Here's some tables:
http://nhbccampaigns.co.uk/landingpa...4/appendix.htm
We used similar when I was a site chippy.
Floor deflection in itself is usually no problem if you don't mind the slope, strain on the walls and ceiling boards can be another matter.
I have a wooden floor that's on 3"x2" joists that are supported every 4ft or so, it's been loaded with some serious weights since I installed it, no problems.
Lawrence.