Code-Required Fire Protection
Firestopping Services in Denver, Colorado
Every commercial building in Colorado requires firestopping. When pipes, cables, and ducts penetrate fire-rated walls and floors, those openings must be sealed with tested and listed firestop systems to maintain the building's fire compartmentalization. Andrex Insulation has been installing firestopping systems across the Front Range for over 38 years — documented, inspected, and code-compliant from day one.
What Is Firestopping and Why Does Your Building Need It?
Firestopping is the practice of sealing openings and penetrations in fire-rated walls, floors, and ceiling assemblies to restore and maintain their original fire-resistance rating. In a commercial building, fire-rated assemblies are designed to compartmentalize fire and smoke, preventing them from spreading between floors and rooms. But every time a pipe, cable, conduit, or duct passes through one of these fire-rated barriers, it creates an opening that compromises the assembly's integrity.
Without proper firestopping, fire and smoke can travel through these penetrations in minutes, bypassing the fire-rated barriers that the building depends on for occupant safety and structural protection. A two-hour fire-rated wall with an unsealed pipe penetration effectively has a zero-hour rating at that location. The fire barrier is only as strong as its weakest point.
The International Building Code (IBC), which Colorado has adopted, requires firestopping of all penetrations in fire-rated assemblies under Section 714. This is not optional — it is a code requirement on every commercial building project. Building inspectors will check firestopping installations before issuing a certificate of occupancy, and improperly installed or missing firestopping will result in failed inspections and project delays.
Firestopping is also commonly referred to as firestop, fire barrier, penetration seals, or fire safing. Regardless of what it is called on your project, the requirement is the same: every penetration through a fire-rated assembly must be sealed with a tested and listed firestop system that matches the specific conditions of that penetration.
Types of Firestopping Systems We Install
Firestopping is not a one-size-fits-all solution. Different conditions require different systems, and each system must be selected from a tested and listed design that matches the specific penetration type, size, and assembly rating. We install all three primary categories of firestop systems.
Through-Penetration Firestop Systems
The most common type of firestopping. These systems seal the annular space around pipes, cables, conduits, cable trays, and ducts that pass through fire-rated walls and floor/ceiling assemblies. Each penetration type and size requires a specific UL-listed system design that has been tested to demonstrate it will maintain the assembly's fire rating. A metallic pipe penetrating a two-hour concrete floor, for example, requires a different firestop system than a bundle of data cables penetrating a one-hour gypsum wall.
Joint Systems
Construction joints occur where fire-rated walls meet floors, where floor slabs meet exterior curtain walls, and at expansion joints in long buildings. These joints are designed to accommodate building movement, but they also create gaps in the fire barrier that must be sealed. Joint firestop systems use flexible, fire-resistant materials that maintain their seal even as the building expands and contracts. Perimeter fire barrier systems at curtain walls are among the most critical, as they prevent fire from spreading vertically along the building exterior.
Opening Protective Systems
Fire-rated assemblies sometimes include openings for access panels, duct penetrations with fire dampers, and other functional requirements. Opening protective systems ensure these openings maintain the fire rating of the surrounding assembly. This includes fire dampers that close automatically when they detect heat, access doors rated to match the surrounding wall or ceiling assembly, and specialized systems for HVAC and mechanical openings in fire-rated barriers.
Firestopping Materials We Use
We stock and install a full range of firestopping materials from industry-leading manufacturers. The specific material used for each installation is determined by the UL-listed system design selected for that penetration condition.
Intumescent Sealants & Caulk
Expands when exposed to heat, sealing gaps around penetrations in fire-rated assemblies. Used for small annular spaces around pipes, conduits, and cables.
Mineral Wool / Safing Insulation
Non-combustible insulation packed into annular spaces before applying sealant. Provides the backing and thermal barrier in many UL-listed firestop systems.
Firestop Pillows
Removable, re-enterable firestop solution for cable trays and large openings where future access is needed. Pillows interlock to fill openings and expand in fire conditions.
Wrap Strips
Intumescent wraps installed around plastic pipe penetrations. When exposed to fire, the wrap expands inward to crush and seal the melting pipe, preventing fire and smoke passage.
