So in addition to fire safety design features such as structural fire blocks between the engine and fuel and passenger compartments, flame retardants help to considerably reduce fire risks in transport. Flame retardants act both by reducing the likelihood of a fire starting and by slowing the development of the fire, reducing smoke and heat release, thereby giving passengers more time to escape.
In the 1950s, the average weight of a car was 1,680kg. Today, the average weight has fallen to around 1,100 Kg. In a modern car, its frame and body are built as a single unit, rather than on a frame. In addition, new, lighter materials are being used in the manufacture of a car’s external as well as internal parts.
Plastics have brought major improvements to car bodies is their shock- absorbing properties. The use of plastics in car bumpers, for example, has not only helped to reduce the physical impact of a collision, it has also reduced any ensuing financial impact from having to repair surface damage caused to the vehicle.
New composite materials are also increasingly used in areas that are not very visible yet their function is invaluable. Composites are particularly important in parts found under the bonnet or dashboard, which are close to the heat of the engine, or which transmit electrical information and can therefore generate high levels of heat.
Examples include high amperage wire and cable jacketing, electric and electronic equipment, battery cases and trays, components of the stereo system, GPS and other computer systems. Plastics used in these applications generally contain flame retardants.
Car interiors have also undergone major changes over the years, with new features being incorporated not only in the instrument panel, but for a variety of different practical and aesthetic purposes.
Flexible and semi-flexible polyurethane foams are now used extensively inside cars - in seats, headrests, armrests, roof liners, dashboards and instrument panels.
Used in insulation panels, they have also helped to improve sounds levels inside the car as you drive, reducing noise from the engine and the friction between the tyres and the road.
Cars mainly catch fire following mechanical failures, breakages, leaks and electrical faults. Fire tests have shown that a fire starting in the engine compartment of a modern car, results in flames reaching the passenger cabin in 10 to 20 minutes. Plastics which are in the engine compartment and body panels represent a very real fire hazard compared to the interior passenger cabin, and yet are not subject to any particular parformance test.
Flames spread by interior materials can result in the death of occupants in around two minutes because of a combination of toxic gases and heat, mainly due to the flammability of non flame retarded automotive plastics.
Use of Flame Retardants
Fire safety requirements for cars are lower than for public transport. However, the fact that the materials used in a car are subject to a huge amount of thermal stress on a daily basis, makes their use practically inconceivable without the application of flame retardants, ensuring that we can enjoy the highest level of fire safety possible while moving from one place to another.
Nitrogen flame retardants, including melamine phosphates and condensates, have advantages of excellent ignition resistence, for instance in printed wiring boards. When melamine is processed with formaldehyde into resins it is applied to coatings in automobiles.
Aluminum hydroxide-based flame retardants for wire and cable, electronic and electrical components, textiles and building materials
Bromine-based flame retardants for electronic enclosures, electronic and electrical components, insulation foams and textiles. DecaBDE is used in a variety of applications because of its compatability with componenet materials, and its effectiveness in providing a high degree of ignition resistence. (See BSEF.com-‘vehicle fire safety’ for full description).
Phosphorous-based flame retardants for rigid and flexible polyurethane foams, coatings, adhesives, sealants and elastomers
Inorganic based flame retardants for fire safety in wires and cables, electronic and electrical components, foams and both nautural and synthetic textiles
Chlorinated flame retardants are used in rubber, flexible plastics and some textiles and are often used in conjunction with other flame retarding additives such as antimony trioxide and aluminium hydroxide.