Studies on the influence of process parameters on the protection performance of the outer layer of fire-protective clothing

Abstract

During an operation, the turnout gear for firefighters must meet two important requirements: thermal protection and comfort. As comfort and protection are inherently incompatible, it is impossible to satisfy both. As part of this study, the outer layer of multilayered turnout suits was analyzed under the influence of various factors such as intensity of heat flux, pick density, and air space between the fabric and the sensor. Choosing Nomex IIIA was based on its inherent properties that are conductive to thermal protection. To simulate the environment encountered during firefighting, benchtop experiments were designed. A system equation for the prediction of the protection time (t-protection) was developed based on a three-factor and three-level Box–Behnken model. The predicted values of t-protection obtained for all the experimental blocks in the design space were subjected to ANOVA analysis which showed that the system equation, as well as the coefficients of linear interactive and square terms, is significant, so the system equation can be efficiently used for predicting t-protection. The validity of the system equation was verified by using the same experimental blocks and estimating t-protection using the Stoll criteria. The accuracy of the system equation was checked by comparing t-protection and t*-protection which revealed a linear relationship with a high correlation coefficient (R2 = 0.975). To analyze the effects of the independent variables on protection time, 3D surface response curves were created. The nature of the surfaces was critically analyzed by developing regression equations for the contours and the diagonals.

Analysis of the Outer Layer Performance of Fire Protective Clothing

“…Surface Response Models (SRM) including Central Composite Design, Box Behnken Design and other methods evaluate linear, quadratic, and cubic data [38]. Ba-Abbad et al reported Box Behnken Design reduced the number of tests, saving time and money without impacting output quality [39].…”

Protective and Comfort Performance of Fire Protective Clothing

“…Within the field of occupational safety, especially in settings with thermal dangers, the design and effectiveness of fire protection clothing (FPC) are of utmost significance in protecting the welfare of those who are exposed to these risks. The outer layer of FPC functions as the main barrier against radiant heat, flame, and other dangerous materials, playing a crucial role in guaranteeing the wearer's safety [1]. The ongoing advancement of textile technology has generated a greater interest in maximizing the efficiency https://doi.org/10.31881/TLR.2024.066 of FPC.…”

“…A study was commenced to examine the plain weave structure using Nomex IIIA fibre where the Box-Behnken experimental method was employed to forecast the radiative thermal protection performance. A greater distance between the heat source and the cloth resulted in a better level of protection, and the model showed a substantial impact [15]. Plain, ripstop and twill architectures were used for another research to https://doi.org/10.31881/TLR.2024.066 determine the effective thermal ageing of FPC on mechanical performance.…”

“…Rare focus was devoted to the pick density of different weave structures by the researchers to assess thermal protection capabilities. R. Rathour et al examined the protection against heat and comfort performance of meta-aramid fabrics with various weave structures (plain, twill, sateen, honeycomb) and thread densities (two and three-plied) [15,17]. These four structures are not only distinct from one other, but they also exhibit a certain degree of predictability, indicating the presence of differences.…”

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

“…[6][7][8][9][10][11] The structural turnout ensemble worn by firefighters principally consists of three layers; outer shell, moisture barrier, and thermal liner, all of which are standardized by the National Fire Protection Association (NFPA) 1971: Standard on Protective Ensembles for Structural Fire Fighting and Proximity Fire Fighting. 12 The outer shell protects the wearer from thermal and physical hazards and is typically made of inherently flame-resistant fibers i.e., polybenzimidazole (PBI), meta-aramid, para-aramid, or poly-benzoxazole (PBO), with a ripstop, plain-weave, or twill fabric structures. 2,13,14 The outer shell is usually finished with a PFAS-based durable water and oil-repellent (DWR) or alternative non-PFAS water repellent finish to protect the wearers against hazardous liquids (Figure 1).…”