What is a fire stop barrier?

A fire stop barrier is a passive fire protection system used to seal openings in walls, floors and ceilings to prevent the spread of fire and smoke. Fire stop barriers contain fires, prevent the passage of smoke and toxic gases, and maintain the integrity of fire-resistance rated construction assemblies. They are a crucial part of a building’s fire protection strategy.

Why are fire stop barriers important?

Fire stop barriers play a vital role in compartmentalizing fires and slowing their spread through a building. They help prevent the passage of flames, hot gases and smoke from one area to another. This contains fires and provides building occupants with extra time to evacuate safely. Fire stop barriers also support and protect important structural elements so that a building continues to stand during a fire. Without proper fire stopping, a building’s fire-resistance ratings will be compromised.

Some key benefits of fire stop barriers include:

• Containing fires – Fire barriers prevent or slow the spread of fire from one area to another, limiting fire damage.
• Maintaining structural integrity – Fire barriers protect floors, walls and load-bearing elements so the building doesn’t collapse.
• Slowing smoke spread – Barriers reduce the passage of smoke, which is the largest threat to life in the event of a fire.
• Compartmentalization – Barriers divide the building into smaller sections to prevent fire and smoke from affecting the entire structure.
• Protecting escape routes – Fire barriers keep exit routes and stairwells free of smoke and flames.
• Preventing spread between units – In multi-family dwellings, fire barriers prevent the spread of fire between units.

What are the different types of fire stop barriers?

There are several different types of fire stop barrier systems available, each with their own advantages and applications:

Firestop mortars

Firestop mortars are cement-based products that are troweled or poured into openings. They cure into hard, fire-resistant masses. Firestop mortars adhere well to concrete and masonry.

Firestop sealants

Intumescent sealants are elastic, flexible sealants that come in caulking tubes. When exposed to fire, they swell and expand to seal off openings. Firestop sealants are good for moving joints and can adhere to plastic and metal.

Firestop pillows

Firestop pillows consist of fire-resistant fill materials enclosed in a heat-reactive wrapping. When exposed to fire, the wrapping expands and the pillows compress to seal openings. They are quick and easy to install.

Firestop collars

Firestop collars wrap around plastic pipes to seal the opening. Metal collar systems are available for large plastic pipes and cable bundles penetrating walls and floors.

Fire-ratedWraps

Fire-rated wraps, spray coats and sheet products can be wrapped or installed around penetrations. Under fire exposure, these intumescent products swell and seal openings.

Firestop blocks and plugs

Mineral fiber firestop blocks are sized to fit into openings and openings around cables and pipes. Firestop plugs are pillow-like blocks available in different sizes to fit into holes.

What are the components of a fire stop barrier system?

A complete firestop system is made up of a number of components working together:

Firestop material

The firestop material is the intumescent product that expands and seals openings when exposed to high heat and flames. This includes sealants, mortars, wraps, pillows and sheet products.

Opening

The opening can be a gap in a wall, floor, ceiling, or where a cable, pipe, duct or other item penetrates an assembly. Openings are classified by size, fire-resistance-rating, and type of penetrating item.

Backing material

Backer rods, mineral wool and other backing materials are placed into openings underneath firestop materials. They regulate depth and prevent sealants from falling through.

Assembly

The wall, floor or ceiling assembly being protected is rated based on the duration of fire resistance. Common assemblies include concrete floors, gypsum wallboard walls, and masonry block walls.

Structural members

Beams, joists, trusses and other structural building frame elements intersect to form openings that must be protected.

Accessories

Clips, collars, fasteners, wraps and tapes help secure firestop systems and support proper installation.

What materials are used in fire stop barriers?

There are several types of fire-resistant materials used to create firestops:

Intumescents

Intumescent materials are the most common firestop products. They expand many times their original volume at high temperatures, sealing off openings. Common intumescents include:

• Graphite-based sealants
• Sodium silicate-based sealants
• Hydraulic cement mortars
• Wraps and pillows

Endothermic materials

Endothermic materials release water vapor or absorb heat, cooling surfaces and resisting temperature increases. Examples include:

• Gypsum
• Calcium silicate
• Cellulose insulation
• Portland cement mortars

Ablative materials

Ablative materials sacrifice themselves during exposure to fire, forming insulating char layers. Types include:

• Mineral wool insulation
• Fiberglass batts
• Vermiculite and perlite boards

What are the requirements for fire stop barriers?

Fire stop barriers have to meet certain standards and comply with local building codes. Some key requirements include:

Fire resistance rating

Firestops must match or exceed the fire-resistance rating of the wall, floor or ceiling assembly they are installed in. Common ratings are 1, 2 and 3 hours.

Penetration seals

Openings made for the passage of cables, pipes, ducts and other penetrants must be properly sealed. Specific firestop designs must be used depending on the size and type of penetrant.

Expansion joints

Joints that allow building movement due to thermal expansion and contraction, vibration, or other forces must be protected with fire-rated joint sealants.

Load-bearing capacity

Firestops in floors and load-bearing walls must maintain their load-bearing function during fire exposure and hose stream testing.

Withstand fire tests

Firestops must be tested by an accredited laboratory and certified to withstand fire, smoke and hose streams. Standard test methods include ASTM E814 and UL 1479.

third party certification

Firestop products should be listed and classified by a third party testing agency, such as Underwriters Laboratories (UL), Intertek or FM Global.

