How to handle the contradictions between GB/T20801 and GB50184?

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Dear colleagues, I have two questions and would appreciate it if you could help discuss them. I’m quite troubled by these issues. There is a purge gas compressor in use at a petrochemical company, with a gas mixture consisting of 73% hydrogen, 4% carbon monoxide, 8.4% methane, and the remaining components being carbon dioxide and nitrogen. The normal pressure of the purge gas is 0.01 MPa (A), while the discharge pressure is 2.4 MPa (A). It has four stages and five rows. 1) Question one: When the first stage of this purge gas compressor is operating normally, the inlet pressure is 0.01 MPa (A). The diameter of the inlet pipe is DN300, with an operating pressure of 10 KPa and a design pressure of 20 KPa. Is it appropriate to classify this pipe as belonging to a category other than those specified for this stage?； 2) The pipeline between the first stage and the compressor outlet pipe is classified as GC2 grade according to the pipeline regulations; in accordance with GB/T20801.5 referenced by these regulations, the inspection grade shall be no lower than Grade IV, and the proportion of radiographic testing shall be no less than 5% ； However, in accordance with the provisions of GB50160 \"Code for Fire Protection Design of Petrochemical Enterprises\" and GBJ16 \"Code for Fire Protection Design of Buildings\", this medium is classified as a Class A flammable gas. As specified in Table 8.1.1 of GB50184-2011 \"Code for Acceptance of Construction Quality of Industrial Metal Piping Projects\", the inspection level is classified as Grade III, and the proportion of non-destructive testing required is not less than 10%. Therefore, it is necessary to discuss how to handle these differences between the various standards; thank you very much for this opportunity to discuss the matter.