What is the minimum Time and Pressure required to test a new welded 4" NPS piping system that is 100 Feet long?

The minimum testing requirements for new welded piping systems are guided by industry standards and regulations. For a new welded 4" nominal pipe size (NPS) system, a hydrostatic test is typically required to ensure the integrity of the welds and the overall installation.

In this case, the correct answer specifies a duration of 24 hours at 50 PSIG. This matches common industry standards for testing new piping systems, where a minimum holding time allows for potential minor leaks to manifest, particularly in welds which may need that additional period to settle in place under pressure.

Using 50 PSIG for this type of piping is also appropriate, as it provides a sufficient pressure to effectively check for leaks while ensuring that the test is safe and compliant with existing regulations. This helps to confirm the reliability and safety of the system before it is put into service.

The combination of 24 hours at this pressure standard is intended to ensure thorough testing while balancing practical considerations for installation and maintenance schedules. Therefore, the duration and pressure specified in the correct answer are in alignment with best practices and safety requirements for gas piping installations.