "Temporary external flush pump"
+ - "System circulating pumps for the mains and a temporary pump for the sections they cannot reach"
```
−# High-Velocity Flushing {toc}
+### No pump source is the norm across projects. The system pumps are already installed and wired, and on a small system with all valves open they reach the flush velocity in the mains, at the cost of passing construction debris through the permanent pump's impeller and seal faces. A temporary external pump is sized for the flush rather than for the design point, keeps debris out of the permanent pumps, and costs a rental, its connections, and a temporary power supply. The split arrangement uses the system pumps where they are enough and brings a temporary pump to the branches and risers the calculation shows they cannot reach. {note}
−## Flush Velocity {note}
+### Where the system circulating pumps are used, the temporary startup screen furnished under [[sync/hydronic-specialties]] shall be in place at each pump suction throughout the flush, and the compatibility of the pump seals and elastomers with the cleaning chemistry shall have been confirmed as [[sync/hvac-pumps]] requires.
−### The minimum flush velocity is the industry-consensus 5 ft/s for carbon steel; 6 to 8 ft/s is preferred and usually achievable in mains. The contractor demonstrates by calculation that every pipe section reaches the minimum, adding targeted jumpers at dead legs that the main flush cannot reach. {note}
+### A temporary flush pump shall be sized from the velocity calculation to deliver, against the head of the flush circuit, the flow that produces the flush velocity in the largest section it serves, and shall be fitted with a suction screen, a discharge isolation valve, and a flow indicator.
−### Flushing shall achieve a minimum velocity of 5 ft/s in every pipe section, demonstrated by the submitted velocity calculation.
+### The flow during each flush pass shall be measured by the system flow station, a temporary flow meter, or the pump differential pressure read against the certified pump curve, and shall be recorded on the flush report with the velocity it produces in the section being flushed.
−### Mains shall be flushed at 6 to 8 ft/s where the pump and pipe size permit.
+## Flush Passes and Sampling {toc}
−### Sections that cannot reach 5 ft/s under main flush flow shall be flushed individually through targeted jumpers until the minimum is met.
+### Flushing shall continue in repeated passes, each pass ending with a sample drawn at the flush drain, until the acceptance values of this standard are met at every sample point.
+### The flush discharge arrangement shall be as indicated in the datasheet.
+
```datasheet
−label: Minimum flush velocity (every section)
−type: range
−unit: ft/s
−min: 5
−max: 8
−step: 0.5
−default: 5
+label: Flush Discharge Arrangement
+type: radio
+options:
+ - "Once-through to drain, refilled with fresh fill water for each pass"
+ - "Recirculated through a temporary filter, then a final once-through rinse to drain"
```
+### Once-through flushing carries every pass of debris and cleaner out of the building and consumes a system volume of water per pass, which on a large loop is a discharge the receiving authority has to accept and a water bill the Owner pays. Recirculating through a temporary bag or cartridge filter removes the suspended debris while keeping the water, and leaves dissolved cleaner and iron in the loop until the final rinse removes them. The recirculated arrangement is chosen where water or discharge capacity is limited, and it needs the final rinse to reach the pH and conductivity values that a filter cannot deliver. {note}
+
+### A flush sample shall be drawn at each flush drain at intervals not exceeding the value indicated in the datasheet, and shall be photographed in a clear container against a white background beside a sample of the fill water.
+
```datasheet
−label: Preferred main flush velocity
+label: Flush Sample Interval
type: range
−unit: ft/s
−min: 6
−max: 8
−step: 0.5
−default: 7
+unit: min
+options:
+ min: 5
+ max: 60
+ setpoints: [5, 10, 15, 30, 60]
+constraint: max
```
−## Flush Pump Source {note}
+### Between passes, every temporary screen shall be removed, inspected, and cleaned, and the quantity and character of the material collected shall be recorded on the flush report.
−### System pumps are selected for design flow at design head, not for high-velocity low-head flushing, so on larger systems they cannot reach 5 ft/s with all valves open. An external high-volume flush pump is then required for the cleaning operation. {note}
+### The photograph log and the screen record are the running evidence of the flush. The trend from brown to clear in the sample jars and from heavy to empty in the screens is what a witness reads to judge that the next pass is the last one, and what the Engineer of Record reads later when a strainer loads in the first season. {note}
−### Where the system pumps cannot achieve the minimum flush velocity with all balancing and control valves wide open, a temporary external flush pump shall be connected for the flushing operation.
+# Equipment Protection During Flushing {toc}
−### The external flush pump shall be sized to deliver 1.5 to 2 times normal operating flow in the section being flushed, with suction strainer, discharge manifold, and flow measurement.
+## Terminal Equipment {toc}
+### Coils, plate heat exchangers, control valves, pressure-independent control valves, flow meters, and automatic flow-limiting cartridges shall be handled during the main flush as indicated in the datasheet.
