Which of the following describes the hydrostatic test requirement for underground piping before service?

Which of the following describes the hydrostatic test requirement for underground piping before service?

• A. 150% of operating pressure with a minimum of 50 psig
• B. 100% of operating pressure with a minimum of 50 psig
• C. 150% of operating pressure with a minimum of 15 psig
• D. 150% of operating pressure with a minimum of 60 psig

Answer: (A)

Hydrostatic testing underground piping before service is about proving the line can hold a pressure higher than normal operation and revealing leaks before it’s put into use. The requirement is to apply a test pressure equal to 1.5 times the maximum operating pressure, with a floor of 50 psi. This creates a safety margin so joints and fittings are stressed enough to show weaknesses, rather than testing at the actual operating pressure which might miss latent flaws. The 50 psi minimum ensures the test is meaningful for low-pressure systems, rather than wasting time and missing issues at a tiny pressure. In practice, you fill the pipe with water, seal the ends, pressurize to the specified test pressure, and hold for a set duration while checking for leaks or deformations. If operating pressure is high, the 1.5x factor raises the test pressure accordingly; if operating pressure is low, the minimum floor keeps the test robust. This approach provides a reliable check before the underground piping is placed into service.

Hydrostatic testing underground piping before service is about proving the line can hold a pressure higher than normal operation and revealing leaks before it’s put into use. The requirement is to apply a test pressure equal to 1.5 times the maximum operating pressure, with a floor of 50 psi. This creates a safety margin so joints and fittings are stressed enough to show weaknesses, rather than testing at the actual operating pressure which might miss latent flaws. The 50 psi minimum ensures the test is meaningful for low-pressure systems, rather than wasting time and missing issues at a tiny pressure. In practice, you fill the pipe with water, seal the ends, pressurize to the specified test pressure, and hold for a set duration while checking for leaks or deformations. If operating pressure is high, the 1.5x factor raises the test pressure accordingly; if operating pressure is low, the minimum floor keeps the test robust. This approach provides a reliable check before the underground piping is placed into service.