Question: I am installing numerous steel carports at California public schools which employ HSS tubing. The California school building authority (DSA) gives us greater design flexibility if we can prove that our carports are built of noncombustible materials per ASTM E136 (furnace test). Can you help me prove that HSS sections are noncombustible per California Building Code 703.4, which references the materials passing ASTM E136?

Answer: I don’t have any information (such as a test report) in this regard, but the ASTM E136 standard deals with assessing the combustibility of building materials, whereby a small sample is put into a small furnace.

The E136 test would give results similar to what ULC has in their Canadian S114 standard, entitled “Standard Method of Test for Determination of Non-Combustibility in Building Materials”. In this regard the steel industry has a ULC letter (available upon request) which declares that steel is non-combustible, and this might be of use. This letter lists some of the criteria in the test, one of which is a 750°C temperature limit. This is the same temperature which ASTM E136-11: Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750°C uses. ULC and ASTM do have some differences; e.g., the time of exposure at 750°C – 15 minutes in ULC S114 and 30 minutes (clause 4.1) of ASTM E136.