Smoke Strips For Doors? Top 99 Best Answers

The role of a fire door is to prevent fire from spreading from room to room and the length of time that the door will contain the fire is specified in the fire rating of the door. An FD30 door will withstand fire for 30 minutes and an FD60 door will withstand fire for 60 minutes. The weak point of a fire door is the gap between the door and the frame and this is where the presence of an intumescent strip is crucial.

We are often asked if and how intumescent strips can be attached and we have the answers here. We should first mention that the installation of fire barriers is best left to professionals. However, you can install or replace intumescent seals yourself with the right tools.

Intumescent strips can prevent the spread of fire and smoke for up to an hour, but should be checked periodically to ensure there are no cracks or damage. If damage is present, the strip should be replaced as soon as possible as the damage is likely to affect its performance in stopping fire and/or smoke.

There are different types of intumescent strips, just fire and fire and smoke.

Only fire, as the name suggests, only works against fire and expands when exposed to heat. The fire and smoke barriers expand in the same way, but also have the ability to stop the spread of smoke even before they expand from the heat of the fire.

Intumescent strips are generally fitted into the door frame but are sometimes located in grooves in the door itself. If your fire door or frame does not have grooves, you can use a router to create a groove suitable for the fire strip.

Selecting the appropriate gasket based on door test evidence is essential to determine the required gasket size. The intumescent strip needs to be cut to length and most have a self-adhesive backing strip to easily stick into the groove.

We have many options and colors for intumescent strips to blend in with their surroundings. You can browse our selection here.

If you know which intumescent strip you want to fit, take a look at our Fitting Guide Library. Here you will find access to all of our product installation guides.

frequently asked Questions

Q. Can I put an intumescent strip on a regular door?

Yes. However, adding an intumescent strip does not make the door a fire door. For fire safety, we always recommend a fire rated door (FD30/FD60 depending on building requirements) and intumescent strips.

Q. Do I need intumescent strips in the door and frame?

no In the event of a fire, the seal will expand far enough to close the gap, no matter where it is placed. No seals are required on either the door or the frame.

Q. Without a brush or flipper, will an intumescent strip stop the smoke as it closes the gap between the door or frame?

Not always. Smoke can travel without fire (and heat), and it’s the heat that expands the streak. The presence of a fin or brush will prevent the cold smoke from passing through the door. We have a great article on how cold smoke intumescent strips work if you’re curious to learn more.

Do you have anymore questions? Check out our Fitting Guide Library or give us a call and speak to one of our intumescent experts for help with your specific project.

Intumescent seals are specially designed sealing strips that expand when exposed to heat and fill the voids between two surfaces (door and door frame), creating a fire seal.

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Adding a fire seal to a standard door does not make it a fire door, a verified designed fire door is compatible with our fire seals.

There is a wide variety of fire doors that require different specifications, so no single seal is the solution. Find test evidence for your doors to determine the type of door that needs to be specified – whatever type and size (or sizes) of seal you tested with us should buy.

Where no test evidence is available from the door manufacturer, the usual recommendation is to use a 15 x 4mm gasket centered on the header and both jambs of a single leaf, single acting door. (If you have any doubts or would like to discuss a specific application please contact our Technical Services Team on 01223 832 851 for further details).

Also, if it is a fire and smoke door (referred to as FD30S) then remember that a fire seal alone is not enough – you should buy a combined smoke and fire door with threshold seal.

What cutter is used to apply intumescent strips?

First, what is an intumescent strip?

Intumescent strip is a piece of plastic extrusion containing a core of intumescent material. It is designed to fit around a door frame or the top and sides of the door itself. In the event of a fire or extreme heat, the intumescent strip will expand to fill any gaps around the door. This will help prevent flames from spreading from one room to another. Additional features along the length of the strip, such as B. “brushes” or “fins” also help to prevent the spread of smoke even before a flame is present.

Preventing the spread of flame and smoke during a building fire helps save lives. It is estimated that there are around 37,000 house fires in the UK each year. The majority of fatalities from fires are caused by inhaling the smoke and toxic gases produced by the fire, rather than the fire itself. Improvements in regulatory standards over the years have helped reduce the spread of flame and smoke throughout of a fire and significantly reducing the number of deaths in the UK each year.

