BS ISO 9611:1996 - Acoustics. Characterization of sources of structure-borne sound with respect to sound radiation from connected structures. Measurement of velocity at the contact points of machinery when resiliently mounted
Current, Under Review
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This International Standard specifies an approximate method of characterizing sources of structure-borne sound by the measurement of one-third-octave-band free velocity level spectra (or, if appropriate, octave-band velocity level spectra) on the supports or other connection points of machines mounted on resilient isolators. This structure-borne sound emission is considered with respect to the airborne or liquid-borne sound radiation of structures connected to the source under test. The results are only valid for applications in which the machine is mounted on sufficiently soft isolators on a sufficiently stiff and heavy foundation.
NOTE 1 More conditions are given in annex H. A survey of the theoretical background is given in annex E.
It is possible to satisfy the requirements for the test arrangement in almost any surroundings.
Velocities measured at defined contact points give no complete description of structure-borne sound emission of the machinery. But, under specific conditions as described in this International Standard for resiliently mounted machinery, they give a subset of the source data required for a characterization.
The results can be used
a) to obtain data for technical specifications;
b) for comparison with machines of similar type and size; and
c) to obtain input data for computations on the transfer of structure-borne sound.
The frequency range for which the method is applicable is limited by a low frequency f1 and an upper frequency f2.
The low frequency limit f1 is set by the requirement that the supports vibrate freely; i.e. they are not affected by the isolators and the foundation structure on which the isolators are mounted. Annex A gives instructions on how to determine f1.
The upper frequency limit f2 is determined by assuming that the supports behave as point sources of structure-borne sound. Annex B gives guidelines for the determination of f2.
BS ISO 9611:1996 - Acoustics. Characterization of sources of structure-borne sound with respect to sound radiation from connected structures. Measurement of velocity at the contact points of machinery when resiliently mounted
