Can a connection with hydrogen be used with a necked flange SN?
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The hydrogen pressure is 2 kilograms. All device connections are SN. Is this safe? I checked the relevant standards; they only state that SN is not allowed in high-temperature areas. I need to use WN; I hope experts can give some guidance. I’ve looked into several types of standard American and European standards. Is there any standard with clear guidelines?
Hydrogen pipelines should be connected by welding; other connection methods are potential sources of leakage. However, the connection to the equipment and valves can be made using flanges or threads. Polytetrafluoroethylene film is used as a filler for threaded connections. . The selection of flanges and gaskets is determined based on the pressure and temperature of the working medium, as well as the required level of sealing. Due to the tendency of hydrogen to leak, high sealing standards are required; flanges with male-female, tenon-socket, or trapezoidal grooves are specified for pressures greater than 2.5 MPa. Based on actual usage conditions and to ensure the sealing of the connections in hydrogen pipelines, the operating pressure is specified to be less than 10 MPa; polytetrafluoroethylene or metal-wound gaskets are used for these pipelines ； When the pressure is 10 MPa or higher, the gasket should be made of hard steel cardboard or annealed copper sheet.