Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
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title: Domestic Water Piping Specialties and Valves
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When to use: assembled accessories and inline specialties on the domestic cold water, hot water,
and hot water recirculation distribution systems of commercial, institutional, and industrial
− buildings -- pressure-reducing valve (PRV) stations, domestic hot water expansion tanks, dielectric
+ buildings — pressure-reducing valve (PRV) stations, domestic hot water expansion tanks, dielectric
isolation fittings at dissimilar-metal connections, inline strainers, pipe identification and valve
tags, pipe sleeves, escutcheons, firestop collars at penetrations, and equipment isolation/drain
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## This standard's defensible territory is the assembled system accessory. {note}
−## The corpus has three close neighbors, and the boundary against each is deliberate. Piping, fittings, joining, hangers, and insulation belong to [[sync/domestic-water-piping]]. General-duty isolation, check, and balancing valves belong to [[sync/plumbing-piping-valves]]. Fixture-protection specialties -- water hammer arresters, thermostatic mixing valves, hose bibbs, trap primers -- belong to [[sync/plumbing-specialties]]. What remains, and what this standard owns, is the assembled accessory: the PRV station as a station, the expansion tank, the dielectric break, the strainer, the identification system, the penetration treatment, and the equipment isolation kit. {note}
+## The corpus has three close neighbors, and the boundary against each is deliberate. Piping, fittings, joining, hangers, and insulation belong to [[sync/domestic-water-piping]]. General-duty isolation, check, and balancing valves belong to [[sync/plumbing-piping-valves]]. Fixture-protection specialties — water hammer arresters, thermostatic mixing valves, hose bibbs, trap primers — belong to [[sync/plumbing-specialties]]. What remains, and what this standard owns, is the assembled accessory: the PRV station as a station, the expansion tank, the dielectric break, the strainer, the identification system, the penetration treatment, and the equipment isolation kit. {note}
## The work of this standard applies to domestic cold water, domestic hot water, and hot water recirculation piping inside the building envelope. {note}
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## The following are specifically excluded and are specified elsewhere. {note}
−- General-duty isolation, check, and balancing valves -- [[sync/plumbing-piping-valves]]
−- Water hammer arresters, thermostatic mixing valves (master and point-of-use), hose bibbs, freezeless wall hydrants, and trap primers -- [[sync/plumbing-specialties]]
−- Supply and distribution piping materials, fittings, joining methods, hangers, and insulation -- [[sync/domestic-water-piping]]
−- Backflow prevention assemblies (RPZ, double-check, PVB) at the building or zone level -- [[sync/backflow-prevention]]
−- Water heaters, tankless heaters, and storage equipment -- [[sync/water-heaters]]
−- Sanitary drainage specialties, cleanouts, and backwater valves -- [[sync/sanitary-drainage-specialties]]
−- Hydronic, chilled, and condenser water piping accessories -- [[sync/chilled-and-condenser-water-piping]]
−- Fire protection piping, specialties, and control valves -- [[sync/fire-protection-piping]]
+- General-duty isolation, check, and balancing valves — [[sync/plumbing-piping-valves]]
+- Water hammer arresters, thermostatic mixing valves (master and point-of-use), hose bibbs, freezeless wall hydrants, and trap primers — [[sync/plumbing-specialties]]
+- Supply and distribution piping materials, fittings, joining methods, hangers, and insulation — [[sync/domestic-water-piping]]
+- Backflow prevention assemblies (RPZ, double-check, PVB) at the building or zone level — [[sync/backflow-prevention]]
+- Water heaters, tankless heaters, and storage equipment — [[sync/water-heaters]]
+- Sanitary drainage specialties, cleanouts, and backwater valves — [[sync/sanitary-drainage-specialties]]
+- Hydronic, chilled, and condenser water piping accessories — [[sync/chilled-and-condenser-water-piping]]
+- Fire protection piping, specialties, and control valves — [[sync/fire-protection-piping]]
- The site water service main upstream of the building water service entrance
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## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
−## Where this standard and the locally adopted plumbing code conflict, the plumbing code shall govern. {note}
+## Where this standard and the locally adopted plumbing code conflict, the plumbing code shall govern.
