Sound Power Level Measurement of Air-conditionning Units in Reverberation Room: Estimation of the Uncertainties and their Use in Laboratory

Résumé et principaux résultats

Article présenté au Symposium International "Managing uncertainties in Noise Measurements and Predictions", Le Mans, juin 2005.
Certification programs and accreditation of testing laboratories require an estimation of the uncertainties of acoustic measurements. The "Guide to the expression of uncertainty in measurement" offers an interesting approach to the estimation of uncertainties and is commonly used in other fields of physics. The GUM method is used to estimate the sound power measurement uncertainty of liquid chilling packages in a reverberation room. The independent quantities are identified and included in the propagation law of uncertainty, showing the importance of both standard uncertainty and sensitivity coefficients. Their study allowed us to sort out the uncertainty components and then to quantify their influence on the uncertainty associated with the one-third octave band values as well as the overall sound levels. These analyses gave us relevant working tracks to improve measurement quality in laboratory: for the case under study, the microphones and sound source locations are the main factors, clearly outclassing the measuring chain errors, for instance.

Thème

Acoustique générale et vibroacoustique

Mots-clés

Acoustique, Calculs d'incertitude, Conditionnement d'air, Groupe d'eau glacée à compression, Mesure de bruit

Auteurs

BESSAC François, BLANQUART Bertrand