Abstract This paper presents experimental studies on the fire behavior of fiber reinforced polymer (FRP) composite laminates and unloaded cellular FRP components with internal liquid cooling. The experiments were conducted to verify the objective of liquid cooling for improving the fire resistance of FRP composite structures for construction applications. Observations show that the pultruded E-glass/polyester composites are vulnerable under ISO-834 fire conditions, and the fire-resistance effect of charring of the resin is insignificant. Liquid cooling is demonstrated to be an efficient way to improve fire-resistance of FRP cellular construction components. With liquid cooling, cellular FRP profiles can satisfy the code requiring 90 min fire resistant design time for building constructions. The cooling effect improves with increased liquid flow rates. In practice, low to moderate flowing rates (0.2–1.0 cm/s) will be sufficient for improving fire resistance of FRP structures and, at the same time, can serve to heat and cool a building.