The Compressed Gas Association, Inc. (CGA) has established CGA C-3-2019 to promote uniformity and serviceability of compressed gas containers produced under the specifications of the U.S. Department of Transportation (DOT) and Transport Canada (TC) for the manufacturers of welded steel compressed gas containers and for the inspectors who may be called upon to qualify welding on such containers. Establishment of standards for procedure and operator qualification and for radiographic inspection was necessary to define parameters concerning the gauge of materials, i.e., thickness, used in compressed gas containers with a maximum service pressure of 900 psi (62.1 bar).

This publication addresses specific production welding techniques and is not intended to cover all welding. When evaluating techniques other than those covered in detail in this publication, refer to ASME Boiler and Pressure Vessel Code, Section IX, "Welding and Brazing Qualifications," for more information. This ASME Code applies to essential variables and material types.

This standard is applicable to DOT/TC specification containers of 900 psi (62.1 bar) maximum service pressure, 454 kg (1000 lb) maximum water capacity, and maximum wall thickness of 0.375 in (9.53 mm).