+
```datasheet
−label: Flush pump source
+label: Terminal Equipment During the Main Flush
type: radio
options:
− - System circulation pumps (velocity verified by calculation)
− - Temporary external high-volume flush pump
− - System pumps for mains, external pump for high-resistance branches
−default: System circulation pumps (velocity verified by calculation)
+ - "Bypassed by a temporary jumper, then flushed individually after the main flush is accepted"
+ - "Flushed through behind a temporary fine-mesh screen at each inlet"
+ - "Flushed through with the permanent strainer screen in place, cleaned between passes"
+default: "Bypassed by a temporary jumper, then flushed individually after the main flush is accepted"
```
−```datasheet
−label: External flush pump capacity
−type: range
−unit: GPM
−min: 100
−max: 600
−step: 50
−default: 350
−```
+### Debris moving at flush velocity scores a control valve seat, packs the narrow channels of a plate heat exchanger, and lodges in the return bends of a coil where no later flush reaches it. Bypassing the equipment keeps the main flush out of it entirely and then flushes each item at a flow its own connections carry, which is the most protective arrangement and the default. Flushing through behind a temporary fine screen avoids the jumpers and lets the flush reach the coil connections, at the cost of a screen that loads quickly and throttles the branch until it is cleaned. Flushing through the permanent screen relies on a 20 mesh screen that passes much of what a flush mobilizes, and is chosen on a small system of unit heaters or fan coils where the devices protected are not fine enough to be damaged by what it passes. {note}
+### Where equipment is bypassed, the jumper shall connect the supply and return at the equipment isolation valves, shall be sized not smaller than the branch it bypasses, and shall be installed before the cleaning circulation begins.
+
+### Where equipment is flushed through behind a temporary screen, the mesh count of the screen shall be as indicated in the datasheet.
+
```datasheet
−label: Flush flow multiple of normal operating flow (section being flushed)
+label: Temporary Flushing Screen Mesh Count
type: range
−unit: x
−min: 1.5
−max: 2
−step: 0.1
−default: 1.7
+unit: mesh
+options:
+ min: 40
+ max: 200
+ setpoints: [40, 60, 80, 100, 150, 200]
+constraint: min
```
−## Flush Color Monitoring {note}
+### A finer screen catches more of what a flush mobilizes and loads sooner, so the mesh count follows the passage size of the device behind it rather than a single value: a plate heat exchanger or a pressure-independent valve cartridge needs a finer screen than a coil with a large tube diameter, and every screen is cleaned between passes regardless of mesh. {note}
−### Flush water is sampled at intervals at the flush drains and its color and clarity logged photographically; the trend from turbid to clear is the visible evidence that debris is being removed. {note}
+### After the main flush is accepted, each bypassed coil and heat exchanger shall be flushed through its own connections to a drain at the flow its connections carry, with the control valve removed or held open, until the discharge runs clear beside the fill water sample.
−### Flush-drain water shall be visually sampled and photographed at intervals until clarity reaches the tap-water surrogate standard, with the log included in the closeout package.
+### Flow-limiting cartridges and pressure-independent control valve cartridges removed for flushing shall be tagged with their location, stored clean, and reinstalled in the valve body they were removed from.
−```datasheet
−label: Flush-color sampling interval
−type: select
−options:
− - Every 10 minutes
− - Every 15 minutes
− - Every 30 minutes
−default: Every 15 minutes
−```
+## Plant Equipment {toc}
−# Flush Water Disposal {toc}
+### Boilers, chillers, heat exchangers, water-source heat pumps, cooling tower and fluid cooler circuits, and other plant equipment shall be isolated from the cleaning and flushing circulation by closed isolation valves or blind flanges, with a temporary bypass across the equipment connections that keeps the circulation path closed.
−## Discharge Coordination {note}
+### Plant equipment shall be opened to the cleaned loop only after the flush is accepted, and shall be operated on the loop only after the passivation charge is in the water.
−### Alkaline cleaner discharges can violate local sewer pretreatment limits, and acid-cleaner discharges almost always require neutralization or off-site disposal. The discharge route must be coordinated with the local authority before the clean begins, not after. {note}
+### The signed report under this standard is the release that [[sync/boilers]] and [[sync/chillers]] require in their pre-startup verification before the equipment is operated on the loop, which is why the equipment is kept out of the flush and brought in only once the water is treated. {note}
−### The Contractor shall obtain written acceptance of the flush-water discharge route from the local sewer authority before introducing cleaning chemistry.
+### Where the plant equipment manufacturer requires an initial flush of the equipment's own water passages, that flush shall be performed after the loop flush is accepted and before passivation begins, and its discharge shall be sampled and recorded with the flush results.
−### Discharge to sanitary sewer shall be neutralized to a pH of 6 to 9 before release where required by the authority having jurisdiction.
+### The expansion tank shall be isolated from the system during cleaning circulation and flushing, and where the system has an air and dirt separator, its blowdown shall be opened at the end of each pass to discharge the material it has collected.
−### Acid-cleaner residue and biocide-bearing water shall be neutralized or removed off-site as regulated waste, with disposal manifests retained.
+## Temporary Connections and Reinstatement {toc}
−```datasheet
−label: Flush water discharge route
−type: radio
−options:
− - Direct to sanitary sewer (authority-approved)
− - Neutralized to pH 6-9 before sanitary discharge
− - Off-site disposal as regulated waste
−default: Neutralized to pH 6-9 before sanitary discharge
−```
+### The fill, drain, and temporary connection points furnished under [[sync/hydronic-piping]] shall be used for the flush, and any additional temporary connection the method statement requires shall be furnished and removed by the Contractor.
