High Visibility and Arc Ratings for Flame Resistance
Written by Hugh Hoagland on . Posted in Worksite Safety.
Two standards are needed to specify clothing for high visibility and flame resistance. Most companies in the U.S. choose ANSI 107 (for high visibility) and ASTM F1506 (for flame-resistance clothing complying with NFPA 70E or OSHA 1910.269). Citing both means you will have clothing (shirts and vests primarily) that are highly visible and arc- and flash-fire resistant. However, the flame-resistance side is often a weakness because of manufacturers or marketers who push “flame-resistant” standards that are misleading or outright deceptive.
On February 28, 2008, Worksafe Victoria, governmental manager of the Australia province of Victoria’s workplace safety system, issued an alert to inform “employers and workers of the danger of synthetic high-visibility clothing catching fire when flames or ignition sources are present.” The alert was prompted after a worker was using a demolition saw to cut a steel upright when sparks ignited the stomach area of his high-visibility shirt. He suffered burns to his stomach area and to both hands after trying to pat out the flames with his bare hands. In this incident, two hazards were present – mobile [work zone] and ignition sources. The high-visibility clothing was worn to make workers more visible, but it “introduced a secondary hazard – flammability.”
The work safety department of Victoria further recognized, “this is a common hazard of high-visibility clothing made from synthetic fibers such as polyester and nylon. They can catch fire or melt. Oxy-cutting, arc welding, grinding and demo-saw cutting are examples of common hot work activities that cause sparks that can ignite these types of materials. Workers should not wear synthetic clothing when performing hot work.”
Using the Right Standards
Electric arcs and flash fire possibilities also call for the right clothing. Some of these synthetic materials have claimed to be “flame resistant” for years, but this is not according to any applicable standard. Many cite NFPA 701 (a curtain standard); or Federal Test Method Standard (FTMS) 191A.6903 (6901), which has no pass/fail criteria and hasn’t been published since the 1980s; ASTM D6413, which has no pass/fail criteria and is basically the FTMS standard above; and the latest misuse is of ASTM F1358 Standard Test Method for Effects of Flame Impingement on Materials Used in Protective Clothing Not Designated Primarily for Flame Resistance, which has a title that speaks for itself.
These are not standards for proving something can take flames and not hurt workers. ASTM D6413 is one of many “small scale” tests used in proper standards, but the right standards use full scale exposures for determining if a material works and use the small scale tests to assure quality only.
While high-visibility clothing made from flammable synthetic materials is common and fine for a signal flagger or construction worker to wear while doing concrete work, true flash fire tested and arc-rated, high-visibility clothing is actually available when it is necessary to wear protective clothing.
Governmental safety organizations rightly expect “employers to provide the highest level of protection that is reasonably practicable for all the hazards that are present. Where mobile (work zone) and flammability hazards are both present, employers must manage both hazards.” The U.S. and Canada mandate this for all roadway work zones, which affect utilities of all sorts. If arc or flame hazards exist when the roadway work zone gear is worn, the worker should be protected from both.
Most melting fabrics are flammable in arc and flash fires even if they have some sort of “flame-resistant or retardant” treatment. Safety departments must determine if the “flame resistance” advertised is adequate for the exposure.
ASTM International and IEC/ISO have set standards for flame resistance testing for electric arc and flash fire, and these include an actual flash fire or arc test. For ASTM, the standards are ASTM F1506 for clothing and ASTM F1891 for rainwear. The most applicable flash fire standard today is from the National Fire Protection Association (NFPA 2112), but these standards have no requirements for visibility so companies use other standards for those requirements.
High-visibility clothing in the U.S. must meet ANSI 107-2004; in Canada it must meet CSA Z96; in EU it must meet EN 471. Australia and New Zealand have AS/NZS 4602:1999, which is similar to EN 471, but these standards do not have flame-resistance requirements. In order to meet the requirements of most workplaces, which have dual hazards, one should choose one of each type of standard in specifying materials, vests, shirts or other high-visibility wear.
The other limitation is that only a few materials combine high visibility with flash-fire and electric-arc protection:
Modacrylic: Unlike “FR-treated” acrylic [a hazard in most applications] modacrylic doesn’t melt. It is the base of most of the new U.S. military fabrics along with Lenzing FR and Twaron. Modacrylic is the winner because it easily holds the fluorescent dyes for these garments and doesn’t melt in arc or flash fire. Modacrylic is also one of the key fibers in DuPont’s new Protera fabric and DriFire undergarments used in arc, military and flash-fire applications. Many companies sell vests from modacrylic, but they should have certification of meeting an arc flash rating (like ASTM F1506 or F1891) or a flash-fire rating (like NFPA 2112) and a high-visibility rating (like ANSI 107 or CSA Z462). Without meeting both types of standards a material is suspect. Performance Textiles, SSM, Gehring Textiles and others sell compliant fabrics that can be used for ANSI 107, ASTM F1506 compliance.
FR-Treated Cotton with fluorescent finish: Though arc-rated materials with “bright colors” meet the Canadian CSA standard for flash-fire applications, there are several experimental “printed” materials just reaching the market that are arc rated and can meet the ANSI 107 visibility requirements. Pyrosafe by Antex is a new material that meets ANSI 107 and has an arc rating but is an arc-rated FR cotton.
Retro-reflective materials: These materials that reflect light back are required in low light traffic applications, but they should be flame resistant/arc rated or be proven not to be a hazard. 3M and Reflexite both have arc-rated options.
Lack of worker visibility is a real hazard in the workplace. Being struck by mobile equipment and mobile equipment fatalities are number one in the workplace. As highly visible work gear has become available and in many workplaces mandatory, the need for multiple-hazard, high-visibility gear has become more apparent. The market has standards which can be cited to assure your workers are protected and in an affordable but compliant manner.
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