Assuming the question deals with the air (gas) needed to start the engine driving the compressor, the answer is, "it depends."
The air starting requirments will depend on the specific engine, the specific starter, supply air pressure, and the required cranking time. The cranking time depends on the engine model, engine condition, ambient air temperature (a variable), fuel type, engine oil viscosity, and design cranking speed. Hot starts will take less air than cold starts. If there's a prelube system, is it air driven as well?
I'll toss out 40 to 80 cubic feet as a starting place but open a dialog with the engine/starter manufacturer(s).