The standard outlines specifications for pressure regulating valves used within household water distribution networks, detailing criteria for materials, design, functionality, testing, and labeling. It specifically addresses direct-acting diaphragm valves that reduce excessive inlet water pressure to safer levels suitable for home plumbing. This guideline is vital for manufacturers, installation specialists, and engineers to ensure dependable and efficient pressure control in residential water systems.
Overview
The standard outlines specifications for pressure regulating valves used within household water distribution networks, detailing criteria for materials, design, functionality, testing, and labeling. It specifically addresses direct-acting diaphragm valves that reduce excessive inlet water pressure to safer levels suitable for home plumbing. This guideline is vital for manufacturers, installation specialists, and engineers to ensure dependable and efficient pressure control in residential water systems.
Audience
Contents
Structure
This section defines the scope of pressure regulating valves intended for household water supply systems, focusing on valves that lower high inlet pressures (up to approximately 1.72 MPa) to controlled, safe outlet pressures. It includes material specifications for components such as valve bodies, diaphragms, springs, and strainers, referencing related Indian Standards for each. Performance requirements specify minimum reduced pressures and flow capacities by nominal valve size. The section also covers marking requirements and outlines the protection of downstream systems through economical pressure regulation.
This part specifies the nominal sizes for pressure regulating valves, which correspond to the nominal bore of connecting pipes. The standard sizes covered include 15 mm to 50 mm diameter valves with corresponding inch designations. Threaded ends conform to Indian Standard IS 554:1975 for pipe threads. Illustrations clarify the correlation between pipe bore and valve nominal size, emphasizing that nominal size is a designation rather than an exact internal measurement.
Details are provided on the materials mandated for various valve parts. Major components like the valve body, disc holder, and bottom cover use leaded-tin bronze (IS 318 Grade 2). Diaphragm covers and spring chambers are cast iron (IS 210 FG 200). Critical functional parts such as body seat rings, adjusting screws, and valve stems employ chromium steel (IS 1570 Part V). Gaskets, fasteners, springs, and strainers follow specified IS grades to ensure durability, corrosion resistance, and mechanical integrity.
This segment highlights construction quality and workmanship criteria. Valve designs must facilitate repair or part replacement without pipeline disassembly. Threaded connections shall comply with IS 554:1975 to maintain pressure-tight joints. The section reiterates material usage per component and stresses ease of maintenance alongside adherence to Indian Standard norms for durability and operational reliability.
Performance mandates include a minimum achievable reduced pressure of 0.17225 MPa at an inlet pressure of 1.7225 MPa. Valve capacity requirements are defined relative to reduced pressure settings, ensuring minimum flow rates based on valve nominal size. The section also specifies strainer screen dimensions and open flow area requirements to maintain optimal operation, alongside pressure deviation limits to guarantee stable pressure regulation.
This section establishes the procedures for assessing valve performance, including tests for reduced pressure deviation and flow capacity. Valves must maintain reduced pressure within prescribed deviations under varying flow conditions and satisfy minimum flow rates as defined in the standard’s tables. Materials used in test specimens adhere to specified Indian Standards. A flowchart illustrates the stepwise testing methodology for clarity.
Every valve must be accompanied by comprehensive instructions detailing correct installation practices, adjustment procedures for setting desired pressure levels, and maintenance guidelines to ensure longevity and efficient function. The section emphasizes adherence to rounding rules per IS 2:1960 for test values and provides examples of typical testing setups. It also suggests regular maintenance as part of operational protocols.
Marking regulations require permanent identification of the manufacturer’s name or trademark and the valve’s nominal size on the product. Optional inclusion of the ISI certification mark is permitted subject to licensing under the Indian Standards Institution Act. The marking guarantees traceability, compliance with quality standards, and ongoing inspection by the ISI. A summary table and flowchart clarify marking requirements.
Frequently Asked
Per IS 9739 Clause 3.1 and Table 1, components such as the valve body, disc holder, bottom cover, drain plug, diaphragm retaining disc, spring discs, and check nuts are made from leaded-tin bronze complying with IS 318:1962 Grade 2. Diaphragm covers and spring chambers use cast iron as per IS 210:1978 FG 200. Replaceable body seat rings, adjusting screws, and valve stems utilize chromium steel following IS 1570 Part V:1972 Grade 12 Cr 13. Additional parts include mild steel tommy bars (IS 226:1975), compressed asbestos fiber gaskets (IS 2712:1979 Grade C), steel fasteners (IS 1363:1967), carbon steel springs (IS 4454 Part I:1975), and stainless steel strainers per IS 6911:1972 with designated alloy grades. The valve ends feature female threaded connections conforming to IS 554:1975, with strainer screen holes sized not exceeding 1/12 of the valve orifice diameter, and a minimum open area at least double the nominal pipe flow area. These material choices promote longevity, corrosion resistance, and mechanical performance.
IS 9739 (1981), Clause 2.1 defines the nominal sizes for pressure regulating valves as 15 mm (1/2 inch), 20 mm (3/4 inch), 25 mm (1 inch), 32 mm (1 1/4 inch), 40 mm (1 1/2 inch), and 50 mm (2 inches). These standardized dimensions correspond to the nominal bore sizes of connecting pipes and ensure compatibility and optimal performance in domestic water supply applications.
The reduced pressure adjustment range, as specified in Clause 5.4 of IS 9739, requires the valve to maintain a controllable reduced pressure of at least 0.17225 MPa. Verification involves a test procedure outlined in Clauses 6.4 and 6.2.1: the valve is installed as per the standard diagram, with the inlet pressure initially set at 0.7 MPa. The test sequence includes opening specific valves and orifices, adjusting the valve to achieve 0.35 MPa reduced pressure, then increasing and decreasing the inlet pressure between 1.05 MPa and 0.35 MPa while recording the reduced pressure. The total deviation in reduced pressure during this range must not exceed 0.07 MPa. This test ensures the valve consistently regulates pressure over the specified range.
Based on IS 9739, pressure regulating valves are subjected to several critical performance evaluations: a hydrostatic test at an inlet pressure of 1.7225 MPa with equal pressure applied downstream to check for leakage and deformation; a capacity test requiring the valve to maintain reduced pressure 0.1171 MPa below the no-flow set pressure while supporting an inlet pressure 0.3445 MPa above the reduced pressure, with minimum flow capacities defined for each nominal size; and an adjustment test to achieve a minimum reduced pressure of 0.17225 MPa at the specified inlet pressure and flow rates. These tests collectively verify valve integrity, flow capacity, and pressure regulation capability.
IS 9739 mandates that pressure regulating valves must be designed to allow continuous water flow even if any component fails, ensuring repairability without interrupting service (Clause 4.6). Additionally, each valve must be supplied with clear, comprehensive instructions covering installation, adjustment, and maintenance procedures as per Clause 7.1. This ensures operational reliability and facilitates proper upkeep and servicing without system downtime.
Ask AI about any clause, requirement, or provision in IS 9739. Get instant, clause-cited responses powered by our indexed library.
Free tier includes 150 queries (50 AI + 100 Reference) · No credit card required