Fire Performance and Characteristics of British Rail Flexible Polyurethane Foam Seating

Despite the many desirable features (light weight, low cost, good comfort characteristics) of polyurethane foams for transport seating, and that modem moulding techniques permit fast production rates and ergonomic feature incorporation, they exhibit problems of relative ease of ignition and propensity to produce smoke and toxic gases when burned. To reduce the latter on BR, the selection of suitable foams is closely controlled, and the facility exists to check flammability and other properties to BS and BR specifications. To evaluate fire performance in the final seating configuration, full-size testing is also undertaken on the foam/covering materials under conditions of accidental ignition. Results variation using the same foam/cover combination has been greater than normal experimental error. A detailed assessment programme, including the use of barrier foams, is being initiated to provide a greater understanding of the fire mechanism, and the uprating of the fire resistance of the whole range of seating.