Trusted innovation

DuPont chemists and pioneers in polymer research discovered different (but related) types of aromatic polyamides in the 1960s, and they figured these inherently flameresistant fibers would change the world of firefighters’ protective clothing. These high temperature resistant fibers—known as Nomex®, optimized for textile properties such as softness, comfort and durability; and Kevlar®, optimized for strength—have been trusted to protect firefighters globally for over 50 years.

Inherent FR versus adding FR chemicals

Nomex® and Kevlar® fibers are inherently flameresistant materials that do not require the addition of flame-retardant treatments to impart or enhance flame retardancy. Therefore, brominated or halogenated FR treatments are not used as ingredients nor intentionally added in the process of making Nomex® or Kevlar® fibers.

Thermally stable up to 800°F (426°C)

Nomex® and Kevlar® fibers are some of the most thermally stable fibers available today that exhibit no melt and no drip characteristics, while also resisting flame and burn upon heat exposure. So, they don’t release off-gases – including benzene – unless temperatures reach 800°F (426°C). The composition and quantity of off-gases vary widely depending on rate of heating, presence of oxygen, and other factors. In some conditions, Nomex® and Kevlar® fibers degrade very slowly and release small quantities of a wide variety of organic compounds in the form of off-gases, similar to wood, wool, cotton, polyester and acrylic.

UV impacts mechanical strength, not thermal stability and flame resistance

The effects of UV rays on loss of mechanical strength of natural and synthetic materials, including cotton, polyester, wool, Nomex® and Kevlar®, have been well studied and reported for several decades.

The thermal stability and flame resistance of Nomex® and Kevlar® fibers, however, remain unaffected after UV ray exposure. Nomex® and Kevlar® fabrics have been used for more than 50 years without a failure in protective performance related to UV exposure in the application. In fact, Nomex® is known for its durability in use given that the lifetime of the garment is much longer than FR-treated cotton. Decomposition from UV light is different than decomposition from combustion, so benzene is not released from UV exposure.

Given the superior flame resistance when compared to other natural fibers, fabrics made with Nomex® and Kevlar® fibers should be a material of choice for the protection of firefighters at the fire station and the fireground.