OSHA has nothing to do with forklift tip testing. The applicable standard is SAE 56, with different sections for different types of forklifts. 56.1 is counterbalance warehouse. 56.6 is offroad telehandlers. I believe that SAE recently distanced itself from these standards because they didn't make enough money selling papers. I believe that there is some sort of manufacturers organization now. In fact these tests are "voluntary" but it will not stop you from getting sued. OSHA just wants to see that it meets the SAE standard. I almost forgot, there is also a ISO version that is very very similar.
As for the test parameters, there are tip goals for 5 different scenarios. Forward and lateral tip with and without loads at different heights. And just because a wheel lifts does not mean that you have failed, the truck must loose stability.
Like most standards, some things are spelled out very specifically and some are not. Several are:
-wind limit or wind loading(if outdoors)
-wheel orientation
-can the operator's weigh help meet the goal
-fuel load
-orientation of moveable attachments
It can get quite involved. To cover ourselves I wrote a 10 page test procedure that basically detailed our interpretation.
