Out of all the measures in place to protect a building from fire, fire doors are among the most visible and frequently used. However, many people do not know the full extent of their role within a...Continue Reading
Out of all the measures in place to protect a building from fire, fire doors are among the most visible and frequently used. However, many people do not know the full extent of their role within a fire protection strategy. As well as providing a safe evacuation route, fire doors help prevent a fire from spreading throughout a building. This is partially due to the use of intumescent strips.
Intumescent strips expand when exposed to extreme heat, closing gaps between the door and frame in the process. This helps stop fire and smoke from passing into other rooms. Depending on the type of strip, you can expect to get 30 to 60 minutes of fire resistance with this installation.
However, intumescent strips can be rendered ineffective when fire doors are frequently misused – a common occurrence in buildings with multiple occupants. For example, in 2019 it was estimated that 64% of premises visited by fire services had fire doors wedged open.
This article will provide an overview of industry best practice surrounding intumescent strips, helping both building owners and health and safety professionals understand their importance within a passive fire protection system.
Do all fire doors need intumescent strips?
All fire doors are rated based on their fire resistance features. This is known as an FD rating and is measured based on several different criteria. FD 30 and FD 60 are the main categories of fire doors. FD 30 means a fire door has a minimum of 30 minutes of fire resistance. A door with a rating of FD60S offers a minimum of 60 minutes of fire resistance and is a smoke sealed door. It is generally accepted that to provide the required level of fire resistance, all fire doors should be reinforced with either intumescent strips, cold smoke seals or a combination of both.
According to the British Standard 476 fire safety standards, most doors need to be S-type (smoke sealed) doors. Having a fireproof door installed with intumescent strips can help the door qualify for these standards. Seals need to limit leakage to a rate of 3 cubic metres of smoke through 1 metre of door edge per hour. If you require additional clarification on fire door requirements, we advise you to contact the manufacturer of your fire door’s make and model.
Fitting intumescent strips to fire doors
Fire door seals are fitted to the stiles and head of a door set, either in the grooves of the doorframe or mounted on the surface. They are designed to swell once the ambient temperature exceeds 200C, which will usually occur within the first 10-20 minutes of a fire. Properly installed intumescent strips will fill gaps between the door and frame to achieve fire compartmentation.
Regulations surrounding intumescent strips also require specific installation and fitting 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.
Maintaining smoke seals and intumescent strips
Intumescent seals and strips require regular maintenance to ensure they stay effective long-term. Fire door strips should be checked at least every six months for imperfections or other issues that might inhibit them from working properly. Any damaged or missing strips should ideally be replaced with a new one of the same size, type and brand as the original.
It’s important to carry out this inspection alongside other fire door maintenance tasks, such as checking hinges, locks, and other door elements. The door frame must be free of damage or gaps and it must close soundly. It must also have a minimum of three hinges that are in good working order. This helps ensure the fire strips maintain the same level of effectiveness as the original installation.
CLM Fireproofing are the UK’s leading experts in passive fire protection, with over 35 years of experience in the industry. Our FIRAS-accredited specialists offer fully compliant fire door inspection, installation and maintenance services (including intumescent strip fitting).
Contact the CLM Fireproofing team today to find out more.