JB/T 9953-2020 Woodworking machines - Measurement of sound pressure level
1 Scope
This standard specifies the measuring instruments, environment, installation of machines and positions of measuring points for measurement of sound pressure level for woodworking machines.
This standard is applicable to the measurement of sound pressure level for all types of woodworking machines (hereinafter referred to as machines).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 3785.1-2010 Electroacoustics - Sound level meters - Part 1: Specifications
GB/T 15173-2010 Electroacoustics - Sound calibrators
3 Measuring instruments
3.1 Class 1 sound level meter in GB/T 3785.1-2010 and Class 1 sound level calibrator in GB/T 15173-2010 shall be used.
3.2 The measuring instruments and sound level calibrators shall be calibrated once every two years.
3.3 Before and after each measurement, the entire measurement system, including the microphone and extension cable, shall be calibrated using a sound level calibrator with a precision superior to ±0.3dB. If the difference between the two calibration values before and after the measurement exceeds 1dB, the measurement is invalid.
4 Measurement environment and correction
4.1 The measurement shall be carried out in a wide and flat outdoor area or a large room, and the ground of the measurement site shall be a reflecting surface.
4.2 During indoor measurement, the distance between the contour surface of the machine under measurement (small protruding parts that have little impact on the measurement, such as handwheels and handles, may be omitted) and the surrounding walls shall be greater than 2m, and there shall be no large reflecting surfaces and obstacles other than the ground within this range.
4.3 During outdoor measurement in a wide and flat area, the ground (reflecting surface) shall be a concrete or asphalt surface, or may be a soil surface. The reflecting surface shall be greater than the projection of the rectangular parallelepiped enveloping surface on it. There shall be no other large reflecting surfaces and obstacles within 2m from the surrounding contour surface of the machine under measurement.
Contents
Foreword i
1 Scope
2 Normative references
3 Measuring instruments
4 Measurement environment and correction
5 Installation and operation of machines
6 Measurement items
7 Positions of measuring points
8 Measurement methods
9 Calculation of average A-weighted sound pressure level
10 Measurement report
Annex A (Normative) Determination of environment corrected value
Annex B (Informative) Record form for measurement of sound pressure level of machines
Figure 1 Positions of measuring points around the machine
Table A.1 Approximate values of the average sound absorption coefficient α of the room
Table B.1 Record form for measurement of sound pressure level of machines
JB/T 9953-2020 Woodworking machines - Measurement of sound pressure level
1 Scope
This standard specifies the measuring instruments, environment, installation of machines and positions of measuring points for measurement of sound pressure level for woodworking machines.
This standard is applicable to the measurement of sound pressure level for all types of woodworking machines (hereinafter referred to as machines).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 3785.1-2010 Electroacoustics - Sound level meters - Part 1: Specifications
GB/T 15173-2010 Electroacoustics - Sound calibrators
3 Measuring instruments
3.1 Class 1 sound level meter in GB/T 3785.1-2010 and Class 1 sound level calibrator in GB/T 15173-2010 shall be used.
3.2 The measuring instruments and sound level calibrators shall be calibrated once every two years.
3.3 Before and after each measurement, the entire measurement system, including the microphone and extension cable, shall be calibrated using a sound level calibrator with a precision superior to ±0.3dB. If the difference between the two calibration values before and after the measurement exceeds 1dB, the measurement is invalid.
4 Measurement environment and correction
4.1 The measurement shall be carried out in a wide and flat outdoor area or a large room, and the ground of the measurement site shall be a reflecting surface.
4.2 During indoor measurement, the distance between the contour surface of the machine under measurement (small protruding parts that have little impact on the measurement, such as handwheels and handles, may be omitted) and the surrounding walls shall be greater than 2m, and there shall be no large reflecting surfaces and obstacles other than the ground within this range.
4.3 During outdoor measurement in a wide and flat area, the ground (reflecting surface) shall be a concrete or asphalt surface, or may be a soil surface. The reflecting surface shall be greater than the projection of the rectangular parallelepiped enveloping surface on it. There shall be no other large reflecting surfaces and obstacles within 2m from the surrounding contour surface of the machine under measurement.
Contents of JB/T 9953-2020
Contents
Foreword i
1 Scope
2 Normative references
3 Measuring instruments
4 Measurement environment and correction
5 Installation and operation of machines
6 Measurement items
7 Positions of measuring points
8 Measurement methods
9 Calculation of average A-weighted sound pressure level
10 Measurement report
Annex A (Normative) Determination of environment corrected value
Annex B (Informative) Record form for measurement of sound pressure level of machines
Figure 1 Positions of measuring points around the machine
Table A.1 Approximate values of the average sound absorption coefficient α of the room
Table B.1 Record form for measurement of sound pressure level of machines
