GB/T 1855-1993

This standard specifies the design, dimensions, materials, and pressure ratings for marine flanged cast iron single arrangement suction stop check box valves. It is applied in shipbuilding and marine engineering for seawater, freshwater, and bilge systems where a combined shut-off, non-return, and suction control function is needed in a compact valve box. The standard ensures interchangeability and reliable operation in ship piping systems under classification society requirements.