Hydronic Specialties
Remade from scratch under the authoring cheatsheet: field inventory from the decision space, pressure-independent control valves owned as one assembly, coil control valves handed to the controls standard, ratings derived from the piping system, a trade-off note beside every choice
Showing changes from Rev 3
to Rev 4
in Hydronic Specialties.
---
title: Hydronic Specialties
category: Mechanical / Piping & Pumps
−toc_depth: 3
description: >
− When to use: Specialty in-line devices installed within closed-loop hydronic
− heating hot water (HHW), chilled water (CHW), and condenser water (CW) piping
− served by a central plant in commercial, institutional, and industrial
− buildings operating within ASME B31.9 limits (up to 160 psig / 250°F). Covers
− manual calibrated balancing valves, automatic flow-limiting valves,
− pressure-independent control valves (PICVs), Y-pattern and basket strainers,
− in-line combination air/dirt separators, chemical pot (bypass) feeders,
− pressure gauges and thermometers with wells, flexible pipe connectors, drain
− and sample valves, and factory coil connection kits.
− Not intended for: pipe, fittings, joining, hangers, and pressure testing
− ([[sync/hydronic-piping]]); pumps and pump-integral accessories
− ([[sync/hvac-pumps]]); expansion tanks and the primary system air separator
− ([[sync/expansion-tanks-and-air-separators]]); valve and fitting insulation
− ([[sync/mechanical-insulation]]); DDC-actuated control valves that are part
− of the control sequence (HVAC controls); steam and condensate specialties;
− plumbing and domestic-water specialties; and fire protection specialties
− (NFPA 13).
+ When to use: The in-line devices that make a closed-loop hydronic distribution system balanceable, protected, readable, and serviceable, installed in heating hot water, chilled water, dual-temperature, and condenser water piping within the ASME B31.9 building-services envelope. Covers manual calibrated balancing valves, automatic flow-limiting valves, differential pressure control valves, pressure-independent control valves furnished complete with their actuator, Y-pattern and basket strainers, suction diffusers, triple-duty valves and pump discharge assemblies, flexible pipe connectors, chemical bypass feeders, makeup water fill assemblies and glycol makeup packages, system relief valves, pressure gauges, thermometers and thermowells, pressure and temperature test plugs, manual air vents and hose-end drain valves, and factory or field-assembled coil connection assemblies.
+ Not intended for: Pipe, fittings, joining, dissimilar-metal isolation, and the piping pressure test (see [[sync/hydronic-piping]]); manual isolation, shutoff, throttling, and check valves (see [[sync/hvac-piping-valves]]); two-way and three-way modulating control of coils and heat exchangers, including the bodies and the electric operators that perform it (see [[sync/hvac-controls-instrumentation]]); expansion tanks, central and in-line air separators, combination air-and-dirt separators, and automatic air vents (see [[sync/expansion-tanks-and-air-separators]]); pumps and the accessories the pump manufacturer mounts before shipment (see [[sync/hvac-pumps]]); backflow prevention assemblies on the makeup water connection (see [[sync/backflow-prevention]]); the chemistry, dosing, and monitoring program (see [[sync/hvac-water-treatment]]); cleaning, flushing, and the initial glycol charge (see [[sync/hydronic-cleaning-and-flushing]]); the placement rules for vibration-isolated equipment (see [[sync/vibration-isolation-and-seismic-restraint]]); flow balancing and its verification (see [[sync/testing-adjusting-and-balancing]]); insulation of the devices (see [[sync/mechanical-insulation]]); boiler trim and boiler relief valves (see [[sync/boilers]]); steam and condensate specialties (see [[sync/steam-and-condensate-piping]]); and domestic water specialties (see [[sync/domestic-water-piping]]).
---
# Scope {toc}
−## This standard governs the materials, ratings, construction, and installation of in-line hydronic specialties in closed-loop heating hot water, chilled water, and condenser water piping systems served by a central plant. {note}
+## Boundary of Work {toc}
−## Hydronic specialties are the field-installed in-line devices — balancing valves, strainers, air/dirt separators, chemical feeders, gauges, thermometers, flexible connectors, and drain/sample valves — that make a hydronic distribution system balanceable, serviceable, and measurable. They are distinct from the pipe that carries the water and from the rotating and pressurization equipment at the plant. {note}
+### This standard governs the in-line specialty devices of a closed-loop hydronic distribution system: the devices that set and measure flow, protect equipment from debris, isolate vibration, admit treatment chemicals and makeup water, relieve overpressure, and let an operator read pressure and temperature at the pipe. It covers the device as a unit of supply, from its end connections inward, and the installation and startup steps that decide whether the device does its job. {note}
−## Applicability {toc}
+### The systems in scope are heating hot water, chilled water, dual-temperature, and condenser water piping operating within the pressure and temperature limits of ASME B31.9 for building services. Above those limits the piping falls under ASME B31.1 and this standard does not apply. {note}
−### This standard shall apply to all hydronic specialties installed in closed-loop HHW, CHW, and CW distribution systems operating within the pressure-temperature envelope of ASME B31.9 (up to 160 psig and 250°F). {note}
+### The piping that carries these devices, the general-duty valves that isolate them, and the pumps and pressurization equipment they serve are each governed by their own standard. This standard defers to those standards rather than restating them: {note}
−### This standard applies to new construction and to renovation work that adds or replaces hydronic specialties within an existing distribution system. {note}
+- Pipe, fittings, joining methods, dissimilar-metal isolation, drain and vent connection locations, straight-pipe provisions at metering devices, and the structural pressure test [[sync/hydronic-piping]]
+- General-duty isolation, shutoff, throttling, and check valves [[sync/hvac-piping-valves]]
+- Two-way and three-way automatic control valves for coils and heat exchangers, together with their electric actuators [[sync/hvac-controls-instrumentation]]
+- Expansion tanks, central and in-line air separators, combination air-and-dirt separators, and automatic air vents [[sync/expansion-tanks-and-air-separators]]
+- The pump, its motor, its baseplate, and the accessories the pump manufacturer mounts before shipment [[sync/hvac-pumps]]
+- Backflow prevention assemblies on the makeup water connection [[sync/backflow-prevention]]
+- The chemistry, dosing, monitoring, and service program that uses the feeders furnished here [[sync/hvac-water-treatment]]
+- Cleaning, flushing, passivation, and the initial glycol charge [[sync/hydronic-cleaning-and-flushing]]
+- Where flexible connectors are required at vibration-isolated equipment, and the thrust restraint that goes with them [[sync/vibration-isolation-and-seismic-restraint]]
+- Flow balancing and the verification of balancing and flow-limiting devices [[sync/testing-adjusting-and-balancing]]
+- Insulation of the devices and the removable covers over them [[sync/mechanical-insulation]]
+- Boiler trim, including the boiler relief valve [[sync/boilers]]
−### Where condenser water serves an open-loop cooling tower circuit, the drain and sample provisions of this standard apply, but tower-side specialties and water treatment hardware are governed by the cooling tower and water treatment standards. {note}
+### Pressure-independent control valves are the one control device this standard owns. Where a project selects them, the valve body, its differential pressure regulator or flow measurement, its maximum flow setting, and the actuator that modulates it are one product furnished under this standard, and no part of that assembly is furnished under [[sync/hvac-controls-instrumentation]]. Two-way and three-way coil control valves that depend on a separate balancing device stay with the controls standard. The split follows the product: a pressure-independent valve is bought, sized, and warranted as one assembly, and dividing it between two standards is how a project ends up with a body that has no actuator or an actuator that does not fit. {note}
−## Exclusions {toc}
+### A hydronic distribution system is installed once and read for the life of the building. The devices in this standard are the only places where an operator can see what the system is doing, adjust it, or clean it without cutting pipe, which is why this standard is as concerned with where they are and whether they can be reached as with what they are made of. {note}
−### The following are outside the scope of this standard and are governed elsewhere: {note}
+### The locations of the devices furnished under this standard shall be as indicated on [[drawing: the mechanical piping plans and details]].
−- Pipe, fittings, joining methods, hangers and supports, pressure testing, flushing, and cleaning — see [[sync/hydronic-piping]].
−- Centrifugal pump assemblies, motors, baseplates, and pump-integral suction diffusers and triple-duty valves — see [[sync/hvac-pumps]].
−- Expansion tanks (bladder, diaphragm, open) and the primary system air separator — see [[sync/expansion-tanks-and-air-separators]].
−- Insulation of pipe, valves, and fittings, including removable insulation jackets — see [[sync/mechanical-insulation]].
−- DDC/BAS-actuated modulating or two-position control valves that are integral to a control sequence — addressed in HVAC controls. (PICVs specified here are furnished as a single hydronic specialty product complete with actuator.)
−- Steam, steam condensate, and trap specialties — not hydronic.
−- Domestic and plumbing water specialties (potable backflow preventers, plumbing pressure-reducing valves, water hammer arresters) — governed by plumbing standards.
−- Fire protection system specialties — governed by NFPA 13 and related fire protection standards.
+## Terms Used in This Standard {toc}
−## Related standards: [[sync/hydronic-piping]], [[sync/hvac-pumps]], [[sync/expansion-tanks-and-air-separators]], [[sync/mechanical-insulation]], [[sync/testing-adjusting-and-balancing]], and [[sync/hvac-water-treatment]]. {note}
+### The following terms carry the meanings given here throughout this standard: {note}
+- Manual balancing valve: a valve with a calibrated relation between handle position and flow coefficient, integral metering ports, and a memory stop, set once by the balancing agency and left
+- Automatic flow-limiting valve: a self-actuating device with a spring-loaded cartridge that holds a fixed flow across a published band of differential pressure without external power or adjustment
+- Differential pressure control valve: a self-actuating valve that holds a constant differential pressure across a branch, a riser, or a group of terminals so the manual balancing devices downstream keep their authority as other branches modulate
+- Pressure-independent control valve: an assembly that combines a differential pressure regulator or a flow measurement with a modulating control valve and its actuator, holding the commanded flow regardless of changes in system differential pressure
+- Control differential pressure range: the band of differential pressure, from the activation minimum to the rated maximum, within which a flow-limiting or pressure-independent device holds its set flow within its published tolerance
+- Metering port: a self-sealing pressure and temperature port on a balancing device through which a differential pressure gauge reads the flow signal
+- Test plug: a self-sealing pressure and temperature port installed in the piping to accept a portable gauge or thermometer probe
+
# Referenced Standards {toc}
## Equipment, materials, and installation 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.
+## Where the contract documents, the adopted building code, or a referenced standard conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
| Standard | Title |
|----------|-------|
−| ASME B31.9 | Building Services Piping |
−| ASME B16.34 | Valves — Flanged, Threaded, and Welding End |
−| ASME B1.20.1 | Pipe Threads, General Purpose, Inch |
−| MSS SP-25 | Standard Marking System for Valves, Fittings, Flanges and Unions |
−| MSS SP-80 | Bronze Gate, Globe, Angle and Check Valves |
−| MSS SP-110 | Ball Valves Threaded, Socket-Welding, Solder Joint, Grooved and Flared Ends |
| ANSI/ASHRAE/IES 90.1 | Energy Standard for Buildings Except Low-Rise Residential Buildings |
−| ANSI/ASHRAE 188 | Legionellosis: Risk Management for Building Water Systems |
+| ANSI/FCI 70-2 | Control Valve Seat Leakage |
+| ANSI/ISA-75.01.01 | Industrial-Process Control Valves: Flow Capacity, Sizing Equations for Fluid Flow Under Installed Conditions |
+| ASME B1.20.1 | Pipe Threads, General Purpose (Inch) |
+| ASME B16.1 | Gray Iron Pipe Flanges and Flanged Fittings: Classes 25, 125, and 250 |
+| ASME B16.5 | Pipe Flanges and Flanged Fittings, NPS 1/2 through NPS 24 |
+| ASME B16.24 | Cast Copper Alloy Pipe Flanges, Flanged Fittings, and Valves |
+| ASME B16.34 | Valves: Flanged, Threaded, and Welding End |
+| ASME B31.9 | Building Services Piping |
+| ASME B40.100 | Pressure Gauges and Gauge Attachments |
+| ASME B40.200 | Thermometers, Direct Reading and Remote Reading |
+| ASME BPVC Section IV | Rules for Construction of Heating Boilers |
+| ASME BPVC Section VIII | Rules for Construction of Pressure Vessels, Division 1 |
| ASTM A126 | Gray Iron Castings for Valves, Flanges, and Pipe Fittings |
+| ASTM A216 / A216M | Steel Castings, Carbon, Suitable for Fusion Welding, for High-Temperature Service |
+| ASTM A351 / A351M | Castings, Austenitic, for Pressure-Containing Parts |
| ASTM A536 | Ductile Iron Castings |
| ASTM B61 | Steam or Valve Bronze Castings |
| ASTM B62 | Composition Bronze or Ounce Metal Castings |
| ASTM B584 | Copper Alloy Sand Castings for General Applications |
−| IMC Chapter 12 | Hydronic Piping (International Mechanical Code) |
+| AWWA C606 | Grooved and Shouldered Joints |
+| IMC | International Mechanical Code, Chapter 12 (Hydronic Piping) |
+| MSS SP-25 | Standard Marking System for Valves, Fittings, Flanges, and Unions |
+| MSS SP-110 | Ball Valves Threaded, Socket-Welding, Solder Joint, Grooved and Flared Ends |
+| NEMA 250 | Enclosures for Electrical Equipment (1000 Volts Maximum) |
+| UL 429 | Electrically Operated Valves |
# Submittals {toc}
## Action Submittals {toc}
−### The Contractor shall submit the following action submittals for review before procurement:
+### The Contractor shall submit the following for the Engineer of Record's review and return before any device covered by this standard is procured:
−- Product data for each specialty type, including body and trim materials, pressure-temperature rating, end connections, and Cv or flow coefficient where applicable.
−- A balancing valve and flow control device schedule listing tag, location, design flow rate, and selected device for each terminal and branch.
−- Strainer schedule listing location, body material, screen mesh size, and blow-down provisions.
−- Pressure-independent control valve (PICV) selection data showing design flow, minimum controllable flow, control range, actuator type, and signal compatibility with the BAS.
−- Manufacturer cut sheets for gauges, thermometers, thermowells, flexible connectors, and chemical feeders, with ranges and ratings highlighted for the specified application.
−- Coil connection kit assembly drawings where factory-assembled kits are specified.
