self-closing taps for water supply purposes
1984 Edition

According to IS 1711 (Clause 4.1, Table 1), recommended materials include: for the body, cover, and lever or pushbutton—grey cast iron, malleable iron, cast brass, and leaded tin bronze adhering to respective IS codes; for the spindle—mild steel or leaded tin bronze; spindle springs made from phosphor bronze wire, spring steel wire, or corrosion-resistant alloys with tensile strength equal or superior to phosphor bronze; cage and valve components from leaded tin bronze; brass washers as per IS standards; seat washers and other washers conforming to IS 4346; and gaskets made from vulcanized fibre or equivalent materials. Additionally, nickel plating of minimum 0.015 mm and optional chromium plating of minimum 0.00025 mm thickness are suggested for corrosion protection and finishing (Clause 7.3). This selection ensures durability, corrosion resistance, and compliance with sanitary requirements.

IS 1711 defines the operation mechanism where the tap is opened by pressing a handle (which may move up, down, or sideways) or by pushing a button, and it automatically closes once the handle or button is released. The force required to fully open the tap must not exceed 70 newtons. For taps operating under water pressure heads exceeding 2 meters, a non-impact closing function is mandatory. Optionally, the taps can be designed to automatically close after dispensing between 5 to 10 litres of water, even if the handle or button remains pressed, achieved through a capillary groove on the valve spindle or an equivalent method. This operation ensures controlled water flow and automatic shutoff to conserve water and prevent wastage.

To ensure no water leakage post-closure, IS 1711 mandates that taps withstand a hydraulic pressure test at 2 MPa for a minimum of 2 minutes without any leakage or sweating (Clause 8.1). An endurance test requires the tap to operate through 50,000 full opening and closing cycles without leakage or failure of springs or other components (Clause 8.3). The operational force needed to fully open the tap should not exceed 70 newtons to maintain smooth functionality (Clause 6.1). Furthermore, the tap must close automatically upon releasing the handle or pushbutton to prevent water wastage. These requirements collectively assure durability, leak-tightness, and water conservation.

IS 1711 prescribes an endurance test involving 50,000 complete open-close cycles to verify durability, with no leakage or functional failure allowed (Clause 8.3). Sampling for testing is done based on lot sizes as per specified tables, with taps selected randomly in accordance with IS 4905-1968 (Clause 9.3). The acceptance criteria stipulate that if none of the sampled taps fail, the lot is accepted; if one or two fail, the sample size is doubled and retested; failure in retesting or more than two initial failures leads to lot rejection unless all taps are individually tested (Clause 9.4). These procedures ensure that taps meet durability and quality standards statistically and reliably.

Yes, IS 1711 requires that the inlet connection threads conform to IS: 554-1975, which specifies the standard pipe threading system, typically British Standard Pipe (BSP) threads. This standardization ensures compatibility and interchangeability with conventional plumbing pipes and fittings, providing reliable and leak-proof connections for self-closing taps. Detailed thread dimensions and specifications can be found in IS: 554-1975.