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IS 901:1988 is the Indian Standard (BIS) for couplings, double male and double female, instantaneous pattern for fire fighting. This standard lays down the requirements for materials, dimensions, and testing of double male and double female instantaneous pattern couplings used for connecting fire hoses and fire fighting equipment. Engineers and fire safety professionals use this code to specify and verify the quality and compatibility of firefighting hose connections.
Specification for Couplings, Double Male And Double Female, Instantaneous Pattern For Fire Fighting
! Always verify that the coupling material matches the environmental requirements (e.g., gunmetal or brass for corrosive/marine environments instead of aluminum).
! Washer dimensions and elasticity are critical to ensure a leak-proof joint during the instantaneous connection under high water pressure.
Consolidated list per BIS. For the text of each amendment, refer to the BIS portal link above.
aluminum alloyleaded tin bronzebrassstainless steel
International Equivalents
Similar International Standards
BS 336:2010BSI - British Standards Institution, UK
HighCurrent
Fire hose couplings and ancillary equipment
Covers the same instantaneous (lug and flange) coupling design, including adapters like double male/female.
NFPA 1963:2019NFPA - National Fire Protection Association, USA
LowCurrent
Standard for Fire Hose Connections
Covers adapters for fire hose connections, but specifies a threaded system (NST) instead of instantaneous.
DIN 14341:1992-04DIN - Deutsches Institut für Normung, Germany
LowCurrent
Transition piece for fire-fighting fittings (Übergangsstück für Feuerlöscharmaturen)
Specifies adapters for the Storz coupling system, a different type of symmetrical quick-connector.
Key Differences
≠IS 901 specifies a hydrostatic test pressure of 21 kgf/cm² (~20.6 bar), whereas the highly similar BS 336:2010 specifies a higher test pressure of 24 bar.
≠Material specifications, while similar in type (bronze, aluminum), refer to different national standards. For example, IS 901 specifies Leaded-Tin Bronze LTB-2 (IS 318), while BS 336 specifies Gunmetal LG2 (BS EN 1982).
≠BS 336:2010 explicitly defines a maximum working pressure of 16 bar, a parameter which is not explicitly stated in IS 901:1988.
≠Marking requirements are different; IS 901 mandates the ISI Certification Mark, while BS 336 requires marking with the British Standard number and pressure rating.
Key Similarities
≈The fundamental operating principle is identical, based on the instantaneous quarter-turn connection with two spring-loaded lugs on the female side engaging a flange on the male side.
≈Both standards define couplings for the same purpose: to act as adapters for connecting two male ends (double female coupling) or two female ends (double male coupling) in a firefighting water delivery system.
≈The primary nominal size of 63 mm (IS 901) and 2.5 inches / 64 mm (BS 336) is common to both standards, allowing for a high degree of physical interchangeability.
≈Both standards permit the use of similar categories of materials, including copper alloys (bronze/gunmetal), aluminium alloys, and stainless steel, recognizing their required strength and corrosion resistance.
Parameter Comparison
Parameter
IS Value
International
Source
Hydrostatic Test Pressure
21 kgf/cm² (approx. 20.6 bar) for 2.5 minutes
24 bar (2.4 MPa) for 2 minutes
BS 336:2010
Maximum Working Pressure
Not explicitly specified
16 bar
BS 336:2010
Copper Alloy Material
Leaded-Tin Bronze, Grade LTB-2 (IS 318)
Gunmetal, Grade LG2 (BS EN 1982)
BS 336:2010
Aluminium Alloy Material
Grade 4600 or 4225 (IS 617)
Grade LM25 or LM6 (BS EN 1706)
BS 336:2010
Nominal Size
63 mm
64 mm (designated as 2 1/2 inch)
BS 336:2010
Washer Material
Natural rubber (Type A of IS 638)
Natural or suitable synthetic rubber (e.g., EPDM), specified by performance requirements.
BS 336:2010
Stainless Steel Material
Grade 04Cr17Ni12Mo2 (IS 1570 Part 5)
Grade 316S11, 316S13, or 316S31 (BS 970-1)
BS 336:2010
⚠ Verify details from original standards before use
Key Values3
Quick Reference Values
standard nominal size63 mm
hydraulic test pressure2.1 MN/m2 (approx. 21 kgf/cm2)