Pipelines built in high-rise buildings, laboratories, and public facilities serve as a major transmission route forflames and toxic gases to move to other floors in the event of a fire. To prevent this problem, a “fireproof filling structure” is used to cover the outer wall of the pipe with a foam material to prevent the transfer of flame by blocking the pipe in case of a fire. This study aims to replace the expandable material used as a fireproof filling structure with an expandable graphite silicone composite and to have excellent insulation and heat insulation performance through the continuity of the effect of expandable graphite and the reinforcement of expandability and flame retardancy.