First is a Mechanics half inch impact wrench.
Coleman Powermate 024-0077CT 1/2″ Air Impact Wrench
4 torque settings up to 230 ft/lbs. (230 ft/lbs., 215 ft/lbs., 195 ft/lbs., 150 ft/lbs.)
230 ft/lbs. maximum torque
1/4″ NPT air inlet with screened filter keeps out unwanted particles
Air requirements: 4.5 CFM @ 90 PSI
So, for this tool we see we need a compressor that can run at a minimum of 4.5 CFM @ 90 PSI.
Next lets look at a Paint Gun