Page 44 - Occupational Health & Safety, July/August 2019

PROTECTIVE APPAREL
Rainwear Performance Considerations for Electric Utility Workers: Innovative Fabrics Bring Protection and Comfort
Utility workers need garments that not only provide protection from arc hazards and foul weather, but also ensure that they can be seen by others, reducing the risk of visibility-related workplace accidents. BY MARK MILLER
Every day, utility workers put their lives on the line. Operational conditions can pose seri- ous threats. Heights are steep. Voltage is high. Weather is volatile. The risk of an electrical
arc incident is ever looming.
The job requires skill, dexterity, and patience; in-
depth knowledge of electricity, wire repair, and safety protocol; and clothing that keeps workers safe, dry, and protected in all conditions. The ideal garments for electric utility workers provide durable protec- tion and exceptional comfort while meeting flame- resistant (FR) and arc-resistant (AR) requirements. For optimally performing rainwear, utility workers and safety managers should select garments that are waterproof, windproof, breathable, and highly visible. Yet traditional protective rainwear is often stiff, heavy, and not breathable. Protection comes at the sacrifice of comfort or vice versa.
Specialists in the science of comfort and protec- tion are making life better for electric utility workers through new fabric technologies. These materials pro- vide not only optimum protection, but also maximum range of motion, minimal bulk, and improved com- fort. As a result, workers can stay on the job longer, maintain focus, and enjoy freedom of movement and breathable comfort in all weather.
Protection from Arc Flash
Electric arcs pose serious safety hazards for electric utility workers. In an arc flash incident, temperatures can reach 35,000° Fahrenheit, with exposure to elec- trical explosion or discharge resulting in burn injury or death. According to the National Fire Protection Association (NFPA), every year, more than 2,000 peo- ple are admitted to burn centers with severe arc flash burns. Proper protective clothing is key to minimiz- ing and possibly preventing burns.
The American Society for Testing and Materials (ASTM) has developed a performance standard for Arc- and Flame-Resistant Rainwear, ASTM F1891-19. Passing this standard ensures that utility worker gear meets minimum thermal and physical performance when exposed to a laboratory-simulated electric arc. This standard also sets minimum requirements for wa- terproofness on the garment fabric and sewn seams.
FR/AR clothing is rated by a hazard risk category (HRC) and an arc rating based on the lower of the arc
thermal protection value (ATPV), or the break-open threshold energy (Ebt). HRC levels range from HRC 1, low risk, to HRC 4, high risk and requiring FR cloth- ing. The HRC is used to determine the arc rating a garment requires to complete a given job task. The higher the arc rating value, the greater the protection.
For maximum worker protection, look for fabrics that offer arc flash protection for the life of the gar- ment, including after wash cycles, and that meet or exceed the standard’s requirements.
For thermal protection, ASTM F1891 sets a mini- mum of 5 calories per centimeter squared (cal/cm2) arc rating (HRC 1) after three wash cycles. In practice, safety managers may require a higher arc rating for the personal protective equipment they specify for their utility workers. This standard also does not have a breathability requirement, which can compromise worker comfort. FR rainwear meeting this standard will be identified on the product label.
Rainwear made with fabrics that meet perfor- mance standards and deliver comfort should be a top consideration in any purchase. ASTM F1891 sets minimum requirements for arc flash protection but does not address other important aspects of rainwear, such as breathability. Newer FR/AR fabric technolo- gies can better address protection and comfort, reduc- ing the need for trade-offs.
Protection from Foul Weather
In severe weather, high-performance arc-rated rain- wear must meet three criteria: 1) waterproof, 2) wind- proof, and 3) breathable.
What is waterproof?
Rainwear must be truly waterproof in inclement weather, engineered to repel nonstop precipitation. Various tests are used to measure waterproofness, in- cluding ASTM D-3393, which is included in ASTM F1891. Fabrics with such coatings as polyurethane or
HRC
Required minimum arc rating, cal/cm2
1
4
2
8
3
25
4
40
Source: NFPA
38 Occupational Health & Safety | JULY/AUGUST 2019
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