Estimating The Uncertainties of Laboratory Acoustic Measurements According to the GUM Method (Inter-Noise 2002)

Résumé et principaux résultats

Présenté à Inter-Noise 2002 (Detroit, Michigan)

Certification programs, accreditation of testing laboratories require to estimate the uncertainties of acoustic measurements. Currently, most of the acoustic measurement uncertainties are estimated by heavy measurement campaigns according to ISO 5725, which lead to global uncertainties, with no distinction between the different components of the uncertainty. The ISO 13025 "Guide to the expression of uncertainty in measurement" offers an alternative approach to estimate those uncertainties and is commonly used in other physics fields. This paper applies the GUM method to estimate the sound power measurement uncertainty of air exhaust devices 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 studies allow us to sort out the uncertainty components and then to quantify their influence on the uncertainty associated to the one-third octave band values as well as the overall sound levels. Those analyses gave us relevant working tracks to improve the measurement quality in the laboratory: for the case under study, the microphones and sound source locations are the main factors, clearly outclassing the measuring chain errors, for instance.

Commissions

Machines thermodynamiques, Mesures et instrumentation, Ventilation des bâtiments résidentiels et tertiaires

Thème

Acoustique générale et vibroacoustique

Mots-clés

Acoustique, Calculs d'incertitude

Auteurs

BESSAC François, BLANQUART Bertrand