NG leakage for threaded fittings

[b1]

Is the probability of a gas leakage is high if in case fittings for pipings and valves would apply threaded joints for small bore piping (2 inches and below). We would like to justify that threaded fittings / valves for this services would also be safe aside from ease of maintenance.

 

[Tmoose]

I'd think the local codes might have already made the decision.

I have observed threaded pipe joints (using tape or paste sealant) in Massachusetts on LP NG residential heating units.