Where are fire stop barriers required?

Firestop barriers are required in the following locations in a building:

Wall and partition intersections

Junctures where fire-resistance rated walls meet floors, ceilings, roofs, and other walls/partitions must be firestopped to seal any gaps.

Penetrations through rated assemblies

All penetrations through fire-resistance rated walls, floors, ceilings and assemblies must be protected with approved firestop systems.

Top of walls

Gaps can form at the top of drywall partition walls. These must be sealed with firestop products like mineral wool or sealant.

Structural joints

Joints in or between building structural elements like floor slabs must be firestopped to prevent internal fire spread.

Head-of-wall joints

The intersections where interior walls meet floors, ceilings or roofs must be sealed to maintain fire compartmentalization.

Expansion joints

Changes in planes and building joints where movement occurs require fire-rated joint sealants.

HVAC openings

Penetrations made for ducts, air transfer openings, dampers and other HVAC system elements need to be firestopped.

What are common fire stop barrier applications?

Some typical areas where fire stop barriers are installed include:

Cable and wire penetrations

Openings made for electrical, data and communications cable bundles running through walls, floors and ceilings.

Pipe penetrations

Holes housing plumbing, gas lines, conduit and other types of pipe passing through rated construction.

HVAC ducts

Penetrations made for heating, ventilation and air conditioning ductwork.

Insulated pipes

Sealing around pipes with insulation covering them.

Sleeve openings

Annular spaces between sleeves and items passing through them, like pipes and cables.

Construction joints

Gaps between adjacent building materials, like floor-to-wall joints.

Top of partition walls

Sealing above gypsum wallboard partitions where they abut ceilings and walls.

Curtain wall joints

Sealing perimeter joints in exterior curtain wall systems.

How are fire stop barriers installed and tested?

Proper installation is critical to ensure firestops function as designed. Installation procedures depend on the application and product used. Here are some general installation and testing guidelines:

Preparation

Opening surfaces must be clean and sound. Backing material is installed if required.

Application

Firestop material is installed per manufacturer instructions. Enough material must be applied to completely fill voids.

Finishing

Excess material is removed and penetration is sealed flush with surfaces. Joints around linear opening seals must be tooled smooth.

Curing

Cure times specified by the manufacturer must be adhered to allow materials to fully harden and stabilize before exposure to fire.

Testing

Installed firestops should be visually inspected. For critical systems, field performance tests such as positive pressure may be done.

Labeling

Labels should identify the firestop system used including manufacturer, model, installation date and inspector.

What construction requirements impact fire stops?

Firestop installations must coordinate with certain construction elements:

Building movement

Expected building shifts and joint movement must be accommodated in firestop designs.

Fire safety system connections

Piping, wiring and ducts for fire safety systems like alarms and sprinklers still require firestopping.

Inspection access

Firestops must allow access for inspection and maintenance when installed in hollow firewalls and smoke partitions.

Insulation

Void spaces in pipe and duct insulation at fire barriers need proper firestopping.

Fire-retardant coatings

Fire-retardant paints and sprays applied on penetrants should be compatible with firestops.

Vibration isolation

Equipment vibration isolators that cross fire barriers require flexible seals to allow controlled movement.

What are common fire stop barrier mistakes?

Some frequent firestop installation errors include:

No firestopping installed

Penetrations are left unsealed, allowing openings for fire and smoke spread.

Improper products used

Wrong firestop materials are specified that do not match opening conditions.

Product mixed incorrectly

Multi-component firestop products are mixed incorrectly or used past pot life.

Gaps between surfaces

Seals are not installed flush with surfaces, leaving hidden gaps.

No backing material

Backing material omitted, causing firestop to fall out or sag when exposed to fire.

Penetrant movement not accommodated

Firestops fail to allow for pipe, cable or building movement and become dislodged.

No follow-up inspection

Installed firestops are not checked for proper application before being concealed.

No firestop maintenance

Compromised or damaged firestop systems are not repaired or replaced.

How are fire stop barriers inspected and maintained?

Ongoing inspection and maintenance is essential to preserve the integrity of fire barrier systems. Recommended actions include:

Initial testing

Installed firestops should be visually examined and physically tested as required. For large projects, third-party inspectors may be used.

Labeling

Applied labels clearly identify each firestop for later inspection. Labels indicate the installer, product used and date installed.

Periodic inspection

Visual inspections should examine firestops for damage, size changes and firestop stability. Damaged or missing labels can indicate problem areas.

System testing

Functional firestop testing such as positive pressure and full-scale hose stream tests may be specified.

Repairs

Any damaged, dislodged or missing firestops must be repaired or replaced immediately using proper materials.

Modifications

All modifications to penetrations or construction must have new, equivalent firestops installed.

Documentation

Inspections and repairs should be documented. Updated drawings, system schedules and installation details should be maintained.

Conclusion

Fire stop barriers are a crucial part of passive fire protection in modern buildings. When properly installed and maintained, they can effectively contain fires, maintain structural integrity and save lives in the event of a fire. A range of firestop materials, components and systems exist to suit different opening types and penetrations. Strict compliance with building codes, manufacturer instructions and construction documents ensures fire barriers perform as intended. Ongoing inspection and repair preserves the functioning of these life-safety systems over the lifetime of a building.