I believe my system is better with blocks, pressure treated runners, and doug fir floor joists, but the problem is that my competitors are selling the gimmick of steel floor joists. So now people think oh steel I have to have steel. Uh, what is your house made of? Wood. How has that held up for you? Anyway that is why i am being forced to offer the steel floor joists, have to keep up with the gimmicks.
The buildings are in Ogden Utah. Spacing will be 16" o.c. As far as spans go that is kind of tough to determine since this style will not allow for runners. If the site is level then I will have good contact, so let's just go with that. A perfectly level site with 100% ground contact at 16" o.c.