[EricH]

Originally Posted by Cal578

What part of R28 says what you can't use? The closest I see to that is section C, which says:

Any adhesive you might use is not part of the "bumper cushion material". I wasn't suggesting, and I don't think the OP was either, that anyone use Great Stuff instead of the pool noodles, just in addition to.

Try the part about "must be constructed as follows (See Figure 4-4)" from the very top of the rule (though I'm 99% certain they meant Figure 4-5). Or the part about hard stuff not extending past 1" beyond the frame perimeter (though if Great Stuff isn't hard, then that won't prohibit it).

Let's put it this way: If your inspector determines that having Great Stuff or some other material in the bumper is illegal, as of right now, you have no way of proving that it is legal to any inspector's satisfaction--they'd have to contact HQ for guidance. If you ask Q&A, and they say that it is legal, bring the Q&A with you to convince skeptical inspectors.