−```datasheet
−label: Discharge pH neutralization band
−type: range
−unit: pH
−min: 6
−max: 9
−step: 0.5
−setpoints:
− - 6
− - 9
−default: 6
−```
+### Temporary jumpers, hoses, screens, injection points, blinds, and drain connections shall be rated for the pressure and temperature of the cleaning and flushing circulation and shall be restrained against movement.
−# Flush Acceptance Testing {toc}
+### Every temporary jumper, screen, hose, blind, and connection shall be removed after the flush is accepted and before passivation circulation begins, and the permanent piping and devices reinstated, except for the injection and sample connections the passivation and the glycol charge require, which shall be removed when those operations are complete.
−## Acceptance Criteria {note}
+### The removal of each temporary item shall be recorded on the reinstatement record against the entry made when it was installed.
−### Flush acceptance moves from a visual clarity check, through field turbidity measurement, to laboratory analysis for total iron and total suspended solids, depending on the rigor the owner requires. Iron and TSS confirm debris removal; pH and conductivity returning near the make-up baseline confirm the cleaner itself has been rinsed out. {note}
+### The joints made when the permanent piping is reinstated shall be leak-tested at the system operating pressure during the first fill after reinstatement and before insulation closes over them.
−### Persistent total iron above 2 mg/L after multiple passes indicates an active corrosion source rather than construction debris, and shall be investigated before acceptance rather than flushed indefinitely. {note}
+### A jumper left in place is a permanent short circuit that starves the equipment it was protecting, and a flushing screen left in place loads steadily until the branch it serves stops. The record of installation against removal is what makes the count come out even. The cleaning of the permanent strainer screens and the removal of the startup screens after flushing are recorded separately under [[sync/hydronic-specialties]]. {note}
−### Water samples shall be collected per ASTM D3370 from the lowest system sample point and from each major zone.
+# Flush Acceptance {toc}
−### Field chemistry tests shall use reagent water of ASTM D1193 Type II minimum purity.
+## Sample Points {toc}
−### The flush shall be accepted only when total iron, total suspended solids, pH, and conductivity all meet the scheduled criteria.
+### Flush acceptance samples shall be drawn in accordance with ASTM D3370 from the lowest drain on each system, from the far end of each main, and from the return at the plant, after the sample line has been purged of standing water.
+### The sample points shall be listed in the method statement and shall not be reduced after cleaning begins.
+
+### A sample drawn at the plant on a system whose far ends were never sampled is a sample of the section nearest the pump. The low point is where the heaviest material settles and the far end of each main is where the velocity was lowest, which is why both are sampled every pass. {note}
+
+## Acceptance Values {toc}
+
+### The flush shall be accepted on the parameters indicated in the datasheet, each measured at every sample point.
+
```datasheet
−label: Flush acceptance protocol
−type: radio
+label: Flush Acceptance Parameters
+type: checkbox
options:
− - Visual clarity only
− - Field turbidity measurement
− - Laboratory total iron and TSS analysis
−default: Field turbidity measurement
+ - "Visual clarity beside the fill water sample"
+ - "Turbidity"
+ - "pH relative to the fill water baseline"
+ - "Conductivity relative to the fill water baseline"
+ - "Total iron"
+ - "Total suspended solids"
+default:
+ - "Visual clarity beside the fill water sample"
+ - "pH relative to the fill water baseline"
+ - "Conductivity relative to the fill water baseline"
+ - "Total iron"
+constraint: all_of
```
−```datasheet
−label: Flush acceptance - total iron limit
−type: range
−unit: mg/L
−min: 0.5
−max: 2
−step: 0.1
−default: 1
−```
+### Each parameter answers a different question. Clarity and turbidity say whether suspended debris is still being carried. pH and conductivity returning to the fill water baseline say whether the cleaner has been rinsed out, because the cleaner is what raised them. Total iron says whether the steel is still shedding scale or has begun to corrode, and total suspended solids put a number on what clarity shows. The default set is what a field kit and a photometer can measure the same day; the laboratory parameters are added where the Owner wants a laboratory record or where a descaler was used. {note}
+### Where visual clarity is selected, the flush shall be accepted only where the sample at every point shows no visible color or suspended matter when viewed beside the fill water sample.
+
+### Where turbidity is selected, the flush shall be accepted only where the turbidity at every sample point does not exceed the value indicated in the datasheet, measured in accordance with ASTM D7315.
+
```datasheet
−label: Flush acceptance - total suspended solids (TSS) limit
+label: Flush Acceptance Turbidity
type: range
−unit: mg/L
−min: 5
−max: 25
−step: 5
−default: 5
+unit: NTU
+options:
+ min: 1
+ max: 20
+ setpoints: [1, 2, 5, 10, 20]
+constraint: max
```
+### Where pH is selected, the flush shall be accepted only where the pH at every sample point is within the difference from the fill water baseline indicated in the datasheet, measured in accordance with ASTM D1293.
