Fire Door Seals and Intumescent Strips: Their Importance and Function

Fire Door Seals and Intumescent Strips: Their Importance and Function

Fire Door Seals and Intumescent Strips: Their Importance and Function

For a company that knows their stuff about all things fire doors, fire safety and protection, come and speak to us here at JST Construction. We try to take the confusion out of the subject because we understand there’s a lot of jargon and complicated elements involved.

As part of this, we write blogs on specific subjects and this one is regarding smoke seals and intumescent strips and the importance and functionality of them. So, let’s get straight into it.

Fire doors play a vital role in protecting people, objects and property. They are of course specially designed to withstand fire, smoke and toxic gases for a number of minutes. This provides time for people to safely escape a building that’s on fire.

There is however, an effective sealing mechanism on every fire door that allows this function to work and this is where seals and intumescent strips come into their own.

Looking to arrange a survey and receive a quotation for fire doors? Call us right away at 0151 355 9232 or use our online contact form

Fire Door Seals and Intumescent Strips

You may be wondering what both these things are, which would be a valid question, so allow us to explain.

Firstly, a smoke seal is the strip that sits between the door and the frame which is usually made out of polypropylene, nylon or rubber.

Its job is to stop the spreading of gas or toxic chemicals in order to protect people in a building which it is very effective at doing.

On the other hand, an intumescent strip, is a piece of fire-resistant material, which is tightly fitted around the frame of a door. In the event of a fire, the intumescent strip will expand, preventing a fire from spreading any further.

Intumescent strips can be commonly made from a wide range of synthetic polymers and resin binders such as silicone or epoxy.

The main difference between the two, is that a smoke seal will not directly protect you from fire itself, however the door it is attached to will. A intumescent strip however, expands when activated, in order to protect from smoke, gas, fumes and fire.

Either way, they both prolong your safety, even somewhat, and allow for some time to escape a building in the event of a fire.

Fire Door Seals – Benefits & Function

The most obvious benefit is something we’ve already touched on, which is the fact that a smoke seal will block smoke, fumes and gases from spreading between rooms or areas meaning people can escape with enough time if there was a fire.

Smoke inhalation is one of the leading causes of fire-related deaths so smoke seals play a massive role in decreasing those figures.

Smoke seals are actually also really good at contributing to energy efficiency of a building.

As you can imagine, the seal is pretty tight meaning heat will remain in a room, nullifying the neat to keep the heating on for long periods of time.

Saving money where you can has never been more important than these times we are currently in.

In the same breath, this could be considered to be more eco-friendly because if you’re not putting the heating on as much you’re being considerate to your carbon footprint which is particularly appealing to businesses and organisations.

Intumescent Strips – Benefits & Function

Similarly to smoke strips, intumescent strips are really clever things when it comes to performing its primary function.

They are specifically designed components that offer an additional layer of protection. They’re typically installed around the perimeter of the doors or within the frame and expand in the event of a fire as they’re heat-activated.

This seals off any gaps or openings so fire and smoke won’t go any further. A further benefit of an intumescent strip is particularly when fire doors are frequently left open or they have larger gaps due to uneven door frames or poor installation. This is because when activated these gaps get filled as the strip expands. 

Contact JST Construction

If you would like some more information on either of these two, or just fire doors in general, then please get in touch with the JST Construction team now. We have lots of experience in dealing with fire safety and protection projects so you’re certainly in good hands. We’ve made getting in touch with us really easy so please pick one of the following methods and we’d be happy to help.

You can call our team on 0151 355 9232. You can send us an email directly to You can also use the online form on our website.