I'm taking no chances when it comes to permits and getting burned when it's time to sell this place. I already have a construction permit in hand and my town has stipulated that the support design must be Sealed by a Professional Engineer (I happen to be one, but will not stamp it myself to avoid any conflict of interest).
I have since found that a company called Thomas Betts, www.tnb.com
, they make support struts and clamps for attaching structures to I beams.
I've not done the calculations yet, but my guess is that the beam will easily be able to support an additional distributed static load under 1000 pounds (coolers, holiday decorations, junk).