This substitution method may be used as a survey method in the field to determine structure borne sound source strength of machines and building service equipment with light-framed structures or elastic supports on heavy-weight concrete floors.
The standardized tapping machine according to ISO 140-7 is used as reference source and the main result is presented in the form of vibration level differences measured with the source and the tapping machine respectively. From this difference, other descriptors may be derived to obtain input data for calculation models described in EN 12354 parts -5 and -2.
Additional measurements may be conducted on a light weight floor, e.g. a timber joist floor, but those results are then valid only for such floors. For airborne noise source strength, the ISO 3740 series of standards may be applied. Refer to EN ISO 16032 or EN ISO 10052 for measurement of sound pressure levels in adjoining rooms.