Sound Solutions (acoustical engineers) regularly measures the existing vibration levels in areas where MRI units are proposed to be located. The equipment is very sensitive to vibration; hence, in hospitals or clinics near major roads, railroads, airports or that have helipads vibration tests are required.
The difficulty acoustical consultants often face is determining when to measure. The sooner the space meets the requirements, the sooner the builders can progress. However, if the room is tested too soon, without certain vibration sources operating (such as: helipads, elevators, HVAC, mechanical equipment) it may pass but the room might not be adequately isolated. The MRI manufacturer does not give much guidance on this topic. They just say that when everything is done the floor needs to meet the requirement even though it is impractical to wait until the end to test.
As a solution, in some cases, more than one test is needed. We make a preliminary test to insure that the larger vibration sources (roads, airports, trains) to not cause vibration levels above the criteria. If the vibration levels from the larger noise levels from the large, immobile sources is a problem, we need to isolate the proposed MRI room or relocate the room further from the source. If those levels are acceptable we will make another measurement to test the vibration levels from mechanical equipment closer to the completion time. Using this approach, if we do find problems with vibration transmission from mechanical equipment, we address that with vibration isolation of that equipment.