Roofing industry introduces new requirement
Compiled by Juli Case
I’ve been asked if my canopy’s wind loads meet I-90. What does that mean?
This was a new one to us, too, and it turns out it comes from the roofing industry. I-90 is a wind uplift rating developed by the Factory Mutual Global insurance group. FM Global has developed a series of product requirements for components used in the buildings they insure and some architects use their ratings even if the building they are designing is not insured by FM Global. I-90 comes from FM 4470, Approval Standard for Class 1 Roofs, and has to do with whether the membrane can withstand 90 pounds per square foot for at least one minute.
