Abstract: The thermal protective performance of 13 heat and flame resistant fabrics made with aromatic polyamide(aramid),polybenzimidazole(PBI),Kermel,PSA,flame-resistant cotton,and blends of Kermel with flame retardant rayon fibers was evaluated in laboratory tests using flame exposures to convective and radiant heat sources.Factors such as heat flux,stillness air layer,fiber type,fabric thickness,weight of fabric,and air permeability were discussed.Experimental results revealed that fiber type,heat flux were important variables.With the weight and thickness increasing,TPPwas increasing.However,air permeability was negative forTPP.