FIRE RESISTANCE REQUIREMENTS

FIRE RESISTANCE REQUIREMENTS

In the pursuit of aesthetic cabin furnishings, aircraft manufacturers and operators must consider one major and important factor when choosing upholstery materials. The must be fire proof and the materials must be prevented from emitting toxic gases. Recent experiments have shown that incapacitation of passengers has resulted from inhalation of toxic gases rather than post crash impact.

Most seat squabs and back supports are manufactured from foam type materials. When heat is applied to this material, cyanide gas is produced during the burning of the material. As means of slowing down this action the seats internal parts are covered with a fire blocking material, which is designed to prevent the foam from burning and consequently allow the occupants a better chance of vacating the aircraft in the event of a cabin fire. 

Because of the problem of smoke and the inability of passengers to see in smoke conditions, legislation is made to use some means of an exit indicating system that is close to the floor level. This legislation is applicable to all transport (passenger) aircraft over 5700kg MTWA for which a type certificate was issued after 1^st January 1958.

How the emergency escape path lighting will be achieved has to be decided by the aircraft operators or manufacturers. The most popular method is to include small aisle lights. which will illuminate under certain conditions.

The height of the escape path lighting system must not be greater than 4ft. The escape path system is designed to indicate to passengers the direction in which to go in the event smoke conditions, and at the same time indicate the areas that contains the emergency exits. 

Escape path lights will be white; red lights will be used to indicate the emergency exit doors.

Although fire-blocking materials are to be used in seat upholstery, the actual covers are also treated with a fire resistant substance. One important point to consider however that is the fire resistant qualities are gradually reduced when the seat covers are dry-cleaned. In most cases, manufacturers indicate the maximum number of times that the covers may be dry-cleaned before the fire resistant treatment has to be reapplied. The number of dry-cleans will depend only upon the manufacturers recommendations.