Summary of Technical Requirements for Pressure Vessels (X)

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For pressure vessels containing liquefied gases (Group 1), the following mandatory requirements apply: 01 LPG storage tanks must have an H2S level of ≤50ppm. 02 Flammable compressed gases and flammable liquefied gas spheres shall undergo leak tests. 03 The shell shall be made of carbon steel and low-alloy steel plates, which shall be subjected to UT inspection on a sheet-by-sheet basis by the plate manufacturer or the spherical tank manufacturer in accordance with the provisions of Table 6. 04 The supports of the LPG storage spheres should be equipped with a fire-resistant layer. 05 Storage spheres for LPG should undergo post-weld heat treatment. 06 Spherical tanks containing explosive liquefied gases shall be equipped with at least two safety valves, one in use and one as a backup. 07 For spherical tanks containing liquid hydrocarbons, a conduit should be installed at the outlet of the overpressure relief device to direct the fluid to a safe location for proper disposal; it must not be discharged directly into the atmosphere. 08 The design pressure is determined as follows: A) In the absence of a safety relief device, the design pressure ≥ 1.05 × the operating pressure at the specified temperature ； B) When a safety relief device is present, the opening pressure of the safety valve shall be 1.05 to 1.1 times the operating pressure at the specified temperature; the design pressure of the container shall be ≥ the opening pressure of the safety valve ； Note: The operating pressure at the specified temperature is determined in accordance with TSG 21-2016 3.1.9.3.