Cast-in-Place Devices
Pre-manufactured firestop sleeves cast into concrete floor slabs during the pour. They provide a ready-made firestop solution for planned pipe and conduit penetrations.
Putty Pads
Intumescent pads applied to the backs of electrical outlet boxes and switch boxes in fire-rated walls. They seal the box opening to maintain the wall's fire rating.
Spray-Applied Firestop Materials
Applied to large areas such as floor-to-curtain-wall joints and multi-penetration openings. Provides a seamless firestop barrier across wide or irregular gaps.
Why Firestopping Matters for General Contractors
If you are a general contractor managing a commercial construction project in Colorado, firestopping directly affects your schedule, your inspections, and your liability. Here is what you need to know.
Inspectors Check Firestopping Before CO
Building inspectors in Denver and throughout Colorado check firestopping installations before issuing a certificate of occupancy. If your firestopping is incomplete, improperly installed, or undocumented, the inspector will fail that portion of the inspection. Failed firestop inspections are one of the most common reasons for delayed certificates of occupancy on commercial projects.
Failed Inspections Delay Your Schedule
When a firestop inspection fails, it triggers a chain of delays: the firestopping contractor has to come back to the site, the correction work has to be completed, and the inspector has to be rescheduled for a re-inspection. That can easily add one to two weeks to your project timeline. By working with a contractor who self-inspects before calling for third-party review, you eliminate the most common cause of these delays.
Documentation That Is Inspection-Ready
Andrex documents every firestopping installation with photographs, UL system numbers, and material specifications. When the inspector asks for documentation, it is already organized and ready. We do not make you chase paperwork at closeout. Our documentation package is built as we install, so it is complete and accurate when you need it.
UL-Listed Systems Matched to Each Condition
We use only firestop systems that have been tested and listed by UL (Underwriters Laboratories) for the specific penetration type, assembly rating, and construction materials on your project. Using the wrong firestop system — even if the materials look correct — can result in a failed inspection because the installation does not match a listed design. Improperly installed firestopping is also a significant liability issue for building owners and general contractors.
Our Firestopping Process
From drawing review to closeout documentation, our seven-step process ensures every firestopping installation is code-compliant, properly documented, and ready for inspection the first time.
Drawing Review
We review your fire-rated assembly drawings and specifications to identify every wall, floor, and ceiling assembly that requires firestopping.
Penetration Identification
Our team walks the site to catalog all penetrations requiring firestopping, including pipes, conduits, cable trays, ducts, and construction joints.
System Selection
We select the appropriate UL-listed firestop system for each penetration type, matching the system to the specific assembly rating and penetrant size.
Professional Installation
Trained crews install each firestop system according to the manufacturer's listed design, ensuring proper depth, coverage, and material application.
Photo Documentation
Every firestop location is photographed before and after installation, creating a visual record tied to the building's fire-rated assembly drawings.
Self-Inspection
Before calling for third-party review, we self-inspect every installation to verify it matches the listed system design. This eliminates re-work and schedule delays.
Closeout Package
We provide a complete documentation package including installation photos, UL system numbers, material certifications, and inspection records for your project files.
Why General Contractors Choose Andrex for Firestopping
We have been installing firestopping systems on commercial projects across Colorado since 1988. Firestopping is not a side service for us — it is a core part of the fire protection work we do on every project.
38 Years of Experience
We have been in the building protection business since 1988. Our crews have installed firestopping on thousands of commercial projects across Colorado, from tenant improvements to high-rise construction.
Every Installation Documented
We photograph every firestop location and maintain a complete record of system numbers, materials, and locations. Your closeout package is built as we install, not assembled after the fact.
Self-Inspect Before Third-Party Review
We check our own work against the listed system design before calling for inspection. This means fewer failed inspections, fewer callbacks, and a smoother schedule for your project.
BBB A+ Rated, EMR Below 1.0
Our BBB A+ rating reflects consistent quality and customer satisfaction. Our Experience Modification Rate below 1.0 demonstrates a strong safety record on the job site.
