This standard represents the minimum requirements for pressure relief devices considered to be appropriate and adequate for use on cylinders having capacities of 1000 lb (454 kg) of water or less. Refer also to Title 49 of the U.S. Code of Federal Regulations (49 CFR) 173.301(f). This standard also applies to DOT-3AX, DOT-3AAX, and DOT-3T cylinders having capacities over 1000 lb (454 kg) of water, and which comply with the design specifications and charging and maintenance regulations of the U.S. Department of Transportation (DOT) or the corresponding specifications and regulations of Transport Canada (TC). This standard also covers requirements for pressure relief devices for CTC/DOT-4L and TC-4LM insulated cylinders containing cryogenic liquids. Pressure relief device requirements for multi-unit tank car tanks (DOT106A and DOT110A-W) are not covered by this standard (see 49 CFR 179.300-15).