Requirements for the installation of overpressure relief devices

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Article 9.1.2(1) of TSG 21-2016, \"Regulations on Safety Technical Inspection of Fixed Pressure Vessels\" (hereinafter referred to as the \"Vessel Regulations\"), specifies the requirements for installing overpressure relief devices as follows: \"Pressure vessels falling within the scope of application of these regulations shall be equipped with overpressure relief devices in accordance with design requirements; however, when the pressure source is external to the pressure vessel and can be reliably controlled, the overpressure relief device does not need to be installed directly on the pressure vessel.\" ” ★Regulatory understanding: (1) Whether a container should be equipped with an overpressure relief device shall be determined by the container designer (design agency), based on the design conditions, in accordance with relevant regulations and standards, as well as taking into account practical engineering experience. (2) “When the pressure source is external to the pressure vessel and is under reliable control, the overpressure relief device does not need to be installed directly on the pressure vessel.” Process equipment such as coolers and separators, in which the medium continuously enters and exits, fall into this category. Container designers can determine on their own that there is no need to install overpressure relief devices, without having to design the client’s requirements statement. (3) For pressure vessels where overpressure may occur during operation, specifically: ① Vessels containing compressed gases or water vapor ； ②Containers for storing liquefied gas ； ③Heated steam generators, reboilers, reheaters ； ④Reactor vessel with increased volume ； ⑤For multi-chamber pressure vessels such as heat exchangers, in cases where a high-temperature medium might leak to the side containing the low-temperature medium and thereby generate steam ； Container designers should consider equipping it with overpressure relief devices ； Give priority to setting it on the container ； If the overpressure relief device is installed on the process pipeline, a written statement from the design client must be obtained.