+
```datasheet
−label: Flush acceptance - pH within band of make-up water
+label: Flush Acceptance pH Difference from Fill Water
type: range
unit: pH units
−min: 0.3
−max: 1
−step: 0.1
+options:
+ min: 0.1
+ max: 2
+ step: 0.1
default: 0.5
+constraint: max
```
+### Where conductivity is selected, the flush shall be accepted only where the conductivity at every sample point is within the percentage above the fill water baseline indicated in the datasheet, measured in accordance with ASTM D1125.
+
```datasheet
−label: Flush acceptance - conductivity within band of make-up water
+label: Flush Acceptance Conductivity Above Fill Water
type: range
−unit: µS/cm
−min: 100
−max: 300
−step: 50
−default: 200
+unit: '%'
+options:
+ min: 5
+ max: 50
+ setpoints: [5, 10, 15, 20, 25, 50]
+default: 10
+constraint: max
```
+### Where total iron is selected, the flush shall be accepted only where the total iron at every sample point does not exceed the value indicated in the datasheet, measured in accordance with ASTM D1068.
+
```datasheet
−label: Open condenser water - ATP microbiological baseline (ASTM D4012)
−type: radio
+label: Flush Acceptance Total Iron
+type: range
+unit: mg/L
options:
− - Required before chemical program online
− - Not required (closed system)
−default: Not required (closed system)
+ min: 0.1
+ max: 10
+ setpoints: [0.1, 0.2, 0.5, 1, 2, 3, 5, 10]
+constraint: max
```
−# Passivation {toc}
+### Where total suspended solids are selected, the flush shall be accepted only where the total suspended solids at every sample point do not exceed the value indicated in the datasheet, measured in accordance with ASTM D5907.
−## Passivation Timing {note}
+```datasheet
+label: Flush Acceptance Total Suspended Solids
+type: range
+unit: mg/L
+options:
+ min: 1
+ max: 50
+ setpoints: [1, 2, 5, 10, 20, 50]
+constraint: max
+```
−### Freshly cleaned carbon steel flash-rusts within hours in oxygen-bearing water, so passivation cannot wait. The inhibitor must be charged and circulation started the same day flush acceptance is achieved. {note}
+### Where total iron remains above its acceptance value after three consecutive passes at the flush velocity, flushing shall stop and the Contractor shall report the result to the Engineer of Record, who shall determine whether the source is construction debris or active corrosion before further passes are made.
−### Adding the long-term water treatment program at its normal operating concentration before passivation is complete will not build a dense passive film, because the operating concentration is too low; passivation deliberately runs at an elevated multiple of operating concentration. {note}
+### Iron that falls with every pass is scale being carried out. Iron that holds steady pass after pass is steel dissolving in oxygenated water, and more flushing adds oxygen rather than removing iron. The distinction decides whether the next step is another pass or an immediate passivation, and it is the Engineer's call because the two look the same in the sample jar. {note}
−### The corrosion inhibitor start charge shall be added and passivation circulation shall begin on the same day flush acceptance is achieved.
+### The acceptance result for each parameter shall be recorded on the flush report with the sample point, the pass number, the time, the measured value, and the fill water baseline it was compared to.
−### The long-term chemical program of [[sync/hvac-water-treatment]] shall not be placed online until passivation is accepted.
+# Flush Water Disposal {toc}
−## Passivation Chemistry {note}
+## Discharge Route {toc}
−### Passivation chemistry must match the long-term water treatment program: molybdate, nitrite, or a molybdate-nitrite blend for carbon steel and mixed metallurgy, and a phosphonate-azole-polymer approach where aluminum is present. Choosing a passivation chemistry incompatible with the program forces a chemistry change at start-up. {note}
+### Flush water, spent cleaner, and neutralized solution shall be discharged by the route indicated in the datasheet.
−### The passivation inhibitor chemistry shall match the long-term program chemistry specified in [[sync/hvac-water-treatment]].
−
```datasheet
−label: Passivation chemistry
+label: Flush Water Discharge Route
type: radio
options:
− - Molybdate-based
− - Nitrite-based
− - Molybdate-nitrite blend
− - Phosphonate-azole-polymer (mixed metallurgy / aluminum)
−default: Molybdate-nitrite blend
+ - "Sanitary sewer under the receiving authority's written acceptance"
+ - "Sanitary sewer after on-site neutralization and testing"
+ - "Off-site haul and disposal as regulated waste"
```
−```datasheet
−label: Passivation dose multiplier (x long-term operating concentration)
−type: range
−unit: x
−min: 1.5
−max: 5
−step: 0.5
−default: 2.5
−```
+### No discharge route is the norm, because the answer follows the chemistry and the receiving authority. Plain flush water and a rinsed alkaline cleaner at flush dilution are accepted to the sanitary sewer by most authorities on notice, and the authority's acceptance is the only paperwork. Spent alkaline cleaner, phosphate, and any descaler sit outside the pH and metals limits that EPA 40 CFR Part 403 lets a local authority impose, and are neutralized and tested before release where the authority permits that, or hauled where it does not. Hauling costs the most per gallon and is the only route open where the authority declines the discharge or where molybdate or dissolved metals exceed its limits. {note}
+### The Contractor shall obtain the receiving authority's written acceptance of the discharge before any cleaner is added to the system, and shall meet every condition that acceptance imposes.
+
+### Flush water, cleaner, and neutralized solution shall not be discharged to a storm sewer, to grade, or to a receiving water.
