MSS SP-71-2018涵盖了灰铸铁旋启式止回阀，其法兰端和螺纹端用于 通用服务。在急倾斜或垂直管线中使用旋启式止回阀需要特殊要求 考虑本标准实施规程还包括直接或通过引用对化学和化学物质的规定 常用材料的机械性能和端部连接的尺寸。

MSS SP-71-2018 covers gray iron swing check valves with flanged and threaded ends for general purpose service. The use of swing check valves in steeply inclined or vertical lines requires special consideration.This Standard Practice also includes, directly or by reference, stipulations on chemical and mechanical properties of materials and dimensions of end connections in common use.