This standard outlines the specifications for washers used in water supply fittings like bib taps, stop valves, pillar taps, and flush valves. It details the required materials, dimensions, performance standards, and marking protocols to ensure effective sealing, durability, and safety without contaminating drinking water or corroding metal components. The guideline is vital for manufacturers, suppliers, and engineers to guarantee compatibility and quality in water service fittings.
Overview
This standard outlines the specifications for washers used in water supply fittings like bib taps, stop valves, pillar taps, and flush valves. It details the required materials, dimensions, performance standards, and marking protocols to ensure effective sealing, durability, and safety without contaminating drinking water or corroding metal components. The guideline is vital for manufacturers, suppliers, and engineers to guarantee compatibility and quality in water service fittings.
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Frequently Asked
As per IS 4346 (1982), Clause 4.1 specifies permitted materials for washers used in water fittings as vegetable tanned hydraulic leather, high-density polyethylene (HDPE), and vulcanized fibre. These materials are chosen for their durability and ability to prevent cracking when taps are fully closed (Clause 5.1). Typically, a quality washer should provide service for at least six months before replacement is necessary (Clause 2.3). The materials ensure reliable sealing and extended lifespan in water service applications.
According to Clause 6.1 and Table 1 of IS 4346, washers are specified by nominal size with minimum thickness, internal diameter, and external diameter ranges. For instance, an 8 mm nominal washer has a minimum thickness of 2.5 mm, internal diameter of 3 mm (with +0.5 mm tolerance), and external diameter between 14.3 mm and 14.5 mm. Thickness tolerance for leather washers is ±5%. These dimensions ensure proper fit and sealing for different tap and valve sizes, maintaining leak-proof performance.
IS 4346 ensures potable water safety by mandating in Clause 3.1 that washer materials must not impart taste or color and must be free from toxicity. The residual chloride content after immersion testing must not exceed 0.2 mg/l. Materials are tested through immersion in potable water at 10°C and 45°C for 24 hours twice to confirm no color or odor transfer and no bacterial growth is promoted. These conditions secure hygienic use of washers in water supply fittings.
Manufacturers must label washer packaging with their identification mark and trade-mark as required by Clause 7.1 of IS 4346. Optionally, boxes may bear the ISI Certification Mark under Clause 7.2, provided the manufacturer is licensed. This mark signifies conformity to Indian Standards and is regulated by the Indian Standards Institution (Certification Marks) Act, ensuring ongoing inspection and quality control by ISI. These markings facilitate traceability and assure product quality.
IS 4346 recommends that a properly manufactured washer should last at least six months under normal usage (Clause 0.3). Immediate replacement is advised upon detecting any leakage to avoid water wastage. Materials specified, including vegetable tanned hydraulic leather, HDPE, and vulcanized fibre, provide durability and resilience. Routine inspections for leaks help maintain system efficiency and water conservation.
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