Page 30 - Occupational Health & Safety, May 2019

PROTECTIVE APPAREL
and arc-rated garments on the market today, so there is no practical difference between FRC and street clothing when it comes to heat stress. However, as noted above, impermeable garments and multi- ple-layer garments DO impede radiation and evaporation, and thus can be a con- tributor to heat stress.
The primary causes of heat stress are poor hydration, lack of shade, and lack of rest breaks, not clothing. Workers who ar- rive well hydrated and rehydrate during rest breaks of appropriate duration and fre- quency, taken in the shade, are extremely unlikely to suffer heat illness. In fact, the
new OSHA awareness campaign on heat stress prevention is “Water, Rest, Shade.” The hydration is of course linked to sweat- ing. The rest breaks are to allow the body to shed metabolic heat created by physi- cal work, and the shade is both cooler and eliminates the sun as a radiant heat load. When clothing is addressed, it is far down the list of issues, and NIOSH and OSHA advice is:
■ Wear light-colored, loose-fitting, breathable clothing
https://www.cdc.gov/niosh/topics/heat- stress/
Notice it’s light color, not light weight,
that actually makes a difference. Dark col- ors can be hotter than light colors by sev- eral degrees. A worker can feel comfortable and yet at be at risk for heat stress, or un- comfortable but not at risk, because fabric type and weight (FR or not, short sleeve or long, etc.) are either found to be unrelated, or inconsequential in comparison to the primary factors of hydration, rest breaks, and shade.
The significant majority of single-layer flame-resistant and arc-rated garments commonly sold in the USA today are now virtually indistinguishable from their non-FR counterparts in design, style, fit, weight, moisture management (wicking), breathability, etc. They pose no more risk of heat stress than whatever non-FR garment would otherwise be worn at work. In fact, as a category, single-layer FR garments may pose LESS risk of heat stress because they are long sleeve, while many non-FR choices are short sleeve.
The idea that FRC causes heat stress originated more than 30 years ago when we had essentially two choices in FR fab- ric; one didn’t wick sweat while the other didn’t breathe well, and neither would ever be mistaken for standard clothing. This misconception persists today out of lack of information. It would be a terrible shame to put American workers at risk of catastrophic or fatal burn injury because of an outdated myth about PPE and heat stress.
Scott Margolin is Vice President of Techni- cal Sales for Tyndale Company. He brings more than 30 years of experience in arc-rat- ed/flame resistant (FR) clothing to his role at Tyndale. He has conducted more than 1,800 arc flashes and nearly 4,000 flash fires at labs in the USA, Canada, Europe, South America, and Asia. He travels and presents globally to share his research and learnings on flash fire, arc flash, and combustible dust hazards to improve worker safety and the fibers, fabrics, and garments used to pro- tect against these hazards. He has authored dozens of technical articles and white pa- pers, given more than a thousand presenta- tions all over the world, and led many web- casts on these subjects. Significantly, he has served as SME (Subject Matter Expert) to OSHA, NFPA, NJATC, ASSP, NECA, and others on a wide variety of FR, PPE, and thermal hazard issues.
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