Air compressor capacity..

i might sugguest each bay has it's own dedicated source of shop air..

What is the volume of the air ? number of tapping points etc, The diameter of the pipe will be dependant on this aspect.

I advice rotary screw compressors, they are likely to be more trouble free.

Thanks SB, the volume of air required is 0.2 cu.m and only 5 tappings.....

If we are to assume that you will purchase this compressor, ask the seller!

from the hoist makers, get the volume of air and pressure required to hoist a vehicle. The air hoist will be the biggest user, followed by the tire machine. Hand tools will be light users.

Then you need a tank that will allow for 2-3 vehicle lifts on stored air, on the basis that once lifted a vehicle will sit and be worked on. Then decide how long you want to wait for the tank to be filled to pressure again. The quicker you want it filled = more horsepower on the compressor.

A compressor salesman wants you to buy a larger one than you really need. I would avoid these cheap Chinese compressors, their warranty will be worthless and they will not last long. USA compressors will cost more, but will give decades of operation if properly maintained.

This link will help.

http://www.truetex.com/aircompressors.htm

Joesph; i agree why so high psi?You should only run 125psi max for line pressure as that is the standard at which most tools are rated What kind of piping do you intend to use? How much power do you have avail, is it sinlge or 3 phase and what voltage/amp? Physically how big is your shop? Are you going to run it around the clock? How many people? What kind of "auto" repair? cars/lt trucks? Or are you going to go into fleet work involving heavier vehicles like tractor/trailers,buses,or construction equip where you would have need for heavier impact tools 1" drive or better on a constant basis? Will there be a sandblasting or paint booth? If so what size? there are many things to consider before installing an air system,not only immed needs but future plans as well.....

Most garages in my area use 5 to 10 HP 2-stage compressors with tanks from 80 to 120 gallons. Most set their top air pressure at 130 - 150 lbs. In my workshop / barn I have an old 5 horse 2-stage on a 60 gallon tank set for 115 lbs. My tools work as well as anybody else's because I use 3/8 'T' style fittings which have a 3/8 opening as opposed to the usual 3/16 - 1/4 opening common to most quick-connect fittings. The line coming off the tank is 1 inch copper, with 1/2 inch drops along the way for my convenience.

Other garages I have seen have up to 3 compressors that can be added to or seperated from the shop air system as needed.