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

Set pressure is the inlet pressure at which the PRV is set to open, and it is the value stamped on the valve nameplate.

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

ASME Code allows accumulation up to 21% above MAWP for fire exposure cases when a single pressure relief valve is installed.

Question 3

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

Accepted Answer

The difference between set pressure and reseating pressure

Answer

Blowdown is the difference between the set pressure and the pressure at which the valve reseats (closes) after opening.

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 520 covers the sizing, selection, and installation of pressure-relieving systems and is a key companion document to API 510.

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

Gas or pressure accumulation in the space between the rupture disk and PRV creates back pressure that can prevent the PRV from opening at its stamped set pressure, requiring a pressure indicator in that space.

(API 510) Certified Pressure Vessel Inspector Practice Test

(API 510) Certified Pressure Vessel Inspector Practice Test

API 510 Pressure Relief Devices