Relief Valve Installation

Question 1

What is a pressure Relief Device?

Answer 1

a device actuated by static inlet pressure and designed to open to prevent a rise of internal pressure in excess of a specified value.

Question 2

What is Accumulation in terms of Pressure Relief Valves?

Answer 2

The pressure increase over the MAWP of the vessel during discharge through a pressure relief device.

Question 3

What is Back Pressure in terms of Pressure Relief Valves?

Answer 3

The pressure that exists at the outlet of a pressure relief device as a result of pressure in the discharge system.

Question 4

What is Curtain Area in terms of Pressure Relief Valves?

Answer 4

The area of the cylinder or conical discharge opening between the seating surfaces … created by lift of the disc.

Question 5

What is Huddling Chamber in terms of Pressure Relief Valves?

Answer 5

An annular pressure chamber located beyond the seat for the purpose of generating rapid opening

Question 6

What is Lift in terms of Pressure Relief Valves?

Answer 6

Travel of the disc away from the closed position when a valve is relieving

Question 7

What is Safety Valve in terms of Pressure Relief Valves?

Answer 7

A pressure relief valve … characterized by rapid opening – normally used with compressible fluids

Question 8

What are 5 common Pressure Relief Valve Installation Issues

Answer 8

Restricted Inlets
Restricted Outlets
Orientation other than stem up, vertical
Lack of Outlet protection from debris and insects
Lack of thrust support

Question 9

When are Stop Valves allowed?

Answer 9

• Will not reduce relief device capacity (selector valves for dual relief protection, each of which has adequate flow capacity)
  -isolates source of pressure
• relief valve maintenance