Two functions
What is the difference between fire and smoke seals?
Intumescent material expands when exposed to elevated temperature and helps protect gaps and hardware details during a fire-resistance test. A smoke seal—often a brush, blade or other tested arrangement—limits ambient-temperature smoke leakage.
A product can combine both functions, but the presence of a brush alone does not prove the correct fire or smoke performance.
| Seal | Primary role | Typical evidence question |
|---|---|---|
| Intumescent | Responds to heat during fire exposure | Type, dimensions, location and continuity |
| Smoke seal | Limits ambient smoke leakage | Leakage classification and threshold arrangement |
| Combined seal | Provides both functions within its field of application | Compatibility with leaf, frame and hardware |
Condition checks
What defects should be recorded?
Look for missing lengths, damage, loose seals, paint build-up that prevents operation, incorrect joints, interruption around hardware and an apparently mixed specification. Confirm that the seal is located in the leaf or frame as required by the evidence.
Do not scrape, relocate or add seals simply to match another door. Older doors may have been designed under different standards; investigate the door and its role before prescribing change.
- Continuous and securely retained
- Not crushed, painted over or damaged
- Correct position and apparent size
- Compatible at hinges, latch and closer points
- Threshold and meeting-stile condition considered
Repair decisions
Can seals be replaced?
Replacement can be appropriate where the original specification is known and the new product is compatible. Where it is not known, a competent specialist should establish an evidence-based repair or recommend proportionate replacement.
Record the product, size, location, installer and date. Retest the door’s closing and latching after work because new seals can change resistance.