Resilient Seated Cast Iron Air Relief Valves for Water Works Purposes
2000 Edition

This standard encompasses resilient seated cast iron air relief valves intended for water mains, including single air valves (both small and large orifices), double air valves, and kinetic air valves. These valves are designed to automatically release or admit air during pipeline operation, ensuring effective air evacuation and ventilation in clear water distribution systems.

As per the standard, valve bodies, covers, and disks are typically made from grey cast iron conforming to IS 210 FG 200. Stems are constructed from high tensile brass (IS 320 HTB 1 or HTB 2) or stainless steel (IS 6603 grades). Seat rings may use natural rubber (IS 11855) or EPDM nitrile rubber. Other components such as high pressure orifices use leaded tin bronze (IS 318 LTB-2) or alternatives like brass and stainless steel. Bolts and nuts are carbon steel (IS 1363) or stainless steel, while gaskets and gland packing use rubber and jute/hemp respectively.

Valves undergo hydrostatic testing where the body, sealed with a blank flange, is subjected to 1.5 times the rated pressure for 5 minutes without leakage or deformation. Functional testing involves mounting the valve on a test bench, applying working pressure, gradually opening the main valve, and verifying air discharge and float operation. Compressed air is introduced below the valve to ensure the float lifts and seals properly, confirming no leakage during operation.

Dimensional requirements vary by valve type and size. For example, single air valves with large orifices have minimum dimensions such as 202 mm by 164 mm suitable for mains up to 100 mm diameter. Double air valves and kinetic air valves have respective dimensional tables specifying parameters like length, width, and suitable main sizes. Spindle diameters for isolating valves are also defined, ensuring compatibility and structural integrity.

Air relief valves should be installed at high points or locations prone to air accumulation within clear water mains, allowing automatic evacuation during operation phases such as filling and emptying. Maintenance includes regular testing on a test bench at working pressure, verifying the float's proper movement and sealing, and ensuring no leakage occurs. Proper installation and periodic functional checks help maintain valve efficiency and protect pipeline integrity.