Understanding FM Approvals' metal edge testing approval

The roofing industry needs more clarity for using FM 4435

Based on calls being received by NRCA's Technical Services Section, there appears to be confusion in the roofing industry regarding FM 4435, "Approval Standard for Edge Systems Used with Low Slope Roofing Systems," FM Approvals' criteria for metal edge testing. Perhaps the confusion lies with the FM 4435 designation also being included in the title of the U.S. national consensus standard for metal edge flashings. Also, there appears to be some lack of understanding by specifiers regarding how they should properly implement FM 4435. Following is a brief explanation to provide some clarity.


The U.S. national consensus standard for testing the wind resistances of metal edge flashings (except gutters) is ANSI/SPRI/FM 4435/ES-1, "Test Standard for Edge Systems Used with Low Slope Roofing Systems." The most current edition of the standard was published in 2017 and is designated ANSI/SPRI/FM 4435/ES-1-2017.

The standard's previous edition, which was published in 2011 and is designated ANSI/SPRI/FM 4435/ES-1-2011, is referenced in the International Building Code,® 2015 Edition (IBC® 2015) and IBC 2018.