What is the standard size of the instantaneous coupling covered by IS 901?

The standard specifies couplings for 63 mm nominal size.

What is the hydraulic test pressure requirement for these couplings?

Every coupling must withstand a hydraulic pressure of 2.1 MN/m2 (21 kgf/cm2) without leakage or sweating.

What are the approved materials for manufacturing these couplings?

Approved materials generally include leaded tin bronze (gunmetal), aluminum alloy, and naval brass.

IS 901

: 1988

Specification for Couplings, Double Male And Double Female, Instantaneous Pattern For Fire Fighting

CurrentSpecializedSpecificationFire Safety · Fire Fighting

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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

Quick Reference Values

standard nominal size63 mm

hydraulic test pressure2.1 MN/m2 (approx. 21 kgf/cm2)

test duration2.5 minutes minimum

Practical Notes

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.