Intumescent and smoke seals

Perimeter fire seals are essential to performance and there are three types available: intumescent, intumescent and smoke seal combined, and concealed intumescent. The first two systems incorporate exposed intumescent strips to the frame jambs and head as a standard, whereas the concealed method houses the intumescent strips behind vertical door lippings but exposed on top. Generally, exposed intumescents are 10mm x 4mm for 30 minute performance and 20mm x 4mm for 60 minutes.

Where complete doorsets are being supplied, all necessary intumescent seals will be included to the frame as a standard, in order to achieve the stated performance. However, the specifier needs to indicate whether the concealed method is required. In the case of pairs of fire-rated doors, a combined intumescent and smoke seal will be incorporated at the meeting stile of the primary leaf corresponding with a plain intumescent in the secondary leaf.

Where doors only are being supplied, seals need to be specified precisely if required. If intumescents are to be fitted by others, they must comply with our fire certification requirements details of which can be found in the BWF-CERTIFIRE data sheets supplied with the doors.

Concealed intumescent seals can be incorporated into the vertical edges of single doors. With pairs of doors, the primary leaf will always feature an exposed combination seal at the meeting stile. The intumescent in the top edge must be exposed and is positioned to run the full width of the door leaf.

Use of a combined intumescent and smoke seal or a separate smoke seal will provide smoke protection in accordance with BS 476 Part 31.1. Approved Document B states that the bottom edge can be ignored, however certain sectors require this edge to be sealed. Contact our Technical Services Department for further clarification.