IS 636 Type A vs Type B: Comprehensive Selection Guide for Fire Hoses

### Understanding IS 636:2018 Standards

Fire fighting hoses must endure immense internal pressures while remaining pliable and resistant to abrasive dragging over jagged rubble, broken glass, and asphalt. The Indian Standard **IS 636:2018** classifies synthetic jacketed delivery hoses into two distinct functional categories:

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1. Type A: Non-Percolating Fire Hose (RRL)

Commonly referred to as **Reinforced Rubber Lined (RRL)** hose: - **Jacket:** Circular seamless woven 100% high-tenacity polyester filament yarn. - **Lining:** Smooth, vulcanized EPDM or synthetic rubber tube internally bonded. - **Percolation:** Zero water seepage through the jacket. All water pumped enters the branch pipe nozzle with minimal frictional resistance. - **Best Suited For:** Commercial towers, warehouses, manufacturing shop floors, municipal fire tenders, and interior structural firefighting.

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2. Type B: Controlled Percolating Fire Hose (CP)

Often called **Controlled Percolating (CP)** hose: - **Lining:** Micro-porous elastomeric inner lining engineered to weep a controlled micro-layer of moisture through the textile jacket. - **Mechanism:** As water courses through the hose under pressure, approximately 1–2% of the water continuously wets the outer jacket. This forms a protective liquid heat shield. - **Best Suited For:** Frontline forest blazes, brush fires, structural attack where glowing embers, falling coals, or scorching debris threaten to melt normal synthetic jackets.

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Pressure Specifications Under IS 636

| Parameter | Type A (RRL) | Type B (CP) | | :--- | :--- | :--- | | **Working Pressure** | 14 kgf/cm² (1.4 MPa) | 14 kgf/cm² (1.4 MPa) | | **Proof Test Pressure** | 21.5 kgf/cm² (2.15 MPa) | 21.5 kgf/cm² (2.15 MPa) | | **Minimum Bursting Pressure** | 36 kgf/cm² (3.6 MPa) | 36 kgf/cm² (3.6 MPa) | | **Abrasion Resistance** | High (over 10,000 cycles) | High |

At Tulsi Fires, all hoses undergo hydrostatic proof testing at our New Delhi manufacturing facility prior to dispatch.