Summarize | Mandatory requirements for pressure vessels containing extremely and highly hazardous (Group 1) media

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1. When carbon steel and low-alloy steel plates with a thickness greater than or equal to 12mm (excluding laminates of multi-layer pressure vessels) are used to manufacture the main pressure components of pressure vessels, ultrasonic testing should be carried out one by one in accordance with NB/T 47013.3-2015, and the passing grade shall not be lower than Level II. 2. Pressure components must not be made of cast iron. 3. Pressure components must not be made of cast steel. 4. After passing the pressure test, a leakage test must be conducted. The type, pressure, and technical requirements of the leakage test shall be stipulated by the designer in the design document. 5. The welded joints between the nozzle (flange) and the shell and the welded joints of the jacketed vessel should adopt full penetration structures. 6. Prepare product welding test pieces. 7. The pipe flange should be in accordance with the HG/T 20592 ~ HG/T 20635 series of standards, and should be a combination of neck butt welding flange, metal spiral wound gasket with reinforcing ring and special-grade high-strength studs. 8. Conduct all non-destructive testing (RT/UT) on the container shell type A and B butt joints. 9. All welded joints need to undergo magnetic particle (MT) or penetrant (PT) testing on their surfaces. 10. Carbon steel and low alloy steel pressure vessels containing extremely hazardous media and their pressure components should undergo post-weld heat treatment. 11. The test pressure of graphite pressure vessels shall not be less than 1.75 times the design pressure. 12. Graphite pressure vessels shall undergo leakage tests on all joints and connections at a test pressure not lower than the design pressure. The test method shall be specified by the designer. 13. For pressure vessels made of graphite, the designer shall put forward the production requirements for bonded test pieces in the design document, and stipulate the number of test specimens, preparation methods, inspection and test methods, qualification indicators, and re-inspection requirements for unqualified samples, etc. 14. Fiber-reinforced plastic containers are not allowed. 15. The process qualification report (CMQ) for graphite pressure vessels should include the permeability coefficient. 16. When it is necessary to enter the interior of the container for periodic inspection, replacement, neutralization, disinfection, cleaning, sampling and analysis must be carried out. The analysis results must meet the relevant standards and specifications. The sampling and analysis intervals must comply with the relevant regulations of the user. 17. During periodic inspection, if the material is unknown, the material must be identified. 18. During periodic inspections, leakage tests should be conducted according to the requirements of the design drawings. 19. The outlet of the safety valve or bursting disc should be equipped with a conduit to guide the discharge medium to a safe place and handle it properly. Toxic media should not be discharged directly into the atmosphere. 20. In order to facilitate the cleaning and replacement of safety valves, a stop valve can be installed between the overpressure relief device and the pressure vessel only with the approval of the person in charge of safety management of the user unit and the establishment of reliable preventive measures. The structure and diameter of the stop valve must not hinder the safe release of the overpressure relief device. 21. The liquid level gauge has a protection device to prevent leakage. 22. In order to minimize the leakage of medium through the safety valve, the safety valve and the bursting disc can be used in series. 23. The bursting disc safety device shall not be used alone, but it can be connected in series with the safety valve. 24. Confirmatory burst tests shall not be used to determine the design pressure of the vessel. 25. The comparative experience design method shall not be used. 26. When the thickness of the steel plate used for the shell is ≥12mm, ultrasonic testing should be carried out one by one, and it shall pass Level II. 27. The 10, 20 and Q345D steel pipes of GB/T 8163 shall not be used. 28. Class III and IV steel pipes of GB/T 12771 shall not be used. 29. Steel pipes complying with GB/T 24593 shall not be used. 30. Class VI steel pipes of GB/T 21832 shall not be used. 31. Q235 series steel plates shall not be used for pressure components. 32. If any welding repair is performed after post-weld heat treatment, the repaired parts should be re-heat treated. 33. For cold-formed pressure components of steel plates, if the deformation rate exceeds the range of Table 4 of p330, heat treatment to restore material properties should be performed after forming. 34. Post-weld heat treatment is required. 35. When there are Class A (excluding Class A joints connecting ball seals and cylinders) longitudinal welding joints, product welding test pieces should be prepared one by one. 36. Its Class A and B welding joints should undergo 100% non-destructive testing (RT/UT/TOFD). 37. For spherical tanks with extremely or highly hazardous media, the inlet and outlet should be opened on the upper pole. 38. Lining composite structures are not allowed. 39. The minimum thickness of the tube sheet should not be less than the outer diameter of the heat exchange tube. 40. Reinforcement circle structure is not recommended. 41. Stuffing function heat exchangers are not allowed. Note: Atmospheric pressure vessels for extremely and highly hazardous media should also be constructed in accordance with GB/T 150, which are not governed by the atmospheric pressure vessel standards.