What is the minimum application rate for a fixed roof tank storing hydrocarbons?

4.1 litres per minute per square metre of liquid surface area (Table 2).

What is the definition of low-expansion foam according to this code?

Foam having an expansion ratio up to and including 20:1 (Clause 3.8).

What are the main types of low-expansion foam systems described?

The code covers various types including surface application, subsurface injection, and semi-subsurface injection systems (Clause 5).

How long must the water supply last for a system protecting a cone roof tank?

For a minimum of 20 minutes at the required application rate (Table 2 and Clause 7).

IS 12835

: 2000

Design and installation of fixed foam fire extinguishing system - Code of Practice, Part 1: Low expansion foam

CurrentSpecializedCode of PracticeBIMFire Safety · Fire Fighting

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This standard provides the code of practice for the design, installation, testing, and maintenance of fixed low-expansion foam fire extinguishing systems. It specifies requirements for system components, design criteria like application rates for flammable liquid hazards, water supply needs, and acceptance testing to ensure system readiness.

Design and installation of fixed foam fire extinguishing system - Code of Practice, Part 1: Low expansion foam

Quick Reference Values

Expansion Ratio of Low-Expansion FoamUp to 20:1

Minimum Application Rate (Cone Roof Hydrocarbon Tank)4.1 L/min/m²

Minimum Discharge Time (Cone Roof Hydrocarbon Tank)20 minutes

Foam Concentrate Proportioning ToleranceNot less than nominal, and not more than +30% of nominal or 1 percentage point, whichever is less restrictive.

Minimum Water Temperature for Foam Generation4°C

Annual Foam Concentrate Sample TestingRequired as per Clause 12.5

Key Formulas

Foam Solution Flow Rate (L/min) = Protected Area (m²) × Application Rate (L/min/m²)

Practical Notes

Ensure foam concentrate is listed for use with the specific proportioning and discharge equipment being installed.

Water supply is the most critical element; hydraulic calculations must verify adequate pressure and flow at the most remote discharge device.

During commissioning, the proportioning test is vital to confirm the correct foam-to-water ratio is being achieved, as incorrect concentration makes the system ineffective.