Sound is radiated both as air-borne and as structure-borne; most sources produce both, thus various noise attenuation principles must be employed. Measures include: the replacement of components with quieter parts and material; the enclosure of particularly noisy components; the selection of quieter types of fan; the replacement of noisy compressed-air nozzles with quieter types; the choice of quieter transmission and cooling systems.
Scope note is not available.