Fire Rated Foam Products

Important Note – Fire Rated Foam Products

HETAS has recently been made aware of a number of incidents relating to the use of self-expanding polyurethane fire rated foam, used in applications for the sealing of materials in proximity to solid fuel appliances and installation components. Some of these cases have involved callout and attendance from the Fire & Rescue service due to the foam products being at risk of igniting under continued appliance operation conditions. Due to the significant risks involved with this type of installation practice, HETAS has below clarified the situation in more detail on these types of products, and their suitability for use in solid fuel appliance installations.

General Guidance

The majority of fire rated filler products available on the market today are designed for use in applications in sealing cavities, to improve the insulation of building materials by reducing the escape of heat and air from the building and in effect improving its overall energy performance. Particular applications include the sealing of fireproof doors, windows and cable ducts, as well as sealing of connections between walls, ceilings and floors, as specified by the product manufacturer and within the relevant instructions.

As these products are solely designed to be used in these types of construction applications, under no circumstances should these products be used for the sealing of any materials in installations concerning solid fuel and biomass burning appliances. Further clarification for the reasoning behind this can be found below.

Fire Foam Applications

In practice, fire rated foam filler products are required to have a verified “Reaction to Fire” rating, confirmed under laboratory test conditions, meaning that the product material does not contribute to the spread of flames in situations of fire and reduce the buildings overall fire protection performance. These ratings in most cases are designated on a letter and number scale (i.e. A1, B3), dependent on the EN test standard used for testing and confirmation. It is important when commencing solid fuel installation works to check the suitability of any materials used, as a reaction to fire rating does not necessarily mean that a product has been verified as a “non-combustible material”.

For non-combustibility of products, Approved Document J provides further guidance, making some reference to reaction to fire, mainly by definition of non-combustibility against the requirements of BS EN 13501-1:2002, ensuring only those products verified as A1 non-combustible are used in solid fuel installation applications.

A reaction to fire rating does not guarantee a period of time in which products can withstand fire, only confirming that the product will not contribute to the spread of fire during its intended use.

In cases such as this where products are used as a material insulator, the product manufacturer is also required to undertake additional testing to confirm the products “Fire Resistance” rating against the relevant BS or EN standard. This testing confirms that the product can withstand fire for a specified period of time, to allow occupants enough time to vacate the premises in incidents of fire. The long-term exposure temperatures stability for materials is determined in a very different test and in most cases, the temperature resistance of these types of foam filler products are only verified to a temperature of around 100oC (based on the caveats of the test).

The required standards to be met for sale in the UK and generally prescribed within the BS 476 series of standards.

Solid Fuel Appliance Applications

Although these products may have test evidence to confirm both their reaction to fire and fire resistance properties, this data will not provide sufficient evidence to enable an installer to confirm that products will provide stability for the longer periods of time at elevated temperatures they will experience near a solid fuel appliance.

During winter months, solid fuel appliances operate for a much more sustained period of time, much longer than the periods verified during the testing of the product. Certain components of solid fuel fired appliance installations can operate at temperatures as high as 400oC+.

It is important therefore that any product used in proximity to solid fuel installations is a suitably rated non-combustible material, and has a verified long-term exposure temperature confirmed by the product manufacturer to withstand the higher exposure temperatures that can be found during continued solid fuel appliance operation.

Technical data sheets supplied by the product manufacturer will include the permissible temperatures and rating information in which installers can make reference against before use of the product. It is important in any incidents whereby the relevant fire rating or performance cannot be confirmed, that the product should not be used under any circumstances. Specialist advice can be obtained from the HETAS technical helpline in instances of uncertainty.

Installers should always ensure that the Building Regulation requirements J4 Protection of Building is met in reducing the significant risk of the building catching fire in consequence of use of solid fuel burning appliances.

Further Information

Contact the HETAS Technical Helpline to discuss this article further. Click here for contact details.


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