ImageExcelCalcs User DvdHntr is not quite one in a million but certainly is one of 3 in 1075 - thats how many calculation posts I have received compared to the number of subscribers. This calculation for floor vibration is a great example of the type of calculations we are looking for - its short, simple, well presented and easy to follow. I have given his calculation a 5 star rating and left an encouraging comment why not take a look at DvdHntr's calculation and leave him an encouraging comment of your own.