• In: Training | On: Jul 31, 2020

About ASME B31.3 Testing Terms


API’s (SIFE) Body of Knowledge includes the pressure testing requirements of ASME B31.3.

The terms used are slightly different to those used in ASME VIII and other codes.

Here’s what the B31.3 terms mean:

• Leak test (This means full hydraulic test at 1.5 x design pressure)

• Pneumatic leak test (A full pneumatic test at 1.1 x design)

• Initial service leak test (This is an ‘operating pressure’ test)

• Sensitive leak test (An air/gas bubble test)

• ‘Alternative’ leak test (This means RT/UT + an air/gas bubble test)

Note that B31.3 uses the term ‘Design Pressure’ rather than MAWP (as in ASME VIII)



The sensitive leak test

There are two ways to do this (see ASME V as well as B31.3):

• Pressurise with air/gas and paint on a soap-type solution

• Pressurise with air/gas, place it underwater and check for bubbles



A quick safety note

For pressure testing in the UK, don’t forget that HSE Document GS4 ‘Safety in Pressure Testing’ is a legal requirement.

See it here:


It’s not included in the API (SIFE) scope.




Questions about the API (SIFE) cert?

If you have any questions about the Wilkinson Coutts API (SIFE) Inspector Cert training (residential or on-line), contact Paul Wilkinson or Craig Coutts :