+- Product data for each device family, identifying the body and trim materials, the pressure-temperature rating at the system design temperature, the end connections, and the size range offered
+- A balancing device schedule listing, for every manual balancing valve, automatic flow-limiting valve, and differential pressure control valve, the tag, the served terminal or branch, the design flow, the selected size, and the published flow coefficient or cartridge rating
+- A pressure-independent control valve schedule listing, for every valve, the tag, the served terminal, the design flow, the maximum flow setting, the minimum controllable flow, the control differential pressure range, the close-off rating, the actuator model, the control signal, and the fail position
+- A strainer and suction diffuser schedule listing, for every unit, the tag, the location, the pattern, the body material, the screen mesh or perforation, and the blowdown provision
+- Flexible connector product data showing the connector type, the elastomer or hose material, the working pressure and vacuum ratings at the design temperature, the published movement allowances, and the control rod arrangement where furnished
+- Chemical bypass feeder product data showing the capacity, the pressure rating, the body material, the closure, and the accessories furnished
+- Makeup water fill assembly or glycol makeup package data showing the inlet pressure rating, the set point range, and the alarm contacts furnished
+- Relief valve selection data showing the set pressure, the relieving capacity, and the certification mark
+- A gauge, thermometer, thermowell, and test plug schedule listing, for every instrument location, the scale range, the dial size, the well insertion and lagging lengths, and the core material
+- Coil connection assembly drawings for factory-assembled kits, showing every component, its rating, and the face-to-face dimensions
```datasheet
−label: Action Submittals
+label: Action Submittals Required
type: checkbox
options:
− - Specialty product data with materials and ratings
− - Balancing and flow control device schedule
− - Strainer schedule with mesh sizes
− - PICV selection data (flow range, actuator, signal)
− - Gauge, thermometer, and thermowell cut sheets
− - Flexible connector product data
− - Chemical feeder product data
− - Coil connection kit assembly drawings
−defaults:
− - Specialty product data with materials and ratings
− - Balancing and flow control device schedule
− - Strainer schedule with mesh sizes
− - Gauge, thermometer, and thermowell cut sheets
+ - "Product data for each device family"
+ - "Balancing device schedule"
+ - "Pressure-independent control valve schedule"
+ - "Strainer and suction diffuser schedule"
+ - "Flexible connector product data"
+ - "Chemical bypass feeder product data"
+ - "Makeup water fill or glycol makeup package data"
+ - "Relief valve selection data"
+ - "Gauge, thermometer, thermowell, and test plug schedule"
+ - "Coil connection assembly drawings"
+default:
+ - "Product data for each device family"
+ - "Balancing device schedule"
+ - "Strainer and suction diffuser schedule"
+ - "Flexible connector product data"
+ - "Relief valve selection data"
+ - "Gauge, thermometer, thermowell, and test plug schedule"
```
−## Informational Submittals {toc}
+### Each schedule shall carry the design flow or the design condition that the device was selected against, so that the Engineer of Record can check the selection without opening the design calculations.
−### The Contractor shall submit the following informational submittals:
+### The Contractor shall bear the cost of resubmission caused by a schedule that omits the design condition or that is inconsistent with the piping or valve submittals for the same location.
−- Manufacturer installation instructions for each specialty type, including required upstream and downstream clearances.
−- Pressure-temperature rating certifications confirming compliance with the system design conditions.
−- Coordination drawings showing specialty locations relative to terminal units, access panels, and service clearances.
+## Closeout Submittals {toc}
+### The Contractor shall submit the following at substantial completion, before the work of this standard is accepted:
+
+- Operation and maintenance data for every device family, including the screen and cartridge sizes installed, the actuator replacement procedure for pressure-independent control valves, and the feeder charging procedure
+- The as-installed pressure-independent control valve schedule recording the maximum flow setting at which each valve was delivered to the balancing agency
+- A strainer cleaning record showing the date each screen was cleaned after flushing and the date each temporary startup screen was removed
+- Relief valve certification and the as-installed set pressure of each valve
+- The fill valve set point and the glycol makeup package set points as left at startup
+- Warranty documentation for each device family
+
```datasheet
−label: Informational Submittals
+label: Closeout Submittals Required
type: checkbox
options:
− - Manufacturer installation instructions
− - Pressure-temperature rating certifications
− - Coordination drawings with service clearances
−defaults:
− - Manufacturer installation instructions
− - Pressure-temperature rating certifications
+ - "Operation and maintenance data"
+ - "As-installed pressure-independent control valve schedule"
+ - "Strainer cleaning and startup screen removal record"
+ - "Relief valve certification and as-installed set pressure"
+ - "Fill and makeup set points as left"
+ - "Warranty documentation"
+default:
+ - "Operation and maintenance data"
+ - "Strainer cleaning and startup screen removal record"
+ - "Relief valve certification and as-installed set pressure"
+ - "Warranty documentation"
```
−## Closeout Submittals {toc}
+# Quality Assurance {toc}
−### The Contractor shall submit the following closeout submittals:
+## Marking and Pressure Rating {toc}
−- Operation and maintenance data for strainers, feeders, and flow control devices.
−- Record balancing valve settings (memory-stop positions and measured flow) as recorded by the balancing agency.
−- Warranty documentation for all furnished specialties.
+### Every valve-form device furnished under this standard shall bear the manufacturer's marking required by MSS SP-25, including the size, the pressure class, and the body material.
+### Every device shall carry a manufacturer's published pressure-temperature rating, under ASME B16.34 or the product standard applicable to its body material, of not less than the working pressure indicated in the datasheet at the maximum design temperature of the system in which it is installed.
+
```datasheet
−label: Closeout Submittals
−type: checkbox
−options:
− - Operation and maintenance data
− - Record balancing valve settings
− - Warranty documentation
−defaults:
− - Operation and maintenance data
− - Record balancing valve settings
− - Warranty documentation
+label: Minimum Body Working Pressure Rating
+type: range
+unit: psig
+min: 125
+max: 400
+setpoints: [125, 150, 175, 200, 250, 300, 400]
+derived: "the design pressure and maximum design temperature of the piping system served, as specified under [[sync/hydronic-piping]]"
+default: derived
```
−# Quality Assurance {toc}
+### Where a device's pressure rating derates with temperature, the rating at the system design temperature shall govern, and the rating at ambient shall not be used.
−## Identification and Marking {toc}
+### The design pressure and temperature of each system are selected under [[sync/hydronic-piping]] and are not asked again here. A specialty is rated against the system it sits in, so the body rating follows from that selection rather than standing as an independent choice, and the field above is derived from it for that reason. The catalog steps are the ones that separate the cast iron, bronze, ductile iron, and steel bodies actually sold for building services. {note}
−### Valves and specialty fittings shall be marked in accordance with MSS SP-25. {note}
+### Where a glycol solution is selected under [[sync/hydronic-piping]], every elastomer seat, seal, diaphragm, cartridge, and gauge fill in a device furnished under this standard shall be rated by its manufacturer for the glycol type and concentration selected.
−## Each specialty device shall bear permanent identification of manufacturer, size, pressure rating, and material in accordance with MSS SP-25.
+## Flow Data and Single-Source Responsibility {toc}
−## Bronze gate, globe, angle, and check valve components within specialty assemblies shall conform to MSS SP-80.
+### The manufacturer of each balancing valve, flow-limiting valve, differential pressure control valve, and pressure-independent control valve shall publish flow coefficient or flow-versus-differential-pressure data for every size and setting, derived from flow testing and stated with the tolerance to which the data apply.
−## Ball valve components within coil connection kits and isolation assemblies shall conform to MSS SP-110.
+### Manual balancing valves throughout the project shall be the product of a single manufacturer, so that the balancing agency works from one set of flow curves and one metering procedure.
−## Threaded end connections shall conform to the pipe thread form and dimensions of ASME B1.20.1.
+### Each pressure-independent control valve shall be furnished with its body, cartridge or flow measurement, and actuator as a single assembly from a single manufacturer, and an actuator from a different manufacturer shall not be fitted in the field.
−## Each specialty device shall carry a pressure-temperature rating not less than the system design pressure and temperature, verified against ASME B16.34 selection criteria.
+### A balancing agency reads flow through a differential pressure signal and a published curve, and a project that mixes balancing valve manufacturers sends the agency to a different curve, a different port spacing, and sometimes a different metering fluid correction at every terminal. Single sourcing the balancing valves is what makes the balancing report internally consistent. {note}
−## All specialties shall be selected for a pressure class of at least 1.5 times the system design pressure.
+# Service Conditions and Common Construction {toc}
−### Selecting devices at a pressure class of at least 1.5 times the system design pressure provides margin for pressure transients, pump shut-off head, and static head in tall buildings without operating any device at its rated limit. {note}
+## Body Materials by Size Band {toc}
−# Environmental and Service Conditions {toc}
+### The body material of devices NPS 2 and smaller shall be as indicated in the datasheet.
−## Hydronic specialties operate continuously in a wetted, often glycol-bearing environment across a wide temperature band; material selection and pressure class must be matched to the actual service fluid and operating envelope, not to a generic rating.
+```datasheet
+label: Body Material, NPS 2 and Smaller
+type: select
+options:
+ - "Bronze"
+ - "Brass"
+ - "Ductile iron"
+ - "Stainless steel"
+default: "Bronze"
+```
−## System design pressure and temperature shall be established for each circuit and used as the selection basis for every specialty in that circuit.
+### The body material of devices NPS 2-1/2 and larger shall be as indicated in the datasheet.
```datasheet
−label: System Design Pressure
−type: range
−unit: psig
−min: 30
−max: 160
−step: 5
−default: 125
+label: Body Material, NPS 2-1/2 and Larger
+type: select
+options:
+ - "Cast iron"
+ - "Ductile iron"
+ - "Carbon steel"
+ - "Bronze"
+ - "Stainless steel"
+default: "Cast iron"
```
+### Bronze and brass bodies match copper tube in the small sizes and avoid a galvanic couple at the joint; brass costs less than bronze and is chosen where the alloy is dezincification resistant, while bronze is the customary body where the fluid or the treatment chemistry is uncertain. Cast iron is the least costly body at the larger sizes within its pressure and temperature limits, ductile iron extends both limits and tolerates the bolting loads of a raised-face mating flange that gray iron cannot, carbon steel is the body where the piping standard sets a rating that iron cannot meet, and stainless steel is chosen where high-concentration glycol, deionized water, or an aggressive treatment chemistry attacks copper alloys and iron alike. {note}
+
+### Bronze bodies shall conform to ASTM B61, ASTM B62, or ASTM B584; brass bodies shall be of a dezincification-resistant alloy; cast iron bodies shall conform to ASTM A126 Class B; ductile iron bodies shall conform to ASTM A536; carbon steel bodies shall conform to ASTM A216 / A216M Grade WCB; and stainless steel bodies shall conform to ASTM A351 / A351M Grade CF8 or CF8M.
+
+### Where an iron or steel body is installed in copper tube, the dissimilar-metal isolation required by [[sync/hydronic-piping]] shall be provided at the connection.
+
+### Where a device family is offered in only one of the materials selected above, the device shall be furnished in that material, and the Contractor shall identify the substitution on the product data submittal.
+
+## End Connections by Size Band {toc}
+
+### End connections of devices NPS 2 and smaller shall match the joining method of the adjacent piping.
+
```datasheet
−label: System Design Temperature (Maximum)
−type: range
−unit: °F
−min: 40
−max: 250
−step: 5
−default: 200
+label: End Connections, NPS 2 and Smaller
+type: select
+options:
+ - "Threaded, NPT"
+ - "Solder end"
+ - "Press-connect for copper tube"
+ - "Grooved"
+ - "Union end"
+derived: "the joining method of the adjacent piping at each device, as selected under [[sync/hydronic-piping]]"
+default: derived
```
+### End connections of devices NPS 2-1/2 and larger shall match the joining method of the adjacent piping.
+
```datasheet
−label: Service Fluid
+label: End Connections, NPS 2-1/2 and Larger
type: select
options:
− - Water
− - Water with corrosion inhibitor
− - Propylene glycol solution (up to 50%)
− - Ethylene glycol solution (up to 50%)
−default: Water with corrosion inhibitor
+ - "Flanged"
+ - "Grooved"
+ - "Wafer-style"
+ - "Lug-style"
+derived: "the joining method of the adjacent piping at each device, as selected under [[sync/hydronic-piping]]"
+default: derived
```
−## Where a glycol solution is the service fluid, all elastomeric seats, seals, and separator media shall be confirmed compatible with the specified glycol type and concentration.
+### The end connection follows the joining method the piping trade uses at that size, which is why both fields are derived rather than chosen here. A threaded device in a press-connect copper system needs an adapter at every end, and a flanged device in a grooved steel system needs a pair of flange adapters, each of which is a joint the piping standard did not plan for. Where the choice does arise it is between a lug body, which can be removed with the downstream pipe in place, and a wafer body, which cannot. {note}
−### Glycol solutions, particularly ethylene glycol, attack some elastomers used in standard water-service seats; EPDM is generally compatible while some nitriles are not, so the selection must be verified rather than assumed. {note}
+### Threaded ends shall conform to ASME B1.20.1.
−# Materials and End Connections {toc}
+### Flanged ends shall conform to ASME B16.1 for iron bodies, ASME B16.5 for steel bodies, and ASME B16.24 for bronze bodies, and shall be of the same pressure class as the mating piping flange.
−## Body material and end connection style are the two selections that recur across every specialty type and are therefore set once at the system level and applied consistently to balancing valves, strainers, and feeders alike. {note}
+### Grooved ends shall conform to AWWA C606 and shall be compatible with the coupling system selected under [[sync/hydronic-piping]].
−## Bronze or brass bodies shall be used on copper piping systems regardless of pipe size.
+## Service Access {toc}
−### Iron-body specialties on copper piping create a galvanic couple that accelerates corrosion of the copper; bronze or brass bodies are mandatory on copper systems, and iron bodies are appropriate only on steel piping. {note}
+### Each device that is read, adjusted, cleaned, or reset in service shall be located so that the operation can be performed from the floor or from a fixed platform, or shall be provided with the access required by [[sync/hydronic-piping]] where it is concealed.
−## Cast iron or ductile iron bodies shall be used only on steel piping systems and only at sizes 2-1/2 in. and larger.
+### Where the parties disagree whether a device is reachable for the operation it requires, the Engineer of Record shall make the initial determination.
+### A strainer that cannot be blown down, a balancing valve whose metering ports face a wall, and a gauge that can be read only from a ladder are each installed correctly and useless. The access requirement is stated once here so that every device family below inherits it. {note}
+
+# Manual Balancing Valves {toc}
+
+## Manual Balancing Valve Construction {toc}
+
+### A manual balancing valve is a throttle and a flow meter in one body. Its handle position sets a known flow coefficient, and the differential pressure read across its metering ports, entered on the manufacturer's curve for that position, gives the flow. It suits constant-flow circuits and the terminals of variable-flow systems where a separate control valve does the modulating and the balancing valve only fixes the maximum. {note}
+
+### The manual balancing valve type shall be as indicated in the datasheet.
