Owens Corning

When Life Safety Matters Most

One of the most complex and least understood areas pertaining to where fire can spread is at the perimeter of a building, making perimeter fire containment systems critical. An understanding of fire containment is important for the safety of occupants in the building, as well as the safety of emergency responders. Even when lives are spared, fire losses can be devastating. A proper perimeter fire containment system helps save buildings, intellectual property and business capital, along with allowing the people inside the structure more time to escape in the event of a fire.

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Enclosure SolutionsSpecifying for Life Safety

Owens Corning® Thermafiber® is committed to providing solutions that help the commercial building professional confidently design, specify, and install durable systems for commercial structures. Access all necessary documents, guide specifications, CAD files, and detailed product data sheets with a single click.

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Technical Consulting Team

Thermafiber Insolutions®

Thermafiber Insolutions® provides all-phase consultation and technical expertise. Technical services include engineering judgements, accurate and detailed CAD drawings, and a knowledge base of building codes and fire-rated insulation application techniques focused on perimeter fire containment solutions without sacrificing design.

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Perimeter Joint and Curtain Wall Assemblies

A critical topic of interest today in the AEC community is the understanding of proper curtain wall design techniques using high-performance system solutions to provide fire safety in multi-story curtain wall applications.  

Paths of Fire Propagation

  • Fire can spread through the interior joint between the rated floor assembly and unrated exterior wall. Fire can also propagate via the exterior of the building, an effect known as “leap frog”.
  • Leap frog fire spread occurs when the fire breaks out the vision glass on the floor where the fire originated, allowing flame and hot gases to escape to the outside of the building.
  • The fire then breaks out the vision glass on the floor above, and enters into the interior space. Fire can also spread via the interior cavity of an unprotected or improperly protected spandrel area when a perimeter fire containment system is not in place.  



Animation of fire propagating through an unprotected perimeter joint.

Unprotected Perimeter Joint

This illustration shows how fire can spread vertically when a curtain wall is left unprotected.


Animation of fire not propagating through a perimeter joint as it is protected.

Protected Exterior Wall and Perimeter Joint

Here, both the curtain wall spandrel and interior joint are protected by a mineral wool perimeter fire containment system, preventing the spread of fire


SIX CRITICAL COMPONENTS OF A TESTED AND LISTED PERIMETER FIRE CONTAINMENT SYSTEM

For a perimeter fire containment assembly to work properly and meet code requirements, certain critical design elements must be included: 

A fire containment system featuring six critical components

1. Thermafiber® FireSpan® mineral wool insulation at the specified thickness

  • Mineral wool insulation is mechanically attached within the spandrel opening.
  • Mineral wool is the only fire-rated insulation material that has been tested and proven to protect spandrel wall components (5 hours of fire exposure at temperatures over 2,000°F).
  • Mineral wool insulation must be tested and approved in UL® or Intertek® designs per ASTM E2307.

2. Mechanical attachment of insulation to the spandrel with Thermafiber® Impasse® Hanger

  • During a fire, there is a lot of turbulence, movement, and gravitational pull.
  • Without mechanical fasteners, the insulation will become dislodged, allowing fire to propagate to the next floor.
  • See specific UL® or Intertek® listings for specific FireSpan® products to be used as well as fasteners and spacings.

3. Backer/reinforcement member

  • A backer bar reinforcement member, which can be a lightweight steel angle, T-bar or hat channel, is placed behind the curtain wall insulation in line with the floor slab. See UL® or Intertek® listings for details.
  • These support members. are required to be a minimum of 20 ga. galvanized steel (unless the listing calls for a specific gauge).
  • The backer/reinforcement member keeps the curtain wall insulation from bowing due to the compression-fit of the safing insulation.
  • Reference the tested and listed system for specifics on providing the proper reinforcement at the safing line.

4. Compression-fit Thermafiber® Safing mineral wool insulation

  • This forms a tight seal in the interior void—the area that is required by code to be sealed so that flame and hot gases cannot pass through the joint.
  • It is important to install Thermafiber® Safing insulation at the proper depth and compression to keep a tight seal.
  • Tested and listed assemblies provide information on the amount of compression and in which direction the Thermafiber® Safing insulation is to be installed. 
Thermafiber® Safing Perimeter Fire Containment Install Instructions and Calculator PDF | 608.01 KB


5. Thermafiber® FireSpan® Mullion Covers to protect exposed vertical mullions

  • Aluminum will melt at 1,220°F, or as early as 9 minutes into a fire.
  • If left exposed, the aluminum framework will melt and cause an early failure in the system.
  • Protect vertical mullions with Thermafiber® FireSpan® 90 Mullion Cover insulation.
  • Thermafiber® Mullion Cover Insulation is attached with either Thermafiber® Spiral Anchors every 12" o.c. or with patented Thermafiber® Mullion Cover Brackets.

