A standard test method to determine the smoulder resistance of mattresses was first issued in Canada in 1968, and revised in 1979. The acceptance criteria are that charring or melting of the surface must not exceed 50 mm in any horizontal direction from the cigarette, and any combustion in the mattress assembly must cease within 10 minutes after the cigarette has stopped burning. Regulations based on this standard have been in force under the Hazardous Products Act since 1982. Assessing the ignition resistance of upholstered furniture is much more complicated than in the case of mattresses. The materials used in their manufacture, and their geometries and constructions may be markedly different.
Many upholstery fabrics are a mixture of fibres.
In addition to fibre composition, the variables known to influence combustion characteristics include fabric weight, construction method, backcoating, dye, sizing, and chemical finishes. Fabrics and filling materials made from natural substances are subject to a smouldering type of combustion. By comparison, synthetic fibres are primarily thermoplastic and tend to melt and shrink when subjected to smouldering ignition sources, but burn rapidly when exposed to flame. At present there are no standard test methods in Canada to evaluate the fire performance of upholstered furniture. The United States and the U.K., on the other hand, have appreciable experience in this field.