When are fire dampers mandatory in ductwork?

Fire dampers must be installed wherever an air duct penetrates a designated fire compartment wall, floor, or fire-rated partition.

What happens to the HVAC system upon fire detection?

The Air Handling Units (AHUs) must automatically trip to prevent the recirculation of smoke into other building zones.

Can AHU rooms be used for general storage?

No, AHU rooms must be dedicated strictly to HVAC equipment and kept entirely free of combustible storage.

IS 1644

: 2011

Fire Safety of Buildings - General: Air Conditioning - Code of Practice

CurrentFrequently UsedCode of PracticeBIMFire Safety · HVAC and Air Conditioning

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This code specifies the fire safety requirements for the design, installation, and maintenance of air conditioning and ventilation systems in buildings. It aims to prevent the spread of fire and toxic smoke through HVAC ductwork by mandating the use of fire dampers, non-combustible materials, proper fire stopping, and automatic AHU shutdown mechanisms.

Lays down provisions for fire safety of air conditioning systems in buildings, including design, installation, and operation.

Quick Reference Values

fire damper ratingMinimum 90 to 120 minutes matching the penetrated fire barrier

AHU shutdown mechanismAutomatic via smoke detectors in the return air stream

duct clearance gapFilled with approved fire-stopping material

insulation flammabilityStrictly non-combustible

Practical Notes

Ensure adequate access doors are provided near fire dampers for periodic inspection and manual resetting.

Ductwork penetrating fire-rated walls must be properly fire-stopped around the perimeter to maintain the compartment's integrity.

Never use combustible materials for duct acoustic lining or external thermal insulation.