TOSACA safety relief valves are a direct spring-loaded suitable for gas, liquid and steam service. The seat can be meta-metal, PTFE or viton.
The safety valves are set at ambient temperature.
Backpressure 10%. If backpressure is > 10% of set pressure then you must put bellows The allowable tolerances or limits as applicable on the operating characteristics are as follows:
a) Set pressure: +- 3% of set pressure. The operating pressure should not exceed 90% of set pressure.
b) Lift: not lower than the value specified by the manufacturer.
Compressible fluids: 10%
Incompressible fluids: 25%
Fire case: 21%
d) Blowdown: not greater than the value stated by the TOSACA, but within the following limits:
Compressible fluids: minimum 7% maximum 10%
Incompressible fluids: minimum: 7% maximum: 20%