One:The marks on a gas cylinder are specified by DOT. For example, on the DOT-3AA and 3A gas cylinders, the following marks are required to be clearly and permanently printed on the shoulder, head, and neck in word or number form with a height of at least 6.35mm (0.25in) if permitted.
1: The number indicating the working pressure is printed immediately after the DOT specification number on the cylinder, such as DOT~3AA2015.
2: Below the DOT mark is a serial number (except for those small gas cylinders that can be identified by the batch number) and an identifying symbol (letter). The symbol and number must be the manufacturer's symbol and number and the symbol must be registered with the Explosives Bureau. Additional symbols can be used to represent buyers or users.
3: The official logo of the inspector next to the serial number and the test date is arranged in such a way that the test date printed later can be easily added
Two: Unqualified blocked gas cylinder, must be given a special mark.
1. The mark on the gas cylinder shall not be changed except for the special provisions in the DOT regulations. Note that changes to series numbers and ownership marks are prohibited unless a detailed report has been made to the Explosives Bureau. The mark on the gas cylinder must be kept clear.
2. In addition to the cylinder symbol proposed above, the DOT regulations require that every packing appliance containing compressed gas (with individual exceptions) carry an appropriate identifying label such as;
Oxygen DOT Oxide Label (yellow label)
Other Non-flammable gas DOT Non-flammable Gas Label (Green label)
Flammable gas DOT Flammable gas label (red label)
