A Burning Question: Performance of Spray Foam Insulation on the Interior Face of Metal Back Pans

2 modules


Course Length
1 hour

Self- Paced


This presentation initially took place the 2020 BES.

Window wall assemblies are a popular exterior wall assembly for high-rise residential apartment buildings. These systems are economical because of efficiencies of factory assembly and rapid installation on site. With the exception of components deemed “minor”—including thermal breaks in the aluminum frames, sealants, etc.—window wall assemblies are considered non-combustible and, therefore, compliant with building code requirements to limit the vertical spread of fire. The thermal performance of window wall systems is relatively weak, limited by thermal bridging through the frames. Thermal performance can be increased with two-component, closed-cell polyurethane foam insulation spray-applied directly to the spandrels. However, the insulation is combustible and too large to be considered a minor component; so, the entire assembly is often considered to be combustible. This presentation describes full-scale fire exposure tests under CAN/ULC-S134, the equivalent to NFPA 285. The outcomes are used to assess if such walls are combustible. The paper will also consider if the test results can be applied to other window wall assemblies and to assess compliance with building codes in the United States, where Canadian window wall systems are often used.

Stéphane Hoffman, PEng

Morrison Hershfield Corporation | Seattle, WA

With a master’s-degree-level education that combines structural engineering, building science, and architecture, Stéphane Hoffman brings a well-balanced consulting approach to the building envelope, blending scientific analysis with an understanding of aesthetics considerations. He is particularly adept at providing innovative design concepts and construction alternatives that provide value by improving durability and increasing energy efficiency. As a key technical leader at Morrison Hershfield, Hoffman has worked on projects throughout North America. He leads the company’s Building Science Analytics Group, combining façade engineering, energy modeling, and enclosure component modeling to assist teams in designing high-performance buildings.


By completing/passing this course, you will attain the certificate Certificate with IIBEC and AIA Logos

Learning Credits

A Burning Question: Performance of Spray Foam Insulation on the Interior Face of Metal Back Pans - Recording
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Added 17 days ago, by Pascal
Added about 1 month ago, by Eric
Added about 2 months ago, by L Allen
Added 5 months ago, by todd
Added 5 months ago, by Randy
Added 7 months ago, by Viesturs
Interesting presentation, but since it is based on Canadian Code, it limits applicability to US work.
Added 9 months ago, by Anonymous
Added 9 months ago, by Trey
Added 9 months ago, by Percy
Very interesting and well presented.
Added 9 months ago, by Robert

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