| Standard | Title |
|----------|-------|
| ASSE 1003 / CSA B356 | Performance Requirements for Water Pressure Reducing Valves for Domestic Water Distribution Systems |
| ASSE 1011 | Performance Requirements for Hose Connection Vacuum Breakers |
−| NSF/ANSI 61 | Drinking Water System Components -- Health Effects |
−| NSF/ANSI/CAN 372 | Drinking Water System Components -- Lead Content (Lead-Free) |
+| NSF/ANSI 61 | Drinking Water System Components — Health Effects |
+| NSF/ANSI/CAN 372 | Drinking Water System Components — Lead Content (Lead-Free) |
| ASME A112.1.2 | Air Gaps in Plumbing Systems |
| ASME B16.18 | Cast Copper Alloy Solder Joint Pressure Fittings |
| ASME B31.9 | Building Services Piping |
| ASME A13.1 | Scheme for the Identification of Piping Systems |
| ASTM F1508 | Angle-Style, Thermoplastic Expansion Tank Connectors |
−| PDI WH-201 | Water Hammer Arresters -- Certification and Sizing |
+| PDI WH-201 | Water Hammer Arresters — Certification and Sizing |
| IPC | International Plumbing Code, Chapter 6 (Water Supply and Distribution) |
| UPC | Uniform Plumbing Code, Chapter 6 (Water Supply and Distribution) |
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# Environmental and Service Conditions {toc}
−## Components shall be selected for the service in which they are installed: domestic cold water, domestic hot water, or hot water recirculation. {note}
+## Components shall be selected for the service in which they are installed: domestic cold water, domestic hot water, or hot water recirculation.
−## Hot water recirculation is the most demanding service because it combines continuous flow, elevated temperature, and continuous thermal cycling. Components rated only for cold water -- particularly elastomeric flexible connectors and dielectric inserts -- fail prematurely in recirculation service. {note}
+## Hot water recirculation is the most demanding service because it combines continuous flow, elevated temperature, and continuous thermal cycling. Components rated only for cold water — particularly elastomeric flexible connectors and dielectric inserts — fail prematurely in recirculation service. {note}
## Components in hot water and recirculation service shall be rated for continuous operation at not less than 180 °F.
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# Pressure-Reducing Valve Stations {toc}
−## IPC Section 604.8 and UPC Section 608 trigger when the static service pressure entering the building exceeds 80 psi. The station is more than the valve: it is the valve plus its strainer, isolation valves, downstream gauge, and -- on most commercial systems -- a bypass. {note}
+## IPC Section 604.8 and UPC Section 608 trigger when the static service pressure entering the building exceeds 80 psi. The station is more than the valve: it is the valve plus its strainer, isolation valves, downstream gauge, and — on most commercial systems — a bypass. {note}
## A pressure-reducing valve shall be installed on the building water service where the static incoming pressure exceeds 80 psi.
−## The PRV setpoint shall be the required pressure at the valve outlet, not the desired pressure at the highest or furthest fixture. {note}
+## The PRV setpoint shall be the required pressure at the valve outlet, not the desired pressure at the highest or furthest fixture.
## The single most common PRV error is setting the outlet pressure to the target fixture pressure without accounting for the static head and friction loss between the valve and the upper floors. The Engineer of Record verifies that the reduced downstream design pressure remains adequate for the highest and most remote fixtures at peak demand. {note}
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### PRV Configuration {toc}
−#### The station configuration shall be selected for the criticality of the served load. {note}
+#### The station configuration shall be selected for the criticality of the served load.
−#### A single PRV with no bypass takes the entire system offline if the valve fails during peak demand. For critical loads -- hospitals, laboratories, manufacturing, and any occupancy that cannot tolerate an interruption -- the choice is between a parallel redundant station and a full-flow bypass that allows the valve to be serviced without dropping the system. {note}
+#### A single PRV with no bypass takes the entire system offline if the valve fails during peak demand. For critical loads — hospitals, laboratories, manufacturing, and any occupancy that cannot tolerate an interruption — the choice is between a parallel redundant station and a full-flow bypass that allows the valve to be serviced without dropping the system. {note}
#### A full-flow bypass or a parallel redundant PRV shall be provided on systems serving critical or continuous-process loads.
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−#### The downstream gauge shall be glycerin-filled to resist vibration and pulsation damage. {note}
+#### The downstream gauge shall be glycerin-filled to resist vibration and pulsation damage.
#### Isolation valves shall be provided upstream and downstream of each PRV to permit removal without draining the system.
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# Domestic Hot Water Expansion Tanks {toc}
−## IPC Section 607 and UPC Section 608 require thermal expansion control on closed systems -- defined as any system with a check valve, backflow preventer, or PRV between the heater and the street, because that device closes the system and removes the street main as an expansion sink. Water expands roughly 2% to 3% when heated from cold fill to storage temperature, and with nowhere to go that expansion drives the system pressure up against the relief valve. {note}
+## IPC Section 607 and UPC Section 608 require thermal expansion control on closed systems — defined as any system with a check valve, backflow preventer, or PRV between the heater and the street, because that device closes the system and removes the street main as an expansion sink. Water expands roughly 2% to 3% when heated from cold fill to storage temperature, and with nowhere to go that expansion drives the system pressure up against the relief valve. {note}
## A thermal expansion tank shall be installed on the cold water supply to each closed domestic hot water system.
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## The expansion tank acceptance volume shall be calculated from the system water volume, cold-fill pressure, relief valve set pressure, and temperature rise, using the manufacturer's published worksheet or the equivalent ASME method.
