This part of GB/T 20801 specifies the basic requirements for safety protection devices and safety protection such as safety relief devices, flame arresters, fire emergency cut-off devices and mechanical interlocking devices for pressure piping systems. For other safety protection requirements not specified in this part, please refer to other parts of GB/T 20801 and the relevant national regulations, standards and specifications. This section applies to the safety protection of pressure piping systems within the scope of GB/T 20801.1.