Intumescent Strips for Fire Doors

What are intumescent strips?

Intumescent strips are fitted to the edges of fire doors. In in extreme heat, these strips expand to seal the gaps between the door leaf and its frame. This allows closed fire doors to act as a barrier to the spread of smoke and flames throughout a building. Therefore, it is essential that fire doors are installed, maintained with their seals intact. They must also be kept shut when not in use.

Intumescent strip fitted to fire door
Intumescent seal on a fire door

Smoke seal vs intumescent strip

‘Intumescent strips’ are embedded in the door, and are dormant under normal conditions. These strips respond to heat, causing them to expand greatly in the event of a fire. This closes the gap between the door and its frame. These seals activate at temperatures that are above human survival levels. Therefore, there is no danger of them expanding and trapping people trying to escape.

A ‘brush’ seal or smoke seal will prevent the escape of cold smoke around the edges of the fire door. While these seals are also intumescent, smoke inhalation can be more dangerous than the fire itself. It is important, when fitting smoke seals, that they do not hinder the full and effective closure of the door.

Do all fire doors need intumescent strips and smoke seals?        

In order to be effective, all fire doors must be fitted with intumescent strips. Without these, the door will not ‘seal’ to the frame in the event of a fire. These seals are essential to slow the spread of the fire throughout the building, providing occupants time to evacuate. If intumescent strips are found not to have been fitted in the event of a fire, the Responsible Person could be prosecuted.

Smoke seals, however, are required as specified in the fire risk assessment. Most commonly this is included on doors approaching escape routes and doors which open on to a common space.

White fire door in a corridor leading onto stairwell
All fire doors must have intumescent strips fitted

Why fit intumescent strips and smoke seals?

Intumescent seals only react to extreme heat, so they don’t seal up until the fire is very close. Before this, smoke from the fire which has accumulated will be able to pass through the gaps around the door. This puts building occupants in danger of smoke inhalation, which can be fatal. Smoke seals prevent this, and are typically either a soft brush or a plastic / rubber flap.

When should smoke seals not be fitted?

There are some applications where a gap should not have smoke seals: e.g. if the fire door has been installed on the exit of a room which has no smoke detectors on its own. In this case, the fire alarm system can only be triggered if smoke can leak out around the fire door and set off the fire alarm system in the circulation spaces, but these cases are quite rare.

Fire door ratings and smoke

Fire doors are rated in accordance with the length of time they will resist a fire. Therefore, a door rated ‘FD30’ will resist the passage of fire for 30 minutes, an ‘FD60’ for 60 minutes. If a fire door is rated FD30s, (‘s’ meaning ‘smoke’), it should have been fitted with the appropriate seal to resist the passage of cold smoke for 30 minutes as well. For more information about how fire doors are rated, visit our blog.

Fire door gaps and smoke seals

British Standards set out details on the permitted gaps around a fire door. The gap along the sides, top, and between the leaves of a double door, must be between 2mm and 4mm. Responsible Persons can use a gap gauge to ensure that their fire door gaps are compliant.

Under-door (threshold) gaps should be in accordance with the manufacturer’s installation instructions for the particular doorset design. This blog provides more information about threshold gaps.

Gap gauge being used to check the gap size around a fire door
Intumescent seals can only be effective with the correct gap size between the door and frame

Can smoke seals be painted?

Fire doors can be painted with ordinary paint. However, fire accessories, including intumescent seals should not be painted, as it can prevent them from being effective in the event of a fire.

Are intumescent strips required in letter boxes?

If a fire door has a letter box installed, this must have been tested and rated to the same standards as the door itself.

If an intumescent letter box needs to be added to a fire door retrospectively, this can only be done if specified in the scope of the fire door’s Certifire Approval documents, and in line with the manufacturer’s instructions. Further to this, alterations can only be made by a trained professional, and with certified hardware. This ensures that the performance of the door, and its associated certification, is not compromised.

What does the threshold drop seal do?  

