Intumescent & Smoke Seals

Compatible intumescent specification is listed in accordance with the fire door dimensional limitations (height, width, area and thickness). The exact specification of compatible intumescent seals will be detailed within the associated documentation for the relevant certification, and this is often shown in the form of a table.  

The table will detail:  

• Compatible intumescent manufacturer and product name / code in relation to the size and configuration of the doorleaf 
• Compatible size and number of intumescent seals needed in relation to the size and configuration of the doorleaf (with reference to meeting stiles on double configuration doors (where applicable)).  

Intumescent seals are not all made from the same materials, they activate at different temperatures and perform in different ways in a fire.  

The intumescent specification should never be changed without separate approval from the relevant Third Party Certification Provider. Always ensure you use the one listed on the relevant documentation and don’t mix and match seals within the same fire door or fire doorset unless it is detailed within relevant certification scope.   

Configuration of doors and location of seals 

Once you have checked the configuration of the doors to ensure that the compatible specification of intumescent and smoke seals is used, (whether they are single acting, single leaf or double acting, double leaf) you must also confirm the exact location of the seals. This will be detailed in the associated documentation for the relevant certification.

The location of the seals is dependent on whether they are mounted in the frame or mounted in the edge of the door. The information will  include limitations of dimensional spacing between seals where more than one seal if present. 

The size of the seals can also change and the material they are made out of can differ, depending on configuration or location within the finished product.  

This information must be cross referenced between the information in the maximum dimensional limitations of the door leaf. 

Around the perimeter of the leaf / frame, it is likely the seals will be interrupted by ironmongery. In this case the associated documentation for the relevant certification will provide further information as to whether additional intumescent protection is required in these areas.  

Intumescent and smoke seals – maintaining the gap between door leaf and frame  

Intumescent seal specification changes depending on the size of fire door leaf. Of equal importance is the dimension of gap between the door leaf and frame (head, sides, threshold gap).  

The relevant associated documentation for the specific certification scope will detail the correct gap and associated tolerances.  

Under no circumstances should the gap be exceeded either during construction of the product within the manufacturing facilities, when the product is initially installed, and throughout the service life of the product.