When you are starting on a program of condition monitoring the answer to this question is unknown. There are many different kinds of machines in use and a single standard cannot mandate the level of vibration for all types of machines.
Therefore, the standard IS 11724 on the assessment of vibration severity provides a framework in which guidelines can be generated for most types of machines running between 600 to 12000 RPM.
We start by classifying the machine based on the power rating and also the type of mounting, we then look at the vibration level and find which band it falls under. This is only a means of specifying the category but does not say if it is good or bad for you.
Based on accumulated experience, we can safely say that if you have never taken special care of vibrational levels in your plant, chances are that the levels you would encounter would hover around C or even D levels - such levels are bound to create problems of maintenance.
If you have an active vibration monitoring and control system in place and take action to reduce vibration, the levels should stay around B levels. Our experience tells us that B levels are healthy for your machines' lives and achievable without high cost.