+
```datasheet
−label: Specialty Body Material (small sizes, 2 in. and smaller)
+label: Manual Balancing Valve Type
type: select
options:
− - Bronze (ASTM B62)
− - Brass (ASTM B584)
− - Steam bronze (ASTM B61)
−default: Bronze (ASTM B62)
+ - "Calibrated ball valve"
+ - "Calibrated globe valve"
+ - "Venturi flow fitting with isolation valve"
+ - "Calibrated butterfly valve"
+default: "Calibrated globe valve"
```
+### A calibrated globe valve gives the finest resolution across its stroke and the widest measuring range, which is why it is the customary balancing valve on coils; a calibrated ball valve costs less and is shorter, at the price of a coarser relation between handle position and flow. A venturi flow fitting measures more accurately than either because its signal does not depend on a handle position, and it needs a separate throttling valve to set the flow. A calibrated butterfly valve is the balancing device available above the size range of the others and throttles usefully over only part of its rotation. {note}
+
+### Each manual balancing valve shall have integral self-sealing metering ports on both sides of the throttling element, positioned so that a differential pressure gauge can be connected with the pipe insulated.
+
+### Each manual balancing valve shall have a memory stop that preserves the balanced position when the valve is closed for service and returns to it when the valve is reopened.
+
+### Each manual balancing valve shall have a position indicator readable without tools, and the memory stop shall be lockable or tamper-resistant.
+
+### The flow measurement accuracy of each manual balancing valve, read through its metering ports against the published curve, shall be within the tolerance indicated in the datasheet across the published measuring range.
+
```datasheet
−label: Specialty Body Material (large sizes, 2-1/2 in. and larger)
−type: select
+label: Manual Balancing Valve Flow Measurement Tolerance
+type: range
+unit: '% of indicated flow'
+min: 3
+max: 10
+setpoints: [3, 5, 10]
+default: 5
+```
+
+### Manual balancing valves NPS 2-1/2 and larger shall be repackable under pressure with the valve open.
+
+## Manual Balancing Valve Sizing {toc}
+
+### The design flow at each manual balancing valve shall be as indicated on [[drawing: the terminal unit and coil schedules]].
+
+### The manual balancing valve sizing basis shall be as indicated in the datasheet.
+
+```datasheet
+label: Manual Balancing Valve Sizing Basis
+type: radio
options:
− - Cast iron (ASTM A126 Class B)
− - Ductile iron (ASTM A536)
− - Bronze (ASTM B62)
−default: Cast iron (ASTM A126 Class B)
+ - "Sized so the design flow falls within the published measuring range"
+ - "Line size"
+default: "Sized so the design flow falls within the published measuring range"
```
−## End connections shall coordinate with the joining method of the connecting pipe as specified in [[sync/hydronic-piping]].
+### A balancing valve reads accurately only where its differential pressure signal is large enough to resolve, and a line-size valve on a small coil runs so far open that the signal is in the noise. Sizing the valve to place the design flow inside the published measuring range often means a valve one or two sizes smaller than the pipe, with the reducers that implies. Line sizing avoids the reducers, and where the piping is already close to the valve's range it costs nothing in accuracy. {note}
+### Where the datasheet selects sizing by measuring range, a balancing valve shall not be selected that requires more than the fraction of its stroke indicated in the datasheet to be closed at design flow.
+
```datasheet
−label: End Connection Style (2 in. and smaller)
−type: select
+label: Maximum Closed Fraction of Stroke at Design Flow
+type: range
+unit: '% of stroke'
+min: 25
+max: 75
+setpoints: [25, 50, 60, 75]
+default: 50
+```
+
+# Automatic Flow-Limiting Valves {toc}
+
+## An automatic flow-limiting valve holds a fixed flow with a spring-loaded cartridge that opens as the differential pressure across it falls and closes as it rises. Within its control differential pressure range the branch sees its design flow no matter what the rest of the system does, so the branch needs no field balancing. Outside the range the cartridge is either fully open and passing whatever the pressure drives, or fully closed and passing less than design. {note}
+
+## Each automatic flow-limiting valve shall hold its rated flow within the tolerance published by its manufacturer across the full control differential pressure range of its cartridge.
+
+## The flow cartridge shall be stainless steel and shall be removable for cleaning, inspection, or replacement without removing the valve body from the line.
+
+## The rated flow and the control differential pressure range of the cartridge shall be marked on a permanent tag on the valve body.
+
+## The cartridge flow setting shall be as indicated in the datasheet.
+
+```datasheet
+label: Flow-Limiting Cartridge Setting
+type: radio
options:
− - NPT threaded (ASME B1.20.1)
− - Solder/sweat
− - Press-connect
−default: NPT threaded (ASME B1.20.1)
+ - "Fixed-rate cartridge, factory set"
+ - "Field-adjustable multi-rate cartridge"
+default: "Fixed-rate cartridge, factory set"
```
+## A fixed-rate cartridge is the simpler and less costly device and suits a terminal whose flow is known when the valve is bought. A field-adjustable cartridge lets a terminal's flow be changed after installation, which matters on a project where the terminal schedule is expected to change or where the same valve model is stocked for several terminal sizes. {note}
+
+## The maximum control differential pressure of each cartridge shall be not less than the value indicated in the datasheet.
+
```datasheet
−label: End Connection Style (2-1/2 in. and larger)
−type: select
+label: Flow-Limiting Cartridge Maximum Control Differential Pressure
+type: range
+unit: psid
+min: 14
+max: 90
+setpoints: [14, 32, 35, 57, 60, 80, 90]
+derived: "the maximum differential pressure across the served branch at the design condition, from the hydraulic calculations"
+default: derived
+```
+
+## The activation differential pressure of each cartridge shall not exceed the minimum differential pressure available across the served branch at the part-load condition.
+
+## The cartridge range is the whole selection. A cartridge whose activation pressure sits above the branch's part-load differential pressure stops limiting at part load and the branch starves; a cartridge whose maximum sits below the branch's full-load differential pressure passes more than design when the pump runs up. The range therefore brackets the branch, which is a calculated quantity rather than a preference, and the field is derived from that calculation. {note}
+
+## Each automatic flow-limiting valve shall be furnished with the housing accessories indicated in the datasheet.
+
+```datasheet
+label: Flow-Limiting Valve Housing Accessories
+type: checkbox
options:
− - Flanged (ANSI Class 125)
− - Flanged (ANSI Class 150)
− - Grooved-end
−default: Flanged (ANSI Class 125)
+ - "Metering ports on both sides of the cartridge"
+ - "Integral isolation ball valve"
+ - "Union end for cartridge access"
+ - "Integral strainer upstream of the cartridge"
+default:
+ - "Metering ports on both sides of the cartridge"
+ - "Union end for cartridge access"
```
−# Balancing and Flow Control Devices {toc}
+## Metering ports let the balancing agency confirm that the cartridge is inside its control range rather than trusting the tag, and the union end is what makes the cartridge serviceable. An integral strainer protects the cartridge where no separate strainer is upstream, and an integral isolation valve saves a fitting on a coil connection that would otherwise need one. {note}
−## Flow control device selection is a system-level hydraulic decision, not a product preference: it is driven by whether the system is constant- or variable-flow, by the pump curve, and by the control strategy at each terminal. The three families below are not interchangeable, and the choice should be made by the Engineer of Record for each circuit. {note}
+# Pressure-Independent Control Valves {toc}
−## Device family selection {toc}
+## Pressure-Independent Control Valve Configuration {toc}
−### The hydronic distribution shall use one of three flow control device families at each branch and terminal: manual calibrated balancing valves, automatic flow-limiting (pressure-independent balancing) valves, or pressure-independent control valves.
+### A pressure-independent control valve holds the flow its actuator commands regardless of the differential pressure the system presents to it, so the terminal is balanced and modulated by one device and the control loop keeps full authority as other terminals open and close. It replaces the separate balancing valve on the terminal it serves, and it is the device most often chosen where a variable-flow system must hold design flow at every terminal under ANSI/ASHRAE/IES 90.1 balancing provisions. {note}
+### Requirements in this section apply where pressure-independent control valves are indicated on [[drawing: the control valve schedule]] for a terminal, a coil, or a heat exchanger.
+
+### Each pressure-independent control valve shall be furnished complete with its actuator as one assembly under this standard.
+
+### The pressure-independent control valve type shall be as indicated in the datasheet.
+
```datasheet
−label: Flow Control Device Family
+label: Pressure-Independent Control Valve Type
type: select
options:
− - Manual calibrated balancing valve
− - Automatic flow-limiting (pressure-independent balancing) valve
− - Pressure-independent control valve (PICV)
−default: Manual calibrated balancing valve
+ - "Mechanical, with field-adjustable maximum flow"
+ - "Mechanical, with factory-set fixed maximum flow"
+ - "Electronic, with integral flow measurement"
```
−### On variable-flow systems pursuing ANSI/ASHRAE/IES 90.1 balancing compliance, the flow control device shall maintain design flow at part-load operating conditions.
+### A mechanical valve holds flow with a differential pressure regulator in the body and needs no signal to do it, which makes it the simplest device and the one that keeps working through a controls outage. A field-adjustable maximum flow lets the balancing agency set and later change the terminal flow at the valve; a factory-set maximum removes that adjustment and with it the chance of a wrong setting. An electronic valve measures flow and closes a loop in the actuator, which gives the building automation system the actual flow and, with a temperature pair, the actual coil load, at a higher first cost and with a dependency on the actuator being powered. No type is chosen without discussion across projects, so the field carries no default. {note}
−### Fixed-orifice manual balancing valves shall not be specified as the sole balancing device on variable-primary systems where part-load flow stability is required for 90.1 compliance.
+### The maximum flow setting of each valve shall be adjustable across the manufacturer's published range for the size and shall be indicated on the valve, and the setting shall be lockable or otherwise protected against unauthorized change.
−#### On a variable-primary system, manually set fixed-orifice circuit setters are balanced at one operating point only; as other branches modulate, the differential pressure across each setter shifts and the flow drifts. Automatic flow-limiting valves or PICVs hold flow across a differential pressure band and are the compliant choice where part-load stability is required. {note}
+## Pressure-Independent Control Valve Flow Performance {toc}
−## Manual calibrated balancing valves {toc}
+### The design flow of each pressure-independent control valve shall be as indicated on [[drawing: the terminal unit and coil schedules]].
−### Manual calibrated balancing valves are field-set, fixed-position devices with a calibrated flow-versus-handle relationship and integral pressure/temperature ports for differential pressure readout; they suit constant-flow circuits and simple two-way constant-flow terminals. {note}
+### Each valve shall hold its commanded flow within the tolerance indicated in the datasheet across its full control differential pressure range.
−### Manual calibrated balancing valves shall include a calibrated memory-stop or locking position indicator that preserves the balanced setting after the valve is closed for service.
+```datasheet
+label: Pressure-Independent Control Valve Flow Tolerance
+type: range
+unit: '% of commanded flow'
+min: 5
+max: 15
+setpoints: [5, 10, 15]
+default: 10
+```
−### Manual calibrated balancing valves shall include integral metering ports for differential pressure or flow measurement during balancing.
+### The maximum control differential pressure of each valve shall be not less than the value indicated in the datasheet.
−### Manual calibrated balancing valves shall be furnished with a means of locking the memory-stop position to prevent unauthorized adjustment.
+```datasheet
+label: Pressure-Independent Control Valve Maximum Control Differential Pressure
+type: range
+unit: psid
+min: 30
+max: 100
+setpoints: [30, 50, 58, 60, 75, 90, 100]
+derived: "the maximum differential pressure across the served terminal at the design condition, from the hydraulic calculations"
+default: derived
+```
+### The activation differential pressure of each valve shall not exceed the minimum differential pressure available across the served terminal at the part-load condition.
+
+### The minimum controllable flow of each valve, expressed as a percentage of its maximum flow setting, shall not exceed the value indicated in the datasheet.
+
```datasheet
−label: Manual Balancing Valve Type
−type: select
+label: Minimum Controllable Flow as a Percentage of Maximum Flow Setting
+type: range
+unit: '% of maximum flow setting'
+min: 1
+max: 15
+setpoints: [1, 2, 5, 10, 15]
+```
+
+### A valve that cannot control below ten percent of its setting spends the mild-weather months cycling between closed and a flow the coil does not need, and the temperature swing shows up in the space. The minimum controllable flow is where the price difference between valve grades actually appears, and a project trades it against how much of the year the terminal runs at low load. {note}
+
+### The inherent flow characteristic of each valve, between the actuator command and the flow held, shall be as indicated in the datasheet.
+
+```datasheet
+label: Pressure-Independent Control Valve Flow Characteristic
+type: radio
options:
− - Calibrated ball-type (circuit setter)
− - Venturi-type with fixed metering element
− - Calibrated globe-pattern
−default: Calibrated ball-type (circuit setter)
+ - "Equal percentage"
+ - "Linear"
+ - "Selectable in the actuator"
+default: "Equal percentage"
```
+### Because the valve holds flow rather than position, its characteristic maps command to flow directly rather than through a pressure drop that shifts with the system. An equal percentage map offsets the coil's own curve so that heat delivered rises nearly in proportion to command; a linear map suits a service whose output is already proportional to flow, such as a heat exchanger at a small approach; a selectable map, available on electronic actuators, lets the controls contractor change the characteristic at commissioning without changing the valve. {note}
+
+### The seat leakage of each valve in the closed position shall not exceed the ANSI/FCI 70-2 class indicated in the datasheet.
+
```datasheet
−label: Manual Balancing Valve Metering Connections
+label: Pressure-Independent Control Valve Maximum Seat Leakage Class
type: select
options:
− - Integral P/T (pressure/temperature) ports
− - Integral differential pressure meter connections
−default: Integral P/T (pressure/temperature) ports
+ - "ANSI/FCI 70-2 Class IV"
+ - "ANSI/FCI 70-2 Class V"
+ - "ANSI/FCI 70-2 Class VI"
+default: "ANSI/FCI 70-2 Class IV"
```
−## Automatic flow-limiting valves {toc}
+### Class IV is the customary rating of a metal-seated valve and is enough where a small leak through a closed coil is harmless; Class VI is bubble-tight and is reached with a soft seat that wears faster at high differential pressure, and it matters on a heating coil in a cooling season or a cooling coil in a heating season where any creep is felt in the space. {note}
−### Automatic flow-limiting valves use a self-actuating cartridge that holds a fixed flow rate across a defined differential pressure band, eliminating manual balancing of the controlled branch; they suit variable-flow systems where each branch must hold its design flow regardless of system pressure swings. {note}
+## Pressure-Independent Control Valve Actuator {toc}
−### Automatic flow-limiting valves shall hold the rated flow within the manufacturer's published tolerance across the device's full control differential pressure range.
+### The actuator furnished with each valve shall be of the motive type indicated in the datasheet.
−### The control differential pressure range of each automatic flow-limiting valve shall bracket the minimum and maximum differential pressure the branch experiences in service.
+```datasheet
+label: Pressure-Independent Control Valve Actuator Motive Type
+type: radio
+options:
+ - "Electric modulating"
+ - "Electronic thermal"
+ - "Pneumatic"
+default: "Electric modulating"
+```
−### Flow cartridges shall be removable for service and replacement without removing the valve body from the line.
