Liquid and vapor transfer connections for the industrial gases listed in Table 1 (argon, carbon dioxide, liquefied natural gas (LNG), nitrogen, nitrous oxide, and oxygen) are specified in this standard and in Appendix A. An obsolete/limited standard flanged connection system for oxygen, nitrogen, and argon is also specified in Appendix B. The specified connections are intended for use with liquid transport equipment, such as: cargo tanks, portable tanks, and railway tank cars, but do not apply to barges and marine tankers. Termination points at liquid production plants and on stationary storage vessels that directly interface with this transport equipment are also included. The connections in this standard are intended for use exclusively with the specified products. These connections are not intended for use on uninsulated or insulated (DOT 4L) cylinders, tubes, or on small equipment using connections less than 1 in (25 mm). The physical design of the fittings, other than the connection configuration at the coupling point, is also beyond the scope of this standard.

Specialized vacuum-jacketed bayonet connections, which are required for some cryogenic products, are not included in this standard.

Before the adoption of the standard connection, companies involved in the transport of industrial gases used a variety of proprietary connections. This standard has been developed to offer standard transfer connections that provide mechanical protection for product integrity to decrease possible incidents from product transfill errors at transport equipment loading and unloading stations. Also, using industry standard connections eliminates the need for adapters.