When installing brand new doors in a renovation property or new construction, it is not uncommon to see “complete door sets” turn up on site. These complete sets consist of a frame mounted door with hinges already installed and intumescent strips. However, there are many situations where a door needs to be cut to fit an existing frame, requiring the intumescent strip to be reapplied on site. Alternatively, existing doors often need to be retrofitted with fire and smoke seals to comply with the latest regulations. In these situations you will need to reach for your router or trimmer and cut the correct width of slot to allow the intumescent strip to be attached.

Intumescent strips are manufactured in a variety of widths and typically come with a self-adhesive backing that easily attaches to common frame and door materials. Typically you would use 10mm or 15mm wide strips for a 30 minute fire door and 20mm wide strips for a 60 minute fire door. However, it is highly recommended to check the door manufacturer’s specifications as the correct width of the strips used is a crucial factor in determining whether the door conforms to the relevant building codes or not.

So; What is the best and easiest way to cut slots for intumescent strips? There are two popular methods, both of which require a router or trimmer along with the right cutter.

The traditional method was to select a straight plunge cutter of a width to match the strip. The next step in the process was to adjust the depth setting on the cutter so that it dips just deep enough to accommodate the gasket. While this method is certainly effective, it can be “cumbersome” to set up and often difficult to use accurately.

The alternative and more effective method is to select a grooving cutter specifically designed to cut a slot or channel – perfect for intumescent strips. This type of cutter requires the body of the router or trimmer to be held at a 90 degree angle to the frame or door. Available in common widths for corresponding widths of intumescent strips, each cutter is manufactured to be dimensionally accurate to ensure the strip fits perfectly. The bearing guide on the cutter makes operation effortless and it automatically sets to a depth of cut of 4mm; which fits most brands of standard intumescent strips on the market today. Maxitek intumescent strip cutters are available in 10mm and 15mm widths. If a 20mm groove is required, simply make a cut with the 15mm router bit and then set the depth 5mm lower to complete the 20mm width of cut.

Of all the measures to protect a building from fire, fire doors are among the most visible and commonly used. However, many people do not understand the full extent of their role within a fire safety strategy. Fire doors not only provide a safe escape route, but also help prevent a fire from spreading throughout the building. This is partly due to the use of intumescent strips.

Intumescent paint expands in extreme heat, closing gaps between the door and frame. This prevents fire and smoke from spreading to other rooms. Depending on the type of intumescent strip, you can expect a fire rating of 30 to 60 minutes with this installation. However, intumescent strips can become ineffective if fire doors are subject to frequent abuse – a common occurrence in multi-occupancy buildings. For example, in 2019 it was estimated that 64% of premises visited by firefighters had open fire doors.

This article first provides an overview of industry best practices related to intumescent strips, helping both building owners and health and safety professionals to understand their importance within a passive fire protection system. A few installation guidelines are then addressed so that those responsible for fire maintenance can be confident that they are complying with fire door regulations.

What are intumescent strips?

Intumescent strips are fitted to fire doors and when exposed to extreme heat, they expand to close any gaps or edges that could allow smoke and fire to spread.

How much protection does an intumescent strip offer?

Intumescent strips for fire doors are generally rated to provide approximately 30 to 60 minutes of fire resistance and will help contain the fire to an area and prevent it from spreading. This, in turn, gives residents ample time to safely evacuate the building while emergency services extinguish the fire.

Do all fire doors require intumescent strips?

All fire doors are rated based on their fire resistance properties. This is known as the FD rating and is measured using a variety of criteria. FD 30 and FD 60 are the main categories of fire doors. FD 30 means that a fire door has at least 30 minutes of fire resistance. A door rated FD60S provides at least 60 minutes fire resistance and is a smoke tight door. It is generally accepted that all fire doors should be reinforced with either intumescent strips, cold smoke seals or a combination of both to achieve the required level of fire resistance.

