DuPont Uses Thermo-Man to Highlight Value of Flame-Resistant Garments
Oct 1, 2001 12:00 PM
A FIERY demonstration by DuPont Advanced Fibers Systems provided a graphic reminder of the importance of wearing flame resistant clothing. With the right clothing, burn injuries can be reduced significantly in the event of a flash fire at a loading rack or other location.
The demonstration was conducted during Fire-Rescue International 2001 in New Orleans, Louisiana, August 24-27. DuPont used the press conference to promote its heavily instrumented Thermo-Man demonstration unit and to highlight the thermal protection properties of its Nomex garments.
The Thermo-Man demonstration unit provides an opportunity for a live audience to observe up-close some of the most advanced flash-fire testing technology that is available for protective apparel. Data collected from the demonstration unit generates readily understandable predicted burn injury rates.
The Thermo-Man instrumented manikin is the most advanced life-size thermal-burn-injury evaluation system in the world today, according to DuPont officials. It features a 6-ft, 1-inch high-temperature composite manikin with 122 sensors that measure heat transfer through a garment. Amount, degree, and location of predicted burn injury can be calculated from the sensor data.
In addition to the demonstration unit, DuPont has a laboratory version that is used for more accurate studies. The Thermo-Man laboratory in Richmond, Virginia, performs a wide array of tests in controllable, reproducible exposure conditions applicable to a wide variety of products and industries.
Flash Fire Impact
While less precise, the Thermo-Man demonstration unit leaves an audience with a clear understanding of what happens in a flash fire. “With this unit, we're able to show that the most severe burns are caused by ignited clothing, not by the original flash fire,” said Thomas E Neal, Neal Associates Ltd. “Clothed areas can be burned more severely than exposed skin.”
During the first demonstration at the fire fighters conference, the Thermo-Man manikin was wearing typical polyester work clothes — shirt and pants. The four-second flash fire caused the clothing to ignite and melt. In fact, the flames continued and remnants of the polyester dripped from the manikin for several minutes after the flash fire. Instruments showed that second- and third-degree burns occurred over 92% of the manikin.
“Ignited clothing can cause extensive third-degree burns,” Neal said. “Most flame exposures are more than sufficient to ignite flammable clothing or cause burn injury to exposed skin. Clothing can reach 600°F.”
Burn injuries are a serious concern, first of all, because they can be fatal. Survival from a burn accident depends on age, health, exposure intensity and time, and the area of the body burned.
For instance, someone 20 to 29 years old has at least a 90% chance of survival with burns that don't exceed 25% of the body. At 75% body burn, survivability drops to around 60%. The older the person, the lower the chance of survival regardless of total area seriously burned.
“Burns over 20% to 25% of the body are most survivable,” Neal said. “However, more than half of those with burns over 75% will die of their injuries.”
Those that live can face lengthy, painful recoveries. The cost can exceed $1 million for a single burn case. Treatment can last years and require extensive skin grafting and rehabilitation. The burn victim may never be able to return to work.
Flame-retardant garments offer some of the best protection from a flash fire. In a second flash fire demonstration at the fire fighters conference, the manikin was wearing flame-resistant shirt and pants. The clothing changed color but did not burn.
“Flame-resistant clothing will not ignite and melt or drip,” Neal said. “It resists breakdown and maintains a thermal barrier to isolate the worker from the thermal exposure. Air is trapped between the worker and the barrier to provide additional insulation from the exposure.
“The result is reduced burn injury and increased survivability. The instruments recorded a 25% body burn in the second demonstration. Just 9% were third-degree burns.”
Neal pointed out that protective clothing selection should be based on the probable worst-case exposure in the workplace. Flame-resistant workwear should provide a good functional fit for protection and comfort.
Loose fitting clothing provides additional thermal protection due to increased air spaces. Sleeves, shirt, and outerwear should be fully buttoned. Workers should wear appropriate head, hand, and foot coverings.
Protective clothing must be kept free of contaminants. Flammable oils, greases, and chemicals reduce the effectiveness of the garments.
Beneath the flame-resistant clothing, workers should wear non-melting undergarments made of cotton, wool, silk, or rayon. Underwear made of these materials will increase thermal insulation and protection. Meltable undergarments can increase burn severity due to melt adhesion to the skin.
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