+
+### Where on-site neutralization is selected, the discharge pH shall be held at or above the lower limit and at or below the upper limit indicated in the datasheets, measured at each batch before release or continuously during a flowing discharge, and the readings shall be recorded on the disposal record.
+
```datasheet
−label: Molybdate passivation target (as MoO4 2-)
+label: Discharge pH Lower Limit
type: range
−unit: mg/L
−min: 500
−max: 1000
−step: 50
−default: 750
+unit: pH
+drawing_ref: "the receiving authority's written discharge acceptance"
+options:
+ min: 5
+ max: 7
+ step: 0.5
+default: deferred
+constraint: exact
```
```datasheet
−label: Nitrite passivation target (as NO2-)
+label: Discharge pH Upper Limit
type: range
−unit: mg/L
−min: 1500
−max: 2400
−step: 100
−default: 1900
+unit: pH
+drawing_ref: "the receiving authority's written discharge acceptance"
+options:
+ min: 8
+ max: 11
+ step: 0.5
+default: deferred
+constraint: exact
```
−## Passivation Circulation {note}
+### Where a descaler was used, the neutralized solution shall additionally be tested for dissolved iron, copper, and zinc against the receiving authority's limits before release, and shall be hauled off-site where any limit is exceeded.
−### Carbon steel mains need a longer passivation circulation than copper-dominant systems to build the film; HHW systems are circulated warm toward operating temperature, while CHW and condenser water systems can only run at ambient with the pumps on. {note}
+### Hauled waste shall be transported in accordance with DOT 49 CFR, and the manifests shall be retained with the disposal record.
−### Passivation circulation shall continue for the scheduled duration with the inhibitor maintained within the passivation target band.
+### The volume discharged on each pass, the neutralization readings, and the haul manifests shall be recorded on the flush water disposal record.
−### HHW systems shall be passivated at elevated temperature approaching operating temperature; CHW and condenser water systems shall be passivated at ambient temperature with pumps running.
+# Passivation {toc}
+## Passivation Timing {toc}
+
+### Freshly cleaned carbon steel in oxygenated water begins to rust within hours. The rust that forms is loose and porous, and the inhibitor film that passivation builds has to form through it rather than on clean metal. The passivation charge goes in the same working day the flush is accepted for that reason, and a system that has to wait is kept circulating so the surface stays uniform until it does. {note}
+
+### The passivation inhibitor shall be charged and passivation circulation begun within eight hours of flush acceptance.
+
+### Where passivation cannot begin within eight hours of flush acceptance, the system shall be kept full and circulating until it does, and the flush acceptance samples shall be repeated immediately before the passivation charge is made.
+
+### The passivation charge shall be made through the chemical bypass feeder furnished under [[sync/hydronic-specialties]] or through a temporary injection connection, with the system full and vented and every terminal and plant device reinstated and open to flow.
+
+## Passivation Chemistry and Dose {toc}
+
+### The passivation inhibitor chemistry shall be the chemistry of the ongoing treatment program for that system, as indicated in the datasheet.
+
```datasheet
−label: Passivation circulation duration
−type: range
−unit: h
−min: 12
−max: 168
−step: 12
−default: 48
+label: Passivation Inhibitor Chemistry
+type: select
+derived: "the closed system corrosion inhibitor chemistry selected for the system under [[sync/hvac-water-treatment]]"
+options:
+ - "Molybdate"
+ - "Nitrite"
+ - "Molybdate and nitrite blend"
+ - "Phosphonate with azole and polymer"
+ - "Silicate"
+ - "Borate and nitrite"
+default: derived
```
+### The passive film is built by one chemistry and maintained by the same one. A system passivated with nitrite and then placed on a molybdate program spends its first months with a film that is neither, and the corrosion rate during that transition is what the first coupon reads. Taking the chemistry from the ongoing program is what makes the passivation and the program one continuous treatment. {note}
+
+### The passivation dose shall be as indicated in the datasheet, expressed as a multiple of the concentration the ongoing program holds as its control range for that chemistry.
+
```datasheet
−label: Passivation circulation temperature - HHW
+label: Passivation Dose as a Multiple of the Program Control Concentration
type: range
−unit: °F
−min: 100
−max: 180
−step: 10
−default: 120
+unit: '× control concentration'
+options:
+ min: 1
+ max: 5
+ setpoints: [1, 1.5, 2, 2.5, 3, 4, 5]
+constraint: exact
```
+### Where the datasheet carries no passivation dose, the dose shall be the inhibitor supplier's published passivation dose for the chemistry selected, stated in the method statement and recorded on the passivation record.
+
+### An azole copper inhibitor shall be included in the passivation charge of every system containing copper or copper-alloy surfaces, at the residual the ongoing program maintains under [[sync/hvac-water-treatment]].
+
+### On a glycol system, the inhibitor package in the inhibited glycol charged under this standard is the passivation charge, and a separate passivation inhibitor shall not be added to the glycol unless the compatibility verification under [[sync/hvac-water-treatment]] covers the combination.
+
+## Passivation Circulation {toc}
+
+### Passivation circulation shall continue, with the inhibitor residual held within the passivation target throughout, for the duration indicated in the datasheet.
