A fire stop is a passive fire protection system designed to prevent the spread of fire, smoke, and heat between different areas of a building. It typically consists of materials that seal openings and joints in fire-rated walls, floors, and ceilings. By blocking these pathways, fire stops help contain a fire to its origin, allowing more time for occupants to evacuate and for firefighters to respond. Common materials used for fire stops include fire-resistant caulk, intumescent sealants, and fire stop pillows. These materials expand when exposed to heat, filling gaps and creating a barrier. Proper installation of fire stops is crucial for maintaining the integrity of fire-rated assemblies and ensuring overall building safety.