What Are Intumescent Strips?

Fire doors are tested to incredibly high standards and given a specific rating. To comply with building regulations for commercial buildings, houses of multiple occupancy (HMOs) and other buildings where fire doors are legally required, they must meet precise standards to get the seal of approval and be given the status of a fire door.

There are numerous features that go into constructing a fire door, but the key feature has to be the intumescent strips. 

What Is an Intumescent Strip?

In essence, an intumescent strip is a fire-resistant strip that sits around the edges of a door, between the fire door and the door frame. It's an integral part of the fire protection system.

How Do Intumescent Strips Work?

Intumescent strips will expand when they reach a certain temperature, usually around 200 degrees. A fire can easily reach this temperature within ten minutes and can get as hot as 600-800 degrees.

As the intumescent strips expand, it blocks fire from escaping for a specific amount of time, based on the door's rating.

It's important to note, though, that these seals, and a fire door itself, will not fully protect people in the event of a fire.

When buying a new fire door, it's vital to note the fire rating as this will inform you of how long it will offer fire protection. Find out more about fire resistance ratings in our guide to fire doors and how they work.

Do You Need Intumescent Strips on Fire Doors?

In a word, yes. Without an intumescent strip, a fire door wouldn't function correctly. Extreme heat, fire and smoke would escape far more quickly on a door that hasn't got an intumescent strip.

What Is the Difference between a Smoke Seal and an Intumescent Strip?

You may have heard the term smoke seal as well as an intumescent strip. Smoke seals, while installed in the same area, are designed to block toxic smoke from seeping through the gaps between the door and the door frame.

There are a couple of main differences between smoke seals and intumescent strips:

1) Smoke seals are designed for blocking smoke solely from passing through the door, whereas an intumescent strip can stop the fire from spreading and stop smoke passing through (on some models).

2) Smoke seals are always visible between the door frame and the door, whereas an intumescent seal is only visible once heat reacts with it and the seal expands.

3) Smoke seals surround the entire door edge, whereas an intumescent strip surrounds the top and side edges.

What Are Intumescent Strips Made of?

The precise make-up of intumescent seals varies by design. However, usually, they consist of resin binders and synthetic polymers like epoxy or silicone.

Where Are Intumescent Strips Fitted?

There are two options when it comes to fitting intumescent seals:

1) Around the edges of your door frames.

2) Around the edges of your fire door.

Most fire doors will have a groove designed for the addition of an intumescent seal.

Do All Fire Doors Need Intumescent Strips?

For a fire door to be given a fire-resistance rating, they require either smoke seals to prevent smoke leakage or an intumescent material. Ideally, you'd want a combination of smoke seals and intumescent strips. This will increase fire safety in your home or building and reduce the chances of smoke inhalation for as long as the fire rating specifies.

This should hopefully prevent smoke and fire from spreading so that everyone in the building can evacuate safely before the fire service arrives and takes control of the situation.

Buy high-quality fire doors at Vibrant Doors

At Vibrant Doors, we strive to provide a wide selection of internal doors in a range of styles and at a great price. The same is true of our fire door range. All of the products are supplied by well-known and reputable manufacturers such as Climadoor, Deanta, JB Kind and XL Joinery.

Our fire door range includes FD30 and FD60-rated options, meaning it will block fire spreading for a minimum of thirty minutes for an FD30-rated door to an hour for an FD60-rated door.

With the wide range of materials, glazing and finishes to choose from, not to mention a 10-year guarantee against manufacturing defects and free delivery when you spend £750 or more with us, now is a great time to upgrade your internal doors for added protection.

It's the intumescent strip and smoke seal that make internal fire doors safe. It's the stylish design and high-quality materials that make the fire doors in our collection swoon-worthy. Shop online today and get in touch for additional help and advice.