+
```datasheet
−label: Passivation circulation temperature - CHW / condenser water
+label: Passivation Circulation Duration
type: range
−unit: °F
−min: 60
−max: 80
−step: 5
−default: 70
+unit: h
+options:
+ min: 8
+ max: 168
+ setpoints: [8, 12, 24, 48, 72, 120, 168]
+constraint: min
```
−# Corrosion Coupons {toc}
+### Where the datasheet carries no passivation circulation duration, the duration shall be the inhibitor supplier's published passivation period for the chemistry selected, stated in the method statement and recorded on the passivation record.
−## Coupon Installation {note}
+### The inhibitor residual shall be measured at the start of circulation, at intervals not exceeding 24 hours, and at the end, and the charge shall be topped up where the residual falls below the passivation target.
−### Corrosion coupons are the physical evidence trail that passivation worked; without them there is no objective data to distinguish a well-passivated system from one whose chemical program is merely holding corrosion in check at higher ongoing cost. {note}
+### On a heating system, the passivation circulation may be heated by the system heat source once the inhibitor charge is in the water.
−### A corrosion coupon rack holding the system's representative metallurgies shall be installed in a flowing stream in each zone of the system at the start of passivation.
+### A passive film forms faster and denser at operating temperature on steel, which is why a heating system is passivated warm where its boiler is ready to run, and why the boiler is allowed on the loop at this stage and not before: the water is now treated. A chilled water or condenser water system is passivated at ambient temperature with the pumps running, and needs the longer end of the duration band to reach the same film. {note}
−### Coupons shall include carbon steel and, where copper is present, copper, matching the system metallurgy.
+### Passivation shall be accepted where the inhibitor residual, the pH, and the total iron measured at the end of circulation are within the control ranges the ongoing program holds for that system under [[sync/hvac-water-treatment]], and the end-of-passivation analysis shall be recorded on the passivation record.
−### Coupons shall be first read at 90 days per ASTM D2688, with subsequent reads at 6 months and annually, by the water treatment provider under [[sync/hvac-water-treatment]].
+## Open Condenser Water Systems {toc}
+### The field piping of an open condenser water system is cleaned and flushed under this standard, and its passivation is the first weeks of its treatment program, during which the galvanized surfaces are passivated by pH control and the system receives its start-up disinfection under [[sync/hvac-water-treatment]]. The cooling tower basin and fill are cleaned under [[sync/cooling-towers]]. {note}
+
+### An open condenser water system shall be released to the water treatment service provider for start-up disinfection and initial program treatment under [[sync/hvac-water-treatment]] immediately after the piping flush is accepted, and the flush report shall record the date and time of that release.
+
+# Corrosion Coupon Rack {toc}
+
+## Rack Installation {toc}
+
+### A corrosion coupon rack shall be installed on each closed system at the start of passivation circulation.
+
+### The rack shall be located where indicated on [[drawing: the mechanical piping plans]], piped across a differential pressure that keeps water flowing through it continuously, with an isolation valve at each end, a flow-regulating valve, and a flow indicator, and shall be reachable for coupon changes from the floor or from a permanent platform.
+
+### The rack shall hold a coupon of each metallurgy indicated in the datasheet.
+
```datasheet
−label: Corrosion coupon metallurgies installed
+label: Corrosion Coupon Metallurgies
type: checkbox
options:
− - Carbon steel
− - Copper
− - Admiralty brass
− - Galvanized steel
+ - "Carbon steel"
+ - "Copper"
+ - "Admiralty brass or copper-nickel"
+ - "Galvanized steel"
+ - "Stainless steel"
+ - "Aluminum"
default:
− - Carbon steel
− - Copper
+ - "Carbon steel"
+ - "Copper"
+constraint: all_of
```
−```datasheet
−label: Number of coupon rack locations
−type: range
−unit: locations
−min: 1
−max: 6
−step: 1
−default: 2
−```
+### The datasheet selection shall be widened to include every metallurgy present in the wetted path of the system.
−```datasheet
−label: First coupon read interval (ASTM D2688)
−type: select
−options:
− - 30 days
− - 60 days
− - 90 days
−default: 90 days
−unit: days
−```
+### Each coupon holder shall insulate the coupon electrically from the rack and from the adjacent coupons.
−# Glycol Systems {toc}
+### Coupons shall be pre-weighed and serial-numbered by their supplier, shall be installed with the flow direction marked on the holder, and shall have their initial weight certificates delivered with the coupon installation record.
−## Glycol Charge Sequence {note}
+### The coupon installation record shall state the rack location, each coupon's metallurgy, serial number, initial weight, and installation date, and the name of the party who installed it.
−### On glycol loops the sequencing is explicit: clean and flush with water only, accept the flush, drain 100 percent of the flush water, then charge inhibited glycol at design concentration. Charging glycol into a dirty system embeds construction debris in the glycol where it cannot be flushed out without a full dump and re-clean, and cleaning with glycol in the system wastes expensive fluid and can degrade its inhibitor package. {note}
+### The coupons installed at passivation stay in place through the first read interval, and their reading, replacement, and acceptance criteria are governed under [[sync/hvac-water-treatment]]. Installing the rack at passivation rather than at hand-off is what gives the program a baseline that includes the passivation period itself, which is the period in which a poorly passivated system shows its highest corrosion rate. {note}
−### Automotive antifreeze shall not be used; its inhibitor package is not optimized for long-term hydronic service and its dyes and bittering agents interfere with field chemistry tests.
