True or False: Metal LPG tubing shall be connected with "long nut" type flare fittings.

The correct assertion is that metal LPG tubing must be connected using "long nut" type flare fittings. This requirement is in line with safety standards set forth in ABYC guidelines and other relevant regulations concerning gas installations. Long nut flare fittings provide a more secure and leak-resistant connection because they allow for a greater surface area for sealing and they can accommodate the thermal expansion and contraction of metal tubing.

Metal LPG systems are subject to substantial pressure and potential temperature changes, so the use of appropriate fittings is crucial to ensuring a tight seal and preventing leaks, which can lead to dangerous situations.

While some alternative fittings may be suitable for different applications or materials, the recommendation for long nut flare fittings specifically addresses the necessity for robust connections in high-pressure environments of LPG systems. This is particularly important to maintain safety standards in marine settings, where maintenance and accessibility can be limited.

Thus, the classification that metal LPG tubing connections should utilize long nut flare fittings aligns with best practices for safety and reliability in gas line installation.