+### An electric modulating actuator is the norm on a pressure-independent valve because the valve's flow accuracy depends on a repeatable stroke, which a motor and gear train provide. A thermal actuator is small, quiet, and inexpensive, strokes slowly, and suits a terminal such as a radiant panel or a chilled beam where a slow response is acceptable. A pneumatic actuator is chosen where a control air system is retained under [[sync/hvac-controls-instrumentation]]. {note}
+### The actuator control signal shall be compatible with the modulating output of the building automation system.
+
```datasheet
−label: Automatic Flow-Limiting Cartridge Style
+label: Pressure-Independent Control Valve Actuator Control Signal
type: select
options:
− - Fixed-rate cartridge (factory-set flow)
− - Field-selectable cartridge (multiple flow rates)
−default: Field-selectable cartridge (multiple flow rates)
+ - "0 to 10 V DC"
+ - "2 to 10 V DC"
+ - "4 to 20 mA"
+ - "Floating three-point"
+ - "Two-position"
+ - "Networked digital"
+derived: "the modulating control signal selected under [[sync/building-automation-system]]"
+default: derived
```
+### The signal is a system-level decision made once for every actuator on the project, so the field is derived from the building automation system standard rather than chosen here. A networked digital actuator carries its position, its flow where measured, and its diagnostics over the network in place of a single analog wire, and is the option that makes an electronic valve's flow measurement visible to the operator. {note}
+
+### The actuator fail-safe mechanism shall be as indicated in the datasheet.
+
```datasheet
−label: Control Differential Pressure Range
−type: select
+label: Pressure-Independent Control Valve Actuator Fail-Safe Mechanism
+type: radio
options:
− - 2 to 32 psid
− - 2 to 57 psid
− - 4 to 80 psid
−default: 2 to 32 psid
+ - "None, holds last position"
+ - "Spring return"
+ - "Electronic capacitor return"
+default: "None, holds last position"
```
−## Pressure-independent control valves {toc}
+### An actuator with no fail-safe mechanism stays where it was when power was lost, which is the correct behavior for most terminals and is the least costly and quietest actuator. Spring return drives the valve to a defined position on loss of power and is chosen where a coil must be protected from freezing or where a heating valve left open would overheat a space; it costs more, draws more power to hold position, and is louder. Electronic capacitor return gives the same defined fail position without the spring, with a lower holding load and a capacitor that ages. {note}
−### A pressure-independent control valve (PICV) combines a differential pressure regulator, a flow limiter, and a modulating control valve with actuator in a single body; it both balances and modulates a terminal, eliminating a separate balancing valve and giving the control loop constant authority regardless of system pressure changes. {note}
+### Where a fail-safe mechanism is selected, the position the valve takes on loss of power shall be as indicated in the datasheet.
−### Each PICV shall be selected for the terminal design flow and shall maintain that flow as a maximum across the device's full control differential pressure range.
+```datasheet
+label: Pressure-Independent Control Valve Fail Position on Loss of Power
+type: radio
+options:
+ - "Closed"
+ - "Open"
+ - "Last position"
+drawing_ref: "the control valve schedule on the controls drawings"
+default: deferred
+```
−### Each PICV shall be selected so the terminal minimum controllable flow falls within the device's controllable range.
+### Where no fail-safe mechanism is selected, the fail position shall be last position.
−#### A PICV sized only to design flow can lose control authority near minimum flow if the controllable range is too narrow; the specifier must provide both the design flow and the minimum controllable flow (typically 10 to 15% of maximum Cv) as selection criteria.
+### The close-off differential pressure rating of the actuator and valve together shall be not less than the value indicated in the datasheet.
−### Each PICV shall be furnished complete with its modulating actuator as a single product unless the Contract Documents explicitly assign actuator supply to the BAS contractor.
+```datasheet
+label: Pressure-Independent Control Valve Close-Off Rating
+type: range
+unit: psid
+min: 50
+max: 300
+setpoints: [50, 75, 100, 150, 200, 232, 300]
+derived: "the pump shutoff differential pressure at the valve location, from the pump selection under [[sync/hvac-pumps]]"
+default: derived
+```
−#### On some projects the BAS contractor expects to furnish actuators separately; the specification must state explicitly whether the PICV is furnished complete with actuator or whether the actuator is furnished by others, to avoid a gap or a duplicate purchase.
+### The actuator shall be furnished with the feedback and override features indicated in the datasheet.
−### The PICV actuator control signal shall be compatible with the building automation system output specified in [[sync/building-automation-system]].
+```datasheet
+label: Pressure-Independent Control Valve Actuator Features
+type: checkbox
+options:
+ - "Position feedback signal"
+ - "Flow feedback signal"
+ - "Manual override"
+ - "Visible position indicator"
+default:
+ - "Visible position indicator"
+```
+### The actuator supply voltage shall be as indicated in the datasheet.
+
```datasheet
−label: PICV Actuator Supply
−type: select
+label: Pressure-Independent Control Valve Actuator Supply Voltage
+type: radio
options:
− - Furnished complete with actuator (this section)
− - Valve body only; actuator furnished by BAS contractor
−default: Furnished complete with actuator (this section)
+ - "24 V AC or DC"
+ - "120 V AC"
+default: "24 V AC or DC"
```
+### A 24 V supply is the norm because it is what the field controller already provides and it keeps the actuator wiring in the low-voltage class; a 120 V actuator is chosen where a valve is driven directly from a line-voltage source with no controller between them. {note}
+
+### The actuator enclosure shall be rated under NEMA 250 as indicated in the datasheet.
+
```datasheet
−label: PICV Actuator Control Signal
+label: Pressure-Independent Control Valve Actuator Enclosure Rating
type: select
options:
− - 0-10 VDC modulating
− - 2-10 VDC modulating
− - 4-20 mA modulating
− - Floating (3-wire)
− - Two-position (on/off)
−default: 0-10 VDC modulating
+ - "NEMA Type 1"
+ - "NEMA Type 2"
+ - "NEMA Type 3R"
+ - "NEMA Type 4"
+ - "NEMA Type 4X"
+ - "NEMA Type 12"
+default: "NEMA Type 1"
```
+### A dry conditioned interior is the norm, so the field defaults to Type 1. Type 2 adds a drip shield for a mechanical room ceiling where condensate from a chilled water line above can land on the actuator; Type 3R is the outdoor minimum; Type 4 is hose-directed water and Type 4X adds corrosion resistance for a washdown or a corrosive space; Type 12 excludes dust and dripping oil in an industrial interior. {note}
+
+### Actuators installed outdoors shall be rated NEMA Type 3R or better.
+
+### Actuators installed in a washdown area, a corrosive space, or an outdoor location subject to salt spray shall be rated NEMA Type 4X.
+
+### Actuators installed below chilled water piping or in any location where condensate can drip on them shall be rated NEMA Type 2 or better.
+
+### Each actuator shall be listed to UL 429 or shall carry an equivalent listing from a nationally recognized testing laboratory for the assembled valve and actuator.
+
+## Pressure-Independent Control Valve Coordination with the Control System {toc}
+
+### The Contractor shall furnish each pressure-independent control valve assembly and shall deliver it to the piping installer before the section that serves it is closed and pressure tested.
+
+### The controls contractor shall wire, power, and commission each actuator under [[sync/building-automation-system]], and shall confirm the control signal and fail position against the control valve schedule.
+
+### The Contractor shall set each valve to its scheduled maximum flow before the balancing agency begins work, and shall record the setting on the as-installed schedule.
+
+### A separate balancing valve shall not be installed in series with a pressure-independent control valve on the same terminal unless indicated on [[drawing: the terminal unit piping details]].
+
+### The verification of each valve's held flow shall be performed by the balancing agency under [[sync/testing-adjusting-and-balancing]].
+
+### The valve is bought under this standard and lives in the controls contractor's system, and the seam between the two is where a wrong signal, an unset maximum flow, or a fail position nobody chose shows up at startup. Naming who sets the flow and who confirms the signal is what closes the seam. {note}
+
+# Differential Pressure Control Valves {toc}
+
+## A differential pressure control valve holds a constant differential pressure across the branch, riser, or terminal group it serves by throttling as the upstream pressure rises, so that the manual balancing valves downstream see the differential pressure they were balanced at no matter what the rest of the system does. It is the device that lets a variable-flow system keep manual balancing at the terminals instead of buying a pressure-independent device for every one. {note}
+
+## Branch differential pressure control shall be provided as indicated in the datasheet.
+
```datasheet
−label: PICV Control Differential Pressure Range
−type: select
+label: Branch Differential Pressure Control
+type: radio
options:
− - 5 to 60 psid
− - 5 to 75 psid
− - 7 to 90 psid
−default: 5 to 60 psid
+ - "None"
+ - "Differential pressure control valve at each riser or branch"
+ - "Differential pressure control valve at each terminal group"
+default: "None"
```
−### Terminal design flow {toc}
+## Most systems balance at the terminals and control the pump on a remote differential pressure sensor, which is why no branch control is the default. A differential pressure control valve at each riser or branch is chosen where a tall building or a long distribution puts the terminals nearest the pump under a differential pressure that overwhelms their balancing valves at part load; one at each terminal group brings the same stability closer to the terminals at the cost of more valves and more impulse lines to keep tight. {note}
−#### The design flow and minimum controllable flow for each terminal shall be taken from the terminal schedule.
+## Where differential pressure control valves are selected, each shall hold its set differential pressure within the manufacturer's published tolerance across the flow range of the served branch.
−#### Terminal flow assignments are coordinated from the equipment schedule on the drawings: [[drawing: terminal unit schedule]].
+## The set differential pressure of each valve shall be adjustable in the field across a range that includes the value indicated in the datasheet, and the setting shall be lockable.
−# Strainers {toc}
+```datasheet
+label: Differential Pressure Control Valve Set Point
+type: range
+unit: psid
+min: 2
+max: 60
+setpoints: [2, 4, 6, 8, 10, 15, 20, 25, 30, 40, 60]
+derived: "the design differential pressure across the served branch, from the hydraulic calculations"
+default: derived
+```
−## Strainers protect downstream coils, control valves, pumps, and PICVs from debris carried in the fluid; type, body material, and screen mesh are all selected to match the protected equipment and the expected debris load rather than applied as a single standard. {note}
+## Each differential pressure control valve shall be furnished with a partner valve or an upstream metering point that carries the impulse connection, and the impulse line shall be copper or stainless steel tubing with an isolation valve at each end.
−## Strainer type {toc}
+## Each differential pressure control valve shall have metering ports on both sides of the throttling element so that the held differential pressure can be verified with the same instrument used on the balancing valves.
−### Y-pattern strainers shall be used for general protection at sizes up to 2 in. and where the pressure drop allowance is modest.
+# Strainers {toc}
−### Basket (pot) strainers shall be used at sizes 3 in. and larger and where a large dirt-holding capacity or low pressure drop is required.
+## Strainer Pattern and Location {toc}
+### A strainer protects the device downstream of it, and its pattern, screen, and blowdown are chosen for that device and for the dirt load the system is expected to carry rather than as a single project-wide standard. A coil with narrow passages needs a finer screen than a pump; a large main needs a basket that can be cleaned without draining the riser. {note}
+
+### The strainer pattern shall be as indicated in the datasheet.
+
```datasheet
−label: Strainer Type
+label: Strainer Pattern
type: select
options:
− - Y-pattern
− - Basket (pot) strainer
−default: Y-pattern
+ - "Y-pattern"
+ - "Simplex basket"
+ - "Duplex basket"
+default: "Y-pattern"
```
−## Screen and mesh {toc}
+### A Y-pattern strainer is compact, is available in every size and end connection, and is cleaned by removing its screen or by blowing it down, which on a large main means a shutdown or a valved bypass. A simplex basket strainer holds far more dirt at a lower pressure drop and is cleaned from the top without disturbing the piping, at a larger footprint. A duplex basket strainer has two baskets and a changeover valve so that one basket is cleaned while the other is in service, and is chosen where the served equipment cannot be shut down to clean a screen. {note}
−### Strainer screens shall be stainless steel.
+### Strainers shall be installed at each location class selected in the datasheet.
−### Strainer screen mesh shall match the protection requirement of the downstream equipment.
+```datasheet
+label: Strainer Location Classes
+type: checkbox
+options:
+ - "Suction of each pump not served by a suction diffuser"
+ - "Inlet of each chiller, boiler, and heat exchanger"
+ - "Supply to each coil and terminal unit"
+ - "Upstream of each control valve NPS 2-1/2 and larger"
+ - "Upstream of each pressure-independent control valve"
+ - "Makeup water connection upstream of the fill valve"
+default:
+ - "Suction of each pump not served by a suction diffuser"
+ - "Inlet of each chiller, boiler, and heat exchanger"
+ - "Makeup water connection upstream of the fill valve"
+```
−#### Coil and control valve manufacturers frequently require finer protection than the system default; the mesh size is a per-location selection driven by equipment manufacturer requirements, not a single value applied system-wide. {note}
+### Additional strainers shall be installed where shown on [[drawing: the mechanical piping plans and details]].
−### Where a downstream equipment manufacturer specifies a minimum strainer mesh, the finer of that requirement and the scheduled mesh shall govern.
+### A strainer at every coil protects every coil and doubles the number of screens an operator has to clean, and on a system that has been flushed and is treated, most of those screens never collect anything. A strainer at the plant equipment and at the pump catches the debris that a shutdown would otherwise find in the pump, and the coil strainers are added where the coil passages or the pressure-independent valve cartridges are fine enough to be blocked by what the plant strainers pass. {note}
+## Strainer Screens {toc}
+
+### Strainer screens shall be of the material indicated in the datasheet.
+
```datasheet
−label: Strainer Screen Mesh
+label: Strainer Screen Material
type: select
options:
− - 20-mesh (general service)
− - 40-mesh (coil and control valve protection)
− - 60-mesh (fine equipment protection)
−default: 20-mesh (general service)
+ - "304 stainless steel"
+ - "316 stainless steel"
+ - "Monel"
+default: "304 stainless steel"
```
+### Type 304 stainless steel holds up in treated closed-loop water and inhibited glycol and is the screen material nearly every strainer ships with; Type 316 resists the chloride pitting that an open condenser water loop or a poorly controlled treatment program can produce; Monel is chosen for seawater and brackish makeup where both stainless grades pit. {note}
+
+### The screen of strainers NPS 2 and smaller shall be woven mesh of not coarser than the mesh count indicated in the datasheet.
+
```datasheet
−label: Screen Perforation (large basket strainers)
−type: select
+label: Strainer Screen Mesh, NPS 2 and Smaller
+type: range
+unit: mesh
+min: 20
+max: 100
+setpoints: [20, 40, 60, 80, 100]
+default: 20
+```
+
+### The screen of strainers NPS 2-1/2 and larger shall be perforated plate with holes not larger than the diameter indicated in the datasheet.