+# Glycol Charge {toc}
−### Glycol systems shall be cleaned and flushed with water only; glycol shall not be present during cleaning.
+## Charge Sequence {toc}
−### One hundred percent of the flush water shall be drained after flush acceptance before glycol is charged.
+### Glycol charged into a dirty system binds the construction debris into a fluid that cannot be flushed out without dumping the whole charge, and a cleaner circulated in glycol consumes the fluid's inhibitor package and sends the spent glycol down the drain as regulated waste. The sequence is water first, glycol last. {note}
−### The system shall be charged with inhibited industrial-grade glycol at the design concentration after flush acceptance and drain-down.
+### A system that will carry glycol shall be cleaned, flushed, and accepted on water under this standard before any glycol is introduced.
−### Pre-charge water chemistry and post-charge glycol concentration shall both be recorded in the glycol charge record.
+### After flush acceptance, the system shall be drained from every low point, and the volume of water that cannot be drained shall be estimated and recorded in the glycol charge calculation.
+### The glycol type and concentration shall be as selected under [[sync/hydronic-piping]], or where the loop is a snow melt loop, as selected under [[sync/snow-melt-systems]].
+
+### The glycol charge calculation shall state the system fluid volume, the residual water volume, the quantity of concentrate or premixed solution required to reach the design concentration, the dilution water source, and the expected makeup rate, and a copy shall be delivered to the party sizing the glycol makeup package under [[sync/hydronic-specialties]].
+
+### Where [[parameter: site-ambient-temperature-minimum]] is below 32°F, piping outdoors or in unconditioned space shall be drained or charged with glycol on the same working day the flush is accepted, and shall not be left full of water overnight.
+
+## Charging Method {toc}
+
+### The glycol shall be charged by the method indicated in the datasheet.
+
```datasheet
−label: Glycol type
+label: Glycol Charging Method
type: radio
options:
− - Inhibited industrial-grade propylene glycol
− - Inhibited industrial-grade ethylene glycol
−default: Inhibited industrial-grade propylene glycol
+ - "Premixed solution delivered at the design concentration"
+ - "Field blended in a mixing tank from concentrate and dilution water, then pumped into the system"
+ - "Concentrate pumped into the drained system, followed by dilution water, then circulated to blend"
```
−```datasheet
−label: Design glycol concentration (by volume)
−type: range
−unit: '%'
−min: 20
−max: 50
−step: 5
−default: 35
−```
+### No charging method is the norm across projects. A premixed solution arrives at a known concentration in dilution water the fluid supplier controlled, which is the simplest to verify and the most expensive to buy and ship. Field blending in a tank uses concentrate and site water and reaches the design concentration before the fluid enters the pipe, at the cost of a tank, a transfer pump, and a dilution water analysis. Blending in the system saves the tank and leaves the concentration unknown until circulation has mixed it, with the residual water in the low points diluting the result and the first refractometer reading taken at the plant telling nothing about the far end. {note}
−# Reinstatement and Acceptance {toc}
+### Where the glycol is field blended or diluted in the system, the dilution water shall meet the glycol manufacturer's published limits for hardness, chloride, and sulfate, judged against [[parameter: site-water-supply-hardness]], and softened or deionized water shall be used where the site supply exceeds those limits.
−## System Reinstatement {note}
+### The inhibitor package in an inhibited glycol reacts with the calcium and magnesium in hard water to form a precipitate that settles in the coils and consumes the inhibitor, which is why the fluid supplier publishes a dilution water limit and why hard-water sites blend with softened or deionized water. {note}
−### After flushing and passivation, the temporary bypasses come out and the protected equipment is returned to service; any temporary strainers must be removed or cleaned so they do not become a permanent restriction.
+### Glycol shall be charged through a temporary transfer pump or through the glycol makeup package, with the system vented at every high point during the charge, and shall be circulated until the concentration measured at the plant and at the most remote terminal agree within two percentage points by volume.
−### All spool-piece jumpers and temporary flush connections shall be removed and the permanent piping, coils, exchangers, and valves reinstated.
+### The concentration shall be measured by refractometer in accordance with ASTM D3321 at the plant and at the most remote terminal, and the freeze point corresponding to the measured concentration shall be taken from the fluid supplier's published table or measured in accordance with ASTM D1177.
−### Temporary flush strainers shall be removed, or cleaned and confirmed clear, before the system is returned to service.
+### The glycol charge record shall state the fluid product and lot numbers, the quantity charged, the dilution water source and its analysis, the refractometer readings and the freeze point they correspond to, which also serve as the fill reading required under [[sync/hydronic-piping]], and the pH and reserve alkalinity of the charged fluid.
−### Permanent strainers and basket filters shall be inspected and cleaned after the first 48 hours of operation following reinstatement.
