This paper presents the behavior of six reinforced columns (RC) under two fire exposure conditions. To understand the role of stirrup spacing, the volumetric ratio of stirrups and all other parameters kept the same for all the set of columns. The volumetric ratio of stirrups in the columns is 0.5% with 6, 8, and 10 mm dia. stirrups at 75, 130, and 200 mm spacing, respectively. Experimental tests were conducted on six reinforced concrete columns of cross-section 230 × 230 mm2 and length 860 mm. The experimental investigations confirmed that the columns with 6 and 8 mm dia. stirrups show high load carrying capacity than the columns with 10 mm dia. stirrups, this trend is true when columns subjected to 120 and 180 min duration of heating under ISO fire curve. In case of columns subjected to 120 min ISO fire curve, columns with 8 mm dia. stirrups at 130 mm spacing carried approximately 10% higher load carrying capacity when compared to columns with 10 mm dia. stirrups at 200 mm spacing. Whereas columns heated for 180 min fire duration, columns with 6 mm and 8 mm dia. stirrups at 75 mm and 130 mm spacing, respectively, carried approximately 8% higher load carrying capacity compared to columns with 10 mm dia. stirrups at 200 mm spacing. © 2020, Springer Nature Singapore Pte Ltd.