This depends on what the problem is. If you are trying to eliminate vibration, these peaks indicate where your effort should be concentrated. The amplitude of the peaks (either relative or normalized) can give further information depending on how the data are reduced.
Dave:
Intensity measurements are more usefull in a laboratory setting. I am a former consultant on industrial noise, and I would suggest either engaging someone in the field or doing some study yourself.
Acoustical Consultants can be found on these web sites:
Institute of Noise Control...
