Guide — Construction Site Fire Safety
Fire Safety During Construction
Construction and renovation sites are among the highest fire risk environments. Hot work, temporary services, accumulated combustibles, and compromised compartmentation combine to create conditions where fires can spread rapidly. The Joint Code of Practice on the Protection from Fire of Construction Sites and Buildings Undergoing Renovation (JCA Joint Code) sets the industry standard.
Why construction fires are severe
Buildings under construction typically lack the passive fire protection measures of completed structures: fire compartmentation is incomplete, fire stopping is not yet installed, and temporary electrical supplies are often used. A fire that would be contained by an FD30 fire door in a completed building can spread across an entire unpartitioned floor on a construction site within minutes.
Hot work permit procedure (six steps)
Written permit for every hot work operation; specifies location, duration, controls, and responsible person
Minimum 3 m clearance from hot work area; non-combustible shield where clearance not achievable
Appropriate type at hand during hot work; CO₂ or dry powder for electrical/gas work
Person remains in the hot work area for 60 minutes after work stops to detect smouldering ignition
Final check of area and adjacent spaces including above ceilings and behind walls
Both the permit issuer and operative sign off on completion of controls
Temporary fire detection during works
If building works disable or isolate the existing fire detection system, temporary detection must be provided. This is particularly important for overnight periods when the site is unoccupied. Battery-operated interlinked smoke alarms in key areas (including roof voids if roof work is being done) provide a minimum level of protection. The full detection system must be reinstated before the building is re-occupied.
Combustible materials and waste management
The accumulation of timber offcuts, packaging, and insulation materials inside a building under construction dramatically increases fire load. Good site housekeeping — removing waste at the end of each working day — is one of the most effective fire prevention measures on any construction site.
Maintaining fire compartmentation during renovation
Any penetration of a fire-resisting wall, floor, or ceiling for services (cables, pipes, ducts) must be fire stopped on completion using an approved fire stopping product rated for the compartment boundary. Temporary penetrations during works must be sealed at the end of each working day. This is a common defect found in post-renovation fire risk assessments. See our loft fire safety guide for specific guidance on roof space fire stopping.
Interaction with home insurance
Most domestic building insurance policies have specific conditions for construction works including: notification of works over a certain value, compliance with a hot work code of practice, and maintaining a minimum level of fire detection. Failure to comply — particularly ignoring hot work permit requirements — can invalidate a claim following a construction fire. Always inform your insurer before major works begin.
Frequently asked questions
FAQ