OSHA CFR 1910.169(b)(3)(ii) states, “No valve of any type shall be placed between the air receiver and its safety valve or valves.”
Topics: Did You Know?, Pressure Relief Valves, Detailed Engineering, OSHA, PRV, Relief System Design, Relief Header, Set Pressure, Exit Pipe Fitting
Per ASME B31.3-2016, Sections 322.6.3. (see Figure 1) and 302.2.4 (f) (see Figure 2), a thermal relief valve may be set up to 120% of the design pressure of the protected system with the owner’s approval, as long as, the allowable accumulation criteria in 302.2.4.(f) are met. Set pressures lower than 120% of the design pressure may be required depending on the allowable accumulation pressures in 302.2.4 (f).
Topics: Did You Know?, Pressure Relief Valves, Detailed Engineering, PRV, Relief System Design, Relief Header, Set Pressure, Exit Pipe Fitting
"In a conventional PRV application, when the allowable overpressure is 10%, the built-up backpressure should not exceed 10% of the set pressure. A higher maximum allowable built-up backpressure may be used for allowable overpressures greater than 10 % provided the built-up backpressure does not exceed the allowable overpressure."
Topics: Did You Know?, API 521, PRV, Set Pressure, Allowable Backpressure, Spring Loaded Valves
Have you come across a conventional pressure relief valve relieving to a flare header? Did you know that, under certain circumstances, you need to verify if the Cold Differential Test Pressure (CDTP) is properly compensated for the superimposed backpressure from the flare header?
Topics: Did You Know?, Pressure Relief Valves, Flare Header, API 521, PRV, Cold Differential Test Pressure, CDTP, Relief Header, Set Pressure