+# Acceptance and Hand-Off {toc}
−## Acceptance and Hand-Off {note}
+## Cleaning, Flushing, and Passivation Report {toc}
−### The signed cleaning, flushing, and passivation report is the trigger that hands the system off to the water treatment provider and clears the TAB contractor to begin. {note}
+### The Contractor shall deliver a signed cleaning, flushing, and passivation report for each system, stating the system identification and boundary, the fill water source and baseline, the cleaning method, chemistry, dose, duration, and temperature, each flush pass with its flow, velocity, and sample results at every sample point, the acceptance values and the results compared against them, the passivation chemistry, dose, residuals, duration, and end-of-passivation analysis, the coupon installation record, the glycol charge record where one was made, the disposal record, the reinstatement record, and the signatures of the party who performed the work and of the witness.
−### The Contractor shall deliver the signed cleaning, flushing, and passivation report, with all acceptance test results and the coupon installation record, as the documented hand-off to the water treatment provider and TAB contractor.
+### The report shall be delivered to the Engineer of Record, the balancing agency, the commissioning authority where one is engaged, and the water treatment service provider within five working days of passivation acceptance, and before any of the events that this standard makes conditional on it.
−```datasheet
−label: Acceptance documentation level
−type: radio
−options:
− - Signed flushing and passivation reports only
− - Reports plus full laboratory iron, TSS, and pH results
− - Reports, laboratory results, and photographic flush-color log
−default: Reports plus full laboratory iron, TSS, and pH results
−```
+### The report is the single hand-off document. The balancing agency reads it as the release to begin, the boiler and chiller startup technicians read it as the release to run on the loop, and the water treatment service provider reads it as the baseline the program starts from. One document with one set of signatures is what keeps four parties from each asking for a different one. {note}
−# Warranty {toc}
+## Care Until the Program Is Online {toc}
−## The Contractor shall warrant that the system was cleaned, flushed, and passivated in accordance with the accepted method statement and that the documented acceptance criteria were met.
+### From passivation acceptance until the ongoing program is placed online under [[sync/hvac-water-treatment]], the Contractor shall keep each system full, vented, and circulated at least once each week.
−## Coil and heat-exchanger fouling traceable to omitted or incomplete flushing shall be corrected by the Contractor at no cost to the Owner during the warranty period.
+### Where more than 30 days pass between passivation acceptance and the program going online, the inhibitor residual shall be re-tested and restored to the passivation target before the hand-off sample is drawn.
+### Where a section is re-flushed after a leak repair under [[sync/hydronic-piping]], the passivation of that section shall be repeated under this standard, and the Contractor shall bear the cost of the repeat passivation and of the inhibitor consumed.
+
+# Delivery, Storage, and Handling {toc}
+
+## Every cleaning chemical, passivation inhibitor, and glycol product brought to the site shall be labeled and accompanied by a Safety Data Sheet in accordance with OSHA 29 CFR 1910.1200.
+
+## Chemicals shall be stored in their original labeled containers within secondary containment sized for the largest container, with acids stored apart from alkaline products.
+
+## Glycol shall be stored in sealed containers, protected from freezing and from contamination, and a container that has been opened and left unsealed shall not be charged into the system.
+
+## Temporary pumps, filters, tanks, and hoses shall be removed from the site when the work of this standard is complete, and spent chemical containers shall be triple-rinsed or disposed of as the product label directs.
+
+# Warranty {toc}
+
+## The Contractor shall warrant that each system was cleaned, flushed, passivated, and charged in accordance with the accepted method statement and that the values recorded in the report were measured as stated, for the period indicated in the datasheet, measured from the date of substantial completion.
+
```datasheet
−label: Cleaning and flushing workmanship warranty period
+label: Cleaning and Flushing Warranty Period
type: range
unit: months
−min: 12
−max: 24
−step: 6
+options:
+ min: 12
+ max: 36
+ setpoints: [12, 18, 24, 36]
default: 12
+constraint: min
```
−# Spare Parts {toc}
+## Where the contract General Conditions specify a longer warranty period than the datasheet, the longer period shall govern.
−## The Contractor shall turn over unused corrosion coupons of each installed metallurgy for the first scheduled coupon change-out.
+## Fouling, blockage, or corrosion discovered within the warranty period that the Engineer of Record attributes to construction debris, cleaner residue, incomplete passivation, or an incorrect glycol charge shall be corrected by the Contractor at no cost to the Owner, including the re-cleaning, re-flushing, and re-passivation of the affected system, the treatment chemical and glycol lost, the cleaning or replacement of fouled coils, strainers, seals, and heat exchangers, and the removal and reinstatement of insulation and finishes to reach them.
−## The Contractor shall provide the Owner with the chemical product data and Safety Data Sheets for the passivation inhibitor and glycol in service.
+## Where the parties disagree whether a fouling or corrosion finding arose from the construction-phase cleaning or from the ongoing treatment program or the operation of the system, the Engineer of Record shall make the initial determination.
−```datasheet
−label: Spare corrosion coupon sets turned over
−type: range
−unit: sets
−min: 0
−max: 4
−step: 1
−default: 1
−```
+## The unassigned cost in a cleaning warranty is never the flush itself. It is the coil that has to be pulled, the glycol that has to be drained to reach it, and the balance that has to be redone afterward. Naming those costs here, and naming who decides whether the debris came from construction, is what makes the warranty enforceable without an argument. {note}