Which type of fittings can fail due to vibration fatigue when used with metal LPG tubing?

Short nut fittings are particularly susceptible to failure due to vibration fatigue when used with metal LPG tubing. This is primarily because short nut fittings do not provide as much engagement or contact area with the tubing compared to other types of fittings. The vibrations from engine components or other sources of mechanical movement can lead to loosening, stressing the connection and potentially causing leaks or failures.

In environments where vibration is a constant factor, it is essential to use fittings that can withstand the additional strain. The design of the short nut fitting, which has limited torque capacity and a reduced surface area for securing the joint, makes it more vulnerable to the cumulative effects of vibrations over time. In contrast, other fittings, such as long nut fittings or those with a greater thread engagement, provide enhanced stability and are better equipped to handle such mechanical stresses.