British Standard 476 fire safety norms require most doors to be Type S (smoke-tight). A fire rated door with intumescent strips can help the door qualify to these standards. Gaskets must limit leakage to a rate of 3 cubic meters of smoke through 1 meter of door edge per hour. If you require additional clarification on fire door requirements, we recommend that you contact the manufacturer of your fire door make and model.

If a door does not meet the regulatory definition of a fire rated door, the addition of intumescent strips alone does not mean it offers the same level of protection as a fire rated door. Even if there’s nothing stopping you from installing intumescent strips on a regular door, the door still won’t meet the legal requirements.

Fire break regulations

The primary reference point for compliant fire doors is their fire rating, which is provided by the manufacturer in the form of test data. These ratings indicate how long a door can withstand fire damage. For example, a fire door rated FD30 means it has a fire resistance rating of 30 minutes (these can range from FD30 to FD240). To find out more, consult our guide to fire door regulations.

A building’s regulations also determine where its fire doors are located and where fire break strips must be installed. For a standard fire door, the door leaf must be able to move within the frame and to allow for this there must be a small gap around the perimeter.

As a rule, the gap in a fire door should not be larger than 3 mm – 4 mm, namely on the two longitudinal edges of the door and across the top edge of the door leaf. The gap at the bottom of the door needs to be around 10mm for smoke free conditions, but where smoke seals are in place this gap should be reduced to 3mm – 4mm.

Attaching intumescent strips to fire doors

Fire door seals are fitted to the jamb and head of a door panel, either in the grooves of the door frame or surface mounted. They are designed to swell once the ambient temperature exceeds 200°C, which is typically within the first 10 to 20 minutes of a fire. Properly installed intumescent strips fill the gaps between the door and frame to create a fire compartment.

Intumescent strip regulations also require specific installation and assembly based on your building and fire door type. For example, some doors require a cold smoke seal to protect people and property from smoke damage. In cases where smoke leakage is important to detect a fire, cold smoke seals may not be required.

How to adjust intumescent strips

Intumescent strips are fairly easy to install provided the fire door in question has the correct grooves. Otherwise you will need to create grooves with a cutter equal to the width of the intumescent strip.

Once you have your groove in place you can measure and cut your strip to ensure it is the correct width for the door. You should then check that the groove is clean and free of dust or dirt. Otherwise the adhesive backing of the strip may not stick properly in the groove. After installing the strip, you should test the door to be sure the door will still close properly. You may need to use a door closer for it to close properly. In this case, according to fire protection regulations, it must be a door closer of class 3 or higher.

Can you paint insulation strips?

While it’s not advisable to paint over a smoke seal, painting intumescent stripes is a bit more ambiguous. For example, if you want to paint your intumescent strip, you’ll want to avoid applying too much or getting paint on the “brush” strip section. Although painting an intumescent strip is unlikely to affect its effectiveness, from a fire safety perspective it is most likely best to play it safe.

Maintenance of smoke seals and intumescent strips

Like all other firestop materials, intumescent strips should never be “put on and forget”. Intumescent strips can crack, warp, or partially detach from a door with age. They can also take damage from door use or building repairs. As such, they should be inspected at least every six months for defects or other issues that may affect their proper functioning. Any strip that is damaged or missing should ideally be replaced with a new strip of the same size, style and brand as the original.

It is important to perform this inspection along with other fire door maintenance tasks such as: B. checking hinges, locks and other door elements. The door frame must be free of damage or gaps and close properly. In addition, at least three hinges must be in perfect condition. This helps the fire strips maintain the same effectiveness as the original installation.

CLM Fireproofing is the UK’s leading expert in passive fire protection with over 35 years experience in the industry. Our FIRAS accredited specialists provide fully compliant fire door inspection, installation and maintenance services (including fire strip installation). Contact the CLM Fireproofing team today to learn more.

Building codes state where you have fire doors, these would require intumescent strips. In the event of a fire, the door would not prevent the spread of fire for half as long without the intumescent strips, putting the occupants or occupants of that building at much greater risk of injury and/or death.

