Performance Requirements for Pressure Vacuum Breaker Assembly
|Publication Date:||1 January 1998|
Vacuum breakers, other than air gaps, shall be classified into four general types:
a. Atmospheric Type (See ASSE Standard #1001) b. Pressure Type (ASSE #1020, as described in this standard); c. Back Siphonage (See ASSE Standard #1056); and d. Pressure Type (See ASSE #1058).
The assembly shall be designed to accommodate nominal pipe sizes 15 to 50 mm (1/2" to 2" inches).
Working Pressure Range
Assemblies shall be designed for a minimum rated working pressure of at least 1034 kPa (150 p.s.i).
a. Cold water service shall range from 0.55 degrees C to 43 degrees C (33 degrees F to 110 degrees F).
b. Hot water service shall range from 0.55 degrees C to 82.2 degrees C (33 degrees F to 180 degrees F) minimum.
Pressure vacuum breaker assemblies are for installation in water supply lines to prevent the entrance of non-potable material into the potable water supply by backsiphonage only. It is not for use in any system where backpressure can be applied to the assembly.
When a supply pressure is between 7 to 14 kPa (1 to 2 p.s.i.), the air inlet valve is open and the assembly will continuously discharge. Due to this probability of water discharge from the atmospheric air inlet valve, the assembly shall only be installed where water discharge does not cause damage.