what is the standard of different light levels at various points in any installation?

Answer 1

There are several handbooks that might have some information on this. It depends on what you are talking about. I've used 75 to 100 foot candles for offices, 50 foot candles in production areas and less for warehouses. Down to just a few foot candles for parking lots.

Operating rooms, inspection area's etc. also have higher levels. Lighting manufacturers also have software to help you predict the light levels for various designs.