Page 45 - Occupational Health & Safety, July/August 2019

polyvinyl chloride may offer initial waterproofness but can lose their effectiveness over time. And fabrics with just a water-repellent finish can be completely ineffective in keeping water out when the garment experiences any pressure, such as from taking a knee or leaning against an object. Look for garments with an integrated, du- rable, waterproof, breathable membrane.
Ideally, the fabric will have low water pick-up, meaning that the garments won’t get heavy in the rain from water saturating the shell fabric. Less water pick-up also means faster dry-out, reducing the cold, clammy feeling that comes from using damp gear.
Garments should be rigorously tested for waterproofness under extreme weather conditions. Standards do not capture all potential conditions, so testing beyond the standards, including style qualifi- cation and simulated or real-life storm testing, is important.
What is windproof?
Arc-rated rainwear must be totally windproof to protect work- ers in cool and windy weather conditions. Wind chill can make the air outside feel more than 10 degrees cooler than it really is! The most effective fabrics block the wind while also allowing the body’s moisture vapor to escape.
Windproofness is determined by measuring air permeability through the fabric and associating this measurement with the re- sulting heat loss at different wind speeds. Fabrics with an air per- meability rate of 1.0 cubic feet per minute (cfm) or less are consid- ered truly windproof.
What is breathable?
Effective arc-rated rainwear needs not only to protect against liquid penetration, but also to be highly breathable. In one hour, our bodies can release 1⁄4 cup of perspiration at rest, more than 4.5 cups during vigorous activity, and almost 17 cups during extremely heavy exertion. If this moisture vapor can’t escape from the utility worker’s rainwear to allow for evaporative cooling, the worker will quickly become wet and uncomfortable, losing focus and risking injury. Look for fabrics that let sweat evaporate through the fabric membrane, while also blocking wind and water, to help keep the wearer comfortable.
Fabric breathability can be evaluated by the Ret test. This widely
THERE TO PROTECT by TEXTECH IN A FLASH
Introducing CarbonX Arc
Weight: 5.0 oz/yd2
Professionals and enthusiasts across numerous industries have come to rely on CarbonX® to provide superior protection in extreme conditions. CarbonX Arc is no exception. At 5.0 oz, CarbonX Arc is one
of the lightest-weight NFPA 70E Category 2 protective fabrics on the market. It is constructed of a CarbonX fabrics, CarbonX required by ASTM F1506. CarbonX Arc combines this extraordinary level of protection with maximum
XX Arc XContact us at 207.756.8606 and www.carbonx.com.
Untitled-1 1
7/2/19 11:35 AM
www.ohsonline.com
JULY/AUGUST 2019 | Occupational Health & Safety 39
Circle 29 on card.
W. L. GORE & ASSOCIATES