API 510 Pressure Relief Devices 2

Question 1

What is the maximum PRV inspection interval permitted by API 510 for a pressure relief valve in clean, non-corrosive, non-fouling service with documented good performance history?

Accepted Answer

10 years

Answer

1 year

Answer

3 years

Answer

5 years

Question 2

During bench testing of a pressure relief valve, the valve opens at 108% of its stamped set pressure. What is the most likely cause?

Accepted Answer

Seat fouling, corrosion, or deposits are preventing normal opening

Answer

The valve spring is too weak

Answer

The test bench pressure gauge is out of calibration

Answer

The valve inlet diameter is too small for the test flow

Question 3

Which type of pressure relief device provides zero leakage before activation and is non-reclosing after operation?

Accepted Answer

Rupture disk

Answer

Conventional spring-loaded safety relief valve

Answer

Pilot-operated pressure relief valve

Answer

Balanced bellows relief valve

Question 4

A pressure indicator or 'tell-tale' gauge is required between a rupture disk and a downstream PRV. What is its primary function?

Accepted Answer

To detect premature rupture disk failure or leakage and alert operators

Answer

To indicate when the PRV has fully opened during a relief event

Answer

To measure the normal operating pressure of the protected vessel

Answer

To verify the set pressure of the PRV after installation

Question 5

A pressure vessel with an MAWP of 150 psig is protected by a single PRV set at 150 psig. During a fire exposure scenario, what is the maximum allowable vessel pressure?

Accepted Answer

181.5 psig

Answer

150 psig

Answer

165 psig

Answer

172.5 psig

Question 6

Which of the following is NOT an acceptable method for testing and inspecting a pressure relief valve according to API 576?

Accepted Answer

Calculation-only verification without any physical actuation of the valve

Answer

Bench testing with air or nitrogen at a certified test facility

Answer

In-situ pop testing on the vessel using a lift assist device

Answer

Visual inspection combined with bench testing after removal from service

Question 7

What distinguishes a 'relief valve' from a 'safety valve' in pressure relief device terminology?

Accepted Answer

A relief valve opens gradually in proportion to overpressure; a safety valve opens with a rapid full-lift pop action

Answer

A relief valve is used only for gas service; a safety valve is used only for liquid service

Answer

A relief valve has a higher flow capacity than a safety valve of the same size

Answer

A relief valve requires an external power source; a safety valve is self-actuating