Fire doors play a crucial role in preventing the spread of fire and smoke. Fire doors are classified according to their required fire rating FD30, FD60, FD90 and FD120, where the number represents the number of minutes the door can contain the fire. Fire doors that also require smoke control are typically listed as FD30S, FD60S, FD90S and FD120S.

A standard fire door requires the door leaf to move freely within the frame and for this to be possible there needs to be a small gap around the perimeter. If the gap is too wide, it can affect the door’s ability to restrict the spread of fire and smoke.

Intumescent materials such as moldings, locks and smoke seals play a major role in preventing the spread of fire and smoke. They help reduce property damage and most importantly, prevent death and injury.

Intumescent strips are located within the door itself. When activated by heat, the materials swell and form a seal. In the case of a fire door, it creates a seal to fill the gap between the door and the door frame. This prevents the fire from spreading and helps contain it in that particular room/compartment.

Intumescent strips can also be found lining all window frames in a fire door as a fire would cause the window to shatter and the fire to spread quickly without the intumescent strip in place.

How big should the gaps be around a door and its frame?

The gap between the door and the frame is extremely important and must be suitable for the built-in intumescent seal.

As a general rule, the gap should not exceed 3-4mm, this should be maintained along the two long edges and also across the top of the door leaf. The gap at the bottom of the door is approximately 8-10mm* for smoke-free conditions, but also 3-4mm when smoke seals are required.

* Check the door manufacturer’s instructions

The effectiveness of intumescent strips

A video from Lorient shows how effective the intumescent strips are and the damage done without this precaution. The Grenfell Tower tragedy highlighted the importance of fire safety and due to a lack of proper precautions, this horrific event claimed the lives of 72 people.

details

Intumescent strips are attached to doors to swell up in the event of a fire, sealing the gap between the door and frame.

An intumescent strip is often installed as a combined unit containing a fire resistant material and a cold smoke seal. The intumescent material expands when exposed to heat and seals the door once a fire spreads. The brush or vinyl sheet, which is effectively a draft excluder, helps prevent smoke from entering through the door in the early stages of a fire.

Does painting over affect the integrity of the “intumescent strips” in the event of fire?

The defaults

BS8214:2008 Code of Practice for Fire Doors; states: Painting smoke seals or combined intumescent and smoke seals should be avoided.

If your fire doors are only protected with a simple intumescent strip (no cold smoke seal) then they can be painted over as long as they are not damaged by the painter’s preparation. Heavy sanding or the use of chemical strippers and heat guns during renovation must be avoided.

BS8214 states that you can apply a maximum of five coats of conventional oil based paint or varnish to the strip without affecting its effectiveness.

recommendations

You can only paint over a firestop strip that is designed for fire protection. A smoke seal must not be painted over. Also, be careful not to damage the stripe from the painter’s preparations.

references

British Standards – BS 8214 Code of Practice for Fire Doors

We all understand and appreciate how important fire doors are to our safety, especially in workplaces and other public buildings. Fire doors are part of a building’s passive fire safety system and are fundamental to fire safety strategies for any building. They provide critical protection within a building, such as B. escape routes, stairs and corridors, and slow the spread of a fire outbreak.

Effective fire doors ensure spaces are partitioned to contain fire and noxious smoke in the area where the fire originates and to protect occupants and contents in other areas of the building. It is therefore of the utmost importance that these fire doors function properly – they must be fitted with the correct hardware and have the correct signage required for fire and escape doors. Glazed fire doors must also meet fire safety requirements with the right glazing materials and standards. However, in order for these fire protection interior doors to be able to develop their full effect, they must not be impaired in any way.

Here are some common building fire safety mistakes and things you should NEVER do specifically with fire doors:

Never lock a fire door

Emergency fire doors shall not be locked or secured in such a way that they cannot be opened easily and immediately by persons who need to use them in an emergency.

Never leave a fire door open

A fire door must not be left open under any circumstances. Aside from the obvious consequences of potential loss of life or injury and damage caused by a fire spreading through a building, it is actually illegal to hold a fire door open. Therefore, all fire doors MUST be equipped with an automatic locking system.

