Standard practice for architects in our office is to spec between 1/8" and 1/4" pitch per foot to interior drains or out overhead doors.
For residential projects, pitching floors to drain out doors is popular in our area as the county building department requires that floor drains at overhead doors be connected to a triple basin seperator. The triple basin seperates oil, gas, and solids and keeps them from draining into the sanitary sewer system. In case you're wondering, triple basins get to be fairly expensive: fiberglass or metal basins, extra piping, excavation, etc. They also have to lids that are readily removed for inspection and maintenance.
If you're concerned about tool boxes rolling around and cabinets not sitting level, why not leave a 3' strip of the slab level at one side or the rear of the garage and pitch from that point to the door? Most logical people aren't going to be hosing down their loaded toolboxes or storage cabinets in place so you don't need that section to drain.
Aahz is right. Lift installers will use steel or high density plastic shims to plumb the posts of a lift on a pitched floor. We did a GM dealership about two years ago with over 20 2 post lifts and 2 4 post lifts. Every single post had to be shimmed to accomdate the floor. What he didn't say is that installing a lift on a severly pitched slab WILL cause clearance issues with some cars. In our case, the dealership had to designate one row of lifts for trucks and suvs and limit cars to the other three rows. It wasn't a big deal in our case since there were so many lifts, but could be disasterous to someone at home with one lift and a low ground clearance sports car. Problem is maginifed with assymetrical lifts where lift point is closer to the front of the car.
This post makes me wonder how much pitch we have to the drains on heavy equipment repair bays and repair training bays for my current project.
