Swing Check Type Reflux (Non-Return] Valves for Water Works Purposes, Part 1: Single-Door Pattern
2004 Edition

Per IS 5312 Part 1 (2004), acceptable materials include grey cast iron (IS 210 FG 200) for the body, cover, and door with alternatives like spheroidal graphite cast iron or cast steel. Hinge and door pins are made from stainless steel (IS 6603 12Cr12) or high tensile brass. Seat rings use leaded tin bronze (IS 318 LTB 2) or stainless steel variants. Bolts and nuts are carbon steel as per IS 1363. Other components such as plugs and bushes follow similar material provisions ensuring durability and compliance.

This standard applies to reflux valves with nominal bore sizes ranging from 50 mm to 600 mm. The valves are designed to operate under nominal pressure ratings of 1.0 MPa and 1.6 MPa, accommodating waterworks systems requiring these pressure limits. It excludes other valve types such as double disc and lift check valves.

Valves undergo hydrostatic testing as per IS 5312 Part 1, which includes body tests at 1.5 MPa for PN 1.0 and 2.4 MPa for PN 1.6 held for five minutes, and seat tests at 1.0 MPa and 1.6 MPa respectively for two minutes. Testing is conducted with inlet pressurization and closed ends to check for leakage and permanent deformation. Valves must pass without leakage or distortion to be accepted.

By-pass valves must meet minimum size requirements specified in the standard's Table 4, ensuring sufficient flow capacity. They can be mounted either alongside or integrated with the reflux valve and must include an air release plug to avoid air lock. The valve door face must have a minimum thickness of 5 mm, and materials for critical components like hinge pins and plugs must comply with durability standards to guarantee reliable operation.

Valves are to be marked with raised inscriptions indicating the manufacturer's name or trademark, nominal pressure rating (e.g., PN 1.0 or PN 1.6), valve size in millimeters, flow direction arrow, and cast heat number for traceability. Optionally, the BIS Standard Mark may be applied if the manufacturer holds the appropriate license. These markings ensure clear identification and compliance during installation and maintenance.