Pipefitter Pipe Testing and Inspection 4

Question 1

When performing a pneumatic pressure test, what is the maximum test pressure typically allowed before a preliminary check at a lower pressure is required?

Accepted Answer

50 psig

Answer

ASME B31.3 requires a preliminary pneumatic leak check at no more than 10 psig, with full test pressure not exceeding 1.1 times design pressure, and a 50 psig incremental hold is standard before raising pressure further.

Question 2

Which type of inspection method is used to detect surface and near-surface discontinuities in non-magnetic piping materials?

Accepted Answer

Liquid penetrant testing (PT)

Answer

Liquid penetrant testing (PT) is suitable for non-magnetic materials to detect surface-breaking defects, while magnetic particle testing requires ferromagnetic material.

Question 3

During a hydrostatic test, at what point should a visual inspection of all joints and connections be performed?

Accepted Answer

After reaching and holding test pressure

Answer

Visual inspection for leaks is conducted after the system has reached and stabilized at full test pressure and the required hold time has begun.

Question 4

What is the purpose of a 'soak period' during a hydrostatic leak test?

Accepted Answer

To allow pressure to stabilize before reading gauges

Answer

The soak period allows pressure to stabilize throughout the system so that an accurate, steady gauge reading can be taken before the final inspection.

Question 5

A pipefitter notices the pressure gauge drops slightly during a hydrostatic test but no leaks are visible. What is the FIRST step to investigate?

Accepted Answer

Check for temperature changes in the test fluid

Answer

A temperature drop in the test fluid causes volume contraction, which can result in a pressure decrease without any actual leak, and should be investigated first.

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Pipefitter Pipe Testing and Inspection 4