+
+```datasheet
+label: Strainer Screen Perforation, NPS 2-1/2 and Larger
+type: range
+unit: in.
+min: 0.033
+max: 0.1875
+setpoints: [0.033, 0.045, 0.0625, 0.125, 0.1875]
+```
+
+### A 20 mesh screen catches the pipe scale, weld slag, and sealant that reach a strainer after flushing and is the count small strainers are sold with, which is why it is the default. Finer mesh protects a device with finer passages and loads up faster, so it is selected where the downstream device needs it rather than everywhere. The perforation of a large screen follows the size of the strainer and the dirt-holding capacity wanted, with the smaller holes on the smaller sizes and the larger holes where a main strainer must not throttle the pump, so the large-size field carries no default. {note}
+
+### Where the manufacturer of the device downstream of a strainer publishes a maximum particle size finer than the selected screen, the finer screen shall be furnished at that strainer.
+
+### The net free area of each screen shall be not less than the multiple of the pipe cross-sectional area indicated in the datasheet.
+
+```datasheet
+label: Minimum Screen Net Free Area as a Multiple of Pipe Area
+type: range
+unit: 'times pipe area'
+min: 2
+max: 6
+setpoints: [2, 3, 4, 6]
+default: 3
+```
+
+### A temporary fine-mesh startup screen shall be provided as indicated in the datasheet.
+
+```datasheet
+label: Temporary Startup Screen
+type: radio
options:
− - 1/16 in. perforated
− - 1/8 in. perforated
− - 3/64 in. perforated
−default: 1/16 in. perforated
+ - "Fine-mesh startup screen furnished, removed after flushing"
+ - "None"
+default: "Fine-mesh startup screen furnished, removed after flushing"
```
−## Body material {toc}
+### A startup screen catches the construction debris that the first fill carries and that the permanent screen would pass, and it is removed once the flushing under [[sync/hydronic-cleaning-and-flushing]] is complete. Left in place it loads steadily and starves the pump in the first season, which is why its removal is a recorded closeout item. A project that flushes through a temporary bypass and never runs the pump on unflushed water has no use for one. {note}
−### Strainer bodies shall be bronze on copper piping and at sizes 2-1/2 in. and smaller.
+## Strainer Blowdown and Service Provisions {toc}
−### Strainer bodies shall be cast iron or ductile iron only on steel piping and only at sizes 3 in. and larger.
+### The blowdown connection on strainers NPS 2-1/2 and larger shall be as indicated in the datasheet.
```datasheet
−label: Strainer Body Material
−type: select
+label: Strainer Blowdown Connection
+type: radio
options:
− - Bronze (ASTM B62)
− - Cast iron (ASTM A126 Class B)
− - Ductile iron (ASTM A536)
−default: Bronze (ASTM B62)
+ - "Plugged blowdown tapping"
+ - "Valved blowdown with hose-end outlet and cap"
+ - "Valved blowdown piped to drain"
+default: "Valved blowdown with hose-end outlet and cap"
```
−## Blow-down and isolation {toc}
+### A plugged tapping is the least costly and means the strainer is cleaned by removing its screen, which on a large main means isolating and draining the section. A valved hose-end outlet lets the operator blow the screen down into a bucket or a hose without opening the strainer; piping the blowdown to a drain removes the bucket and is chosen in a mechanical room with a floor drain within reach and on any strainer that will be blown down often. {note}
−### Strainers 3 in. and larger shall be furnished with a blow-down connection and valve.
+### Strainers NPS 2 and smaller shall have a plugged blowdown tapping or a removable cap that gives access to the screen.
−### Each strainer 3 in. and larger shall be provided with upstream and downstream isolation so the screen can be serviced without draining the system.
+### The cover of basket strainers shall be as indicated in the datasheet.
−#### Servicing a basket strainer on a live system without a blow-down valve and isolation requires shutting down and draining the whole system; blow-down and isolation provisions on strainers 3 in. and larger keep routine screen cleaning from becoming a system outage. {note}
+```datasheet
+label: Basket Strainer Cover
+type: radio
+options:
+ - "Bolted cover"
+ - "Quick-opening cover"
+default: "Bolted cover"
+```
−### The blow-down connection shall be valved and capped or plumbed to an accessible drain.
+### A bolted cover is the lower-cost closure and is opened with tools; a quick-opening cover with a yoke or swing bolts is opened by hand and is chosen where the basket is cleaned frequently or where the strainer sits where a wrench cannot be swung. {note}
+### Each strainer NPS 2-1/2 and larger shall have a tapping on each side of the screen for a pressure gauge or a test plug, so that screen fouling can be read as a differential pressure.
+
+# Suction Diffusers {toc}
+
+## A suction diffuser is a combination inlet elbow, flow straightener, and strainer mounted directly on the pump suction, used where the straight suction run required by [[sync/hvac-pumps]] cannot be achieved. Whether one is used is decided under that standard; this section governs the device where it is selected. {note}
+
+## Requirements in this section apply where a suction diffuser is selected as the suction flow conditioning under [[sync/hvac-pumps]].
+
+## Each suction diffuser shall combine, in one body, an inlet elbow with full-length straightening vanes, a permanent strainer, and an outlet that matches the pump suction connection.
+
+## The permanent strainer of each suction diffuser shall be stainless steel perforated plate of the perforation selected for strainers NPS 2-1/2 and larger, with a net free area not less than the multiple of pipe area selected under Strainer Screens.
+
+## A temporary fine-mesh startup screen shall be furnished with each suction diffuser where the temporary startup screen is selected under Strainer Screens, and shall be removed after flushing.
+
+## Each suction diffuser shall have a blowdown tapping at the bottom of the strainer chamber, a tapping for a pressure gauge or test plug on the pump side of the strainer, and an adjustable support foot that carries the weight of the diffuser and the suction piping to the floor or the base.
+
+## Suction diffusers shall be furnished in the body material selected for devices NPS 2-1/2 and larger, or in the pump manufacturer's body material where the diffuser is mounted by the pump manufacturer before shipment.
+
+## The support foot is what keeps the weight of the diffuser and the suction piping off the pump volute, whose allowable nozzle load is small. A diffuser hung from its own flange bolts loads the volute with the full weight of the elbow and the water in it, and the misalignment that follows is blamed on the pump. {note}
+
+# Triple-Duty Valves and Pump Discharge Assemblies {toc}
+
+## The pump discharge needs a check valve, an isolation valve, and, on a constant-speed pump, a means of throttling to the design point. A triple-duty valve combines all three in one body; separate valves do the same three jobs in three bodies with three sets of joints. The choice turns on the pump drive and on the space available at the discharge. {note}
+
+## The pump discharge assembly shall be as indicated in the datasheet.
+
```datasheet
−label: Strainer Blow-Down Provision
−type: select
+label: Pump Discharge Assembly
+type: radio
options:
− - Valved blow-down with hose-end and cap
− - Valved blow-down piped to drain
− - None (sizes under 3 in.)
−default: Valved blow-down with hose-end and cap
+ - "Triple-duty valve"
+ - "Separate check valve, balancing valve, and isolation valve"
+ - "Separate check valve and isolation valve without a balancing valve"
```
−# Combination Air and Dirt Separators (In-Line) {toc}
+## A triple-duty valve saves two joints and a length of discharge piping and gives the balancing agency a calibrated throttle at the pump, which is what a constant-speed pump needs to be set to its design point. Separate valves cost more in fittings and let each function be selected and serviced on its own, and a spring-loaded silent check valve chosen separately closes more quietly than the check in most triple-duty bodies. On a variable-speed pump the throttle is not needed, because the drive sets the operating point, and a balancing valve at the discharge only adds pressure drop the drive then has to overcome; the third option removes it. No arrangement is the norm across projects, so the field carries no default. {note}
−## This section covers in-line combination air/dirt separators installed within the distribution piping to scrub residual microbubbles and suspended dirt at points of low velocity or high temperature; it does not cover the central air separator at the expansion tank, which is governed by [[sync/expansion-tanks-and-air-separators]]. {note}
+## Where a triple-duty valve is selected, it shall combine a non-slam check, a calibrated throttling plug with a memory stop and a position indicator, and a drop-tight shutoff in one body, with metering ports on both sides of the throttling plug.
−## In-line combination air/dirt separators are coalescing-media devices that capture microbubbles and settle out suspended particles; they supplement, but do not replace, the primary system air separator. {note}
+## Where a triple-duty valve is selected, its pattern as straight or angle shall be as indicated on [[drawing: the pump piping details]].
−## In-line air/dirt separators shall use a coalescing internal medium sized for the full design flow of the served circuit.
+## Where separate valves are selected, the check valve and the isolation valve shall conform to [[sync/hvac-piping-valves]] and the balancing valve, where one is included, shall conform to Manual Balancing Valves.
−## Each in-line air/dirt separator shall be furnished with an automatic air vent at the top and a valved dirt blow-down at the bottom.
+## Where a triple-duty valve is installed on the discharge of a variable-speed pump, the throttling feature shall be set fully open and shall not be used for balancing unless the Engineer of Record directs otherwise in writing.
−## Where magnetic dirt separation is specified, the separator shall include a removable magnetic element serviceable without isolating the unit from the line.
+# Flexible Pipe Connectors {toc}
−### Magnetic separation captures the ferrous particles (magnetite) that coalescing media alone passes; it is most valuable on systems with steel piping or cast iron components where iron oxide sludge forms. {note}
+## A flexible connector at an equipment connection keeps the piping from short-circuiting the equipment's vibration isolation, absorbs the small motion an isolated machine makes, and takes up minor misalignment between the equipment nozzle and the pipe. Where connectors are required at isolated equipment, and whether they need thrust restraint, is decided under [[sync/vibration-isolation-and-seismic-restraint]]; this section governs the connector itself. {note}
−### The in-line air/dirt separator type shall be specified, including a magnetic element where the system includes steel piping or cast-iron components.
+## Flexible connectors shall be installed at each location required by [[sync/vibration-isolation-and-seismic-restraint]] and at each additional location shown on [[drawing: the mechanical piping plans and details]].
+## The flexible connector type shall be as indicated in the datasheet.
+
```datasheet
−label: In-Line Air/Dirt Separator Type
+label: Flexible Connector Type
type: select
options:
− - Coalescing air/dirt separator
− - Coalescing air/dirt separator with magnetic element
−default: Coalescing air/dirt separator
+ - "Twin-sphere elastomeric connector"
+ - "Single-sphere elastomeric connector"
+ - "Braided stainless steel hose"
+ - "Braided bronze hose"
+ - "Multiple-arch elastomeric expansion joint"
```
−### The in-line air/dirt separator body material shall be specified for the served circuit.
+## An elastomeric sphere absorbs vibration across a wide frequency band and takes lateral and angular offset, and a twin sphere takes roughly twice the movement of a single sphere in the same face-to-face length. A braided metal hose takes lateral offset only, transmits more of the high-frequency vibration, and is the connector that survives a temperature or a fluid an elastomer will not; bronze hose is chosen on copper tube to avoid a dissimilar-metal joint. A multiple-arch expansion joint is a movement device first and a vibration isolator second, and is chosen where the connection must also absorb thermal growth. No type is the norm across projects, so the field carries no default. {note}
+## The elastomer compound of elastomeric connectors shall be as indicated in the datasheet.
+
```datasheet
−label: In-Line Separator Body Material
+label: Flexible Connector Elastomer Compound
type: select
options:
− - Brass
− - Carbon steel
− - Carbon steel, epoxy-coated
−default: Carbon steel
+ - "EPDM"
+ - "Nitrile"
+ - "Neoprene"
+ - "Fluoroelastomer"
+ - "Not applicable, metal hose selected"
+default: "EPDM"
```
−### The in-line air/dirt separator connection size shall be specified to match the served circuit's design flow.
+## EPDM holds up in hot and chilled water and in propylene and ethylene glycol at hydronic concentrations, and it is attacked by petroleum oils. Nitrile is selected where petroleum oil contamination is expected and has a lower upper temperature limit; neoprene sits between the two and is the compound many connectors are sold with; fluoroelastomer is selected where a chemistry attacks the other three. {note}
+## The end connections of each flexible connector shall match the joining method of the adjacent piping.
+
```datasheet
−label: In-Line Separator Connection Size
+label: Flexible Connector End Connections
+type: select
+options:
+ - "Floating carbon steel flanges"
+ - "Floating stainless steel flanges"
+ - "Threaded union ends"
+ - "Grooved ends"
+derived: "the joining method of the adjacent piping at each connector, as selected under [[sync/hydronic-piping]]"
+default: derived
+```
+
+## The working pressure rating of each flexible connector at the system design temperature shall be not less than the value indicated in the datasheet.
+
+```datasheet
+label: Flexible Connector Working Pressure Rating
type: range
−unit: in.
−min: 0.75
−max: 4
−step: 0.25
−default: 2
+unit: psig
+min: 150
+max: 300
+setpoints: [150, 200, 225, 250, 300]
+derived: "the design pressure and maximum design temperature of the piping system served, as specified under [[sync/hydronic-piping]]"
+default: derived
```
−# Chemical Pot (Bypass) Feeders {toc}
+## Flexible connectors installed at a pump suction shall be rated for full vacuum at the system design temperature.
−## Chemical pot feeders, also called bypass feeders, are pressure vessels piped in a bypass loop across a pump or pressure differential; they allow treatment chemicals to be added to the closed loop for initial passivation and periodic make-up without breaking the system open. {note}
+## An elastomeric sphere that is rated for pressure alone can collapse inward under the vacuum a pump suction develops when a strainer loads up or a suction valve is throttled, and a collapsed connector starves the pump. The vacuum rating is unconditional at the suction because the condition that produces it is not a design case but a fault the system will eventually see. {note}
−## Coordinate feeder chemistry, dosing, and treatment program with [[sync/hvac-water-treatment]]. {note}
+## Where thrust restraint is required under [[sync/vibration-isolation-and-seismic-restraint]], the control rod assembly shall be furnished by the connector manufacturer and shall be rated for the pressure thrust at the piping test pressure specified under [[sync/hydronic-piping]].
−## Each closed-loop system shall be provided with at least one chemical pot feeder piped in a bypass across an available pressure differential.
+## Flexible connectors shall not be used to correct misalignment beyond the lateral and angular offsets published for the connector, and shall be installed without twist.
−## The pot feeder shall be furnished with inlet and outlet isolation valves, a fill funnel or top fill port, a vent, and a drain.
+## Flexible connectors shall be installed at the manufacturer's published face-to-face length, and the piping on each side shall be supported so that the connector carries no piping weight.
−## The pot feeder vessel capacity shall be sized for the chemical volume required for initial treatment of the system fluid volume.
