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2002, 12

A. Jagniatinskis, B. Fiks

About the declaration of noise emitted by technical devises

language: Russian

received 05.06.2002, published 25.10.2002

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ABSTRACT

The article deals with estimation the uncertainty in determination of A-weighted sound power level. In the European countries producers and suppliers of potentially noisy equipment mandatory have obligations to declare noise emission value in the technical specification. According to the international (ISO) and counterpart European (EN) standards A-weighted sound power level LWA is mainly used as a declared value. There are seven standards (all are described in ISO 3740) available for sound power measurements with different characteristics. The A-weighted power levels may be calculated from measured levels in octave or in one-third-octave bands. In the article theoretically estimated, that the A- weighted sound power level calculations from octave levels LWA,1 and calculations from one-third-octave levels LWA,1/3 may be different up to (+-)1.0 dB. It is shown for which noise spectra the difference LWA,1/3 - LWA,1 is significant. As example household freezer emitted noise measurements carried out in the reverberation room. Declared value calculations in one-third octave bands in compare with calculations in octave bands gives a difference of 1 dB.

10 pages, 5 figures

Сitation: A. Jagniatinskis, B. Fiks. About the declaration of noise emitted by technical devises. Electronic Journal “Technical Acoustics”, http://www.ejta.org, 2002, 12.

REFERENCES

1. ISO 4871:1996, Acoustics - Declaration and verification of noise emission values of machinery and equipment.
2. EN 60704-3:1994, Test code for the determination of airborne acoustical noise emitted by household and similar electrical appliances - Part 3: Procedure for determining and verifying declared noise emission values.
3. ISO 7574-1:1985, Acoustics - Statistical methods for determining and verifying stated noise emission values of machinery and equipment - Part 1: General considerations and definitions.
4. ISO 7574-2:1985, Acoustics - Statistical methods for determining and verifying stated noise emission values of machinery and equipment - Part 2: Methods for stated values for individual machines.
5. ISO 7574-4:1985, Acoustics - Statistical methods for determining and verifying stated noise emission values of machinery and equipment - Part 4: Methods for stated values for batches of machines.
6. ISO 3740:2000, Acoustics - Determination of sound power levels of noise sources - Guidelines for the use of basic standards.
7. ISO 3741:1999, Acoustics - Determination of sound power levels of noise sources - Precision methods for broad-band sources in reverberation room.
8. ISO 3743-1:1994, Acoustics - Determination of sound power levels of noise sources - Engineering methods for small, movable sources in reverberant fields - Part 1: Comparison method for hard-walled test rooms.
9. ISO 3743-2:1994, Acoustics - Determination of sound power levels of noise sources using sound pressure - Engineering methods for small, movable sources in reverberant fields - Part 2: Methods for special reverberation test rooms.
10. ISO 3744:1994, Acoustics - Determination of sound power levels of noise sources using sound pressure - Engineering method in an essentially free field over a reflecting plane.
11. ISO 3745:1983, Acoustics - Determination of sound power levels of noise sources - Precision methods for anechoic and semi-anechoic rooms.
12. ISO 3746:1995, Acoustics - Determination of sound power levels of noise sources - Survey method.
13. ISO 3747:2000, Acoustics - Determination of sound power levels of noise sources - Survey method using a reference sound source.
14. ГОСТ 23941-79 Шум. Методы определения шумовых характеристик. Общие требования.


 

Aleksandras Jagniatinskis Aleksandras Jagniatinskis, Ph.D. (Tech.), head of the acoustic laboratory at Thermoizoliacija Institute, Vilnius, Lithuania:
http://www.vgtu.lt/institutai/termoizoliacija/akustikos_lab.htm
Chairman of TC-31 (technical committee - 31 "Akustica" at Lithuanian Standardization Board) Field of activities includes building acoustics and community noise. Author of more than 50 articles on acoustic measurements and noise control
E-mail: aljagn(at)takas.lt

 
 

Boris Fiks , Ph.D.(Tech.)1985 at Kaunas Polytechnic Institute, Education: Vilnius University, Applied mathematics Diploma. Now - senior research fellow of the acoustic laboratory at Thermoizoliacija Institute, Vilnius, Lithuania. Field of interest: digital data processing of ultrasound and acoustic signals; acoustic measurements and their precision. Author of about 30 articles on digital measured data processing in elektroacoustics.
E-mail: borisasf(at)delfi.lt