Alternatives to the use of chemical flame retardants in upholstered furniture
Fire Safe Upholstered Furniture – In a project commissioned by the Swedish Contingencies Agency (MSB,) SP Fire Research has investigated if sufficient fire safety can be achieved in upholstered furniture without the use of flame retardant chemicals.
Upholstered furniture can be a fire risk
It has been known for decades that upholstered furniture represents a fire risk. Such furniture can contain relatively large amounts of easily ignitable and very combustible materials. The foam used for the padding is usually the primary challenge with regard to fire. When the foam burns it releases large amounts of heat and produces dense, toxic smoke. Less flammable furniture would therefore contribute to increasing fire safety significantly. This may be relevant for example in homes, institutions, hotels and in other applications.
Some flame retardants represent a risk for health and environment
In order to meet relatively stringent fire safety requirements, flame retardant chemicals are often added to the materials. Some flame retardants may be harmful to health and environment, which is why there is a concern that the use of these chemicals will increase if stricter requirements on furniture are implemented. SP Fire Research has, on behalf of the Swedish Contingencies Agency (MSB), investigated if sufficiently fire safe upholstered furniture can be achieved without the use of flame retardant chemicals. Fire properties can be improved by, for example, a conscious choice of materials in coverings and fire barriers (a textile placed between the cover material and the padding). The project was carried out in 2015 by SP Fire Research in Trondheim and Borås in cooperation.
Various combinations of cover materials, fire barriers and foams were tested on a small scale in the cone calorimeter (ISO 5660) in order to examine which combinations of materials could potentially produce good fire behaviour in upholstered furniture, see Figure 1. In this context, good fire behaviour means that the furniture releases small amounts of heat and produces little smoke after being ignited. It is also an advantage if the material combination is difficult to ignite. Based on this screening, material combinations were chosen for medium scale testing in a corner mock-up assembly. The material combinations in the mock-up were exposed to a small gas flame and to a wooden crib corresponding to crib 5 of BS 5852, see Figure 2. Upholstered furniture in the UK market must comply with certain criteria when tested using crib 5, which is much stricter than in Norway and Sweden.
We wanted to investigate products that are common in the Scandinavian market and cooperated with Swedish suppliers to select materials for the tests. We tested a total of seven cover materials, two types of polyester wadding and three materials used as fire barriers between cover and foam. The same type of foam was used in all material combinations.
Results and conclusions
The tests showed that the heat release can be reduced by using a fire barrier between the cover and the foam. The barrier with the greatest density supplied the most significant impact while the effects of the lightest barrier were more dependent upon the cover material with which it was combined. Based on the results of the experiments, we believe that it is clearly possible to improve the fire safety of upholstered furniture without the addition of chemical flame retardants to the materials. This requires however, a conscious choice when combining materials. We have noted that there are several interesting products on the market, of which many have very different application areas than for use in upholstered furniture and could be further investigated in possible future studies.
We also recommend that a voluntary system for fire classification of upholstered furniture should be considered. This would be useful for both private households and for purchasers of furniture for commercial and government applications (hotels, hospitals, prisons, ships, offshore, etc.).
Alternative strategies to the use of chemical flame retardants can be downloaded from www.spfr.no
Main Image: Test of material combinations in a corner mock-up assembly.
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