Firestop

Firestop is a passive fire protection measure designed to restore and maintain the fire-resistance of walls, floors, and other assemblies after penetrations or openings are created for utilities such as pipes, cables, and ducts. By sealing gaps around penetrations, firestop systems help prevent the spread of flames, heat, and smoke between compartments, preserving the intended fire rating of the construction.

Firestop materials and devices include intumescent sealants and mortars, mineral wool or cementitious backfill, and specialty components such as collars, wraps, pillows, and blocks. These products are used as part of a listed firestop system, which is tested as an assembly to demonstrate its performance in a given opening or joint and is labeled by the manufacturer for specific substrates and penetrants.

Standards and testing for firestop systems vary by region but commonly involve formal laboratory fire testing and listing. In the United States, tests such as UL 1479 and ASTM E814 are used to evaluate penetration firestops, and compliance with applicable building codes (for example, the IBC and IFC) is required. European and other markets use regional test standards and product listings appropriate to their codes.

Installation requires adherence to the specific listed system for each penetration. Installers must follow manufacturer instructions, prepare substrates, use the correct materials, ensure proper fill without voids, and accommodate movement in joints. Maintenance and periodic inspection are often required, especially after renovations, to ensure firestop integrity remains intact.

Firestop is distinct from fireproofing, which protects structural elements themselves rather than sealing penetrations.