In underground propane installations, the use of flare nuts is?

In underground propane installations, the use of flare nuts is?

• A. Allowed with proper sealing
• B. Allowed above ground only
• C. Must be replaced with welded joints underground
• D. Not allowed

Answer: (D)

Underground propane lines must have joints that are permanent, secure, and resistant to soil conditions. Flare fittings rely on a nut and a formed flare to seal, but those joints can loosen or corrode over time when buried, settled, or exposed to moisture and soil chemicals. That makes a leak pathway that’s hard to inspect and repair underground, creating a serious safety risk. For underground sections, joints should be welded or otherwise rated for underground service to form a solid, long-lasting seal. Flare fittings may be used above ground where allowed by code, but they’re not permitted underground.

Underground propane lines must have joints that are permanent, secure, and resistant to soil conditions. Flare fittings rely on a nut and a formed flare to seal, but those joints can loosen or corrode over time when buried, settled, or exposed to moisture and soil chemicals. That makes a leak pathway that’s hard to inspect and repair underground, creating a serious safety risk. For underground sections, joints should be welded or otherwise rated for underground service to form a solid, long-lasting seal. Flare fittings may be used above ground where allowed by code, but they’re not permitted underground.