−## The expansion tank pre-charge pressure shall equal the static cold-fill pressure at the tank location and shall be field-verified and adjusted before the system is placed in service. {note}
+## The expansion tank pre-charge pressure shall equal the static cold-fill pressure at the tank location and shall be field-verified and adjusted before the system is placed in service.
−## Factory pre-charge defaults to a nominal value -- commonly 40 psi -- that is correct for almost no multi-story building. A tank in an upper-floor mechanical room sees lower static fill pressure than one in the basement, so the pre-charge must be set to the actual cold-fill pressure at the tank elevation. A tank installed at the factory default in a building whose fill pressure differs will not perform as sized. {note}
+## Factory pre-charge defaults to a nominal value — commonly 40 psi — that is correct for almost no multi-story building. A tank in an upper-floor mechanical room sees lower static fill pressure than one in the basement, so the pre-charge must be set to the actual cold-fill pressure at the tank elevation. A tank installed at the factory default in a building whose fill pressure differs will not perform as sized. {note}
## The expansion tank pre-charge pressure shall be field-verified and adjusted to match the system cold-fill pressure at the tank location before the system is filled.
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# Equipment Isolation and Drain Valve Packages {toc}
−## Equipment served by the domestic water system shall be isolatable and drainable without affecting the rest of the distribution. {note}
+## Equipment served by the domestic water system shall be isolatable and drainable without affecting the rest of the distribution.
−## Water heaters, booster pumps, and water treatment equipment must be serviceable in place. The isolation package -- full-port ball valves on each connection, a hose-end drain valve, unions for removal, and gauge and thermometer provisions -- lets a technician valve off, drain, and remove the equipment without shutting down the building. The package may be a factory kit or field-assembled from the same components. {note}
+## Water heaters, booster pumps, and water treatment equipment must be serviceable in place. The isolation package — full-port ball valves on each connection, a hose-end drain valve, unions for removal, and gauge and thermometer provisions — lets a technician valve off, drain, and remove the equipment without shutting down the building. The package may be a factory kit or field-assembled from the same components. {note}
## Each water heater, booster pump, and water treatment unit shall be provided with full-port isolation valves on each piping connection.
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−## Flexible connectors at rotating equipment shall be rated for the system pressure and temperature. {note}
+## Flexible connectors at rotating equipment shall be rated for the system pressure and temperature.
## A rubber flexible connector rated for 125 psi cold water will fail in hot water recirculation service. Galvanized braid corrodes rapidly in hot water; the connector's temperature rating must cover the actual service conditions, not just a nominal cold water rating. {note}
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# Pipe Sleeves, Escutcheons, and Firestopping {toc}
−## Every pipe passing through a wall, floor, or ceiling shall be sleeved. {note}
+## Every pipe passing through a wall, floor, or ceiling shall be sleeved.
−## A sleeve protects the pipe at the penetration, accommodates movement, and -- at rated assemblies -- carries the firestop system. The sleeve and its annular fill are selected for whether the assembly is fire-rated. {note}
+## A sleeve protects the pipe at the penetration, accommodates movement, and — at rated assemblies — carries the firestop system. The sleeve and its annular fill are selected for whether the assembly is fire-rated. {note}
## Each pipe penetration of a wall, floor, or ceiling shall be provided with a sleeve.
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## The annular space shall provide a minimum clearance of 1/2 in. on each side of the pipe, including its insulation, and shall not exceed the maximum gap of the listed firestop system.
−## An escutcheon shall be provided at each exposed pipe penetration in finished areas. {note}
+## An escutcheon shall be provided at each exposed pipe penetration in finished areas.
## Escutcheons must be sized for the insulated outside diameter of the pipe, not the bare pipe. Where the pipe is insulated under a separate section, the insulated OD is a coordination item and a common RFI source; confirm the insulated OD before ordering. {note}
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# Testing {toc}
−## The completed system shall be hydrostatically tested before it is concealed or placed in service. {note}
+## The completed system shall be hydrostatically tested before it is concealed or placed in service.
## The hydrostatic test verifies that every joint and specialty connection in the assembled system holds pressure. PRVs and expansion tanks are isolated or removed during the test because their working pressure and acceptance volume would otherwise mask or be damaged by the test pressure. {note}
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## Each PRV station shall be installed with clearance to read the gauge, adjust the setpoint, and remove the valve without disturbing adjacent work.
−## Each expansion tank shall be supported independently of the connected piping and located where its pre-charge can be checked and adjusted in service. {note}
+## Each expansion tank shall be supported independently of the connected piping and located where its pre-charge can be checked and adjusted in service.
## A tank that hangs on the piping it serves overloads the connection and makes the air valve inaccessible; mount it on a dedicated support with the air valve reachable. {note}
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- One spare PRV repair cartridge per size
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