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

API 510 allows inspection intervals up to 10 years for PRVs in proven non-corrosive, non-fouling services where performance history justifies the extension.

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

Opening above set pressure typically indicates seat fouling, corrosion, or scale buildup that is mechanically preventing the valve disk from lifting at the correct pressure.

Question 3

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

Accepted Answer

Rupture disk

Answer

A rupture disk is a solid membrane that provides zero leakage before burst and is non-reclosing, meaning it must be replaced after every activation.

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

The tell-tale detects premature disk failure or leakage so operators can replace the disk before vessel pressure reaches the PRV set pressure, maintaining the dual-protection integrity.

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

For fire exposure with a single PRV, ASME Code allows 21% accumulation above MAWP: 150 × 1.21 = 181.5 psig maximum allowable pressure.

(API 510) Certified Pressure Vessel Inspector Practice Test

(API 510) Certified Pressure Vessel Inspector Practice Test

API 510 Pressure Relief Devices 2