scope:

The U.S. Department of Transportation (DOT) Hazardous Materials Regulations in Title 49 of the U.S. Code of Federal Regulations (49 CFR) Part 180.407(g)(3) require that MC-330 and MC-331 anhydrous ammonia cargo tanks that are constructed of quenched and tempered steel or constructed of other than quenched and tempered steel but without post-weld heat treatment be internally inspected by the wet fluorescent magnetic particle method at certain prescribed intervals. Cracks and other defects found during the inspection shall be repaired in accordance with the requirements in 49 CFR Part 180, Subpart E, "Qualification and Maintenance of Cargo Tanks," if a cargo tank is to be returned to transportation service [1].¹

In order to promote uniformity within the industry, the Compressed Gas Association (CGA) has prepared these guidelines for use by personnel having responsibility for the inspection and repair of these cargo tanks.

¹References are shown by bracketed numbers and are listed in order of appearance in the reference section.