Reinforced concrete is an important construction material for infrastructure in industrial facilities for oil and gas production and in refineries for processing crude oil. Due to the prevailing harsh environmental conditions, the steel reinforcement in reinforced concrete structures takes place at a rapid pace diminishing their service life. Non-metallic materials have emerged as a potential solution to combat the enormous cost of repair and rehabilitation of structural elements due to corrosion of steel reinforcement in concrete structures. The use of glass fiber reinforced polymer (GFRP) bars in reinforced concrete structures has gained popularity in recent years. This is mainly due to the development of a new generation of high-quality and high-tensile strength GFRP bars, which would ensure a maintenance-free service life of concrete structures of more than 100 years. A typical application is the reinforced concrete slabs supported on the ground and make up a large part of oil and gas installations. The effects of fire on GFRP reinforcing bars are particularly pronounced due to their plastic nature and susceptibility to fire. The polymeric matrix in which the fibers are embedded can lose its strength at high temperatures. This paper presents a finite element simulation of unloaded concrete slabs reinforced with GFRP bars subjected to fire. The effect of various types of GFRP bars, cover to the reinforcement, concrete strength, and selected fire types are presented. Once fire safety with a 2-hour fire rating is assured, ground supported slabs reinforced with GFRP bars can be used in large areas of industrial facilities.