Flash Fire Performance
Comparing Flash Fire Performance
To compare the protective capabilities of Westex fabrics in relation to Nomex® IIIA, thermal instrumented manikin tests were conducted at The University of Alberta, home to one of the very few independent flash fire manikin laboratories in the world. In service since 1989, lab workers have conducted thousands of tests for hundreds of clients. During testing, a manikin is exposed to a flash fire created by propane burners, and the resultant heat rise is measured by 110 thermocouples. Heat fluxes are precisely controlled to applicable standards, and a computer collects the data and, by comparison to the Stoll curve, is able to predict the extent, severity and location of second- and third-degree body burn.
This testing reported here is, to the best of our knowledge, the largest and most comprehensive independent series ever conducted and published. All aspects of the protocol were strictly controlled to ensure maximum reliability and repeatability of results. All coveralls were commercially available, produced by a major manufacturer and sourced off-the-shelf in the same size and style. All were identically laundered and conditioned to full applicable standards prior to testing. All testing was conducted to the ASTM F1930 Standard Test Method, and all data points reflect the average of at least three replicates or more. The computer generated body burn results are individual determinations of NFPA 2112 testing and are representative of the average. This three-second exposure data along with a complete burn curve are included in the charts below.
The comparative weights offered in the marketplace for shirts and pants constructed with Westex fabrics are 7 oz/yd2 (237 g/m2) and 9 oz/yd2 (305 g/m2) compared to 41/2 oz/yd2 (153 g/m2) and 6 oz/yd2 (203 g/m2) Nomex® IIIA fabric respectively. Therefore, the manikin tests were conducted segregating categories of “Shirting” and “Pant/Coverall” weights to accurately represent the garments that are commercially available.
Complete Burn Curve
Although three seconds has been established as the time frame to analyze the performance of secondary clothing, additional exposure times in the range of 1.5 to four seconds were examined to more completely profile fabric protective performance. The charts below are highlighted up to three seconds and below 50% body burn in accordance with NFPA and CGSB standards and definitions. Within these parameters, Westex fabrics have a protective advantage over Nomex® IIIA throughout the entire range of the burn curve. The issue of relevance in comparing secondary protective clothing fabrics above these levels should be carefully considered. If your exposure potential is four to five seconds or produces body burns near to or over 50%, Westex highly recommends protective clothing systems of multiple flame resistant layers or primary protective clothing such as turnout gear.
