Thermal Protective Performance of Plated Weft-Knitted Structures Using Para-Aramid and FR Polyester Under Different Thermal Exposures

Abstract

Firefighters operate in environments with intense thermal hazards, necessitating clothing that offers both flame resistance and thermal comfort. This study reports the development and evaluation of double-faced plated weft-knitted fabrics using inherently flame-resistant para-aramid yarn on the outer surface and varied proportions of FR polyester and para-aramid on the inner surface. The effects of yarn composition and arrangement on thermal resistance, air permeability, and flame retardancy were systematically assessed. Thermal protective performance was evaluated under radiant, convective, and contact heat exposures in accordance with ASTM and ISO standards. The results indicated that plated structures enhanced thermal insulation due to increased fabric density and trapped still air, while the plain knit structure showed slightly better flame resistance due to its compact loop formation. Among all samples, the 70/30 para-aramid/FR polyester composition demonstrated the best balance between flame resistance and thermal comfort. This study establishes plated knitted fabrics as a promising design strategy to achieve both thermal protection and comfort, offering valuable insights for the development of firefighter suits and other heat-protective garments.