I work in Minnesota for a firm which fabricates wood trusses and other projects. A consulting engineer I know, asked me about the topic because of my wood background. Since I didn't know the answer I thought I would post it on the forum to not only gather information, but also to educate myself.
I did check with someone with the State of Minnesota Building Code Division who thought that the builders association puplished some guide lines. The person I spoke with also indicated that a major criteria was that the components be capable of carrying the loads they were designed for.