What needs to be noted for extremely or highly hazardous media

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Mandatory requirement 1 in the standards: Pipe flanges must use a combination of necked butt welding, metal wound gaskets with reinforcement rings, and high-strength studs of special grade. TSG 21-2016 \"Regulations on Safety Technical Inspection of Fixed Pressure Vessels\" 3.2.5(2) ； For example: Flange: WN50(B)-25FM; Material: S30408Ⅱ, HG/T20592-2009. Metal wound gasket: B50-25; Material: 0232, HG/T20610-2009. Studs: M16x90; Material: 35CrMoA, HG/T20613-2009. Nuts: M16; Material: 30CrMoA, GB/T6175-2016. 2: All butt joints of types A and B must undergo non-destructive testing. TSG 21-2016 \"Regulations on Safety Technical Inspection of Fixed Pressure Vessels\" P23 3.2.10.2.2.2(1) ； For example: Welded joints of types A and B must undergo 100% X-ray inspection; in accordance with standard NB/T 47013.2-2015, a grade II pass is required, and the quality level of the radiographic inspection shall not be lower than grade AB. TSG 21-2016 \"Regulations on Safety Technical Inspection of Fixed Pressure Vessels\" 3.2.10.2.3.1 (1) 3: The surfaces of all welded joints must be inspected using magnetic particle testing or penetrant testing; magnetic particle testing is preferred for carbon steel, while penetrant testing is required for other materials. All welded joints must undergo 100% penetrant testing, to meet the requirements of standard NB/T 47013.5-2015, with a grade of I as the acceptance criterion. TSG 21-2016 \"Regulations on Safety Technical Inspection of Fixed Pressure Vessels\" 3.2.10.2.3.1 (1) 4: If the vessel is made of carbon steel or low-alloy steel plates with a thickness of 12 mm or more, ultrasonic testing shall be carried out on each plate individually. TSG 21-2016 \"Code for Safety Inspection of Fixed Pressure Vessels\" 2.2.1.4.1 (1) 5: The equipment must undergo leak tests. Leak tests include airtightness tests, ammonia leak detection tests, halogen leak detection tests, and helium leak detection tests. TSG 21-2016 \"Code for Safety Inspection of Fixed Pressure Vessels\" 3.1.18 If a airtightness test is conducted, the test pressure shall be equal to the design pressure. TSG 21-2016 \"Regulations on Safety Technical Inspection of Fixed Pressure Vessels\" 3.2.13.1 6: Indication of the maximum allowable operating pressure. If the equipment is equipped with overpressure relief devices such as safety valves or burst discs, and a gas-tightness test is used, it is necessary to specify the maximum allowable operating pressure of the vessel (the highest pressure that can be sustained based on the calculated effective thickness). TSG 21-2016 \"Regulations on Safety Technical Inspection of Fixed Pressure Vessels\" 3.1.18 7: Welding test pieces must be prepared. For pressure vessels for which product welding test pieces are to be made, TSG 21-2016 \"Regulations on Safety Technical Inspection of Fixed Pressure Vessels\" 3.2.4.1 states that, for example: 1) The raw materials for the test plates must be of qualified quality, and they must have the same steel grade, the same specifications, and the same heat treatment condition as the materials used in the vessel. The test plate should be placed at the extension of the longitudinal weld of the shell segment, and welded simultaneously with the shell segment. 2): The test plate shall be welded by the welder who welds the container, under the same conditions and using the same welding process as those applied to the container. 3): Identification marks for test plates, including: container number ； Material steel grade ； Welder’s stamp number. 4): Test plate size: It shall meet the requirements regarding the type and quantity of specimens needed for the tests, in accordance with NB/T 47016-2011. Dimensions of the butt joint test plate: the length should be greater than or equal to 300 mm, and the width should be greater than or equal to 250 mm. 5): After the visual inspection of the weld joints of the test plates shows they are satisfactory, they must undergo 100% radiographic testing to ensure they are also satisfactory. 8: Cast iron and cast steel shall not be used. TSG 21-2016 \"Regulations on Safety Inspection of Fixed Pressure Vessels\", 2.2.3.1; TSG 21-2016 \"Regulations on Safety Inspection of Fixed Pressure Vessels\", 2.2.4.1. 9: Vessels made of carbon steel or low-alloy steel must undergo post-weld heat treatment. TSG 21-2016 \"Regulations on Safety Inspection of Fixed Pressure Vessels\", 3.2.11(2). 10: A conduit shall be installed at the discharge outlet of safety valves or rupture disks to direct the discharged medium to a safe location where it can be properly handled; toxic media must not be discharged directly into the atmosphere. TSG 21-2016 “Regulations on Safety Technical Inspection of Fixed Pressure Vessels”, 9.1.2(3) 11: If a level gauge is present, protective devices to prevent leaks are required. TSG 21-2016 “Regulations on Safety Technical Inspection of Fixed Pressure Vessels”, 9.2.2.1(5) Mandatory requirements in GB150: 1: Steel grades 10, 20 as specified in GB/T 8163, and Q345D steel pipes shall not be used. GB/T 150.2-2011 “Pressure Vessels”, 5.1.3 2: Steel plates of the Q235 series shall not be used. GB/T 150.2-2011 “Pressure Vessels”, D.1(g) 3: Steel pipes specified in GB/T 12771 shall not be used. GB/T 150.2-2011 “Pressure Vessels”, 5.2.4 4: Steel pipes specified in GB/T 24593 shall not be used. GB/T 150.2-2011 “Pressure Vessels”, 5.2.5 5: Steel pipes of Class VI as specified in GB/T 21832 shall not be used. GB/T 150.2-2011 “Pressure Vessels”, 5.27 Mandatory requirements in GB151: 1: Packing box heat exchangers shall not be used in applications involving volatile, flammable, explosive, toxic, or valuable media. GB/T 151-2014 “Heat Exchangers”, 6.11.1 “6.11.1.1 Packing box heat exchangers are not suitable for use with volatile, flammable, explosive, toxic, or valuable media.” 2: When expansion jointing is used, the thickness of the tube sheet (excluding corrosion allowance) shall be no less than the outer diameter of the heat exchange tubes. GB/T 151-2014 “Heat Exchangers”, 7.4.2.1 (1) Requirements in HG20580~20585: 1: The nominal pressure class of the vessel flange shall be no less than 1 Mpa. HG/T 20583-2020 “Code for Structural Design of Steel Chemical Vessels”, 4.1.6 2: The nominal pressure class of the pipe flange shall be no less than 2 Mpa. HG/T 20583-2020 “Code for Structural Design of Steel Chemical Vessels”, 4.2.3 3: The sealing surface of the vessel flange shall be of the M-FM type. HG/T 20583-2020 \"Code for Structural Design of Steel Chemical Vessels\" Appendix A 4: The sealing surface of pipe flanges shall use M-FM. HG/T 20583-2020 \"Code for Structural Design of Steel Chemical Vessels\" Appendix B 5: Equipment forgings shall be of grade III or IV; HG/T 20581-2020 \"Code for Structural Design of Steel Chemical Vessels\" 5.4.3(5)