What is valve backseat?

A backseat is a seating arrangement inside the bonnet. It provides a seal between the stem and bonnet and prevents system pressure from building against the valve packing when the valve is fully open. Back seats are often applied in gate and globe valves (source: wermac.org).

What is a valve test?

Valve “type testing” is a new protocol where valves are tested at the operating pressure and temperature ranges specified by the manufacturer. This requires that some valves are tested at temperatures down to the cryogenic range and/or over 1000 degrees F.

Why do you Backseat a valve?

A backseat is a seating arrangement inside the bonnet. It provides a seal between the stem and bonnet and prevents system pressure from building against the valve pakking, when the valve is fully open. Back seats are often applied in gate and globe valves.

What is a valve closure test?

Closure tests are required to test the closure mechanism of several types of valves, including gate, globe, plug, check, and ball valves. Shell leakage tests are required for valves that are used in “full open” and “full closed” service, such as check, stop, and isolation valves.

What is globe valve used for?

Globe valves, so-called because of their outside shape, are widely used in plant piping. They are suitable for manual and automatic operation. Unlike the gate valve, globe valve can be used for regulating flow or pressures as well as complete shutoff of flow.

What do you need to know about the backseat test?

The test shall be performed based on valve manufacturer approved test procedure. The requirement for the test is addressed in API Std. 598. The backseat feature is a feature that allows valve packing being replaced while it is in the service. The valve shall be mounted in test bench with fully opened position and valve ends closed.

What is the backseat feature of a valve?

The backseat feature is a feature that allows valve packing being replaced while it is in the service. The valve shall be mounted in test bench with fully opened position and valve ends closed. The packing gland shall be loose or packing not installed.

What is the valve seat leak test ( closure test )?

The valve seat leak test is performed after successful completion of valve shell test (Body Test). The test shall be performed based on the valve manufacturer approved valve seat leak test procedure. The most of these procedures are driven by the requirements of the API Std 598 and ASME B16.34

What is the PSI of a valve backseat test?

For example, if you have a 900 Ib, 20 inch valve with A216 Gr. WCB material, your MAP will be 2252 psi (as per Table 2-1.1 ASME B16.34). The 110 % of this value will be 2477 psi. So your backseat test pressure will be 2477 psi. Backseat Test Duration The valve test duration depends on the valve size as per API Std 598.