Measurement uncertainties in the sound power procedures based on sound intensity

Sound power determinations were carried out on two different hydraulic fluid power pumps according to ISO 9614 part 2 Standard. Each pump was mounted on a specific hydraulic circuit under controlled conditions of installation and operation and three different scanning paths were selected on the measurement surface in order to have different scan line densities on each partial surface. After an initial warm-up period, a dataset of ten consecutive sound power determinations were carried out while each pump was running in fixed continuous mode. For each scanning configuration, the repeatability uncertainty values were obtained by measuring the variation of the sound power levels over the time. These results were compared with the accuracy values determined according to the sound field indicator criteria specified in the Standard.