Which of the following is true about hydrostatic testing before underground piping is placed into service?

Which of the following is true about hydrostatic testing before underground piping is placed into service?

• A. It must be performed at 150% of operating pressure with minimum 50 psig
• B. It must be performed at 200% of operating pressure with minimum 60 psig
• C. It must be performed at 120% of operating pressure with minimum 30 psig
• D. It is not required

Answer: (A)

Hydrostatic testing of underground piping is about proving the system can hold pressure and that joints and seams are sound before it goes into service. The correct approach uses a test pressure equal to 1.5 times the operating pressure, with a floor of at least 50 psig. This creates a safety margin that helps reveal leaks or weak connections without over-stressing the pipe. Higher test pressures aren’t required and can risk damage, while smaller pressures or skipping the test won’t reliably show whether the system would fail under normal use.

Hydrostatic testing of underground piping is about proving the system can hold pressure and that joints and seams are sound before it goes into service. The correct approach uses a test pressure equal to 1.5 times the operating pressure, with a floor of at least 50 psig. This creates a safety margin that helps reveal leaks or weak connections without over-stressing the pipe. Higher test pressures aren’t required and can risk damage, while smaller pressures or skipping the test won’t reliably show whether the system would fail under normal use.