Pressure that exists at the outlet of a safety valve as a result of pressure in the discharge system.
The 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. .