The consequences of wedging a fire door open can be catastrophic on multiple levels. First, an open fire door is obviously not fit for purpose as it does not prevent flame or smoke from entering other parts of the building and endangering life. Secondly, a wedged fire door can be legally considered to knowingly endanger life, and those responsible could be fined or even imprisoned. Third, in the event of a fire and a fire door proven to be wedged, insurance policies may be void and insurance companies may be within their right not to pay for fire damage that occurs.

Never allow a fire door to be blocked

A fire door not only prevents the spread of fire and smoke within a building, but can also be an important escape route. When access to the fire door is blocked this safety route is severely compromised – therefore all passageways and corridors leading to a fire door should be kept clear at all times.

Enfield doors

Our team of experts is always at your side with advice and action and will give you well-founded and pragmatic advice based on many years of experience and successful installations.

If you would like more information about our company, please click here, or please contact us and we will respond as soon as possible. We look forward to helping you.

It is not uncommon for apartments and public buildings to have emergency doors for residents in an emergency. Some of the most commonly used are currently known as smoke check doors, sometimes also referred to as life check doors and fire doors. Although each of these doors may be of a similar nature, they serve two distinct purposes. However, both are designed to create a seal that will keep the deadly flames and smoke away from those within those structures at the time.

While smoke check doors are designed to keep combustible objects and smoke out, fire doors are designed to keep the flames out in a separate partition. In any case, these doors can also be used in apartments because of the security that these doors offer. So if you’re interested in how these doors can serve the same purposes for your family, you should contact your local firefighting professional for recommendations.

However, here is some basic information you should know.

First, it’s important to start with the anatomy of both doors and their fundamental differences. For example, the fire door was designed to be enclosed by the building’s fire walls. Its overall function is to prevent the flames from spreading through doors. In addition, when people think about the structure and purpose of the fire door, they will most likely find that fire doors can always serve as smoke doors as well, but not the other way around. Simply put, when people review the differences between the fire door and smoke door, it is important to note that smoke doors do not always have the same capabilities and features as the fire door. This is because smoke control doors are not designed to prevent the spread of flames from room to room.

Identify the distinct characteristics of each

Luckily both doors are very easy to identify if you want to know the difference. Because these doors must always be clearly marked for everyone. In addition to the signs on the doors, people can also tell the difference between each by the materials used by the manufacturer. For example, you can see the differences between wood, aluminum and steel in a smoke control door. Everyone should also know in advance that fire doors are made of fireproof materials so that they can withstand the flames for a long period of time.

protective functions

When people are in a building with a fire, it is important for people to know that the fire doors they see in the building are designed to compartmentalize the flames for at least a 30 to 120 minute period . One of the main functions of the fire door is to protect people from the harmful effects of fire. The type of doors used can also make a difference in protection as these doors are not usually automated but remain closed during these times.

For people who may not know the main reason for a smoke check door, it is important to know that these doors are made with special seals. Spartan Doors smoke control doors use high quality Kilargo door seals. These seals are designed to protect people by only activating when a smoke alarm is triggered.

considerations

These doors are only built to last. Therefore, it is important that problems with one or both of these doors are addressed immediately. In fact, it doesn’t matter if the damage is minor and not severe, as all issues must be reported and fixed. The aim is to make locating the certifications on the doors easier as serial numbers and dates can be found on the edge of these doors. This information can be used for a variety of situations and circumstances, including questions to the manufacturer and local firefighter.

Fire door seals, commonly referred to as intumescent seals, are designed to expand under heat. In the event of a fire, they expand to fill the gaps between the fire rated door leaf and frame, preventing fire from spreading to other parts of the building.

Wherever possible, intumescent strips should be fitted into the frame or paneling of fire doors. If this is not possible, the intumescent seals can be built into the edge of the door.

The materials contained in the gaskets (such as sodium silicate or graphite) differ depending on the gasket manufacturer and expand at different rates. When installing or replacing fire door seals, it is important to use the same type of seal around the door.

