Marking of manholes?
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Hey experts, could you help me out? I need to figure out what material the ’Ⅷ’ in the designation \"Manhole MFM Ⅷ b-8.8(F4) 500-1.6\" refers to. I couldn’t find any information on this in the standards This marking refers to a flanged manhole with a horizontal drop cover and neck weld, in accordance with HG/T21524 standards
Ⅷ material refers to 304 stainless steel
Suggestion: The poster should look up the standards more; they contain corresponding code notation methods. Correction: The original poster said that the values specified in HG/T21524 are incorrect; the applicable range for HG/T21524 is 2.5–6.3 MPa, whereas the value given in your standard is 1.6 MPa. Therefore, it should be HG/T21523, so that you can find the appropriate materials for category VIII ； I have another question: what kind of gasket is F4? Is the gasket code incorrect? It should be F-304 or some other gasket code that starts with F?
Yes, I wrote the pressure wrong; the minimum pressure is 2.5 MPa. Is F4 a tetrafluoro gasket? It was written for me by a teacher. Let me help him modify the drawing; there’s no Class VIII material specified in HG/T21524