FR Layering for Comfort and Compliance

While monitoring and auditing multiple potential layered outfits does impose extra effort on a safety team, it benefits the organization's workforce and bottom line.

• By Brian Schmidt
• Aug 14, 2007

WARM summer weather and changing fall and spring weather conditions can cause problems for safety professionals, because workers in arc-flash-hazard workplaces forgo protective workwear and accessories in favor of relief from the heat. That’s why a comprehensive flame-resistant compliance program needs to educate workers on the value of layering appropriate FR clothing and accessories to provide maximum personal comfort, while still maintaining appropriate aggregate protective ratings for the entire clothing collection.

All too often, workers and even compliance professionals look at, for instance, NFPA 70E protective ratings in terms of one protective garment, even though the standard clearly suggests layering garments to achieve required Hazard/Risk Category (HRC) and Arc Thermal Protective Value (ATPV) ratings. In cold-weather work environments, insulated outerwear can regularly achieve an NFPA 70E HRC rating of 4 with an ATPV of more than 50, providing compliance as long as underwear, bottoms, and shirts from nonmelting flammable natural materials are worn.

However, work environments in which heavy outerwear creates significant issues with worker discomfort need to be assessed by safety professionals not only in terms of compliance, but also in terms of comfort. As reliable and tested FR fabric technology has evolved, FR workwear manufacturers have been able to come up with more options for FR workwear that offer increased comfort while maintaining or even increasing ATPV ratings. FR-treated fabrics and other new technologies are decreasing reliance on inherently FR artificial fabrics or heavy woven natural-fiber fabrics that sacrifice breathability and comfort in favor of FR compliance.

Some of the more popular new options for FR workwear that work well as part of a group of layers include FR-treated knits, such as sweatshirts, mock turtlenecks, and Henley-collar shirts. Knit garments are inherently more flexible and provide less movement resistance to workers than clothes made from woven fabrics, such as canvas, denim, and twills. Knits are inherently more breathable than woven fabrics, providing increased comfort in warmer workplaces. This additional comfort is the reason that many workers prefer knit garments, such as sweatshirts and T-shirts, over woven garments for workwear when flame resistance isn't part of the purchase decision.

Useful Combinations
At a minimum, NFPA 70E allows ATPV values for each individual layer to be added together when layering FR garments to reach the required ATPV rating for each hazard/risk category:

(In actual testing, layered FR garments regularly achieve higher ATPV ratings than the simple sum of their individual ratings thanks to air gaps and other factors. But because actually quantifying this behavior requires testing and certification of each specific set of layers, it's best to simply be conservative and go with the basic sum-of-the-layers ATPV rating when evaluating layered FR workwear.)

One potential example of layered FR is a worker in a pair of canvas dungarees (ATPV 15.7) and an FR twill shirt (ATPV 8.6). Together with appropriate underwear, footwear, and gloves, this outfit meets HRC 2 specifications. With the addition of canvas bib overalls (ATPV 16.0) and a midweight sweatshirt (ATPV 21.8), this worker now surpasses HRC 3 requirements. Another worker could start with denim jeans (ATPV 25.0) and a mock turtleneck (10.9) at HRC 2 and add the sweatshirt alone to achieve HRC 3 compliance.
Another versatile clothing option for worker comfort and standards compliance is the vest, which can be paired with FR sleeves to provide up to HRC 4 compliance in hazard areas but can be worn unzipped in non-hazard environments for increased comfort. In regions and seasons with rapidly changing weather conditions, vests provide significant flexibility under coats, over sweatshirts, or over shirts to combine protection with comfort throughout the day.

The Importance of Worker Education
FR compliance may not be a full-time requirement for workers. As a result, providing them with options for "on-demand" FR protection is a good option for increasing compliance. Of course, even workers who spend only a small portion of the work day in an FR hazard environment need to prepare with nonmelting flammable natural-material underwear such as 100 percent cotton T-shirts, FR-compliant footwear (for environments at HRC 2 and above), and other standard requirements. However, a simple unlined coverall can provide, for instance, HRC 2 compliance as needed over non-FR 100 percent cotton clothing.

Promoting FR layering to a workforce does require safety professionals to educate their workers on the standards requirements for all layers to achieve compliance and to regularly monitor all of the layers in workers' FR workwear outfits. This ensures appropriate care is being taken to match protection with hazards throughout the work day. Workers who are not properly educated often will mix and match inappropriate non-FR layers in such a way as to create a hazard situation, such as wearing a nylon jacket over an FR shirt and assuming the FR layer will protect them in a hazard situation. (In all cases, the outermost layer must be FR-compliant.)

While monitoring and auditing multiple potential layered outfits does impose extra effort on a safety team, the benefits to an organization's workforce and its bottom line through increased compliance outweigh the extra time and effort invested in education and monitoring.

This article originally appeared in the August 2007 issue of Occupational Health & Safety.