What is the minimum pressure for a hydrostatic test of piping?

The correct answer reflects the required standard for conducting a hydrostatic test on piping systems, which is crucial for ensuring their integrity and safety. A hydrostatic test involves filling the piping system with water, then pressurizing it to verify that it can withstand pressures greater than normal operating conditions without leaking or failing.

In this case, the standard dictates that the minimum pressure for the hydrostatic test should be 110% of the operating pressure. This ensures that the piping is not only capable of handling its intended operational pressure but can also endure potential fluctuations or surges in pressure during its service life. Additionally, the stipulation that this test pressure cannot be less than 50 PSIG provides a baseline requirement, ensuring that even low-pressure systems are adequately assessed for their capability to operate safely.

This testing practice is essential in preventing leaks, spills, or catastrophic failures, which can have significant environmental and safety implications, especially for underground storage tanks that hold potentially hazardous materials. The given options for the test pressure illustrate various approaches to pressure safety checks, but only the correct choice aligns with the recognized safety and engineering benchmarks in the field.