What Is Firestopping?
Firestopping is a critical passive fire protection system that seals openings and penetrations in fire-rated assemblies — including walls, floors, and ceilings — to prevent the spread of fire, smoke, and toxic gases between compartments of a building.
In New York City, firestopping is required by the NYC Building Code for all fire-rated penetrations, including pipe penetrations, cable trays, HVAC ducts, conduit penetrations, and structural joints. Failure to properly firestop these openings can result in failed inspections, project delays, and — most critically — danger to building occupants.
Our Firestopping Services
Ali Firestop provides complete firestopping installation and inspection services for new construction and renovation projects across all five boroughs of New York City. Our certified installers work with UL-listed firestopping systems from leading manufacturers including 3M, Hilti, STI, and Specified Technologies Inc.
Penetration Firestopping
We seal all types of penetrations through fire-rated walls and floors, including:
- Plastic pipe penetrations (PVC, CPVC)
- Metal pipe penetrations (copper, steel, cast iron)
- Electrical conduit penetrations
- Cable and cable tray penetrations
- Combination penetrations (multiple services in one opening)
- HVAC duct penetrations
- Insulated pipe penetrations
Joint Firestopping
Construction joints, perimeter joints, and head-of-wall joints all require firestopping to maintain fire-rated assembly integrity:
- Floor-to-floor joints
- Wall-to-wall joints
- Head-of-wall / top-of-wall joints
- Curtain wall and façade joints
- Expansion joints
- Seismic joints
Firestopping Products We Install
Ali Firestop works with the full range of UL-listed firestopping products to match the right system to every application:
- Firestop Sealants & Caulks — For pipe, conduit, and cable penetrations
- Firestop Pillows & Blocks — For cable tray and conduit bundles
- Intumescent Wraps & Collars — For plastic pipe penetrations
- Firestop Boards — For large openings and complex assemblies
- Mortar & Putty Systems — For cast-in-place and retrofit applications
- Spray-Applied Systems — For large or complex joint applications
NYC Firestopping Code Compliance
New York City has some of the strictest building code requirements in the country. Ali Firestop's team is fully trained on the NYC Building Code Chapter 7 (Fire and Smoke Protection Features), NFPA 101, and ASTM E814 / UL 1479 testing standards. We ensure every installation meets the required fire resistance rating and is documented for your inspection package.
Firestopping Documentation
After project completion, Ali Firestop provides complete firestopping documentation including:
- As-built firestop drawings
- UL system numbers for all installed assemblies
- Installer certifications
- Product data sheets and SDS sheets
This documentation supports your DOB filing and third-party inspection requirements.