For underground sprinkler piping, what type of joints is required?

For underground sprinkler piping, what type of joints is required?

• A. Underground pipes must use gasketed joints.
• B. Underground pipes must use threaded joints.
• C. Underground pipes must use gasketed joints.
• D. Underground pipes must be welded joints.

Answer: (C)

Gasketed joints are required for underground sprinkler piping. This choice ensures a watertight seal in buried conditions and accommodates soil movement and temperature changes without leaking. Gasketed joints use an insulating seal between pipe sections, which is more reliable for buried installations than relying on thread sealants for threaded joints or on field welds. While threaded joints can leak over time under ground movement, and welded joints are difficult to inspect and repair in buried lines, gasketed joints provide a durable, serviceable solution that NFPA 13R typically requires for underground piping.

Gasketed joints are required for underground sprinkler piping. This choice ensures a watertight seal in buried conditions and accommodates soil movement and temperature changes without leaking. Gasketed joints use an insulating seal between pipe sections, which is more reliable for buried installations than relying on thread sealants for threaded joints or on field welds. While threaded joints can leak over time under ground movement, and welded joints are difficult to inspect and repair in buried lines, gasketed joints provide a durable, serviceable solution that NFPA 13R typically requires for underground piping.