These requirements cover regulators used to reduce the pressure of compressed industrial gases from a source or storage cylinder pressure of not more than 5500 psig (37.91 MPa) to the use pressure. Regulators covered by these requirements are intended for use with compressed gases such as air@ carbon dioxide@ inert gases@ fuel gases@ nitrogen@ nitrogen oxide@ and oxygen. Regulators for welding@ cutting@ and heating operations are intended for use in accordance with the Standard for the Design and Installation of Oxygen-Fuel Gas Systems for Welding@ Cutting@ and Allied Processes@ NFPA 51. These requirements do not cover: LP-Gas pressure regulators for equipment intended for installation and use in accordance with requirements of the Liquefied Petroleum Gas Code@ NFPA 58. Such regulators are evaluated under the Standard for LP-Gas Regulators@ UL 144. Regulators for handling liquids under cryogenic temperatures. The regulating performance flow characteristics of the regulator@ and the physiological effects of regulators to be used with medical gases.