What are the three main hazard classifications?

Light Hazard (LH), Ordinary Hazard (OH) divided into Groups I, II, and III, and High Hazard (HH) divided into Process and Storage categories. (Clause 5 & Table 1)

Can pipe schedules be used for designing a system for an office building?

Generally no. Office buildings are typically classified as Ordinary Hazard, which requires hydraulic calculations. Pipe schedules are only for Light Hazard systems. (Clause 11.2)

IS 15105

: 2002

Design and Installation of Fixed Automatic Sprinkler Fire Extinguishing Systems - Code of Practice

CurrentEssentialCode of PracticeBIMFire Safety · Fire Fighting

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This code provides comprehensive guidelines for the design, installation, and maintenance of fixed automatic sprinkler fire extinguishing systems in buildings. It details the classification of fire hazards, requirements for water supplies, component specifications, system layout principles, and testing procedures to ensure system reliability.

Design and Installation of Fixed Automatic Sprinkler Fire Extinguishing Systems - Code of Practice

Quick Reference Values

Max floor area per sprinkler (Light Hazard)21 m²

Max distance between sprinklers (Light Hazard & Ordinary Hazard)4.6 m

Design density for Ordinary Hazard Group I (OH-1)5 mm/min

Assumed area of operation for Ordinary Hazard Group I (OH-1)72 m²

Minimum water supply duration for Ordinary Hazard Group II (OH-2)90 min

Minimum pressure at highest sprinkler0.35 bar (or as specified by manufacturer)

Maximum floor area controlled by one installation valve (Light Hazard)4650 m²

Key Formulas

p = (6.05 x 10^5 * Q^1.85) / (C^1.85 * d^4.87) — Hazen-Williams formula for pressure loss (in bar per metre)

Practical Notes

This 2002 version has been superseded by IS 15105:2021. The 2021 version should be used for all new projects and contains significant updates.

Hydraulic calculations are mandatory for Ordinary Hazard (OH) and High Hazard (HH) systems. Pipe schedule tables can only be used for small Light Hazard (LH) systems.

Careful coordination with architects and other MEP (Mechanical, Electrical, Plumbing) services is essential to ensure correct sprinkler placement and avoid clashes with ducts, lights, and structural members.