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Containers equipped with overpressure relief devices: The mandatory requirements for containers that have overpressure relief devices are as follows: 01 The design documents must include calculations regarding the safe discharge capacity of the pressure vessel, as well as the discharge volume of the safety valve or the discharge area of the rupture disc； When software simulation calculations are unavailable or impossible to conduct, the design entity shall, in consultation with the client or user, decide on the use of overpressure relief devices. 02 The operating pressure of the overpressure relief device shall not be higher than the design pressure of the container; if a maximum allowable working pressure (MAWP) is specified in the drawings, it shall not be higher than that maximum allowable working pressure. 03 If an airtightness test requirement is specified during the design phase, the designer shall provide the maximum allowable operating pressure. 04 When an explosion disc is used in series with a safety valve, no fragments shall be generated after the explosion disc activates. 05 To enable online calibration of safety valves, a rupture disc device can be installed between the safety valve and the container; generally, no shut-off valve is used. 06 To facilitate the cleaning and replacement of safety valves, a stop valve may be installed between the overpressure relief device and the pressure vessel only with the approval of the person in charge of safety management at the using unit, and after reliable preventive measures have been put in place; the structure and diameter of the stop valve must not prevent the safe operation of the overpressure relief device. 07 Generally, the design pressure of the container (or MAWP, if applicable) is used as the starting pressure for the overpressure limit. 08 For containers used in continuous operation, a stop valve can be installed between the container and the relief device for maintenance purposes; however, it must remain in the fully open position and be sealed with a lead seal.