Performance Requirements for Pressure Vacuum Breaker Assembly
|Publication Date:||1 February 2004|
The assembly shall contain an independently acting check valve force loaded to the closed position, and an independently acting air inlet valve located downstream of the check valve that is force loaded to the open position. The assembly shall also include two tightly closing shutoffs, one at the inlet of the assembly and one at the outlet of the assembly and two tightly closing test cocks one immediately upstream and one immediately downstream of the check valve.
Vacuum breakers, other than air gaps, shall be classified into three general types:
a. Atmospheric Type (See ASSE Standard #1001);
b. Pressure Type (ASSE #1020, as described in this standard); and
c. Back Siphonage (See ASSE Standard #1056).
The device shall be designed to accommodate nominal pipe sizes 1/2 NPS to 2 NPS (15 DN to 50 DN).
Working Pressure Range
The minimum rated working pressure of the device shall not be less than 150.0 psi (1034.3 kPa).
a. Cold water service shall range from 33.0 °F to 110.0 °F ( 0.6 °C to 43.3 °C).
b. Hot water service shall range from 33.0 °F to not less than 180.0 °F ( 0.6 °C to 82.2 °C).