Firestops

Firestops are passive fire protection systems designed to seal openings and joints in fire-resistance rated walls, floors, and ceilings to prevent the spread of fire, smoke, and hot gases through penetrations such as pipes, cables, and ducts. By maintaining or restoring the fire resistance of a rated assembly, firestops help contain fires within compartments and provide time for evacuation and suppression.

Firestop products encompass a range of materials and devices, including intumescent sealants and mastics, putties and gels, mineral wool or mineral fiber insulation, rigid blocks and boards, and mechanical devices such as firestop collars or sleeves around penetrations. Modular or composite systems may combine several components to fit irregular openings. The appropriate choice depends on the penetrant type, size, clearance, and the required fire rating.

Installation and performance are critical to effectiveness. Firestops must be installed following the manufacturer's instructions and the specific listed system for the assembly. Installation should be performed by trained technicians to ensure proper sealing, alignment, and coverage; improper installation can create gaps or reduce the rating. Firestops must accommodate movement, vibration, and thermal expansion when applicable and be compatible with surrounding materials.

Standards and testing: Firestop systems are evaluated in standardized fire-resistance tests (such as those conducted under UL 1479 / ASTM E814) and are listed or labeled by accredited testing laboratories (for example, UL or FM Global). The stated rating (for example, 1-hour or 2-hour) reflects the duration the assembly remains fire-resistant under test conditions.

Maintenance and renovation: After alterations, penetrations, or renovations, re-evaluation or re-rating of the affected assembly may be required. Regular inspections help verify continued effectiveness. Firestops are a component of broader passive fire protection and are not a substitute for properly designed and installed rated assemblies.