Two new studies from the University of Alberta demonstrate how to make the production, maintenance, and wearing of firefighting gear safer.
Researcher Saiful Hoque’s study of fabrics and fibers shows how to make firefighters’ clothing safer. Image Credit: Naimur Rahman
One study demonstrated that certain fibers in protective gear deteriorate when subjected to warm water, highlighting potential degradation during real-life firefighting scenarios and routine laundering. The other study investigated the water utilized in fiber production, uncovering several harmful dye compounds that seep from the fabrics, potentially compromising their protective attributes.
The findings of both studies show vulnerabilities and potential ways to improve the materials currently being used in firefighters’ clothing, and for maintenance.
Saiful Hoque, Graduate Research Fellow, Faculty of Agricultural, Life & Environmental Sciences, University of Alberta
Wear and Care
The fibers were submerged in both purified neutral pH and acidic water, with temperatures ranging from 40 °C to 90 °C, for up to 1,200 hours, after which they were examined for physical, chemical, and other types of damage. The hydrothermal aging results indicated that fabric blends containing para-aramid/polybenzimidazole, or PBI, experienced a 68 % faster reduction in strength when exposed to moisture compared to similar fire-protective fabrics that did not include PBI.
Firefighters’ outer jackets and trousers are often made from high-performance fiber blends that include PBI due to the fiber's flexibility and resistance to extreme temperatures.
However, a previous study led by Hoque revealed that the manufacturing process of PBI fibers involves sulfuric acid, leaving residual sulfur in the fibers. This sulfur residue increases the fabric's susceptibility to moisture, potentially causing the protective garments to degrade prematurely.
Hoque notes that these findings could assist manufacturers of high-performance fibers and protective fabrics in refining their production methods to enhance the durability and effectiveness of their products.
Hoque added, “PBI fibers are still good to use, but it’s critical that producers develop ways to remove the residual sulfur from those fibers.”
Laundering of firefighting gear also needs to be changed up, by washing clothing with PBI fibres separately, Hoque advises.
“This prevents the risk of damage to neighboring fabrics that don’t contain PBI fibers and wouldn’t otherwise experience degradation in warm water,” Hoque further stated.
Additionally, according to Hoque, the same study demonstrated for the first time that meta-aramid fibers, another type frequently seen in protective apparel, exhibited “remarkable resistance” to heat and water stress, even when exposed to acidic water. For instance, after 1,200 hours at 90 degrees Celsius in water, a fabric sample with 93 % meta-aramid fibers lost only 4 % of its tensile strength.
Thanks to this research, the efficiency of high-performance fibers in withstanding heat and water is now better understood. This enables producers to make “more informed decisions in the selection and design of materials for more durable gear for firefighters,” Hoque added.
It also opens up the possibility of employing meta-aramid fibers in other products that are regularly exposed to water, such as maritime safety equipment, he noted.
According to Hoque, a thorough examination of the various yarns and fibers offers an enhanced understanding of their durability.
He stated, “We can now offer manufacturers suggestions for optimum fiber blends and fabric configurations that strike a better balance between long-term protection and comfort.”
Responsible Manufacture
Hoque’s second study created a mechanism for assessing the water used in the trials, which fabric manufacturers might utilize to make their manufacturing processes more ecologically friendly.
The investigation found three dye-related substances known to be hazardous to the environment, “particularly when they leach into water systems.”
Despite being inappropriate to use, “it is possible that some manufacturers still employ these compounds, so this information can help them prevent environmental pollution and adopt more sustainable practices.”
Hoque collaborated with a diverse team on these studies, including ALES associate professor Patricia Dolez, professor Hyun-Joong Chung, and master’s student Ankit Saha from the Faculty of Engineering. The team also featured professor James Harynuk, research associate Paulina de la Mata, and PhD candidate Trevor Johnson from the Faculty of Science.
The two studies were supported through funding from the Natural Sciences and Engineering Research Council of Canada, Mitacs, and Davey Textile Solutions Inc. In-kind contributions came from Innotex and DuPont. Additional support for the research was provided by the University of Alberta's Protective Clothing and Equipment Research Facility, the University of Alberta nanoFAB, and the University of Alberta Department of Chemistry.
Journal References:
Hoque, M. S., et. al. (2024) Analysis of Hydrothermal Aging Water of Fire-Protective Fabrics Using GC × GC–TOFMS and FID. Fibers & Polymers. doi:10.1007/s12221-024-00540-5
Hoque, M. S., et. al. (2024) Hydrothermal aging behavior of high-performance polymeric fibers: Mechanical performance at the yarn scale and chemical analysis. Journal of Polymer Science. doi:10.1002/pol.20230950