STEPS TO TAKE TO ADD NOISE LEVELS
Determine the possible total noise level from running several machines for your space (with a known noise output) simultaneously.
Ascertain the resultant noise level if a new machine is added to an existing noisy area.
Establish the effect that background noise levels will have on the overall noise level within your area.
Please note: The Addition of Decibels (dB) is not a simple task given that the Decibel scale is logarithmic.
Calculate the added resultant noise level expected by providing a number of noise levels.