Nomex is a synthetic aromatic polyamide polymer manufactured both as a textile and in sheet form. It was first developed in the early 1960s by the DuPont chemical company as material to make fireproof suits for racing drivers and pilots.
After a series of fatal motor-sport crashes involving several prominent race car drivers in 1964, DuPont scientists set their minds to developing a material that could withstand the extreme temperatures generated by a racing collision.
Today, Nomex garments are still used by racing drivers, as well as firefighters, military pilots and tank crews, NASA astronauts and industrial workers the world over. Even Batman’s suit is made of it.
This is because Nomex is tough stuff:
- It can indefinitely withstand temperatures in excess of 200°C
- It is unaffected by most solvents and resists attack by acid and
- In densified form, Nomex can withstand electrical stresses of 18-40kV/mm
- It is impervious to attack from insects, fungi or mould
- In its solid form its tensile strength remains unaffected at -200°
- It does not deteriorate when exposed to radiation (although it will not protect the wearer)
Unlike traditional fabrics that have been treated with a flame retardant chemical (such as Proban,) the chemical makeup of Nomex means the material itself is inherently fire resistant. This means that the fire resistant properties of the garment can be expected to last its entire lifetime whereas flame retardant treatments eventually wash out of fabrics to which they are applied.
Nomex does not melt or drip, merely chars when exposed to high temperatures for prolonged periods, it will never get hot enough to combust but fabric scorching or charring occurs at around 350C in air and the fabric fully carbonises at approximately 427°C.
The testing DuPont undertake is rigorous:
“After exposing fibres of NOMEX to dry air at 500°F(260°C) for 1,000 hours and then returning them to room temperature, the breaking strength and toughness of NOMEX is approximately 65% of that exhibited before exposure.”
Nomex is still the industry leader in flame retardant and protective fabrics after 40 years, although the price point is higher than some of its competitors. Still, if its good enough for Batman…