BPFI Knowledge Centre
Smoke Control
Guidance for assessing smoke seals, leakage paths, threshold gaps and smoke-control performance within fire door systems.
Introduction
Smoke control is a critical part of fire door performance. In many fire events, smoke spread can present a serious life-safety risk before direct flame spread reaches occupants.
Fire doors located in escape routes, corridors, stairwells and compartment boundaries should be assessed not only for fire resistance, but also for their ability to limit smoke movement where smoke control is part of the intended building strategy.
This guidance supports practical assessment of smoke seals, threshold gaps, perimeter gaps, latching, door alignment and other leakage paths.
Core Principle
A fire door that resists flame spread may still perform poorly if smoke can pass freely around or through the doorset.
Smoke-control assessment should therefore consider the complete doorset, including the door leaf, frame, seals, threshold, hardware and operational condition.
Smoke Control Factors
Perimeter Gaps
Excessive gaps around the head and sides of a door may allow smoke leakage and reduce the effectiveness of the fire separation.
Smoke-control assessment should be integrated into broader Inspection processes and ongoing maintenance programmes.
Defects associated with smoke leakage should also be classified using structured Defect Classification methodologies.
Threshold Gaps
Large under-door gaps can create significant smoke leakage paths, particularly in corridors and escape routes.
Smoke Seals
Missing, damaged, compressed, painted-over or poorly installed smoke seals may reduce the ability of the doorset to limit smoke movement.
Positive Latching
Doors that do not latch correctly may not remain closed under pressure differences, air movement or normal building use.
Common Smoke-Control Defects
Defect
Likely Impact
Response
Inspection Guidance
Smoke-control inspection should be practical and repeatable. Inspectors should look for visible leakage paths and defects that may prevent the door from closing, latching or sealing correctly.
Recommended checks include:
- Check head and jamb gaps
- Check threshold clearance
- Check smoke seal condition and continuity
- Confirm door closes fully from different opening angles
- Confirm positive latching
- Check frame alignment and distortion
- Check for penetrations, holes or unsealed hardware changes
Practical Repair Approaches
Seal Replacement
Damaged or missing smoke seals may be replaced where the door and frame remain suitable and the repair can be installed continuously.
Door Adjustment
Hinges, closers, latches and strike plates may require adjustment to restore closing and latching performance.
Threshold Treatment
Excessive threshold gaps may require assessment of floor levels, drop seals, threshold plates or other suitable remediation methods.
Frame Remediation
Frame movement, separation or distortion should be assessed where it affects seal compression, alignment or door operation.
Evidence Requirements
Smoke-control repairs should be documented where practical, particularly where defects were identified through BWOF, IQP, council or building owner review.
Recommended evidence includes:
- Before and after photographs
- Seal type or product reference where available
- Gap measurements before and after repair
- Confirmation of closing and latching operation
- Door ID and location reference
- Repair date and repair personnel
Practical Position
Smoke-control performance should be treated as a core part of fire door lifecycle management, not as a secondary cosmetic concern.
Small gaps, damaged seals or poor latching may appear minor, but can materially affect smoke spread and escape route conditions.
A practical smoke-control assessment should therefore consider the complete doorset, the building use, the location of the door and the likely impact on occupants during a fire event.