Refer to the fire rating certificate and supporting documents for details of the type of intumescent seals that are compatible with the fire door. Only the use of compatible products, correctly installed and maintained, will ensure that the fire door achieves the specified fire rating. Incorrect information can endanger life and property in the event of a fire.

When does a door need an intumescent strip?

Building codes state where you have fire doors, these require intumescent strips. In the event of a fire, without the intumescent strips, the fire would spread much faster due to the small gaps around the door and its frame, putting the occupants or occupants of that building at much greater risk of injury and/or death.

A standard fire door requires the door leaf to move freely within the frame and for this to be possible there needs to be a small gap around the perimeter. If the gap is too wide, it can affect the door’s ability to restrict the spread of fire and smoke. Intumescent materials such as moldings, locks and smoke seals play a major role in preventing the spread of fire and smoke. They help reduce property damage and most importantly, prevent death and injury.

Intumescent strips are located in the door itself or in the door frame, when activated by heat the materials swell and form a seal e.g. B. in a fire door, a seal to fill the gap between door and door frame. This prevents the fire from spreading and helps contain it in that particular room/compartment.

An intumescent strip is a piece of fireproof material that is placed around the frame of a door. In the event of a fire, the strip expands, preventing the fire from spreading. Depending on the product, an intumescent strip is fire resistant for up to 30 or 60 minutes.

If it is not possible to fit the intumescent strip into the door frame, you can create a groove to fit the strip. You can use a router to create a space wide enough to insert the intumescent strip. We have written a guide on how to apply intumescent strips that you can follow.

There are many different specifications for intumescent strips and it is important to understand which type you need for your door. For further help and advice you can contact our team.

How does an intumescent strip work?

Intumescent strips are extruded plastic strips with a core of intumescent material. The intumescent chemicals react when exposed to heat. The intumescent strip swells and seals the door, preventing fire from penetrating the gaps.

Some intumescent strips also include a smoke seal, such as B. the Lorient Fire & Smoke Seal, which prevents smoke from penetrating through the fire door. This is important as it prevents toxic smoke from entering the rest of the building, reducing the risk of damage or injury.

Intumescent strips and fire doors

All fire doors require intumescent strips – some require only fire rated products and others require fire and smoke control. Building regulations or your architect will advise you of the specifications required for your fire doors. You can also look at door manufacturers’ test reports as they indicate the products used to achieve the fire rating – typically this would be either 30 minutes (FD30) or 60 minutes (FD60). One of the most recognized fire door standards would be BS476 and all of our intumescent strips would conform to these standards.

If the required specification relates to smoke protection, a fire and smoke protection strip must be installed. These may be referred to as FD30S or FD60S doors. These doors may also require the installation of a drop down seal to achieve smoke classification.

Fire and smoke insulation strips combine fire protection with smoke sealing. The smoke seal is either a brush heap or a rib (or fin) that must make contact between the door and the frame to prevent the spread of smoke. The single rib intumescent strips, like the Lorient DS range, also have an acoustic rating to reduce sound transmission through doors.

Of all the measures to protect a building from fire, fire doors are among the most visible and commonly used. However, many people do not understand the full extent of their role within a fire safety strategy. Fire doors not only provide a safe escape route, but also help prevent a fire from spreading throughout the building. This is partly due to the use of intumescent strips.

Intumescent paint expands in extreme heat, closing gaps between the door and frame. This prevents fire and smoke from spreading to other rooms. Depending on the type of intumescent strip, you can expect a fire rating of 30 to 60 minutes with this installation. However, intumescent strips can become ineffective if fire doors are subject to frequent abuse – a common occurrence in multi-occupancy buildings. For example, in 2019 it was estimated that 64% of premises visited by firefighters had open fire doors.

This article first provides an overview of industry best practices related to intumescent strips, helping both building owners and health and safety professionals to understand their importance within a passive fire protection system. A few installation guidelines are then addressed so that those responsible for fire maintenance can be confident that they are complying with fire door regulations.

What are intumescent strips?

Intumescent strips are fitted to fire doors and when exposed to extreme heat, they expand to close any gaps or edges that could allow smoke and fire to spread.

How much protection does an intumescent strip offer?

