Real Estate Funds & UBTI in a IRA

Let's say you wanted to invest some of your IRA money with a real estate fund. You will have an "interest," be a member of this fund who owns the property. The fund is setup as a partnership so you will get a K1. Assuming you don't do any prohibited transactions. When would UBTI come into play? I've researched it to death and can't figure out the answer.

 

Thanks!

Curtis