This investigation examines the impact of optical properties, i.e. reflectivity, transmissivity, and absorptivity of the fabric on performance of the fire retardant fabric of various aged group firefighters. In the present computational model, radiative heat transport through a three-layer porous fabric is taken into account through reflection, emission, absorption, and transmission. In order to compare the outcomes with the experimental model and achieve great agreement, Beer’s law is utilized in the present analysis for the porous fabric. For the analysis of heat transport in living tissue, the Pennes bioheat transfer model is used. Different thermophysical and thermo-physiological parameters of the skin and blood based on the ages are used to model different age of the firefighters. To estimate the times of thermal damage with varying degrees of severity, the Henriques burn integral model is adopted. This paper demonstrates that fabric optical properties show different temperature distribution profile for different age group firefighters. The outcomes of this present investigation help to choose different optical properties of the fabric in designing the protective clothing that provides better protection to different aged firefighters against radiant heat flux.