Intumescent strips for fire doors are generally rated to provide approximately 30 to 60 minutes of fire resistance and will help contain the fire to an area and prevent it from spreading. This, in turn, gives residents ample time to safely evacuate the building while emergency services extinguish the fire.

Do all fire doors require intumescent strips?

All fire doors are rated based on their fire resistance properties. This is known as the FD rating and is measured using a variety of criteria. FD 30 and FD 60 are the main categories of fire doors. FD 30 means that a fire door has at least 30 minutes of fire resistance. A door rated FD60S provides at least 60 minutes fire resistance and is a smoke tight door. It is generally accepted that all fire doors should be reinforced with either intumescent strips, cold smoke seals or a combination of both to achieve the required level of fire resistance.

British Standard 476 fire safety norms require most doors to be Type S (smoke-tight). A fire rated door with intumescent strips can help the door qualify to these standards. Gaskets must limit leakage to a rate of 3 cubic meters of smoke through 1 meter of door edge per hour. If you require additional clarification on fire door requirements, we recommend that you contact the manufacturer of your fire door make and model.

If a door does not meet the regulatory definition of a fire rated door, the addition of intumescent strips alone does not mean it offers the same level of protection as a fire rated door. Even if there’s nothing stopping you from installing intumescent strips on a regular door, the door still won’t meet the legal requirements.

Fire break regulations

The primary reference point for compliant fire doors is their fire rating, which is provided by the manufacturer in the form of test data. These ratings indicate how long a door can withstand fire damage. For example, a fire door rated FD30 means it has a fire resistance rating of 30 minutes (these can range from FD30 to FD240). To find out more, consult our guide to fire door regulations.

A building’s regulations also determine where its fire doors are located and where fire break strips must be installed. For a standard fire door, the door leaf must be able to move within the frame and to allow for this there must be a small gap around the perimeter.

As a rule, the gap in a fire door should not be larger than 3 mm – 4 mm, namely on the two longitudinal edges of the door and across the top edge of the door leaf. The gap at the bottom of the door needs to be around 10mm for smoke free conditions, but where smoke seals are in place this gap should be reduced to 3mm – 4mm.

Attaching intumescent strips to fire doors

Fire door seals are fitted to the jamb and head of a door panel, either in the grooves of the door frame or surface mounted. They are designed to swell once the ambient temperature exceeds 200°C, which is typically within the first 10 to 20 minutes of a fire. Properly installed intumescent strips fill the gaps between the door and frame to create a fire compartment.

Intumescent strip regulations also require specific installation and assembly based on your building and fire door type. For example, some doors require a cold smoke seal to protect people and property from smoke damage. In cases where smoke leakage is important to detect a fire, cold smoke seals may not be required.

How to adjust intumescent strips

Intumescent strips are fairly easy to install provided the fire door in question has the correct grooves. Otherwise you will need to create grooves with a cutter equal to the width of the intumescent strip.

Once you have your groove in place you can measure and cut your strip to ensure it is the correct width for the door. You should then check that the groove is clean and free of dust or dirt. Otherwise the adhesive backing of the strip may not stick properly in the groove. After installing the strip, you should test the door to be sure the door will still close properly. You may need to use a door closer for it to close properly. In this case, according to fire protection regulations, it must be a door closer of class 3 or higher.

Can you paint insulation strips?

While it’s not advisable to paint over a smoke seal, painting intumescent stripes is a bit more ambiguous. For example, if you want to paint your intumescent strip, you’ll want to avoid applying too much or getting paint on the “brush” strip section. Although painting an intumescent strip is unlikely to affect its effectiveness, from a fire safety perspective it is most likely best to play it safe.

Maintenance of smoke seals and intumescent strips

Like all other firestop materials, intumescent strips should never be “put on and forget”. Intumescent strips can crack, warp, or partially detach from a door with age. They can also take damage from door use or building repairs. As such, they should be inspected at least every six months for defects or other issues that may affect their proper functioning. Any strip that is damaged or missing should ideally be replaced with a new strip of the same size, style and brand as the original.

