The maximum design operating gas pressure for piping inside a residential home shall not exceed _______ psi.

• A. 2 psi
• B. 3 psi
• C. 5 psi
• D. 7 psi

Answer: (C)

Gas piping inside a home is designed to operate at relatively low pressure. The limit of 5 psi as the maximum design operating pressure is set so that all components used in typical residential systems—piping, fittings, regulators, and appliance inlets—are safely compatible and can handle normal fluctuations without failing. In practice, most residential gas work operates well below this level, with regulators dialing the pressure down to appliance-friendly levels (often measured in inches of water column, far less than 1 psi). If higher pressures were allowed, you’d need specialized high-pressure piping, different materials, and stricter safety requirements. So the standard design limit for residential piping is 5 psi.