How Do Flame Retardants Work?

Many people confuse the terms “flame retardant” and “flame resistant.”  Flame resistance is the characteristic of a substance not supporting combustion in air (not burning), while a flame retardant is a product that is added to a flammable substance to achieve the property of flame resistance.

In the world of Flame Resistant Clothing, there are two basic classes of fibers, commonly referred to as inherent and treated. Inherent fibers are typically synthetic, and are engineered to be flame resistant. Treated fabrics are typically made with natural fibers and utilize flame retardants to achieve flame resistance. Both engineering paths are equally valid ways of producing FR fabrics. Both use chemistry and are made by proven, trusted manufacturers who guarantee FR for the life of the garment.

To understand how the flame resistance of these fabrics works, it’s helpful to first understand the Fire Triangle.

As explained in the video below, there are three basic ways to extinguish a fire:

1) Remove the heat

2) Remove the fuel

3) Remove the oxygen (i.e. water removes heat, and a CO2 extinguisher removes oxygen)

There are two primary mechanisms of flame resistance among FR fabrics in common use in the USA today. We refer to these as solid phase and Modacrylic. Many fibers work in the solid phase; when the fiber temperature is raised enough, the fabric chars instead of continuously burns. By removing the fuel the fire extinguishes…no fuel, no fire.  Aramids (ie Nomex, Glenguard) and FR cottons (such as UltraSoft, MVM) work this way. Modacrylic fiber flame resistance (FRMC, DH, Tecasafe, etc) is gas phase; when heated, micro-pores in the fiber act similar to a halon fire extinguisher, releasing gases that displace the oxygen and insulate from heat, stopping the fire before it can start.

Both inherent and treated fabrics, and both solid and gas phase FR mechanisms, can produce reliable and durable FR properties and quality fabrics.  They work differently but achieve the same result; they’re equally effective in suppressing fire and protecting the wearer. Always remember, any FR garment will provide superior protection to not wearing FR at all.  But be aware – not all FR fabrics are created equal…there are plenty of poor and even counterfeit products out there.  Only buy your FRC from experienced and reliable sources.

Want to learn more? Browse our blog posts for more helpful information about FR fabrics and the answers to other frequently-asked questions. Plus, find out about FR product options and how our managed program can help you maximize compliance and protection while enhancing service and satisfaction.