Fire Door Seals: Intumescent Strips, Smoke Seals and Correct Fitting
Fire door seals are part of the complete doorset specification. Although intumescent seals and smoke seals are often fitted together, they do different jobs and should not be treated as interchangeable.
Intumescent seals and smoke seals
Intumescent material expands when exposed to heat, helping close gaps around the door as part of the doorset’s fire-resisting performance. Smoke seals are intended to restrict smoke leakage under the conditions for which they are designed. Some products combine intumescent and smoke-control functions.
The correct seal type, dimensions, location and fitting method depend on the door’s supporting evidence and manufacturer’s instructions. Do not assume that a seal with similar dimensions can replace the specified product.
Preparation and installation
Before fitting or replacing a seal, confirm the required profile and location. Check whether the seal is fitted to the leaf or frame, how it is retained and whether a groove or other preparation is specified. Cutting, routing or enlarging a groove should not be undertaken unless the method is permitted.
The installation should avoid damaged sections, unintended interruptions, contamination and finishes that interfere with the seal’s operation. Adhesives and fixing methods must be suitable for the specified seal and substrate.
Diagnosing seal-related problems
A damaged or missing seal may be visible, but a door that binds or will not close may have another cause. Frame distortion, hinge condition, floor interference, latch alignment and closer operation may all need consideration. Replacing a seal without identifying the cause can leave the original problem unresolved.
Proudman’s FIX fault-finding resource can be introduced as a way to explore possible causes of common fire doorset symptoms. It should support diagnosis, not be presented as a substitute for the door manufacturer’s instructions or a competent technical assessment.
Do not confuse seals with fire stopping
Seals around the door leaf are different from fire stopping at the frame-to-wall junction. The latter addresses the gap between the frame and surrounding construction and requires a suitable, evidenced system for the actual installation.
When inspecting fire door seals, record what is present, its condition and any visible defect. If the specified seal cannot be identified or the proposed replacement is not supported by the documentation, obtain appropriate technical advice before proceeding.
