top of page

ASME B31.3 Limitations Tubing Joints

ASME B31.3 Limitations Tubing Joints

Tubing joints are covered by para. 315, and include flared, flareless, and compression-type tube fittings. ASME B31.3 provides some listed tubing joints; however, many tubing joints used in process piping are proprietary fittings that are qualified as unlisted components. The following are the listed standards covering tubing joints:

  • SAE J513, Refrigeration Tube Fittings—General Specifications

  • SAE J514, Hydraulic Tube Fittings

These listed components are permitted for use in Normal Fluid Service, provided that they are used within the pressure-temperature limitations of the fittings and joint. They are required to be safeguarded when used under severe cyclic conditions; however, it is highly unlikely that this will occur, because it requires the tube joint to be at over 80% of the allowable displacement stress range. Unlisted tube fittings must be qualified in accordance with para. 304.7.2.

Taper Thread

Minimum Thickness for Threaded Pipe


Located in Calgary, AlbertaVancouver, BCToronto, OntarioEdmonton, AlbertaHouston TexasTorrance, CaliforniaEl Segundo, CAManhattan Beach, CA; Concord, CA; We offer our engineering consultancy services across Canada and United States. Meena Rezkallah.

bottom of page