The structural requirements for LPG pressure regulating devices as well as their safety devices are specified in the standard DIN EN 16129 "Pressure regulators, automatic change-over devices, having a maximum regulated pressure of 4 bar, with a maximum capacity of 150 kg/h, associated safety devices and adaptors for butane, propane, and their mixtures". The pressure regulating devices with safety devices described in this standard shall also meet the requirements of Annex I of the pressure equipment directive, if applicable. The European standard describes a variety of different LPG pressure regulators used in the individual Member States of the European Union. The connections are given as a standard, and the national regulations apply to the use of the connections. In the individual Member States of the European Union, various connection pressures are set for the connection of LPGs to which the pressure regulators are fixed at the factory. These standards refer to the national operating requirements of the Member States for the cessation of safety equipment. The additional requirements for screwed connections, overpressure safety devices, pressure regulating devices with safety diaphragms and pressure regulators with thermal shut-off devices (TAE) listed in DIN 4811 have been included in DIN EN 16129. For this reason, the relevant sections and appendices of DIN 4811 have been adapted or deleted. In Germany, certain operating regulations exist, For example, low-pressure LPGs are generally operated in a domestic environment at a nominal pressure of 50 mbar according to DIN EN 437. In addition, In the case of commercially used devices, partial higher pressures occur, and when the vapor pressure is relieved during removal from a liquefied-gas storage container, the liquefied-gas pressure has to be released in two stages in certain, fixed stages. In accordance with current operating conditions as well as in accordance with the national requirements for the use of liq...