Toward the future of firefighter gear: Assessing fluorinated and non-fluorinated outer shells following simulated on-the-job exposures

In 2022, the occupation of firefighting was categorized as a "Group 1" carcinogen, meaning it is known to be carcinogenic to humans. The personal protective equipment that structural firefighters wear is designed to safeguard them from thermal, physical, and chemical hazards while maintaining thermo-physiological comfort. Typically, the outer layer of structural turnout gear is finished with a durable water and oil-repellent (DWR) based on per- and polyfluoroalkyl substances (PFAS) that helps limit exposure to water and hazardous liquids. The PFAS-based aqueous emulsion typically used in DWR finishes is highly persistent and can cause various health problems if absorbed into the body through ingestion, inhalation, and/or dermal absorption. In response, the U.S. Fire Service has begun using non-PFAS water repellants in firefighter turnout gear. This study aims to evaluate the performance of both traditional PFAS-based and alternative non-PFAS outer shell materials. The study involved exposing both PFAS-based and non-PFAS DWR outer shell materials in turnout composites to simulated job exposures (i.e., weathering, thermal exposure, and laundering) that artificially aged the materials. After exposures, samples were evaluated for repellency, durability, thermal protection, and surface chemistry analysis to determine any potential performance trade-offs that may exist. Non-PFAS outer shell fabrics were found not to be diesel/oil-repellent, posing a potential flammability hazard if exposed to diesel and subsequent flame on an emergency response. Both PFAS-based and non-PFAS sets of fabrics performed similarly in terms of thermal protective performance, tearing strength, and water repellency. The surface analysis suggests that both PFAS and non-PFAS chemistries can degrade and shed from fabrics during the aging process. The study indicates that firefighters should be educated and trained regarding the potential performance trade-offs, such as oil absorption and flammability concerns when transitioning to non-PFAS outer shell materials.

Characterization of Sweat Drying Performance of Single Layered Thermal Protective Fabrics Used in High-Risk Sector Workers' Clothing

Absorption and transportation of moisture from sweat are the crucial properties of the fabrics used in performance clothing. Sweat moisture is a significant factor that may cause discomfort to the wearer. The majority of the injuries and fatalities that happen to the high-risk sector workers in their line of duty may be caused by inadequate comfort provided by the protective uniform. The purpose of this study is to scientifically investigate the sweat drying performance of the different protective fabrics used in high-risk sectors' workers' clothing. Firstly, this study experimentally analyzed the sweat drying of protective fabrics with different attributes under various ambient environments and wearers' internal physiology. Secondly, this study explained the phenomena of sweat drying in protective fabric through the theory of heat and mass transfer. Sweat drying performance of the fabrics used in functional clothing mainly depends on the evaporative resistance regardless of the presence of water and oil repellent coating on the fabric surface. The drying performance increases with the increased wetted area and increased air flow. The wetted area depends on the absorption and wicking properties of the fabrics. The findings of this research will advance the field by developing knowledge on sweat drying performance of fabrics used in protective clothing; in turn, this could provide better comfort and safety to high-risk sectors' workers.

Characterizing the Tensile Strength of the Fabrics Used in Firefighters' Bunker Gear under Radiant Heat Exposure

More than 60,000 firefighters' injuries were reported by the National Fire Protection Association in the U.S. in 2019. Inadequate protection by bunker gear could be a reason for most of the injuries. Firefighters repeatedly encounter thermal hazards due to their job responsibilities. Degradation could occur on bunker gear fabric during thermal exposure. It has been found that the presence of moisture affects performance as well, which may come from wearers' sweat. Proper evaluation of the tensile strength of the fabrics used in bunker gear could provide information essential for maintenance the overall integrity of the gear. An evaluation of the tensile strength of fabrics when exposed to 10, 15, and 20 kW/m2 radiant heat flux in the presence of moisture is reported. In each fabric system, a total of sixty-four different samples were prepared for four different types of fabric and four levels of moisture which were exposed to three different radiant heat flux for five minutes. Heat flux and moisture levels have significant impact on tensile strength. The effect of moisture on tensile strength in a three-layered fabric system is higher than that for a single layer fabric. An understanding of the impact of heat and moisture on fabric strength has been achieved.

Characterization and Modeling of Thermal Protective and Thermo-Physiological Comfort Performance of Polymeric Textile Materials-A Review

In 2017, more than 60,000 firefighters and oilfield-workers injuries and fatalities occurred while they were working under various thermal hazards such as flame, radiant heat, steam, etc., or due to their significant heat stress related discomfort. The majority of these burn injuries and fatalities results from an inadequate protection and comfort provided by firefighters' and oilfield-workers' fire protective polymeric textile materials used in their workwear. Hence, both the thermal protective and thermo-physiological comfort performance of fabrics used in workwear significantly contribute to limit firefighters' and oilfield-workers' skin burns and heat stress. Considering this, previous studies have focused on characterizing and developing empirical models to predict the protective and comfort performance based on physical properties of the fabrics. However, there are still some technical knowledge gaps in the existing literature related to this. This paper critically reviewed the literature on characterization and modeling of thermal protective and thermo-physiological comfort performance of fire protective textile fabric materials. The key issues in this field have been indicated in order to provide direction for the future research and advance this scientific field for better protection and comfort of the firefighters and oilfield-workers.