Complete Fire Protection Picture
Because we also install spray-applied fireproofing (SFRM) and intumescent coatings (IFRM), we understand how firestopping fits into the complete fire protection scope. One subcontractor for all your fire protection needs.
Fast Bid Turnaround
Send us your plans and specifications, and our estimating team will provide a competitive bid with fast turnaround. We know schedules are tight and pricing needs to be accurate.
Firestopping Service Area: Colorado & Wyoming
Andrex Insulation provides firestopping services throughout the Colorado Front Range and beyond. Our primary service area includes Denver, Colorado Springs, Boulder, Fort Collins, Aurora, Lakewood, Arvada, Westminster, Thornton, and Centennial. We also regularly take on firestopping projects in Wyoming, including Cheyenne, Casper, and Laramie.
For larger commercial projects outside our primary service area, we are happy to discuss travel and logistics. Our crews are experienced with multi-week projects across the region and can mobilize quickly to meet your schedule requirements.
Frequently Asked Questions About Firestopping
What is firestopping?
Firestopping is the process of sealing openings and penetrations in fire-rated walls and floor/ceiling assemblies to restore the original fire-resistance rating. When pipes, cables, conduits, or ducts pass through a fire-rated barrier, they create openings that allow fire and smoke to spread between compartments. Firestop systems seal these openings using tested and listed materials such as intumescent sealants, mineral wool, firestop pillows, and wrap strips.
Is firestopping required by building code in Colorado?
Yes. The International Building Code (IBC), which Colorado has adopted, requires firestopping of all penetrations, joints, and openings in fire-rated assemblies. Section 714 of the IBC specifically addresses penetration firestopping requirements. Building inspectors will check firestopping installations before issuing a certificate of occupancy, and failed inspections will delay your project schedule.
What types of firestop systems do you install?
We install three primary categories of firestop systems: through-penetration firestop systems for pipes, cables, conduits, and ducts passing through fire-rated walls and floors; joint systems for construction joints between walls and floors and curtain wall perimeter joints; and opening protective systems including fire dampers and access panels in fire-rated assemblies. Each installation uses a specific UL-listed design matched to the exact penetration type and assembly rating.
How do you document firestop installations?
Every firestop installation is photographed and documented with the UL system number, the specific materials used, and the location within the building. We maintain a complete documentation package that includes installation photos, system identification, and material certifications. This package is provided at project closeout and makes third-party inspections straightforward.
Can you firestop existing buildings during renovation?
Yes. Renovation and tenant improvement projects frequently require firestopping of new penetrations made in existing fire-rated assemblies. We work with building owners, property managers, and general contractors to identify penetrations that need firestopping in existing structures, select appropriate UL-listed systems, and install them to meet current code requirements.
Do you coordinate with fire protection engineers?
Yes. On complex projects, we work directly with fire protection engineers and architects to review fire-rated assembly drawings, identify all penetrations requiring firestopping, and select the appropriate UL-listed systems for each condition. We also coordinate with other trades on-site to ensure penetrations are firestopped before they become inaccessible behind finished walls or ceilings.
What areas do you serve for firestopping?
We provide firestopping services throughout Colorado and Wyoming, including Denver, Colorado Springs, Boulder, Fort Collins, Aurora, and the entire Front Range corridor. We regularly travel for larger commercial projects across the region.
Ready to Get a Bid on Firestopping?
Send us your plans and specifications. Our estimating team will review your fire-rated assemblies, identify all penetrations requiring firestopping, and provide a competitive bid with fast turnaround.
Our Other Building Protection Services
Spray-Applied Fireproofing (SFRM)
Cementitious fireproofing applied to structural steel for 1-4 hour fire ratings. Products include BlazeShield II and Monokote.
Learn MoreIntumescent Fireproofing (IFRM)
Thin-film coatings that provide fire protection with a clean, architectural finish on exposed structural steel.
Learn MoreSpray-Applied Insulation
Thermal and acoustic insulation using Monoglass and K-13 spray-applied fiber systems for commercial buildings.
Learn More