IEC 61672-2-2013 pdf download.Electroacoustics – Sound level meters – Part 2: Pattern evaluation tests.
3 Terms and definitions
For the purposes of this document, in addition to the terms and definitions given in IEC 61672-1 and IEC 62585, the terms and definitions given in IEC 61000-4-2, IEC 6 1000-4-3, IEC 61000-4-6, ISO/IEC Guide 98-3, and ISO/IEC Guide 99 also apply.
4 Submission for testing
4.1 At least three specimens of the same pattern of sound level meter shall be submitted for pattern-evaluation testing. As a minimum, the laboratory shall select two of the specimens for testing. At least one of the two specimens shall then be tested fully according to the procedures of this Standard. The laboratory shall decide whether the full tests shall also be performed on the second specimen or whether additional limited testing is adequate to approve the pattern.
4.2 An Instruction Manual and all items or accessories that are identified in the Instruction Manual as integral components for the normal mode of operation shall be submitted along with the three sound level meters. Examples of additional items or accessories include a microphone extension device or cable and peripheral equipment.
4.3 If the manufacturer of the sound level meter supplies devices that are to be connected to the sound level meter by cables, then the devices and cables shall be submitted with the sound level meter.
5 Marking of the sound level meter and information in the Instruction Manual
5.1 It shall be verified that the sound level meter is marked according to the requirements of IEC 61672-1.
5.2 It shall be verified that the Instruction Manual contains all the information that is required by IEC 61672-1. as relevant to the facilities provided by the sound level meter.
5.3 If the sound level meter does not conform to the requirements of 5.1 and 5,2, no pattern-evaluation tests shall be performed.
5.4 After completion of all tests, the information shall be reviewed to ensure that it is correct and that no applicable acceptance limits are exceeded.
6 Mandatory facilities and general requirements
6.1 No test specified in this part of IEC 61672 shall be omitted unless the sound level meter does not possess the facility described for the test. When the design of a sound level meter. which has been pattern approved, is changed and a new pattern approval is requested, then, at the discretion of the laboratory, it is not necessary to repeat those tests for electroacoustical performance characteristics that are not affected by the design change.
6.2 A time-weighting sound level meter shall be verified to be able to display A-frequency- weighted, F-time-weighted sound level and to be able to indicate overload and under-range conditions.
6.3 An integrating-averaging sound level meter shall be verified to be able to display A- frequency-weighted, time-averaged sound level and to be able to indicate overload and under-range conditions.
6.4 An integrating sound level meter shall be verified to be able to display A-frequency- weighted sound exposure level and to be able to indicate overload and under-range conditions,
6.5 All display devices for the sound level meter shall be verified to be able to display sound levels or sound exposure levels with the resolution required by IEC 61 672-1. The range of the display shall be at least the minimum specified in IEC 61672-1.
6.6 If a sound level meter is capable of measuring maximum or peak sound levels, or both, it shall be verified that a hold feature is provided.
7 Environmental, electrostatic, and radio-frequency tests
7.1 General
7.1.1 Before conducting, but not during, the tests described in the Clause 7, the indication of A-weighted sound level at the calibration check frequency shall be checked by application of the sound calibrator specified in 4.4. If necessary, the sound level meter shall be adjusted to indicate the required sound level under reference environmental conditions. For multichannel devices, the corresponding indications shall be checked for all channels selected for testing.
7.1.2 Environmental conditions at the time of checking the indication shall be recorded.
7.1.3 The effect of environmental conditions on the sound pressure level produced by the sound calibrator shall be accounted for in accordance with the procedure in the Instruction Manual for the sound calibrator and data from its calibration. The effects shall be evaluated relative to the sound pressure level produced under reference conditions.
7.1.4 For environmental tests, a sound calibrator shall be used to provide a known sound pressure level at the microphone of the sound level meter. For class I sound level meters, the calibrator shall conform to either the class LS or class I specifications of IEC 60942. For class 2 sound level meters, the calibrator shall conform to either class LS, class 1, or class 2 specifications of IEC 60942. If the sound calibrator conforms to the requirements of the applicable performance class for a nominal frequency of 1 kHz, the environmental tests shall be performed at the nominal frequency of I kHz. The effects of static pressure, air temperature, and relative humidity on the sound pressure level produced in the coupler of the sound calibrator, over the range of environmental conditions specified for the tests, shall be known.
NOTE The range of environmental conditions specified for pattern-evaluation tests exceeds the range specified in IEC 60942 for class LS sound calibrators.
7.1.5 The sound level meter shall be set to perform a typical measurement of time-weighted sound level, time-averaged sound level, or sound exposure level on the reference level range. The frequency weighting shall be set to A weighting.
7.1.6 Time-weighted sound levels, time-averaged sound levels, or sound exposure levels indicated by the sound level meter in response to the signal from the sound calibrator shall be recorded for each test condition. When necessary, time-averaged sound levels shall be calculated from the indications of sound exposure level and elapsed time in accordance with IEC 61672-1. Averaging times for time-averaged sound levels or integration times for sound exposure levels shall be recorded.
7.2 Uncertainties for measurements of environmental test conditions
The actual uncertainty of measurement shall not exceed 0,2 kPa for measurements of static pressure. The actual uncertainty of measurement shall not exceed 0,3 °C and 4 % relative humidity for measurements of air temperature and relative humidity, respectively. These measurement uncertainties shall be determined for a coverage probability of 95 %.IEC 61672-2 pdf free download.