Carbon dioxide, also known as CO2, is a colorless, odorless, non-flammable, and slightly acidic liquefied gas. It is sold commercially worldwide under pressure in steel cylinders or bottles called tanks.
CO2 tanks can be used for a variety of things. Most popular uses include carbonated beverages, beer making, paintball guns, medical-grade usage, metal fabrication applications, catering, and fire extinguishing.
CO2 tanks need to be hydro-tested every five years, and the test date should be noted on the top of the canister. CO2 tanks need to be taken to a DOT certified hydro-testing facility if they need filled. Once certified, the certification number is stamped onto the tank.