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IS 4927:1992 is the Indian Standard (BIS) for unlined flax canvas hose for fire fighting. This standard prescribes the requirements for materials, dimensions, construction, and testing of unlined flax canvas hoses used for firefighting. It outlines critical performance metrics such as bursting pressure, proof pressure, and percolation rates to ensure durability and reliability during fire emergencies.
Specification for Unlined Flax Canvas Hose for Fire Fighting
! Unlined flax canvas hoses are intentionally designed to allow slight percolation (weeping) of water. This keeps the exterior wet and protects the hose from burning when dragged over hot embers.
! Because they are made of natural flax fibers, it is critical to completely drain and thoroughly dry these hoses before rolling and storage to prevent rotting and mildew.
Consolidated list per BIS. For the text of each amendment, refer to the BIS portal link above.
flaxcanvastextile yarn
International Equivalents
Similar International Standards
BS 6391:1983British Standards Institution (BSI), United Kingdom
HighWithdrawn
Specification for fire-fighting hoses and non-percolating layflat delivery hose assemblies
Covers Type 1 (unlined) percolating hose made from natural or synthetic fibres.
DIN 14811:1982-10Deutsches Institut für Normung (DIN), Germany
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Feuerlöschschläuche; Druckschläuche und Einbände (Fire-fighting hoses; Pressure hoses and jackets)
Specifies requirements for fire hoses, including an unlined linen class (Class L).
NFPA 1961 (Historical Editions, e.g., pre-1970s)National Fire Protection Association (NFPA), USA
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Standard on Fire Hose
Early editions covered unlined linen hoses before the technology was largely replaced in the US.
Key Differences
≠The Indian standard specifies lower minimum pressure test values; for example, a minimum burst pressure of 3.5 MPa, whereas BS 6391:1983 required 4.5 MPa for a Type 1 hose.
≠IS 4927 specifies a 'Kink Burst Pressure' test with a minimum burst value (2.45 MPa). In contrast, BS 6391:1983 required the hose to withstand the proof pressure (2.25 MPa) while kinked without bursting.
≠IS 4927 defines a narrower range for the percolation (weepage) rate compared to the typical performance characteristics specified under the older British Standard.
≠Standard delivery lengths in IS 4927 are strictly defined (15 m, 22.5 m, 30 m), while other standards like BS 6391 allowed for length to be specified by the purchaser, with a default of 25 m.
Key Similarities
≈All standards are based on the same core technology: a seamless, circularly woven jacket made from flax yarn, designed to percolate water.
≈The fundamental purpose of the hose is identical: the percolating (weeping) action of the wet hose protects it from damage by radiant heat and flying embers.
≈The primary performance tests are conceptually the same, including hydrostatic proof pressure, burst pressure, and measurement of the percolation rate.
≈All standards specify requirements for marking the hose, including the manufacturer's name, the standard number, and the year of manufacture for traceability.
Parameter Comparison
Parameter
IS Value
International
Source
Nominal Internal Diameter
63 mm
63.5 mm (2.5 in)
BS 6391:1983 (Type 1)
Hydrostatic Proof Pressure
2.1 MPa
2.25 MPa
BS 6391:1983 (Type 1)
Minimum Burst Pressure
3.5 MPa
4.5 MPa
BS 6391:1983 (Type 1)
Minimum Kink Burst Pressure
2.45 MPa
Must withstand 2.25 MPa (proof pressure) without bursting
BS 6391:1983 (Type 1)
Percolation Rate at 0.7 MPa (per meter)
0.5 to 1.67 l/min/m
Typically between 0.4 to 2.0 l/min/m
BS 6391:1983 (Type 1)
Maximum Mass per Unit Length (63mm hose)
0.55 kg/m
0.56 kg/m
BS 6391:1983 (Type 1)
⚠ Verify details from original standards before use
Key Values5
Quick Reference Values
standard internal diameters63 mm and 70 mm
standard lengths15 m and 30 m
proof pressure2.1 MPa
minimum bursting pressure3.5 MPa
working pressure0.7 MPa
Tables & Referenced Sections
Key Tables
Table 1 - Requirements of Unlined Flax Canvas Hose
Why is the percolation test important for unlined hoses?+
It ensures the hose weeps enough water to protect its canvas jacket from fire damage, but not so much that it causes a significant drop in delivery pressure.
What are the standard diameters specified in this IS code?+
The standard internal diameters are 63 mm and 70 mm.
What is the minimum bursting pressure for flax canvas fire hoses?+
The minimum bursting pressure required is 3.5 MPa.