+# Chemical Bypass Feeders {toc}
−### A feeder too small for the system volume forces repeated fill cycles for initial dosing; the vessel is sized so initial passivation chemistry can be charged in a practical number of fills relative to system fluid volume. {note}
+## A chemical bypass feeder is a small pressure vessel piped across a differential pressure in the system so that treatment chemical placed in it is carried into the loop without opening the system. It is how the inhibitor charge and every later top-up reach a closed loop, and it is sized to the system volume rather than to a project-wide standard. The chemistry that goes into it is governed by [[sync/hvac-water-treatment]], and the initial charge after cleaning is governed by [[sync/hydronic-cleaning-and-flushing]]. {note}
−## The pot feeder and its bypass piping shall be rated for the system design pressure.
+## A chemical bypass feeder shall be provided for each closed hydronic system at the location shown on [[drawing: the mechanical piping plans and details]].
+## Each feeder shall be piped in a bypass across a differential pressure with an isolation valve at the inlet and at the outlet, and the bypass shall be arranged so that the feeder can be charged with the system in operation.
+
+## The feeder capacity shall be not less than the value indicated in the datasheet.
+
```datasheet
−label: Chemical Pot Feeder Capacity
−type: select
−options:
− - 1 quart
− - 2 quart
− - 1 gallon
− - 2 gallon
− - 5 gallon
−default: 2 gallon
+label: Chemical Bypass Feeder Capacity
+type: range
+unit: gal
+min: 1
+max: 20
+setpoints: [1, 2, 5, 10, 20]
+derived: "the system fluid volume and the initial inhibitor charge required under [[sync/hvac-water-treatment]]"
+default: derived
```
+## The feeder pressure rating shall be not less than the value indicated in the datasheet.
+
```datasheet
−label: Chemical Pot Feeder Pressure Rating
+label: Chemical Bypass Feeder Pressure Rating
+type: range
+unit: psig
+min: 125
+max: 300
+setpoints: [125, 150, 200, 300]
+derived: "the design pressure of the piping system served, as specified under [[sync/hydronic-piping]]"
+default: derived
+```
+
+## The feeder body material shall be as indicated in the datasheet.
+
+```datasheet
+label: Chemical Bypass Feeder Body Material
type: select
options:
− - 125 psi
− - 150 psi
− - 300 psi
−default: 150 psi
+ - "Carbon steel"
+ - "Epoxy-lined carbon steel"
+ - "Stainless steel"
+ - "Cast iron"
+default: "Carbon steel"
```
+## A carbon steel vessel is the least costly and holds up where the feeder is kept full of treated water between charges; an epoxy lining protects the vessel where concentrated chemical sits against the steel before it disperses, and stainless steel does the same without a lining that can be chipped by a funnel or a scoop. Cast iron is the body on the smallest feeders and is chosen where the vessel is a pot rather than a tank. {note}
+
+## The feeder closure shall be as indicated in the datasheet.
+
```datasheet
−label: Chemical Pot Feeder Body Material
−type: select
+label: Chemical Bypass Feeder Closure
+type: radio
options:
− - Carbon steel
− - Carbon steel, epoxy-lined
− - Cast iron
−default: Carbon steel
+ - "Threaded cap"
+ - "Quick-opening cap"
+default: "Threaded cap"
```
+## A threaded cap seals on a gasket and is opened with a wrench; a quick-opening cap swings on a yoke and is opened by hand, which matters where the feeder is charged often or sits where a wrench cannot be swung. {note}
+
+## Each feeder shall be furnished with the accessories indicated in the datasheet.
+
```datasheet
−label: Feeder Side-Stream Filtration
+label: Chemical Bypass Feeder Accessories
type: checkbox
options:
− - Bag or cartridge filter on bypass loop
−defaults: []
+ - "Filter bag and support basket"
+ - "Air vent at the top of the vessel"
+ - "Drain valve at the bottom of the vessel"
+ - "Pressure gauge on the vessel"
+ - "Sight glass"
+default:
+ - "Air vent at the top of the vessel"
+ - "Drain valve at the bottom of the vessel"
```
−# Gauges, Thermometers, and Wells {toc}
+## A filter bag turns the feeder into a coarse side-stream filter between charges and catches the sludge that a dispersant lifts off the pipe walls, at the cost of a bag that has to be changed; the vent and the drain are what let the vessel be emptied before it is opened, and a feeder without them is charged by an operator who opens it under pressure. {note}
−## Gauges and thermometers make a hydronic system legible: they confirm pump operation, differential pressure across coils and strainers, and supply/return temperatures. They are specified by range and location so the operating value sits where the instrument reads accurately. {note}
+# Makeup Water Fill and Relief Devices {toc}
−## Pressure gauges {toc}
+## Makeup Water Fill {toc}
−### Pressure gauges shall be selected so that the normal operating pressure falls within the middle third of the dial scale.
+### A closed loop loses water through vents, packing, and service, and something has to replace it. On a water system that something is a pressure-reducing fill valve on the potable makeup; on a glycol system an automatic potable makeup would dilute the glycol with every top-up, so the makeup comes from a package that pumps premixed solution from a reservoir. The set point the fill holds is coordinated with the expansion tank under [[sync/expansion-tanks-and-air-separators]] and is not chosen here. {note}
−#### A gauge whose full scale equals the operating pressure runs at the top of its range, where resolution and accuracy are poor; selecting full scale at roughly twice the operating pressure puts the needle in the readable middle third. {note}
+### The makeup water fill method for each closed system shall be as indicated in the datasheet.
−### Each pressure gauge shall be provided with a gauge cock or needle valve for isolation and for snubbing pulsation.
+```datasheet
+label: Makeup Water Fill Method
+type: radio
+options:
+ - "Automatic pressure-reducing fill valve"
+ - "Glycol makeup package with reservoir and pump"
+ - "Manual fill only"
+default: "Automatic pressure-reducing fill valve"
+```
−### Pressure gauges on hydronic service shall be liquid-filled to damp needle flutter from pump pulsation.
+### An automatic fill valve keeps the system full without attention and is the norm on a water system. A glycol makeup package holds the glycol concentration through every top-up and gives the operator a low-level alarm that says the system is losing fluid, at the cost of a reservoir to keep filled. Manual fill is chosen on a small system, or on a system where an undetected leak fed by an automatic fill would do more damage than a low-pressure trip, because a system that cannot refill itself announces its leak. {note}
+### Where a glycol solution is selected under [[sync/hydronic-piping]], the makeup shall be by glycol makeup package unless the datasheet selects otherwise.
+
+### Where an automatic pressure-reducing fill valve is selected, its inlet shall be rated for not less than [[parameter: site-water-supply-pressure-maximum]], and its outlet set point range shall include the fill pressure coordinated under [[sync/expansion-tanks-and-air-separators]].
+
+### Each pressure-reducing fill valve shall have an integral strainer, an integral check, a fast-fill bypass or lever, and an adjustable set point with a locking device.
+
+### Each pressure-reducing fill valve shall be installed with an isolation valve on each side and a pressure gauge or test plug on the system side.
+
+### The backflow prevention assembly on the makeup water connection shall be furnished and installed under [[sync/backflow-prevention]].
+
+### Where a glycol makeup package is selected, it shall comprise a reservoir, a pump, a pressure switch that starts the pump at a falling system pressure set point, a check valve on the discharge, and the alarm contacts indicated in the datasheet.
+
```datasheet
−label: Pressure Gauge Dial Size
−type: select
+label: Glycol Makeup Package Alarm Contacts
+type: checkbox
options:
− - 2-1/2 in.
− - 3-1/2 in.
− - 4-1/2 in.
−default: 4-1/2 in.
+ - "Low reservoir level"
+ - "Pump running"
+ - "Pump run time exceeded"
+default:
+ - "Low reservoir level"
```
+### The glycol makeup reservoir capacity shall be not less than the value indicated in the datasheet.
+
```datasheet
−label: Pressure Gauge Range
−type: select
−options:
− - 0-30 psi
− - 0-60 psi
− - 0-100 psi
− - 0-200 psi
− - 0-300 psi
−default: 0-100 psi
+label: Glycol Makeup Reservoir Capacity
+type: range
+unit: gal
+min: 10
+max: 100
+setpoints: [10, 25, 50, 100]
+derived: "the system fluid volume and the expected makeup rate, from the glycol charge calculation under [[sync/hydronic-cleaning-and-flushing]]"
+default: derived
```
+### A low-level alarm is the contact that makes a glycol package worth its cost, because a falling reservoir is the only early sign that a glycol system is leaking. A pump-running contact lets the building automation system trend how often the package tops up, and a run-time contact catches a pump running continuously into a leak. {note}
+
+## System Relief Valves {toc}
+
+### Every closed hydronic system that can be isolated from the boiler relief valve, and every closed system without a boiler, shall be protected by a pressure relief valve installed at the location shown on [[drawing: the mechanical piping plans and details]].
+
+### The relief valve at the boiler is furnished with the boiler under [[sync/boilers]]. This section governs the relief valve on a chilled water system, on a heat exchanger secondary loop, or on any portion of a heating system that an isolation valve can separate from the boiler relief. A relieved system is one the expansion tank cannot over-pressurize when the fill valve fails open or the fluid is heated with the tank isolated. {note}
+
+### The relief valve set pressure shall be as indicated in the datasheet.
+
```datasheet
−label: Pressure Gauge Fill
−type: select
+label: System Relief Valve Set Pressure
+type: range
+unit: psig
+min: 30
+max: 160
+setpoints: [30, 50, 75, 100, 125, 150, 160]
+derived: "the lowest published working pressure rating of any component in the protected system, coordinated with the expansion tank rating under [[sync/expansion-tanks-and-air-separators]]"
+default: derived
+```
+
+### The relief valve certification shall be as indicated in the datasheet.
+
+```datasheet
+label: System Relief Valve Certification
+type: radio
options:
− - Glycerin-filled
− - Silicone-filled
− - Dry with snubber
−default: Glycerin-filled
+ - "ASME BPVC Section IV, HV mark"
+ - "ASME BPVC Section VIII, UV mark"
+ - "Manufacturer-rated, not ASME certified"
+default: "ASME BPVC Section IV, HV mark"
```
−## Thermometers and wells {toc}
+### A Section IV valve is the relief valve sold for heating boilers and hydronic heating systems, is rated in Btu per hour, and is what an inspector expects to find on a heating loop. A Section VIII valve is rated in flow and is chosen where the system is rated above a Section IV valve's limits or where the jurisdiction treats the vessel as an unfired pressure vessel. A manufacturer-rated valve is offered on chilled water and process loops where no code requires a certified valve, and it costs less. {note}
−### Thermometers shall be provided at supply and return of each major piece of equipment and where indicated for system monitoring.
+### The relieving capacity of each relief valve shall be not less than the heat input to the protected system where the system is heated, and shall be not less than the maximum makeup flow with the fill valve fully open where it is not.
−### Every thermometer and every temperature sensor inserted into the piping shall be installed in a thermowell.
+### Relief valve discharge shall be piped full size, without a valve, to a location where the discharge is visible and cannot scald a person, and shall terminate with an air gap above a floor drain or a receptor.
−#### A thermowell isolates the instrument from the pressurized fluid so it can be removed or replaced without draining the system, and it lets a future digital or infrared instrument reuse the same penetration. {note}
+### The discharge piping shall be supported so that its weight is not carried by the relief valve.
−### Where a temperature reading point is provided for future or portable instrumentation, a thermowell shall be installed without a thermometer.
+# Pressure Gauges {toc}
+## A pressure gauge is how an operator sees whether a pump is running, a strainer is loading, or a system is holding its fill pressure, and it is only as useful as its range and its location allow. The gauges at the pumps are selected under [[sync/hvac-pumps]]; this section governs the gauge as a device and the gauges elsewhere in the system. {note}
+
+## Pressure gauges shall be installed at each location class selected in the datasheet.
+
```datasheet
−label: Thermometer Type
−type: select
+label: Pressure Gauge Location Classes
+type: checkbox
options:
− - Bimetal dial, adjustable angle
− - Liquid-in-glass, adjustable angle
− - Digital
− - Thermowell only (no thermometer)
−default: Bimetal dial, adjustable angle
+ - "Inlet and outlet of each chiller, boiler, and heat exchanger"
+ - "Each side of each strainer NPS 2-1/2 and larger"
+ - "Expansion tank connection"
+ - "System side of the makeup water fill"
+ - "Base of each riser"
+default:
+ - "Inlet and outlet of each chiller, boiler, and heat exchanger"
+ - "Expansion tank connection"
+ - "System side of the makeup water fill"
```
+## Additional pressure gauges shall be installed where shown on [[drawing: the mechanical piping plans and details]].
+
+## Pressure gauges shall conform to ASME B40.100 and shall be of the accuracy grade indicated in the datasheet.
+
```datasheet
−label: Thermometer Range
+label: Pressure Gauge Accuracy Grade
type: select
options:
− - 0-160°F
− - 0-250°F
− - 30-300°F
− - 40-280°F
−default: 0-250°F
+ - "ASME B40.100 Grade B"
+ - "ASME B40.100 Grade A"
+ - "ASME B40.100 Grade 1A"
+ - "ASME B40.100 Grade 2A"
+default: "ASME B40.100 Grade A"
```
+## Grade A, accurate to one percent through the middle half of the scale and two percent at the ends, is the commercial gauge sold for building services and reads a pump head or a strainer drop well enough; Grade 1A is accurate to one percent across the scale and is chosen where the gauge is the reference for a fill pressure or a relief setting; Grade 2A is the test-gauge accuracy and is bought where the gauge stands in for a calibrated instrument. Grade B is the utility gauge and is accepted where the reading is a presence check rather than a number. {note}
+
+## The gauge dial size shall be as indicated in the datasheet.
+
```datasheet
−label: Thermowell Stem/Insertion Length
+label: Pressure Gauge Dial Size
type: range
unit: in.
min: 2.5
−max: 9
−step: 0.5
−default: 4
+max: 6
+setpoints: [2.5, 3.5, 4.5, 6]
+default: 4.5
```
+## The scale range of each gauge shall be selected so that the normal operating pressure at that location falls between one third and two thirds of full scale, with the full-scale value as indicated in the datasheet.
+
```datasheet
−label: Thermowell Material
−type: select
−options:
− - Brass
− - 304 stainless steel
− - 316 stainless steel
−default: Brass
+label: Pressure Gauge Full-Scale Range
+type: range
+unit: psig
+min: 30
+max: 400
+setpoints: [30, 60, 100, 160, 200, 300, 400]
+derived: "twice the normal operating pressure at the gauge location, from the hydraulic calculations"
+default: derived
```
−# Flexible Pipe Connectors {toc}
+## A gauge reading near the bottom of its scale cannot resolve the change the operator is looking for, and a gauge reading near the top has no margin for a transient. Ranging the gauge at about twice the operating pressure puts the needle in the part of the dial where the movement is accurate, which is why the range follows the location rather than the project. {note}
−## Flexible pipe connectors at pump and equipment connections absorb vibration, accommodate minor misalignment, and reduce structure-borne noise. The connector type is selected for the service pressure, temperature, and any seismic requirement, and suction-side connectors carry an extra vacuum constraint. {note}
+## Gauges at a pump suction or at any point that can fall below atmospheric pressure shall be compound gauges reading vacuum and pressure.
