Which option describes pipes approved for use in sprinkler systems?

• A. Light Hazard Occupancies
• B. Installed Pipes
• C. Listed Pipe
• D. Nonmetallic Pipe

Answer: (C)

The pipes used in sprinkler systems must be approved for sprinkler service, which is shown by being listed. A listed pipe has been tested and evaluated by a recognized testing laboratory (like UL or FM) and is specifically approved for sprinkler use. ThisListing ensures the pipe meets required pressure ratings, material compatibility with fittings and gaskets, and proper installation requirements. The other options don’t denote approval status: a light hazard occupancy is a type of space being protected, not a pipe approval designation; installed pipes is not a recognized term; nonmetallic pipe refers to material type, which may or may not be approved for sprinkler use unless it is listed for that purpose.