Web stiffeners increase the BCI joist allowable reactions, which can help a design pass analysis. For approved web stiffener installation, please refer to the following Boise Cascade publications: Design Guide, Installation Guide, Contractor's Guide, and Specifier's Guide.
Web stiffeners are required for some hangers. Cautionary notes are included in the Design Reports when required.
Here is the web site to locate the current specifier guide for your product and region: https://www.bc.com/manufacturing/bci-joists/