The final touch: A look at four flame-resistant fabric finishes
As flame-resistant (FR) protection has become commoditized, fabric and garment manufacturers have focused on traditional textile attributes to differentiate their products. After fabrics are dyed, a multitude of finishes can be applied to enhance the wearer’s experience, including moisture wicking, antimicrobial/odor control, stain release and bug repellent. Each finish has varying degrees of effectiveness and wear life. Below we explore these fabric finishes in more detail and what each means for FR clothing and its protection.
Wicking fabric is designed to pull sweat and moisture away from skin toward the outside of fabric in order to evaporate quicker. This process is often referred to as “moisture management.”
Wicking is accomplished by a combination of the fiber used in the fabric and the weave or knit used in the manufacturing process.
Cellulosic or natural fibers like wool are hydrophilic, meaning the fabric is able to absorb sweat and moisture. On the other hand, synthetics like polyester are hydrophobic, meaning the fabric doesn’t like moisture or sweat. Hydrophobic fibers can be treated with hydrophilic finishes to compensate for the lower moisture and water absorption capacity of these fibers.1
Wicking and FR clothing: Wicking fabric is typically lightweight, soft and breathable. FLF’s FRMC® fabric, and FR fabrics made by Polartec® and TECGEN®, offer moisture wicking technology and excellent breathability. These features provide all day comfort in hot or cold temperatures by wicking moisture away from the skin while allowing air to pass through the garment to cool the wearer.
Antimicrobial/odor control fabric has properties that combat odor and/or resist hazardous microorganisms. Antimicrobial fabric resists mold, mildew and bacterial growth and also typically has odor control or release properties that make them durable and long lasting.2
Antimicrobial Properties and FR clothing: Antimicrobial fabrics can be formed by incorporating antimicrobial fibers into the FR yarn or by treating the pre-formed FR yarn or fabric with antimicrobial agents during the dyeing or finishing process.
1. One method includes antimicrobial fibers that are formed into yarn that is subsequently woven or knitted into a fabric. Pre-formed fibers may be coated with antimicrobial additives to create antimicrobial fibers.3
2. Alternatively, antimicrobial additives can be added during the fiber forming process so that the antimicrobial additives are at least partially embedded in the final antimicrobial fibers which are then formed into yarn. The antimicrobial fibers can be mixed with the FR fibers and the fiber mixture formed into flame resistant, antimicrobial yarns that are subsequently woven or knitted to form the desired flame resistant, antimicrobial fabric.3
3. A final application applies antimicrobial agents during the dyeing or finishing processes to preformed yarn or preformed fabric to impart antimicrobial properties.
Stain release fabrics allow stains that have been absorbed into a garment to wash out. This is different from stain repellent fabrics that resist water and oil-based substances. With stain repellent fabrics, water will bead up on the surface of the fabric whereas with stain release fabrics, stains temporarily soak into the fabric.
Stain release fabrics:
- Allow stains to wash out easily
- Retain natural absorbency
- Provide long-lasting protection
- Look better longer
- Retain natural softness
- Allow fabric to breathe naturally4
The release technology works by drawing the water, surfactant and detergent through the fabric during the wash cycle to release and ultimately removing the stain.4 The hydrophilic “water-loving” finish of the stain release draws in the detergent and water, allowing stains to wash out more easily.
Stain Release and FR Clothing: Some fabric manufacturers combine the benefit of stain repellent qualities with stain release features. Fabrics stay cleaner and are more durable, better looking and longer lasting than other types of fabrics.4
Bug repellent is used for the treatment of clothing to provide a barrier of protection against mosquitoes and other types of biting and disease-transmitting insects. Bug repellent is a fabric finish that can be applied by the wearer, and doesn’t have to be completed in the manufacturing process. The most common bug repellent that is safe for application to FR fabric is Permethrin, which has been proven in tests not to damage or negatively affect the protective properties of FR clothing.
Permethrin is a specially designed formula that bonds with fabric to provide protection for six weeks or longer, and is non-flammable. Like other pesticides, Permethrin is a neurotoxin that is regulated by the EPA, so following safety precautions and usage instructions is very important. Permethrin does not repel insects but works as a contact insecticide, causing nervous system toxicity that leads to death or knockdown of an insect.5
Bug Repellent and FR Clothing: It is important to use an insect repellant like Permethrin that has been arc tested and shown to have no adverse effects on the protective properties of the FR clothing. In lab testing, insect repellent with DEET was applied to an FR shirt per the repellent label and directions. The results of the test indicated DEET propagates the flame and can contribute to body burn in the event of an electric arc or flash fire. As a result, DEET should not be used on FR clothing.
Important Note: Permethrin is recommended for use on FR clothing only and not for use on skin.
FR fabric finishes supplement protection while enhancing the wearer experience by ensuring comfort, maximizing professional appearance and garment wear life, and/or mitigating challenges in the work environment.
Critically, since end user comfort is a key driver of compliance with both employer safety policy and industry standards, FR fabric finishes can positively impact FR garment acceptance and use. Correspondingly, FR fabric finishes ultimately help ensure workers are properly protected when arc flash or flash fire hazards are present in the work environment.
5 Fire Tech Tips; DEET Mosquito Repellant Reduces the Flame Resistance of Firefighters’ Nomex Clothing; Leslie Anderson, Program Leader & Tony Petrilli, Project Leader, United States Department of Agriculture & Forest Service, July 2005