全世界使用了数以百万计的液化石油气（LPG）钢瓶，为广泛的消费和工业应用提供燃料。在美国和加拿大，液化石油气钢瓶配有CG-7泄压阀，设计用于在钢瓶中的过度压力降至可接受水平后排放和重新关闭（重新密封）。本出版物的目的是为填充、储存、分发、检查、维护或重新鉴定液化石油气钢瓶的人员提供参考材料和指南，并确保符合适用的安全和监管要求；以及正确选择、处理和维护钢瓶阀门和CG的信息- 7 PRV。此信息仅限于美国交通运输部和加拿大交通运输部的可再充装气瓶设计。就本出版物而言，液化石油气包括但不限于丁烷、商用丙烷、丙烯以及这些产品的混合物。

Millions of liquefied petroleum gas (LPG) cylinders are used worldwide to provide fuel for a wide range of consumer and industrial applications. In the United States and Canada, LPG cylinders are equipped with a CG-7 pressure relief valve designed to discharge and reclose (reseal) after the excessive pressure in the cylinder is reduced to an acceptable level.The purpose of this publication is to provide:Reference material and guidelines to personnel who fill, store, distribute, inspect, maintain, or requalify LPG cylinders and to ensure compliance with applicable safety and regulatory requirements; andInformation on proper selection, handling, and maintenance of cylinder valves and the CG-7 PRV. This information is limited to U.S. Department of Transportation and Transport Canada refillable cylinder designs.For the purposes of this publication, LPG includes but is not limited to butane, commercial propane, propylene, and mixtures of these products.