−## Flexible connectors shall be provided at the suction and discharge of each base-mounted pump and where vibration isolation of equipment from piping is required.
+## The gauge case fill shall be as indicated in the datasheet.
−## Each flexible connector shall be rated for the system design pressure and temperature at the installed location.
+```datasheet
+label: Pressure Gauge Case Fill
+type: radio
+options:
+ - "Glycerin"
+ - "Silicone"
+ - "Dry with pulsation snubber"
+default: "Glycerin"
+```
−## Flexible connectors installed on pump suction shall be rated for full vacuum at the operating temperature.
+## A liquid fill damps the needle flutter that pump pulsation produces and lubricates the movement, and glycerin is the fill on nearly every liquid-filled gauge sold for building services. Silicone keeps its viscosity at low temperature and is chosen for a gauge outdoors or in a cold space where glycerin thickens. A dry gauge with a snubber damps the pulsation in the connection instead of in the case and is chosen where a liquid fill is not wanted, such as a gauge that will be read in bright sun where the fill yellows. {note}
−### A spherical rubber connector can collapse under the vacuum that can develop at a pump suction; suction-side connectors must be verified for both pressure and full vacuum at operating temperature, or a connector type not subject to collapse must be used.
+## The Bourdon tube material shall be as indicated in the datasheet.
−## Where the project is in a seismic design category requiring flexible joints, connector selection and anchorage shall comply with the project seismic requirements.
+```datasheet
+label: Pressure Gauge Bourdon Tube Material
+type: radio
+options:
+ - "Phosphor bronze"
+ - "316 stainless steel"
+default: "Phosphor bronze"
+```
+## Phosphor bronze is the tube material of a commercial water gauge and holds up in treated water and glycol; a stainless tube is chosen where the fluid attacks copper alloys or where the gauge is stocked for a range of services. {note}
+
+## The gauge isolation shall be as indicated in the datasheet.
+
```datasheet
−label: Flexible Connector Type
−type: select
+label: Pressure Gauge Isolation
+type: radio
options:
− - Spherical (single-arch) EPDM
− - Spherical (twin-arch) EPDM
− - Stainless steel braided hose
− - Rubber expansion joint (multi-arch)
−default: Spherical (twin-arch) EPDM
+ - "Needle valve"
+ - "Ball-type gauge cock"
+ - "Needle valve with pulsation snubber"
+default: "Needle valve"
```
+## A needle valve isolates the gauge for replacement and, throttled, damps pulsation; a gauge cock is a quarter-turn shutoff that is faster to operate and gives no damping; a needle valve with a snubber adds a porous element that damps hard pulsation without throttling, and it is the combination chosen on a reciprocating source or a dry gauge. {note}
+
+## Each gauge shall be installed with its isolation device between the pipe and the gauge, and shall be installed where the dial is readable from the floor or platform without a mirror or a ladder.
+
+## Gauge connections shall be taken from the top or the side of the pipe, and shall not be taken from the bottom where sediment collects.
+
+# Thermometers and Thermowells {toc}
+
+## A thermometer at each side of a heat exchanger, a coil bank, or a plant machine is the operator's first check on whether the machine is doing its job, and a thermowell at each of those points is what lets the thermometer be replaced, or a portable instrument inserted, without draining the system. The thermowells that carry control sensors are furnished under [[sync/hvac-controls-instrumentation]]; this section governs thermometers, their wells, and the spare wells for portable instruments. {note}
+
+## Thermometers shall be installed at each location class selected in the datasheet.
+
```datasheet
−label: Flexible Connector Flange/End Material
−type: select
+label: Thermometer Location Classes
+type: checkbox
options:
− - Carbon steel flanges
− - Stainless steel flanges
− - Threaded carbon steel ends
−default: Carbon steel flanges
+ - "Inlet and outlet of each chiller, boiler, and heat exchanger"
+ - "Supply and return of each air-handling unit coil bank"
+ - "Supply and return main at the plant"
+ - "Supply and return of each secondary loop"
+default:
+ - "Inlet and outlet of each chiller, boiler, and heat exchanger"
+ - "Supply and return main at the plant"
```
+## Additional thermometers and thermowells without thermometers shall be installed where shown on [[drawing: the mechanical piping plans and details]].
+
+## Thermometers shall conform to ASME B40.200 and shall be of the type indicated in the datasheet.
+
```datasheet
−label: Flexible Connector Pressure Rating
+label: Thermometer Type
type: select
options:
− - 125 psi
− - 150 psi
− - 232 psi
−default: 150 psi
+ - "Bimetal dial, adjustable angle"
+ - "Bimetal dial, fixed back connection"
+ - "Industrial liquid-in-glass, adjustable angle"
+ - "Solar-powered digital"
+default: "Bimetal dial, adjustable angle"
```
+## An adjustable-angle bimetal dial can be turned to face the operator after the well is installed, reads from across a mechanical room, and is the thermometer nearly every hydronic system is built with. A fixed-back bimetal dial costs less and suits a well that already faces the reading position. An industrial liquid-in-glass thermometer reads more precisely and is fragile, and is chosen where the reading is a reference rather than a check. A solar-powered digital thermometer reads to a tenth of a degree, needs light on its display, and is chosen where the accuracy justifies its cost. {note}
+
+## The thermometer dial size shall be as indicated in the datasheet.
+
```datasheet
−label: Suction-Side Full Vacuum Rating Required
+label: Thermometer Dial Size
+type: range
+unit: in.
+min: 3
+max: 5
+setpoints: [3, 5]
+```
+
+## A 5 in. dial is read from across a room and is the size sold for plant equipment; a 3 in. dial suits a coil connection where the reading is taken close up and the larger dial would not fit the well spacing. Neither is the norm across a whole project, so the field carries no default. {note}
+
+## The scale of each thermometer shall span from below the minimum to above the maximum service temperature at its location, with the upper limit as indicated in the datasheet.
+
+```datasheet
+label: Thermometer Scale Upper Limit
+type: range
+unit: °F
+min: 100
+max: 300
+setpoints: [100, 150, 200, 250, 300]
+derived: "the service temperature range at the thermometer location, from the system design temperatures specified under [[sync/hydronic-piping]]"
+default: derived
+```
+
+## The thermometer accuracy shall be within the percentage of scale span indicated in the datasheet.
+
+```datasheet
+label: Thermometer Accuracy
+type: range
+unit: '% of span'
+min: 1
+max: 2
+setpoints: [1, 2]
+default: 1
+```
+
+## Every thermometer inserted into the piping shall be installed in a thermowell, and the thermowell shall be of the material indicated in the datasheet.
+
+```datasheet
+label: Thermowell Material
type: select
options:
− - Required (suction-side connectors)
− - Not required (discharge only)
−default: Required (suction-side connectors)
+ - "Brass"
+ - "304 stainless steel"
+ - "316 stainless steel"
+default: "Brass"
```
−# Drain, Sample, and Vent Provisions {toc}
+## A brass well matches copper tube and treated water, conducts heat to the stem quickly, and costs least; a stainless well is chosen where the fluid attacks copper alloys or where the well is installed in steel pipe on an untreated or open loop, and Type 316 is the grade for a chloride-bearing condenser water loop. {note}
−## Every closed loop must be drainable, fillable, ventable, and — on open circuits — sampleable. These small valves are easy to omit on a riser diagram and impossible to add cheaply later, so their placement is coordinated on the piping plan. {note}
+## The thermowell insertion length shall be as indicated in the datasheet.
−## Hose-end drain valves shall be installed at all system low points and at the low point of each terminal unit runout.
+```datasheet
+label: Thermowell Insertion Length
+type: range
+unit: in.
+min: 2.5
+max: 12
+setpoints: [2.5, 4, 6, 9, 12]
+derived: "the pipe size at the thermowell location, so that the sensitive portion of the stem is within the middle third of the flow"
+default: derived
+```
−### A coil runout without an accessible hose-end drain cannot be drained or fully flushed; drain placement at terminal low points is coordinated on the piping plan, not left to the installer. {note}
+## Thermowells on insulated piping shall have a lagging extension not less than the insulation thickness specified under [[sync/mechanical-insulation]] for that service.
−## Manual or automatic air vents shall be installed at all system high points.
+## Thermowells shall be installed with the stem perpendicular to the flow or angled into it, and shall not be installed pointing downstream.
−## Sample valves shall be provided in open-loop condenser water and process cooling circuits at locations accessible for water sampling.
+## Each thermowell shall be filled with a heat transfer compound before the thermometer stem is inserted.
−### ANSI/ASHRAE 188 requires accessible drain and sample ports for monitoring building water systems; in open condenser water and process cooling circuits, sample valve placement supports the Legionella risk-management program. {note}
+## A well that ends in the boundary layer near the pipe wall reads the wall, not the water, and a well without a lagging extension is buried in insulation with its head unreachable. The insertion length follows the pipe size and the extension follows the insulation, which is why the first is derived and the second is a clause rather than a field. {note}
−## Drain and sample valve locations {toc}
+# Pressure and Temperature Test Plugs {toc}
−### Drain, vent, and sample valve locations shall be coordinated with the piping layout: [[drawing: piping plan low and high points]]. {note}
+## A test plug is a self-sealing port that accepts a portable gauge or thermometer probe, and a pair of them at a coil gives the balancing agency the pressure drop and the temperature difference it needs without a permanent instrument at every terminal. They cost little and cannot be added after the insulation is on, which is why their locations are decided here. {note}
−### The hose-end drain valve size shall be specified and coordinated with the piping plan low points.
+## Test plugs shall be installed at each location class selected in the datasheet.
```datasheet
−label: Hose-End Drain Valve Size
−type: select
+label: Test Plug Location Classes
+type: checkbox
options:
− - 1/2 in.
− - 3/4 in.
− - 1 in.
−default: 3/4 in.
+ - "Inlet and outlet of each coil and terminal unit"
+ - "Each side of each strainer NPS 2 and smaller"
+ - "Inlet and outlet of each heat exchanger not fitted with gauges"
+ - "Each side of each balancing device without integral metering ports"
+default:
+ - "Inlet and outlet of each coil and terminal unit"
+ - "Each side of each balancing device without integral metering ports"
```
−### The air vent type at piping high points shall be specified and coordinated with the piping plan high points.
+## Additional test plugs shall be installed where shown on [[drawing: the mechanical piping plans and details]].
+## Test plugs shall be rated for the system design pressure at the system design temperature, and the core shall be of the material indicated in the datasheet.
+
```datasheet
−label: Air Vent Type at High Points
+label: Test Plug Core Material
type: select
options:
− - Manual coin/key vent
− - Automatic float vent with isolation
−default: Automatic float vent with isolation
+ - "Neoprene"
+ - "EPDM"
+ - "Fluoroelastomer"
+default: "EPDM"
```
−### Whether sample valves are provided at accessible monitoring points on open-loop circuits shall be specified.
+## The core is what seals after the probe is withdrawn, and its temperature limit is the whole selection: neoprene serves chilled water and low-temperature heating and hardens above about 200°F, EPDM serves the full building-services envelope and glycol and is the core most plugs are sold with, and fluoroelastomer is chosen where the fluid or the temperature is beyond what EPDM tolerates. {note}
+## The test plug body shall be of the material indicated in the datasheet.
+
```datasheet
−label: Sample Valve Provision (open-loop circuits)
−type: checkbox
+label: Test Plug Body Material
+type: radio
options:
− - Sample valves at accessible monitoring points
−defaults:
− - Sample valves at accessible monitoring points
+ - "Brass"
+ - "Stainless steel"
+default: "Brass"
```
−# Coil Connection Assemblies {toc}
+## A brass body matches copper tube and treated water; a stainless body is chosen on an open loop or where the fluid attacks copper alloys. {note}
−## A coil connection assembly (coil connection kit) gathers the isolation, balancing, drain, air vent, and union fittings a terminal coil needs into one compact, repeatable package. Factory-assembled kits make every terminal identical and shorten field labor; field-fabricated assemblies allow case-by-case configuration. {note}
+## Each test plug shall have a gasketed cap retained to the body by a chain or a strap.
−## Each terminal coil shall be served by a connection assembly providing isolation, balancing, drain, and air vent functions on both supply and return.
+## Test plugs on insulated piping shall be of extended length so that the cap is outside the insulation.
−## Whether coil connection assemblies are factory-assembled kits or field-fabricated from individual components shall be specified for the project.
+# Manual Air Vents and Drain Valves {toc}
−### Factory-assembled kits give consistent configuration and quality across many identical terminals and reduce field fittings and labor; field fabrication suits projects with few or highly varied terminals. {note}
+## The locations of vent and drain connections are set under [[sync/hydronic-piping]], and the automatic air vents at the air separator and at high points that cannot be reached are furnished under [[sync/expansion-tanks-and-air-separators]]. This section governs the manual vent and the hose-end drain valve as devices. {note}
−## Where a PICV serves the terminal, the coil connection assembly balancing function may be provided by the PICV in lieu of a separate balancing valve.
+## The manual air vent type at accessible high points shall be as indicated in the datasheet.
−## Isolation valves within coil connection assemblies shall be ball valves conforming to MSS SP-110.
+```datasheet
+label: Manual Air Vent Type
+type: radio
+options:
+ - "Coin or key operated vent"
+ - "Screwdriver-slot vent"
+ - "Ball valve with hose-end outlet"
+default: "Coin or key operated vent"
+```
−## Unions or flanges shall be provided so the coil can be removed without cutting the connecting pipe.
+## A coin or key vent is small, seals reliably, and vents a coil or a terminal in a minute; a screwdriver-slot vent is the same device without the captive key and is opened with whatever the operator has; a ball valve with a hose-end outlet vents a large high point quickly and lets the operator direct the discharge into a container, at a larger size and cost. {note}
+## Each manual air vent shall be rated for the system design pressure at the system design temperature and shall discharge where the water released cannot damage equipment or finishes below it.
+
+## Each hose-end drain valve shall be a full-port ball valve conforming to MSS SP-110, with a hose thread outlet and a gasketed cap retained by a chain, in the size required under [[sync/hydronic-piping]].
+
+## Drain valve bodies shall be bronze or brass, and the hose thread outlet shall be capped whenever the valve is not in use.
+
+# Coil Connection Assemblies {toc}
+
+## A coil connection assembly gathers the isolation, strainer, balancing, drain, vent, and test port functions a terminal coil needs into one repeatable arrangement. A factory-assembled kit makes every terminal identical and moves most of the joints into a shop; a field-assembled arrangement lets each terminal be configured to its location and uses the components already specified under this and the neighboring standards. {note}
+
+## Each terminal coil shall be served by a connection assembly of the form indicated in the datasheet.