6. Smoke barrier

  • Smoke inhalation is responsible for the majority of fire-related deaths.
  • To impede the passage of smoke, apply an approved smoke barrier over the top of the safing mineral wool insulation.
  • See specific UL® or Intertek® listings for approved smoke sealants.
Person using a lap top to view the Perimeter fire containment system selector

Decades of leadership in curtain wall fire containment systems

Perimeter Fire Containment System Selector

Thermafiber pioneered the testing of curtain wall fire containment in 1971 and continues to raise the bar with new tests each year. Our newest innovation, the Impasse® curtain wall insulation system, overlaps components during installation to lock in the fire barrier, virtually eliminating the possibility of insulation materials becoming dislodged by fire’s turbulent forces.

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System Options

Specifying for Life Safety

From its inception, Owens Corning® Thermafiber® has been dedicated to improving life safety and fire protection by manufacturing mineral wool insulation for commercial, residential and industrial applications. Owens Corning® Thermafiber® has identified trends in perimeter exterior wall designs and has developed and tested fire containment solutions for those popular designs. These perimeter fire containment solutions are engineered to be code-compliant without compromising design.  


Tested and Listed Perimeter Fire Containment Systems

Thermafiber® Impasse® No Backer Bar™ Aluminum-Framed Curtain Wall Perimeter Fire Containment System

CW-D-1014 Through 1017

Thermafiber® Impasse® No Backer Bar™ Aluminum-Framed Curtain Wall Perimeter Fire Containment System

Thermafiber® Mineral Wool Insulation 07 21 00 Master Guide Specification PDF | 329.82 KB


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Thermafiber® Aluminum-Framed Curtain Wall Perimeter Fire Containment System with Galvanized Steel Back Pan

CW-D-1037

Thermafiber® Aluminum-Framed Curtain Wall Perimeter Fire Containment System with Galvanized Steel Back Pan

Thermafiber® Mineral Wool Insulation 07 21 00 Master Guide Specification PDF | 329.82 KB


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Thermafiber® Impasse® Aluminum-Framed Curtain Wall Perimeter Fire Containment System

CW-D-2039

Thermafiber® Impasse® Aluminum-Framed Curtain Wall Perimeter Fire Containment System

Thermafiber® Mineral Wool Insulation 07 21 00 Master Guide Specification PDF | 329.82 KB


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Thermafiber® Impasse® No Backer Bar™ with FireLedge® Aluminum-Framed Curtain Wall Perimeter Fire Containment System

CW-D-1012 Through 1013

Thermafiber® Impasse® No Backer Bar™ with FireLedge® Aluminum-Framed Curtain Wall Perimeter Fire Containment System

Thermafiber® Mineral Wool Insulation 07 21 00 Master Guide Specification PDF | 329.82 KB

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Thermafiber® Impasse® Zero Spandrel

The Thermafiber® Impasse® Zero Spandrel PFC System will serve any short spandrel design with an F-rating of up to 3-hours.

Thermafiber® Mineral Wool Insulation 07 21 00 Master Guide Specification PDF | 329.82 KB


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Thermafiber® Crimped Backpan

Thermafiber® Crimped Backpan

Thermafiber® Crimped Backpan System simplifies installation and inspection by using a crimped backpan, eliminating extra reinforcement.

Thermafiber® Mineral Wool Insulation 07 21 00 Master Guide Specification PDF | 329.82 KB


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Safety Act Certified

Pioneers in PFC Deliver Recognized Safety

Owens Corning® Thermafiber® was the first insulation manufacturer to be publicly listed with The U.S. Department of Homeland Security (DHS) as having products that have SAFETY Act Designation. Read our brochure or consult our SAFETY Act FAQ to learn more and find out why 4 of the 5 tallest buildings in the western hemisphere trust Owens Corning® Thermafiber®. 

SAFETY Act FAQ PDF | 73.15 KB


SAFETY Act Brochure PDF | 8.18 MB


Designated Safety Act from US Department of Homeland Security certificate

Project Spotlight

Trusted to Protect Iconic Buildings

Owens Corning® Thermafiber® Perimeter Fire Containment Systems can be found in some of the most advanced buildings being constructed today. Here are just a few projects that showcase the safety and durability of our Perimeter Fire Containment Systems.

One world trade center image looking at sky with clouds

One World Trade Center - New York City, NY

Project Details
Salesforce tower featuring the of top of building overlooking water

Salesforce Tower - San Francisco, CA

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181 Fremont skyscraper overlooking city and water

181 Fremont - San Francisco, CA

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Modern commercial building featuring white windows and slanted roof

VIA 57 West - New York City, NY

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Learn about why high-profile buildings coast to coast trust mineral wool for perimeter fire protection.

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Building codes continue to evolve to address life safety issues such as vertical fire spread. Learn about a new testing method—ASTM E2874-19 for assessing risk of fire spread vertically from floor to floor.

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Walls & Ceilings MagazineAssessing Leap-Frog Risk: A New Testing Method

Two ongoing concerns when it comes to vertical fire spread are the “leap-frog” effect and the increased use of combustible cladding materials. To address these, a new testing method—ASTM E2874-19 assesses risk of fire spread vertically from floor to floor. 

Read More

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Even though we’re a global company, we’re always ready to answer your questions. Call to speak with an Owens Corning representative.