This standard represents the minimum requirements for pressure relief devices (PRDs) considered to be appropriate and adequate for use on cylinders with a water capacity less than or equal to 1000 lb (454 kg) of water. Refer also to Title 49 of the U.S. Code of Federal Regulations (49 CFR), CSA B340, Selection and use of cylinders, spheres, tubes, and other containers for the transportation of dangerous goods, Class 2, or CSA B342, Selection and use of UN pressure receptacles and multiple-element gas containers for the transport of dangerous goods, Class 2. This standard also applies to DOT-3AX, DOT-3AAX, and DOT-3T cylinders with a water capacity greater than 1000 lb (454 kg) of water as well as United Nations (UN) pressure receptacles with a water capacity up to 3000 kg of water, and which comply with the design specifications and charging (filling) and maintenance regulations of the U.S. Department of Transportation (DOT) or the corresponding specifications and regulations of Transport Canada (TC).

This standard does not cover PRD requirements for CTC/DOT-4L and TC-4LM insulated cylinders containing cryogenic liquids, see CGA S-1.2, Pressure Relief Device Standards—Part 2—Portable Containers for Compressed Gases. This standard does not cover PRD requirements for multi-unit tank car tanks (DOT106A/TC106A and DOT110A-W/TC110A), see 49 CFR 179.300-15 and CGSB 43.147, Construction, Modification, Qualification, Maintenance, and Selection and Use of Means of Containment for the Handling, Offering for Transport, or Transporting of Dangerous Goods by Rail, as appropriate.