Arc Flash Protection

Steel Grip has provided a line of apparel for workers placed in environments at risk of an electrical arc flash.

For Starters

We recommend you view videos on YouTube that are related to “Arc Flash” to get a good understanding of an arc flash and the severity of arc flash accidents. You will find several videos that show security cameras catching an arc flash incident.  Some videos may be disturbing to viewers so please view with caution.

Existing standards such as NFPA 70E, require the wearing of electrical arc protective apparel. Steel Grip’s compliant line of ArcGear™ suit system was developed for the growing concern over arc flash accidents. Steel Grip has invested resources into extensive fabric and fabric-layering searches. Each fabric combination is then independently tested at the Kinetrics High Current Laboratory located in Toronto, Canada. Steel Grip arc resistant apparel has been tested and certified by an independent consultant to meet the guidelines of the National Fire Protection Association (NFPA 70E), the most commonly used electric worker safety standard in the industry. As a result of these tests, Steel Grip offers a valuable line of protective apparel to meet the needs of workers in the electrical maintenance industry.

Employer Responsibilities

The employer must perform a hazard risk assessment to determine the hazard and ensure the worker wears the appropriate clothing. This can only be accomplished with fabrics, which will not continue to ignite, melt or continue to burn under the exposed hazard.

Protection requires electrical workers to wear several garment components as ONE UNIT and the clothing must fit properly such that it does not interfere with the work task as defined by NFPA 70E.

The protective level of the garments must be equal to or exceed the declared value of the hazard and shall cover potentially exposed areas as completely as possible.

An arc resistant garment should only be exposed to an arc incidence once, as one incident will weaken the arc resistant characteristics of the garments, and the protective integrity of the fabrics has been compromised.

Arc flash PPE categories 1 through 4

NFPA 70E sorts arc flash protection into four categories. Each category sets a minimum arc rating for the clothing system a worker wears, measured in calories per square centimeter (cal/cm²), and spells out the head, face, eye, hearing, hand and foot protection that goes with it. A category is not a description of the job. It is a description of how much thermal energy the clothing has to absorb before a second-degree burn becomes likely.

One naming note, because the old term still shows up on purchase orders every week. What many people call hazard risk category, or HRC, is now the arc flash PPE category. NFPA 70E made that change and removed the old category 0 at the same time. The numbers 1 through 4 did not change, so an HRC 2 garment and a PPE category 2 garment mean the same thing.

Category 1: minimum arc rating 4 cal/cm²

Selected when the estimated incident energy falls between 4 and 7.9 cal/cm². One arc-rated layer covers it: an arc-rated long-sleeve shirt with arc-rated pants, or an arc-rated coverall. With it, a worker needs an arc-rated face shield or an arc flash suit hood, a hard hat, safety glasses or goggles, hearing protection, heavy duty leather gloves and leather footwear.

Category 2: minimum arc rating 8 cal/cm²

Covers 8 through 24.9 cal/cm². The clothing is still a single arc-rated layer, shirt and pants or a coverall, but face protection steps up. Either an arc flash suit hood, or an arc-rated face shield worn together with an arc-rated balaclava. The hard hat, safety glasses, hearing protection, heavy duty leather gloves and leather footwear stay on the list.

This is where most of Steel Grip’s everyday arc-rated line sits: FR shirts, pants, coveralls, jackets and coats in WESTEX UltraSoft® and FR treated cotton whipcord. See Steel Grip’s Category 2 Rated Garments.

Category 3: minimum arc rating 25 cal/cm²

Covers 25 through 39.9 cal/cm², and this is where layering starts. An arc-rated shirt and pants or coverall goes on underneath, with an arc flash suit jacket and suit pants, or an arc flash suit coverall, over the top. The suit hood is required here, not an option. Gloves are arc-rated, or rubber insulating gloves with leather protectors when the task involves energized contact. Hard hat, safety glasses, hearing protection and leather footwear as before.

Worth knowing: the 25 cal/cm² minimum applies to the clothing system as a whole, not to each piece separately. Layers tested together usually rate higher than the individual garments do on their own, which is why Steel Grip has every fabric combination tested as a system at the Kinetrics High Current Laboratory in Toronto rather than rating each layer and adding them up.

Category 4: minimum arc rating 40 cal/cm²

The top of the table, for 40 cal/cm² and above. The build is the same shape as category 3 with a higher-rated suit: arc-rated shirt and pants or coverall, arc flash suit jacket and pants or a suit coverall, a full arc flash suit hood, arc-rated gloves or rubber insulating gloves with leather protectors, hard hat, safety glasses, hearing protection and leather footwear.

If an incident energy study comes back above 40 cal/cm², the tables stop giving an answer and the hazard changes character. At that level the pressure and sound from the blast matter alongside the heat, and the work needs an engineering review rather than a garment selection.

Steel Grip builds past the end of the table as well. The category 4 line runs from 40 cal/cm² jackets, coats and bib overalls up to 100 cal/cm² jackets, bib overalls and hoods in KEVLAR® and NOMEX® IIIA, some with an air kit. See Steel Grip’s Category 4 Rated Gear.

Steel Grip’s ArcGear Elite series is built for category 4 work at 40 cal, in the lightest weight we have ever put on a worker. Heavy 40 cal suits get taken off, and a suit in the locker protects nobody.

Why we build for category 2 and category 4

Steel Grip concentrates its arc flash line on two of the four categories, and between them they cover the whole table. The rule in NFPA 70E is that the arc rating has to meet or beat the hazard, so a category 2 garment also satisfies a category 1 task, and a 40 cal/cm² category 4 suit covers category 3. Two well-built levels do the work of four, which keeps the line simpler to stock, simpler to size, and simpler to get right on the floor. If you are not sure which of the two your task calls for, talk to a Steel Grip rep and bring the incident energy number from your study.

Picking the category is the employer’s call

NFPA 70E gives two ways to get to a number. An employer can work from the standard’s tables using the task and the equipment, or calculate the incident energy from the five parameters listed below. Either way the assessment comes first and the garment comes second. The arc rating of what the worker puts on has to meet or beat the energy the study predicts, and it has to cover the exposed area, because an arc does not stop at a hem or a cuff.

Organizational Standards in the Industry

Today in industry, there are several organizations involved with the issues of protection from electric arc hazards common to all electrical work, and you should be aware of these organizations and their function.

• NFPA 70E -End users most useful standard: Available from NFPA- National Fire Protection Association at nfpa.org
• OSHA – Occupational Safety and Health Administration at osha.gov
• ASTM – American Society for Testing Materials at astm.org
• ISEA – International Safety Equipment Association at safetyequipment.org
• NSC – National Safety Council at nsc.org
• IEEE – Institute of Electrical and Electronics Engineers, Inc. at www.ieee.org