Firefighters don't run off into a burning building or barrel out into a brush fire wearing the closest pair of sweats. Their special outfits are created out of a special combination of materials that resists burning, melting and scorching while allowing them to stay flexible enough to do their jobs. Although it's unknown if firefighters ever wore the closest pair of sweats, it is known that this special combination of materials didn't exist until a large chemical company invented them in the second half of the 20th century.
The main components in most firefighter clothing are Kevlar and Nomex, two fabrics created by chemical giant DuPont in the 1960s. Many protective clothing companies use a mix of the two fabrics, whereas other focus more on the flame-resistant Nomex. Nomex is the fabric that gives the protective gear its resistance to heat and flame while Kevlar adds flexibility, comfort and allows the fabric to breathe.
Kevlar, a copyrighted brand name created by DuPont, was created in 1965 by scientists specialising in crystalline polymer solutions. Nomex, another DuPont copyrighted creation, came into play in 1967 and is hailed as a flame-resistant, melt-proof fibre.
Kevlar is lightweight, durable, flexible and used on everything from vehicle interiors to athletic wear for Olympic athletes. Kevlar has also been used in vehicles, houses and assisting with spacecraft landing on Mars, although it is not clear how the fabric achieved these specific functions. Nomex is used for wire insulation, on structures as support and in a variety of protective clothing worn in the military, by industrial workers and on the fire truck.
A large enough variety of firefighter clothing made of Kevlar and Nomex exists to fill a closet several times over. Clothing made from the materials includes trousers, brush trousers, shirts, full-body jumpsuits and coats. Boots are often constructed from fire-retardant leather and stitched with Kevlar thread or heavy duty treated rubber. Gloves can be made of a soft leather or hide but will also be stitched with Kevlar thread and sometimes include a cuff made from Nomex. Helmets are made of a thick, heat-resistant plastic and often include Kevlar or Nomex ear flaps for added protection.
In addition to being lightweight and flexible, Kevlar increases a garment's durability, strength and helps it resist rips and scrapes. Kevlar is five times stronger the steel as long as it's compared to steel the same amount of steel of equal weight. Nomex works wonders because it carbonises and thickens when it get intensely hot. Thus the Nomex creates a barrier between the firefighter and the fire, protecting the skin from burns.