What vibration levels would you suggest should be expected from a pump in the classification
- a machine above 300kW mounted on a rigid and heavy foundation.
we are suggesting rms accn of 23m/s2 and rms velocity 1.8mm/s - is this too stringent?

No! Not too tight. I would expect better.

Including vane pass frequency that "always" exist?
In my book, there are no "stiff" foundations. Post a picture to convince me you have found one :-). Is it possible to run this separately so you only get vibration from this unit, as some standards prescribe? I find that required when demanding so tight specs and in reality very rarely operatively possible to perform. In some cases however you can find that lo levels and even lower so everything is possible. Olov

OLI makes a point. I have seen pumps with fairly stiff foundations, but if the foundation is truely rigid you get 0 casing vibration.

If you have a good stiff foundation and fluid film bearings, try shaft relative vibration. With rollling element bearings on a rigid foundation, something has to give, and that something may be the bearings.