Garment innovation shields cleanroom workers from fire


CHARLOTTE, N.C.-Filament “NOMEX,” a patented material developed by E.I. du Pont de Nemours and Company (DuPont) for use by NASA, is being incorporated into garments made by White Knight Engineered Products to satisfy recently tightened National Fire Protection Association (NFPA) regulations concerning arc-flash risks within the cleanroom.

Filament NOMEX features properties that immediately extinguish a fabric fire caused by arc-flash by taking the oxygen away from the flame.

Arc-flash protection

Hugh Hoagland, founder of (Newburgh, Ind.)-an organization that works with companies in developing the best arc-resistant materials, and which has been testing the White Knight product-notes that, “An average of 4,000 non-disabling and 3,600 disabling electrical contact injuries in the U.S. workplace occur annually. Of these, 2,000 are arc-flash incidents, with a 2.4 percent fatality rate.”

Although rare, when arc-flash injuries do occur, they can be catastrophic. In a cleanroom environment, arc-flash injury often involves electricians or any personnel working on medium-voltage equipment.

In 1994, OSHA Standard 1910.269 (commonly known as The Apparel Standard) first required arc- and flame-resistant clothing for workers who are exposed to electrical hazards. Stating that clothing cannot increase the extent of injuries resulting from electrical accidents, the standard fostered the development of arc-resistant fabrics and garments.

Last April, however, the National Fire Protection Agency (, in its NFPA 70E, tightened those regulations to include arc-flash personal protective equipment (PPE) in work practice requirements, training for all exposed workers, arc-flash boundaries, and the classification of all live maintenance and repair work as non-routine.

Under arc-flash testing to meet stringent NFPA 70E hazard
isk Category 2, garments with DuPoint's filament NOMEX protected the t-shirt underneath, while a typical polyester garment broke open, melted and ignited the t-shirt.
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The new NFPA rulings also require that workers subject to arc-flash risk not wear garments of polyester or nylon-and approximately 95 percent of all cleanroom garments are made of polyester. In fire or arc-flash situations, when polyester ignites, its melting onto the skin can result in a third-degree burn, or worse.

Click here to enlarge image

White Knight Engineered Products is already producing arc-flash protective garments-featuring DuPont’s filament NOMEX-that it says are in compliance with NFPA 70E Category 1. Automotive manufacturers are already using the garments on a limited basis. “OSHA stated that by early 2005, companies with electricians and maintenance personnel working on live electrical equipment need to be compliant with the regulations,” explains Troy Ohmes, White Knight vice president of product development. “I think we’re the first company to test garments to prove the performance. There are test results from DuPont and the material manufacturer, but at the end of the day, before a customer will use flash-resistant garments, they want to see the actual physical testing results on a full garment.”

In addition to auto manufacturers, Ohmes says microelectronics and pharmaceutical companies may soon be using White Knight’s arc-flash resistant garments. For pharmaceutical use, however, FDA regulations involving microorganism and bacteria growth require garment sterilization procedures, which necessitates further testing to verify that filament NOMEX, when sterilized, retains its flame-resistant (FR) properties.

Hoagland maintains that, “These new garments meet [NFPA 70E] Category 1. In the event the application requires electricians dealing with 480 Volts, Category 2 protection is necessary. By adding a single layer of cotton or a flame-resistant shirt underneath the garment, the user reaches Category 2 protection and is in compliance with all of the new regulations.”

Ohmes notes, “White Knight works with end users for the specific application they need. For instance, the automotive industry to date needs Category 1 garments using the NFPA 70E standard. Our garments test to that specification, and we meet or exceed the requirement.

“Although we are not aware of a single fabric that meets both cleanroom protocol and FR protocol, there are indications that using a combination of inner suits made of FR material, and an outer suit made of FR materials will meet Category 2 requirements. Tests will be done to verify that,” Ohmes says. “We rely on the end user engineers and safety personnel to determine their specific needs, and we meet their request.”

As for future garment enhancements, Ohmes predicts that fabric static dissipation will become more important because of increased miniaturization of devices under development in contamination control environments.