It is important to perform this inspection along with other fire door maintenance tasks such as: B. checking hinges, locks and other door elements. The door frame must be free of damage or gaps and close properly. In addition, at least three hinges must be in perfect condition. This helps the fire strips maintain the same effectiveness as the original installation.

CLM Fireproofing is the UK’s leading expert in passive fire protection with over 35 years experience in the industry. Our FIRAS accredited specialists provide fully compliant fire door inspection, installation and maintenance services (including fire strip installation). Contact the CLM Fireproofing team today to learn more.

In the event of a fire, your first consideration should be the safe evacuation of those in the burning building. However, sometimes fires can spread quickly and hinder the evacuation of people.

The spreading smoke can make it even more difficult to rescue the people trapped in the burning building and hinder the extinguishing work. However, you can take steps to stop a fire from spreading through your building by installing fire doors and regularly inspecting fire doors.

Unlike traditional doors, a fire door is built to be more resistant to fire. It also usually comes with seals around the edges that can stop the spread of fire and smoke to unaffected areas of your building. One of the key components in a fire door is the intumescent strip.

What is an intumescent strip?

An intumescent strip is a thin seal typically placed around the edges of a fire door and door frame. The intumescent strip normally blocks the small gaps between the door and frame where fire flames can seep through and into unaffected parts of your building.

The intumescent strip around the door will expand and block any gaps around the doorway when exposed to the heat of a fire. If the gaps around the door are closed, the spread of a fire can be contained, albeit for a while.

Why should you put intumescent strips on your doors?

They help stop a fire from spreading and give you valuable time to conduct an orderly evacuation.

Intumescent strips also help contain the rapid spread of smoke from the burning part of the building to other areas. Smoke is a leading cause of fire fatalities, not to mention it usually hinders firefighters’ efforts because it obscures visibility.

By stopping the spread of fire, intumescent strips give you more time to save your property.

There are several key reasons why you should ensure your fire doors have intumescent strips including:

Note that the primary function of intumescent strips on fire doors is to contain the spread of a fire, not smoke. To prevent smoke from spreading to other parts of your building in the event of a fire, you also need to install smoke screens around your fire door.

What components are used to manufacture an intumescent strip?

Intumescent seals are typically made from intumescent materials.

An intumescent material is a substance that does not immediately burn when exposed to heat, but usually expands in volume as it decreases in density.

Intumescent seals can be manufactured from a wide range of synthetic polymers and resin binders such as silicone or epoxy.

Where should intumescent strips be placed?

Intumescent seals are usually fixed in the door frame but can also be fitted into grooves along the door.

To determine the ideal placement of intumescent gaskets, it is important to consider your door design.

What Size of Intumescent Strips Should You Use on Your Doors?

As previously mentioned, intumescent strips will help stop fire from spreading throughout your property, but they won’t hold back the raging flames forever. The length of time these strips can hold fire is usually determined by the thickness of the foil used.

The standard intumescent strips available on the market can help contain a fire for either 30 or 60 minutes.

If you need an intumescent seal on your door that can contain a fire for 30 minutes, you should use a foil between 10mm and 15mm thick.

On the other hand, if the seal is to last around 60 minutes, an intumescent film that is at least 20 mm thick should be used.

What is the difference between intumescent strips and smoke seals?

A smoke barrier is a sheet that is usually placed between the door and the entire door frame to prevent toxic smoke from entering other areas of a building that are not yet on fire. Unlike an intumescent seal, which can stop the spread of fire and some smoke, a smoke seal only stops the spread of smoke but does not contain the spread of fire.

The main difference between a smoke seal and an intumescent seal is that a smoke seal once fitted to the door frame is visible, but an intumescent seal is not normally visible.

Note that fire safety experts recommend installing both smoke seals and intumescent seals on fire doors to ensure complete protection in the event of a fire.

When purchasing a fire door for your building, you should check if it comes with both an intumescent strip and a smoke seal. If you purchase a fire door with both components with a 30 minute resistance rating, it should be marked ‘FD30S’. If you are purchasing a fire door with a 60 minute resistance rating it should be marked ‘FD60S’.