What is the maximum design operating pressure for piping systems located inside buildings?

The maximum design operating pressure for piping systems located inside buildings is capped at 5 psi. This limit is established to ensure safety and minimize the risks associated with gas leaks or overpressurization in confined spaces. High-pressure gas systems can pose significant hazards, including potential explosions and fire risks, particularly in residential or commercial environments where people are present.

The 5 psi threshold is aligned with safety protocols that account for the materials used in gas piping, the potential effects of pressure on those materials, and the visibility and accessibility needed for repairs and maintenance. When the operating pressure exceeds this limit, the likelihood of safety hazards increases, leading to stricter regulations on the materials, installation methods, and maintenance practices. Thus, maintaining a maximum of 5 psi for indoor piping systems is a critical safety standard in the National Fuel Gas Code.