Which pipe type must withstand 175 psi at 120°F in sprinkler systems?

• A. Galvanized Steel Pipe
• B. Nonmetallic Pipe
• C. Listed Pipe
• D. Light Hazard Occupancies

Answer: (B)

Nonmetallic piping is the type that must be able to resist 175 psi at 120°F in sprinkler systems. In NFPA 13R, nonmetallic materials used for sprinkler piping (like CPVC, certain PVC, or polypropylene options) have temperature- and pressure-rated limits, and the standard requires a minimum of 175 psi at 120°F to ensure the pipe can safely withstand system pressure even when heated. This rating protects against pressure loss or failure during testing and under fire exposure.

Metal pipes such as galvanized steel typically have higher pressure ratings and aren’t limited to this 175 psi at 120°F requirement, so they aren’t described as needing this specific rating. “Listed” refers to certification of the pipe, not its rating, and “Light Hazard Occupancies” concerns system design category, not the pipe type.