API 510 Pressure Relief Devices

Question 1

What is the term for the pressure at which a pressure relief valve (PRV) is designed to open, as stamped on its nameplate?

Accepted Answer

Set pressure

Answer

Operating pressure

Answer

Accumulation pressure

Answer

Back pressure

Question 2

According to ASME Code and API 510, what is the maximum allowable accumulation above MAWP for a single PRV protecting a pressure vessel during a fire exposure case?

Accepted Answer

21%

Answer

3%

Answer

10%

Answer

16%

Question 3

In pressure relief valve terminology, what is 'blowdown'?

Accepted Answer

The difference between set pressure and reseating pressure

Answer

The pressure increase above MAWP during relief

Answer

The flow rate through the valve at full lift

Answer

The pressure drop across the valve inlet piping

Question 4

Which API standard specifically covers the sizing, selection, and installation of pressure-relieving devices in petroleum and petrochemical plants?

Accepted Answer

API 520

Answer

API 510

Answer

API 570

Answer

API 580

Question 5

When a rupture disk is installed upstream (inlet side) of a pressure relief valve, what is the primary safety concern with this arrangement?

Accepted Answer

Pressure buildup between the disk and PRV can prevent the PRV from opening correctly

Answer

The disk increases the effective set pressure of the PRV

Answer

This configuration is explicitly prohibited by ASME Code

Answer

The rupture disk reduces the total flow capacity by 50%

Question 6

What is the maximum set pressure permitted for a pressure relief valve protecting a pressure vessel with an MAWP of 200 psig in normal (non-fire) service?

Accepted Answer

200 psig

Answer

180 psig

Answer

190 psig

Answer

210 psig

Question 7

According to API 510, who is responsible for establishing the inspection and testing intervals for pressure relief devices?

Accepted Answer

The inspector in conjunction with the owner/user

Answer

The original valve manufacturer

Answer

The local regulatory authority alone

Answer

Only a licensed professional engineer (PE)