Pressure that exists at the outlet of a safety valve as a result of pressure in the discharge system.
The Pressure/vacuum relief valve Pressure/vacuum relief valve is an umbrella term that includes pressure or vacuum relief valve as well as pressure and vacuum relief valve. back pressure Back pressure The back pressure is the sum of built-up back pressure and superimposed back pressure. is the sum of built-up back pressure Built-up back pressure Built-up back pressure is the overpressure of a valve that builds up while the valve is relieving. It is therefore variable. and superimposed back pressure Superimposed back pressure Overpressure that occurs on the outled side of a valve when the valve is blown off into the blow-off system. .