Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
---
title: General-Duty Valves for HVAC Piping
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### The Contractor shall verify, for each valve location, that the valve pressure class equals or exceeds the maximum system working pressure at the design temperature, including static head, pump shutoff head, and fill pressure.
−### Where the calculated maximum system working pressure exceeds 175 psig, Class 125 bodies shall not be used; Class 150 ductile-iron, Class 250 cast-iron, or Class 300 steel valves shall be specified as appropriate to the service.
−
−## Pressure-class ratings used in this Standard. {note}
−
−## The pressure classes below are the working envelopes used throughout this Standard. Steam ratings are saturated-steam ratings; cold-water (CWP / WOG) ratings apply at or below 65 °C unless the manufacturer's pressure-temperature table permits otherwise. {note}
−
−| Body / Class | Saturated steam | Cold water (CWP/WOG) | Typical HVAC use |
−|--------------|-----------------|----------------------|------------------|
−| Bronze Class 125 | 125 psig | 200 psig | Branch isolation NPS 1/4–2 |
−| Bronze Class 150 | 150 psig | 300 psig | Branch isolation, low-pressure steam NPS 1/4–2 |
−| Cast iron Class 125 | 125 psig | 200 psig | Mains NPS 2-1/2–12, ≤175 psig systems |
−| Cast iron Class 250 | 250 psig | 500 psig | Medium-pressure steam, high-rise mains |
−| Steel Class 150 | per ASME B16.34 | per ASME B16.34 | Steam mains 15–125 psig, flanged |
−| Steel Class 300 | per ASME B16.34 | per ASME B16.34 | Steam >125 psig, >175 psig hydronic |
−
```datasheet
label: Maximum System Working Pressure at Valve
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```
+### Where the calculated maximum system working pressure exceeds 175 psig, Class 125 bodies shall not be used; Class 150 ductile-iron, Class 250 cast-iron, or Class 300 steel valves shall be specified as appropriate to the service.
+
+## Pressure-class ratings used in this Standard. {note}
+
+## The pressure classes below are the working envelopes used throughout this Standard. Steam ratings are saturated-steam ratings; cold-water (CWP / WOG) ratings apply at or below 65 °C unless the manufacturer's pressure-temperature table permits otherwise. {note}
+
+| Body / Class | Saturated steam | Cold water (CWP/WOG) | Typical HVAC use |
+|--------------|-----------------|----------------------|------------------|
+| Bronze Class 125 | 125 psig | 200 psig | Branch isolation NPS 1/4–2 |
+| Bronze Class 150 | 150 psig | 300 psig | Branch isolation, low-pressure steam NPS 1/4–2 |
+| Cast iron Class 125 | 125 psig | 200 psig | Mains NPS 2-1/2–12, ≤175 psig systems |
+| Cast iron Class 250 | 250 psig | 500 psig | Medium-pressure steam, high-rise mains |
+| Steel Class 150 | per ASME B16.34 | per ASME B16.34 | Steam mains 15–125 psig, flanged |
+| Steel Class 300 | per ASME B16.34 | per ASME B16.34 | Steam >125 psig, >175 psig hydronic |
+
## Fluid and seat compatibility. {note}
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- Seat / disc renewal kits (per repairable valve type/size)
```