Researcher at the department of Acoustics, National institute for standards NIS-Egypt


Since the audiometer devices that is used at the clinic of Doctor to assess the hearing of the persons and since the measurements and accuracy of measurements is and important thing and since our institute objective is to get accreditation in its all measurements. So that the objective of this work is to present a metrology study necessary for the accreditation of audiometer calibration procedures at the NIS .A model for the calculation of measurement uncertainty was developed. The uncertainty calculation was based on the documents:EA-4/02 Expression of the Uncertainty of Measurement in Calibration(European Co-operation for Accreditation 1999 EA-4/02 p 79) and Guide tothe Expression of Uncertainty in Measurement (International Organization for Standardization 1993 1st edn, corrected and reprinted in 1995, Geneva, Switzerland). Some sources of uncertainty were calculated theoretically (uncertainty type B) and other sources were measured experimentally (uncertainty type A). The global value of uncertainty calculated for the sound pressure levels (SPLs) is similar to that given by other calibration institutions. The results of uncertainty related to measurements of SPL were compared with the maximum uncertainties Umax given in the standardIEC 60645-1: 2001 (International Electrotechnical Commission 2001 IEC 60645-1 Electroacoustics—Audiological Equipment—Part 1:—Pure-Tone Audiometers).Metrological aspects relating to audiometer calibration, traceability andmeasurement uncertainty were quantified