If smoke protection is required by Building Regulations or the fire risk assessment, the maximum gap underneath the fire door is reduced to 4mm. If the gap under a fire door is too large, surface mounted drop-down smoke seals or rebated drop-down smoke seals can be fitted to existing fire doors. When the door closes, a plunger makes contact with the door frame and lowers the seal to the floor, closing the gap under the door. This is usually a suitable solution for gaps of up to 14mm.

Can fire door seals be replaced?

Where a fire door rebate already exists, or the existing rebated fire door seal has been damaged, rebated intumescent fire door seals can be fitted.

Can fire door seals be fitted retrospectively?

Some older fire doors do not comply with the latest specifications. In some cases, this means that they do not have the appropriate intumescent or smoke seals. Fire door seals can be retrospectively added to these fire doors.

To avoid having to cut a rebate in either the door or the frame, surface mounted fire door seals can be fitted. These are stuck to the frame or door with their self-adhesive backing and sometimes nailed as well to give them increased longevity.

Rebated intumescent seal being replaced in a door frame by a qualified professional
Replace intumescent seals if they are damaged

Who can fit fire door seals?

Fire doors should always be professionally installed, as should any work which structurally alters the door or its hardware. Therefore, rebated fire door seals can only be fitted by a qualified professional, whether as a replacement or retrofit.

Surface mounted fire door seals, on the other hand, can be fitted by a ‘Competent Person’. If new fire door seals are fitted for the first time, make sure that fire door hinges, fire door closers and, where necessary, intumescent door lock protection are fitted as well.

Visit our website to see Safelincs’ full range of fire door seals. This includes ‘fire only’ (intumescent) and ‘fire and smoke’ (intumescent and brush) fire door seals. Safelincs supply both rebated and surface-mounted application, in both FD30 and FD60 ratings. If you are still unsure what type of seal your door requires, or whether a retrofit is appropriate for your door, contact our friendly fire door team on 0800 433 4289 or by emailing  firedoors@safelincs.co.uk.

FAQ

Can fire door seals be fitted to the door instead of the frame?

Yes, fire door seals can be fitted to either the door or the frame for a single fire door.

Double doors or door and a half fire doors will need to have fire door seals fitted to the door to ensure that the gap between each leaf is taken into consideration.

Fire Door Closers – How to Improve Ease of Movement Within Care Homes

Freedor Fire Door CloserFor those confined to care homes, moving freely within the immediate environment is essential for their well-being and self-esteem. However, fire regulations require that fire doors, such as those installed in gangways and often in bedrooms, are kept closed to prevent the spread of smoke and flames in the event of a fire. The hydraulic door closers, usually installed for this purpose, make the fire doors difficult to open for the elderly and those who require walking aids. Installing a normal fire door retainer to hold the fire door open against the pressure of a traditional door closer does not fully address this problem, as it still requires the fire door to be opened in the first place before it can be retained in the open position.

This is where Free-Swing Fire Door Closers would be more suitable. They allow the user to open and close the fire door like any other door – without any resistance. The door can also be left open in any desired position. If the fire alarm goes off the fire door will, of course, close and the occupants of the building are protected against the spread of fire and smoke.

Some of Safelincs’ Free-Swing Door Closers require wiring into the fire alarm panel to send a signal to the closer to ensure the door is closed when a fire is detected. Our Freedor Free-Swing Door Closer on the other hand, does not require any wiring at all. Similar to the well known Dorgard, manufactured by the same UK company, the Freedor ‘listens’ for the sound of an alarm system and will close the fire door as soon as the acoustic signal is received. The Freedor unit is battery powered and is also suitable for retro-fitting on existing fire doors.

Harry Dewick-Eisele, Managing Director at Safelincs, explains “The Freedor overcomes the need to install a door closer as well as a retainer. It is fitted in the same position as a traditional fire door closer and deals with the entire issue of the safe opening and closing of fire doors. It is a huge improvement for care homes but also children centres and other public spaces where traditional door closers can lead to difficulties for users.”

If you require any further information call 0800 433 4289 where our Customer Service Team are available to answer any questions you may have.

