Arc Flash Training: Flame Resistant, FR Clothing Vs. Arc Rated Clothing To Protect From Arc Flash

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In the 1950´s fibers were developed that later would be described as flame resistant. At the time the discoverer just documented the discovery and set them aside. Stephanie Kwolek, in 1965 was doing original research looking for run-free panty hose materials to supplement DuPont´s nylon business. In working with polymer type materials she discovered some stronger versions of nylon which had much higher melting temperatures and strength but they weren´t soft enough for hose so the fibers that would become Nomex and Kevlar were a disappointment at the time.

A few years later the US space program and police departments made these fibers useful in many applications because of their flame resistance and strength. In the 1950-70 different groups of chemists working for the Department of Agriculture and the military discovered better ways to flame retardant treat cotton making it viable for flame resistant clothing. These two primary technologies have improved in just the last 15 years and the proliferation of FR clothing has really begun.

In the mid 1960´s test methods were developed to show the differences between natural fibers, melting fibers and true flame resistant fibers. The most known test is popularly called "the vertical flame test". This test has many variations all over the world but most are similar. A flame is inserted below the material and the flame is allowed to burn at a certain height for a length of time and some characteristics like "afterflame", afterglow" and "char length" are measured.

At the time the test was developed it was enough. It excluded ignitable materials which continued to burn in ambient air, like cotton, polyester and nylon but also excluded some other fabrics like wool and silk but passed aramid fiber constructions in most cases and some other materials. By excluding melting fibers and ignitable fibers, this test began to be used to save lives.

Unfortunately, as is usually the case, when this test became more popular some folks figured a way around the test. "Flame Resistant" (so called) polyester and nylon came on the market. The fire fighting industry got rid of these materials because of their harm to firefighters, by adding other tests like oven shrink tests but the market was confused by labels making claims for rainwear, vests, and hoods claiming to be "flame resistant until washed or drycleaned" or flame resistant by a vertical flame test (insert ASTM D6413, Federal Test Method 191A-5901 or 5903 or NFPA 701). The first two tests are not pass/fail tests. They are "test methods" which tell you HOW to do a test but not what it means. We´ll look at each of these in turn:

ASTM D6413, Standard Test Method for Flame Resistance of Textiles (Vertical Test). This is built from the older FTMS 191A-5901 or 5903 which is no longer published. The test method has no pass fail. Many standards use it for quality control of true flame resistant fabrics used for arc flash, flash fire and fire fighting. This test is NEVER enough when used alone. Garments should not be labeled as meeting these standards, there is nothing to meet. It is like saying, my speed was measured in miles per hour without telling anyone the speed or how you were driving and asking if you were driving safely.

NFPA 701: STANDARD METHODS OF FIRE TESTS FOR FLAME PROPAGATION OF TEXTILES AND FILMS. This is specifically for "fabrics or other materials used in curtains, draperies, or other window treatments." To apply this to garments is deceptive. Yet MANY garments do have this standard in their label. This standard is supposed to be certified by a third party company like UL (Underwriter´s Laboratory) which will not certify clothing to this standard.

So what standards do you want to specify for arc flash clothing?

• ASTM F1506 for clothing. Requires vertical flame test AND ASTM F1959 Arc Test Rating

• ASTM F1891 for rainwear or coated fabrics. Requires vertical flame test AND ASTM F1959 Arc Test Rating

• ASTM F2178 for hoods, goggles, goggle balaclava systems. Requires vertical flame test AND ASTM F1959 Arc Test Rating and ANSI Z87.1 rating on the eye protection portion.

• IEC 61482-2 May also be used which is like ASTM F1506 (this standard is used primarily in the EU but requires a notified body to view the testing which is normally done in Canada at tremendous expense). Most companies and countries use the ASTM F1506 standard for this reason.

What questions should I ask of an arc rated fabric supplier?

• Check to see if they perform all ASTM required testing for the standard at the proper frequencies. Some do testing once and NEVER check again. Many don´t even have onsite testing facilities. .

• Check to see if they wash to 100 home launderings and on what frequency. (F1506 only requires 25 washings as a min. NFPA 2112 requires 100 washings. Fabrics should be flame resistant for their life to have a reasonable arc rating).

• Check to see if they ever have washed to 200 home launderings for quality check. (Not required)

• Check to see if they do industrial washes and on what frequency.

• Check to see if they do vertical flame testing and on what frequency. This is for quality control only.

• Check to see what other quality control measures are in effect for flame resistance. Especially important on treated fabrics.

• Check to see what controls they have to assure non-FR materials do not get marked or shipped as FR materials if they sell/manufacture both.

• Check their environmental controls and worker safety controls. This is critical on the ammonia chamber if they use one.

• Check other controls in the lab.

• Ask if they are ISO 9001 certified (not necessarily required but it means they have some written procedures).

• Check written procedures on testing. Check to see if they have the latest versions of the standards they test to.

• Check to see if zippers could increase the extent of the injury. Non-FR or non covered zippers could be an issue.

These questions will help to sort out a company who barely scrapes by or imports with no controls and a quality company.

Hugh Hoagland, ArcWear.com is the largest provider of arc testing of fabrics, clothing and PPE to give arc ratings. He is primary partner in e-Hazard.com which provides arc flash training & electrical safety training and arc flash calculation studies.

He may be reached at:

Hugh Hoagland

13113 Eastpoint Park Blvd.

STE E

Louisville, KY 40223

Office: 502-716-7073

Cell: 502-314-7158

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