Nowadays constructional steel has become the desired choice of structural designers because of its structural properties over other materials. However, during localized fire, structural properties of the portion of the steel degrades rapidly leads to the change in overall collapse pattern of steel members. In this article, the spread and rate of temperature rise along the length and across the depth of beam has been investigated. The experimental study was conducted on hot-rolled parallel flange steel member (NPB 300 × 150 × 36.52) of length 1.5 m. It is exposed under localized fire scenario in open environment. At the mid-point of beam, the simple and economical LPG fuel burner was adopted as the fire source for the test. It is simply supported to simulate free stress condition. The horizontal and vertical spread of temperature in the steel section are noted with temperature measuring device. The temperature variation in steel beam section shows the rapid decrease in temperature in natural environment. The maximum surface temperature was reached up to 760 °C. The temperature of specimen was recorded and further validated in ABAQUS the finite element software. The rate of increase of temperature in fire from initial to final stage and rate of decrease of temperature during cooling both were recorded. The temperature variation along the length and across the depth were found similar in numerical validation when compared with the observed ones. The observed and simulated data were found in good concurrence.