Commentary on the Code
Class 1 Foams
As soon as you hear the mention of Class 1 foam, alarm bells should go off. There is no mention of Class 1 foam in the National Building Code and neither the provinces nor the municipalities have added Class 1 to their definitions or terminology.
In almost all cases, when Class 1 foam is mentioned, they are referring to material that has been tested to American standards, not the required Canadian standards. The test method that they reference when they talk about Class 1 foam is ASTM E84.
The National Building Code of Canada requires that building materials, including spray polyurethane foam, be tested to CAN/ULC S102. This test is similar to the ASTM E84 “tunnel test” but the results that you record and declare are completely different than ASTM E84.
You may say that the National Building Code lists two different types of flame spread which are not greater than 25 and greater than 25 but not greater than 500, so there are classes, but the National Building Code have simply not called them Class 1 and Class 2. That could be true, but it does not change the fact that in Canada , you must test to CAN/ULC S102 and in the United States you must test to ASTM E84. Simply put, materials which have not been tested to CAN/ULC S102 do not meet the requirements of the National Building Code.
If the results achieved from the ASTM E84 and the CAN/ULC S102 were the same or if there was a direct correlation between ASTM E84 and CAN/ULC S102, then an argument could be proposed which would recognize ASTM E84. However, the results are completely different and there is no correlation between the two standards. As an example, the exact same material with the same lot number when tested in accordance with ASTM E84 could achieve a 25 flame spread rating. When that same spray polyurethane foam with the same lot number is tested in accordance with CAN/ULC S102 the results would be in the 250 – 350 range.
A material which achieves a 25 flame spread rating when tested to ASTM E84 is not the same material that when tested to CAN/ULC S102 and achieves a 25 flame spread rating. Conversely a material tested in accordance with the National Building Code to meet Article 18.104.22.168.(1) which is less that 25 flame spread rating would have to achieve a flame spread rating of less than 2 when tested in accordance with ASTM E84.
The National Building Code goes on to say in Article 22.214.171.124.(2) to say that even if you achieve a flame spread rating of 25 or less when tested in accordance with CAN/ULC S102 you still have to protect the material from the interior of the building with a thermal barrier as defined in that Article.
Keep in mind that the contractor must meet the requirements of the authority having jurisdiction, regardless of what the project specification say. You must use the standards specified in the National Building Code, you must protect the combustible insulation as required in the National Building Code and you must meet any standard for the thermal insulation material that is specific in the Code.
The next time you hear “Class 1 Foam”, check into the documentation. Ensure that the material that you use meets the requirements of the National Building Code, either not greater than 25 or greater than 25 but not greater than 500 when tested in accordance with CAN/ULC S102. Provide the protection required for the spray polyurethane foam. When another contractor is responsible for the installation of the thermal barrier, make sure the building owner is informed about the National Building Code requirements for the Protection of Foamed Plastics. Do not be misled about the requirements of the Canadian National Building Code.