Keeping a fire door open legally… and safely

Dorgard Fire Door RetainersFire safety company Safelincs operates a website called firescout that invites visitors to submit photographs of any potentially dangerous situations they have spotted. All entries are anonymous, the idea being to educate rather than ‘name and shame’. Safelincs then offers advice as to whether the situation could incur a fine and how much, if anything, it would cost to remedy the situation.
A common misdemeanour is to prop open a fire door, sometimes with a fire extinguisher – a double transgression!

Fire doors are an essential part of the fabric of a building and have two important functions in the event of a fire; when closed they form a barrier to stop the spread of fire or smoke and when opened they provide a means of escape. They are designed to be kept closed except when people are passing through them. In some businesses, and in places such as care homes or schools, closed fire doors can act as a hindrance to general mobility and moving around to perform essential tasks. However, there is a way in which the situation can be overcome without compromising safety or breaking the law.

Safelincs provide a number of products manufactured by specialist manufacturer Fireco which allow fire doors to be kept open legally and safely. Each of these products works by responding to the sound (anything above 65 decibels) of a fire alarm; the mechanism holding the door open is released and the door closer on the fire door closes it to prevent the spread of fire and smoke spreading around the building.

Dorgard, the first innovative product from Fireco, is a wireless appliance that can be screwed to the base of a door in less than five minutes. The standalone device will then hold the door open at any angle allowing freedom of access throughout the building. Utilising acoustic technology, Dorgard ‘listens’ for a continuous alarm of 65dBA or higher which, once heard, will automatically release the door. Dorgard is available in a variety of colours and finishes which will blend in with any décor.

Fireco also produces the Dorgard Pro System which extends the versatility of Dorgard by linking several different devices and overcomes the issue of noisy workplaces. A transmitter is wirelessly installed next to a fire alarm sounder or hardwired into the fire alarm system. In the event of a fire, Dorgard Pro will wirelessly transmit simultaneously to multiple Dorgard Pro units within a 100 metre range. Safelincs will visit an organisation’s premises and undertake a free survey and make recommendations for siting an effective system.

Another product from Fireco is Freedor, a unique wire free solution that allows a door to free-swing just like a normal door and to be held open at any angle – automatically closing the door in a controlled manner when a fire alarm sounds. It utilises the same technology that is employed in Dorgard but is fixed unobtrusively to the top of the door. Using Freedor allows freedom of access throughout the building for disabled people and people less able to operate the doors, and assists businesses complying with the Equality Act 2010.

All these products have applications in a wide variety of environments and allow easy movement through a building without compromising safety or contravening fire safety regulations.

To find out more about the Fireco range go to www.safelincs.co.uk and follow the link to Fire Door and Exit Equipment or call 0800 433 4289 where there are friendly experts on hand to offer advice.

Why are Fire Door Closers Important?

In order for fire doors to function properly, they should remain closed when the door is not in use. As obvious as this sounds, in a busy office building it can be difficult to ensure that fire doors are being closed. Therefore automatic fire door closers are installed to ensure that, after a door is opened, it naturally returns to a closed position where it can offer the maximum fire safety.

Fire door closers are a legal requirement in most settings

How do fire doors closers work?

Door closers work by using the energy built-up when opening the door, to close it. Fire door closers have different closing strengths depending on the weight of the fire door. The closing strength is otherwise known as the EN power size. Smaller and lighter fire doors do not need as much strength in the fire door closer to shut the door. Many door closer models have an adjustable power size. The configuration of the door closers will also depend on the design of the door (inward/outward closing).

How do I check my door closer is working?

This fire door maintenance checker is a useful guide for checking all parts of your fire door to make sure they are compliant and operational. An unlatched or non-operational door closer will not shut the fire door if a fire breaks out. This could have disastrous consequences.

Which fire door closer do I need?

There are a number of different types of fire door closer available including closers that are even concealed within the doors themselves. Free-swing closers enable the doors to be held safely in an open position or to swing freely on the hinges. This can help to improve accessibility, particularly for anyone with mobility difficulties or in busy areas. In the case of a fire, the fire alarm will trigger these hold-open devices and allow the door closer to close the door.

If you are not sure which fire door closer you need, compare features and prices in this overview of fire door closers. Alternatively, contact our customer support team on 0800 612 6537.