+
```datasheet
−label: Coil Connection Assembly
−type: select
+label: Coil Connection Assembly Form
+type: radio
options:
− - Factory-assembled connection kit
− - Field-fabricated from individual components
−default: Factory-assembled connection kit
+ - "Factory-assembled kit"
+ - "Field-assembled from individual components"
+default: "Field-assembled from individual components"
```
+## A factory kit costs more per terminal, arrives with its components matched and pressure tested, and saves field labor on a project with many identical terminals; field assembly suits a project with few terminals, with terminals that differ, or with a piping trade that already stocks the components. {note}
+
+## Each coil connection assembly shall include, on each terminal, the components indicated in the datasheet.
+
```datasheet
−label: Coil Connection Assembly Functions (each side)
+label: Coil Connection Assembly Components
type: checkbox
options:
− - Isolation ball valve
− - Balancing valve (omit where PICV serves terminal)
− - Union or flange for coil removal
− - Hose-end drain valve
− - Air vent
− - Strainer (supply side)
−defaults:
− - Isolation ball valve
− - Balancing valve (omit where PICV serves terminal)
− - Union or flange for coil removal
− - Hose-end drain valve
− - Air vent
+ - "Isolation ball valve on supply and return"
+ - "Strainer on the supply"
+ - "Balancing device of the type selected for the terminal"
+ - "Union or flanged connection for coil removal"
+ - "Hose-end drain valve on supply and return"
+ - "Manual air vent"
+ - "Test plugs on supply and return"
+ - "Flexible braided hose connections to the coil"
+default:
+ - "Isolation ball valve on supply and return"
+ - "Balancing device of the type selected for the terminal"
+ - "Union or flanged connection for coil removal"
+ - "Hose-end drain valve on supply and return"
+ - "Manual air vent"
+ - "Test plugs on supply and return"
```
+## Isolation ball valves within a coil connection assembly shall conform to [[sync/hvac-piping-valves]].
+
+## The control valve within a coil connection assembly shall be furnished under [[sync/hvac-controls-instrumentation]] unless the terminal is served by a pressure-independent control valve, in which case the valve shall be furnished under this standard and the separate balancing device shall be omitted.
+
+## Flexible braided hose connections to a coil shall be stainless steel braided hose rated for the system design pressure at the system design temperature, with the end connections and the length shown on [[drawing: the terminal unit piping details]].
+
+## A factory-assembled kit shall carry a single pressure-temperature rating for the whole assembly, not less than the rating required under Marking and Pressure Rating, and shall be pressure tested at the factory before shipment.
+
# Installation {toc}
−## Hydronic specialties earn their cost only when they are accessible and oriented for reading and service; installation quality is therefore as much about clearance and orientation as about the joint itself. {note}
+## Placement and Orientation {toc}
−## All specialties shall be installed in accordance with the manufacturer's installation instructions and IMC Chapter 12.
+### Each device shall be installed in accordance with its manufacturer's published installation instructions and IMC Chapter 12, with the flow arrow on the body matching the direction of flow.
−## Strainers shall be installed with the screen pocket oriented to permit blow-down and screen removal without removing the body from the line.
+### Y-pattern strainers in horizontal piping shall be installed with the screen pocket pointing downward or horizontally, and never upward.
−## Strainers in horizontal lines shall be installed with the pocket pointing down or horizontally, never up.
+### Y-pattern strainers in vertical piping shall be installed only where the flow is downward.
−## Balancing valves and flow control devices shall be installed with the manufacturer's required straight pipe length upstream and downstream of the device.
+### A Y-strainer pocket pointing up collects air instead of dirt and lets the dirt settle back into the main when the flow stops; in an upward-flowing vertical run the pocket cannot hold dirt at all. The orientation is unconditional because there is no service in which the other orientations work. {note}
−### Flow control devices read and meter flow accurately only in developed flow; the upstream and downstream straight runs the manufacturer specifies must be honored or the balanced flow will be wrong.
+### Basket strainers shall be installed upright with the cover clearance the manufacturer publishes above them for basket removal.
−## Pressure gauges and thermometers shall be installed where they can be read from the operating floor or an accessible platform.
+### The Contractor shall not install a balancing valve, flow-limiting valve, differential pressure control valve, pressure-independent control valve, or flow measurement element where the straight pipe required under [[sync/hydronic-piping]] is not available, and shall notify the Engineer of Record in writing before installing the device where the required straight pipe cannot be achieved.
−## Flexible connectors shall be installed without offset, twist, or extension beyond the manufacturer's allowable, and with control rods where required to restrain pressure thrust.
+### Balancing devices shall be installed with their metering ports and their position indicators facing the side from which the balancing agency will read them.
−## Air vents shall discharge to a point where dripping will not damage equipment or finishes below.
+### Pressure-independent control valves shall be installed with the actuator above the horizontal centerline of the pipe and with the clearance the manufacturer publishes for actuator removal.
−## Each specialty requiring periodic service shall be installed with the manufacturer's required service clearance and within reach of an access panel where concealed.
+### Gauges, thermometers, and test plugs shall be installed where they can be read or probed from the floor or from a fixed platform.
−```datasheet
−label: Strainer Orientation in Horizontal Pipe
−type: select
−options:
− - Pocket down
− - Pocket horizontal
−default: Pocket down
−```
+### Flexible connectors shall be installed with the equipment set and aligned, and shall not be used to pull the piping to the equipment nozzle.
−```datasheet
−label: Concealed Specialty Access
−type: select
−options:
− - Access panel/door at each concealed specialty
− - Located in accessible ceiling or chase
−default: Access panel/door at each concealed specialty
−```
+### Chemical bypass feeders, fill assemblies, and glycol makeup packages shall be installed where they can be charged and serviced from the floor, with a drain within reach of the feeder drain valve.
−# Testing {toc}
+## Coordination with the Piping Work {toc}
−## Specialties are proven as part of the piping system pressure test and then exercised during balancing; the standard pairs a leak-tightness check with a functional confirmation that flow devices actually meter and hold flow. {note}
+### The Contractor shall deliver each device to the piping installer before the section it serves is closed and pressure tested.
−## All installed specialties shall be subjected to the hydronic piping pressure test specified in [[sync/hydronic-piping]] and shall be leak-free at the test pressure.
+### Devices rated below the piping test pressure specified under [[sync/hydronic-piping]], including gauges, relief valves, fill valves, and elastomeric connectors where their rating is exceeded, shall be isolated or removed from the test boundary and reinstated after the test.
−## Strainer screens shall be inspected and cleaned after initial system flushing and before final balancing.
+### Where a device is set before the piping is complete, its connections shall be capped and its metering ports plugged until the connection is made.
−### Construction debris loads the screens heavily on first fill; cleaning after flushing and before balancing prevents a fouled screen from skewing the flow readings the balancer relies on. {note}
+### A gauge left in a boundary tested at one and a half times the design pressure returns with its movement sprung, and a relief valve left in lifts during the test and is then blamed for weeping. Removing the low-rated devices before the test is cheaper than replacing them after it. {note}
−## Balancing valve and flow control device flow settings shall be verified and recorded by the testing and balancing agency in accordance with [[sync/testing-adjusting-and-balancing]].
+# Testing and Startup {toc}
−## PICV control function shall be verified through the building automation system across the modulating range.
+## Each device shall be leak-free at its joints and at its bonnet, cover, cap, or stem during the piping pressure test under [[sync/hydronic-piping]] or, where it was removed for that test, during the first fill.
+## After the cleaning and flushing under [[sync/hydronic-cleaning-and-flushing]] and before the balancing agency begins work, the Contractor shall remove, clean, and reinstall every strainer screen and shall remove every temporary startup screen, and shall record both on the strainer cleaning record.
+
+## A fouled screen throttles the branch it serves, and a balance set against a fouled screen is wrong the day the screen is cleaned. Cleaning after flushing and before balancing is the sequence that makes the balancing report stay true. {note}
+
+## The Contractor shall confirm that each pressure-independent control valve is set to its scheduled maximum flow and that each automatic flow-limiting valve carries the cartridge scheduled for its branch before the balancing agency begins work.
+
+## The Contractor shall confirm that each gauge reads zero with its isolation valve closed and vented, and that each thermometer reads within its accuracy against a reference thermometer at ambient, before the system is placed in service.
+
+## Each relief valve shall be lifted by hand after the first fill to confirm that it opens and reseats, and the as-installed set pressure shall be recorded.
+
+## Each fill valve and each glycol makeup package shall be set to the fill pressure coordinated under [[sync/expansion-tanks-and-air-separators]], and the set points shall be recorded.
+
+## The flow through each balancing device, flow-limiting valve, differential pressure control valve, and pressure-independent control valve shall be verified and recorded by the balancing agency under [[sync/testing-adjusting-and-balancing]].
+
+## The Contractor shall prepare the following startup records and shall include them with the closeout submittals:
+
```datasheet
−label: Specialty Test Documentation
+label: Startup Records Required
type: checkbox
options:
− - Pressure test included with piping test
− - Strainer cleaning after flush recorded
− - Recorded balancing valve settings
− - PICV BAS function verification
−defaults:
− - Pressure test included with piping test
− - Strainer cleaning after flush recorded
− - Recorded balancing valve settings
+ - "Strainer cleaning and startup screen removal record"
+ - "Pressure-independent control valve maximum flow settings"
+ - "Flow-limiting cartridge schedule as installed"
+ - "Gauge zero and thermometer reference check"
+ - "Relief valve lift test and set pressure"
+ - "Fill and glycol makeup set points"
+default:
+ - "Strainer cleaning and startup screen removal record"
+ - "Pressure-independent control valve maximum flow settings"
+ - "Relief valve lift test and set pressure"
+ - "Fill and glycol makeup set points"
```
# Delivery, Storage, and Handling {toc}
−## Specialty trim — calibrated stops, gauge movements, separator media, and elastomeric connectors — is easily damaged or contaminated before installation; protecting end connections and keeping devices dry and capped preserves both function and warranty. {note}
+## Devices shall be delivered with the manufacturer's markings intact and legible, with end connections capped or plugged, and with metering ports and test plugs fitted with their caps.
−## Specialties shall be delivered with end connections capped or plugged and shall remain capped until installation.
+## Devices shall be stored indoors, off the floor, and protected from impact, weather, and ultraviolet exposure.
−## Gauges, thermometers, and flexible connectors shall be stored indoors, protected from impact, weather, and ultraviolet exposure.
+## Gauges and thermometers shall be stored in their cartons until installation, and a gauge or thermometer that has been dropped shall not be installed.
−## Calibrated balancing valves and PICVs shall be protected from impact that could disturb the calibrated setting or actuator.
+## Elastomeric connectors shall be stored away from sunlight, ozone sources, and petroleum products, and shall not be used after the manufacturer's marked shelf life.
−## Strainer screens and separator media shall be kept clean and dry until the system is ready for service.
+## Calibrated balancing valves, flow-limiting cartridges, and pressure-independent control valve assemblies shall be protected from impact that could disturb the calibrated element or the actuator coupling.
−# Warranty {toc}
+## The Contractor shall bear the cost of replacing a device damaged or contaminated by improper storage or handling.
−## The warranty section sets the minimum coverage the Owner receives; flow control devices and separators carry the longest exposure to wear and fouling and so are called out explicitly. {note}
+## The calibrated element in a balancing valve, the movement in a gauge, and the elastomer in a connector are each ruined by a treatment that leaves a pipe fitting unharmed. The handling rules exist because the damage is not visible when the device is installed. {note}
−## The Contractor shall warrant all hydronic specialties against defects in material and workmanship for the project warranty period, but not less than one year from Substantial Completion.
+# Warranty {toc}
−## Flow control devices, including PICVs and automatic flow-limiting valves, shall carry the manufacturer's standard warranty against failure of the regulating mechanism.
+## The Contractor shall warrant every device furnished under this standard against defects in materials and workmanship for the period indicated in the datasheet, measured from the date of substantial completion.
−## Warranty documentation for each specialty type shall be provided in the closeout submittals.
−
```datasheet
−label: Warranty Period
−type: select
−options:
− - 1 year from Substantial Completion
− - 2 years from Substantial Completion
− - 5 years from Substantial Completion
−default: 1 year from Substantial Completion
+label: Contractor Warranty Period
+type: range
+unit: years
+min: 1
+max: 5
+setpoints: [1, 2, 3, 5]
+default: 1
```
−# Spare Parts {toc}
+## Where the contract General Conditions specify a longer warranty period than the datasheet, the longer period shall govern.
−## Stocking a small set of consumable spares — screens, cartridges, and separator media — lets operators service the items most likely to foul without waiting on procurement. {note}
+## A device that fails to hold its rating, its calibration, or its set flow within the warranty period shall be replaced by the Contractor at no cost to the Owner, including the cost of draining and refilling the affected section, of replacing treatment chemical and glycol lost, and of removing and reinstating insulation and finishes to reach the device.
−## The Contractor shall furnish one spare screen for each size and type of strainer installed.
+## The manufacturer's warranty on pressure-independent control valve actuators and on flow-limiting cartridges shall be assigned to the Owner and shall be not less than the Contractor warranty period.
−## The Contractor shall furnish one spare flow cartridge for each size of automatic flow-limiting valve installed where field-selectable cartridges are used.
+## A replaced device shall carry a warranty running for a full new term from the date the replacement is accepted, or for the remainder of the original term, whichever ends later.
−## The Contractor shall furnish the manufacturer's recommended quantity of replacement separator media or magnetic-element wipes where applicable.
+## The unassigned cost in a specialty warranty is rarely the device. It is the glycol drained to reach it, the insulation rebuilt over it, and the rebalance of the branch it sits in. Naming those costs is what makes the warranty enforceable without an argument. {note}
+# Spare Parts {toc}
+
+## The Contractor shall furnish the spare parts indicated in the datasheet, delivered to the Owner at substantial completion with a transmittal listing each item and the device it fits.
+
```datasheet
label: Spare Parts Furnished
type: checkbox
options:
− - One spare screen per strainer size/type
− - One spare cartridge per automatic flow-limiting valve size
− - Replacement separator media as recommended
−defaults:
− - One spare screen per strainer size/type
+ - "One spare screen for each strainer size and pattern installed"
+ - "One spare cartridge for each flow-limiting valve size and rating installed"
+ - "One spare actuator for each pressure-independent control valve actuator model installed"
+ - "One spare gauge for each range installed"
+ - "One spare thermometer for each type and range installed"
+ - "One test plug gauge adapter and probe kit"
+ - "Filter bags for each chemical bypass feeder, one year's supply"
+ - "Cores and caps for ten percent of the test plugs installed"
+default:
+ - "One spare screen for each strainer size and pattern installed"
+ - "One spare cartridge for each flow-limiting valve size and rating installed"
+ - "One test plug gauge adapter and probe kit"
```
+
+## Spare screens and cartridges let the operator service the devices that foul without waiting on procurement, and the test plug kit is what turns the test plugs into an instrument the operator can actually use. The spare actuator is chosen on a project with many pressure-independent valves, where one failed actuator at a time is the expected failure mode and the terminal is down until it is replaced. {note}