It doesn’t matter if you’re a firefighter or cooking at home. You want to be confident that when you’re dealing with heat and flame that you’re wearing a material that can self-extinguish.
Flame-resistant (FR) fabrics are designed to resist burning and withstand heat but just because your glove is flame-resistant, doesn’t mean that it’s fireproof.
This blog looks at factors you should consider when choosing FR material.
Treated Versus Inherent Flame-Resistant Material:
The difference between treated and inherent flame resistance is simple.
Inherent Flame Resistance is Built In
Like the name suggests, inherently flame-resistant fibers are materials that have flame resistance built into their chemical structure. These are brand names like Rhovyl® or Nomex®.
Treated Flame Resistance Happens in a Lab
Materials like cotton can be chemically altered to become flame resistant. A brand name example of this is Proban®.
According to DuPont™:
“During a fire, chemically dependent fabrics rely on a chemical reaction to extinguish the flame. This reaction is triggered by the heat of the fire and the amount of time the fabric is exposed to the fire.”
The Effects of Washing Flame-Resistant PPE:
Inherent Flame Resistance:
Inherent flame-resistant properties can’t be washed out and won’t be damaged through general washing.
The flame-resistant properties of the material will also not degrade over time.
Be sure to follow the garment’s laundering instructions to extend the lifespan of your PPE.
Treated Flame Resistance:
Chlorine bleach, hydrogen peroxide with hard water, or exposure to oxidizing chemicals may damage fire-resistant garments. The chemical potency of FR-fabrics may diminish over time with repeated washes.
Limiting Oxygen Index:
The limiting oxygen index (LOI) determines the smallest amount of oxygen that will support combustion of a polymer. It’s measured by passing oxygen and nitrogen over a burning sample and reducing the oxygen level until reaching a critical level.
This is a relevant indicator for flame retardancy because it highlights how much oxygen is needed to keep a test material aflame. The higher the index, the more flame retardant the fiber is.
Inherent FR Material:
Rhovyl® is the brand name for polyvinyl chloride.
This naturally non-flammable fiber protects users from heat and flame and is one of the most cost-friendly options.
Due to a low thermal conductivity and a low heat capacity, Rhovyl® absorbs and transfers the least amount of heat.
Rhovyl® has the highest LOI of any textile fiber. This means that Rhovyl® limits flame spread not only when the fire starts but also in the early stages of fire.
Other flame-resistant materials typically become less effective during early stages of fire.
Another benefit of Rhovyl® is that when burning the fibers don’t produce any incandescent droplets that could burn the skin or spread the flame to other materials.
Nomex® is the brand name for meta-aramid, the cousin of para-aramids like Kevlar® — both of which are manufactured by DuPont™.
Para-aramids (like Kevlar®) are inherently flame-resistant but these fabrics are used primarily for its high tensile strength for cut resistance.
Meta-aramids have a lower tensile strength but offer good thermal, chemical and radiation resistance. Though Nomex® will not melt or spread the flame, it does not have as high an LOI as Rhoyvl®.
Treated FR Material:
Proban® takes fibers like cotton and uses a chemical treatment to create a textile with flame-resistant properties.
Proban® fabrics don’t smolder or melt and flame doesn’t spread outside the charred area. While chemically-treated flame-resistant materials may be more cost effective, repeated washes can reduce their FR properties.
When selecting flame-resistant material for repeated use, the best option is to look for a fabric that has FR properties built into its structure. If selecting inherently flame-resistant material, consider how it tested on the limited oxygen index before looking at cost savings.
Need FR gloves for your workplace?
Click the sample button below to get your FREE pair of Sure Knit™ Flame Resistant Rhovyl® Gloves