ISO-11094-1991.pdf
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1、INTERNATIONAL STANDARD IS0 11094 First edition 1991-l l-01 Acoustics - Test code for the measurement of airborne noise emitted by power lawn mowers, lawn tractors, lawn and garden tractors, professional mowers, and lawn and garden tractors with mowing attachments Acoustique - Code dessai pour le mes
2、urage du bruit ahen Bmis par les tondeuses 5 gazon 9 moteur, les tracteurs de pelouse, les fracteurs de jardin et de pelouse, les tondeuses ZI usage professionnel, et les tracfeurs de jardin et de pelouse avec 6quipements de tonte adaptables Reference number IS0 11094:1991(E) Copyright International
3、 Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 10:14:16 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 11094:1991 (E) Foreword IS0 (the International Organization for St
4、andardization) is a worldwide federation of national standards bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the rig
5、ht to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft Inter
6、national Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Inter- national Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 11094 was prepared jointly by Technical Committees ISO/
7、TC 43, Acoustics, Sub-Committee SC 1, Noise and ISO/TC 23, Tractors and machinery for agriculture and forestry, Sub- Committee SC 13, Powered lawn and garden equipment. Annex A of this International Standard is for information only. 0 IS0 1991 All rights reserved. No part of this publication may be
8、reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permlssion In writing from the publisher. International Organization for Standardization Case Postale 56 ? CH-1211 GenCve 20 ? Switzerland Printed In Switzerland ii Copyright I
9、nternational Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 10:14:16 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 11094:1991(E) Introduction This International Standard
10、 describes a method for measuring the air- borne noise emitted by powered grass-cutting machines essentially in accordance with IS0 4872. The method specifies the determination of the acoustical characteristics of a machine in terms of the A-weighted sound power level. The values obtained are the fu
11、ndamental quantities for characterizing the sound output of the machine under test. The A- weighted sound power level of the machine is calculated from measured values of the A-weighted sound pressure level at several microphone positions located on a hypothetical hemispherical surface which en- vel
12、ops the machine. It has, however, been considered appropriate to specify fewer microphone positions than those in IS0 4872. . . . 111 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2
13、007 10:14:16 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD IS0 11094:1991(E) Acoustics - Test code for the measurement of airborne noise emitted by power lawn mowers, lawn tractors, lawn and garden tractors, professional mowers, and lawn and garden
14、tractors with mowing attachments 1 Scope This International Standard specifies methods for measuring the A-weighted sound pressure levels at prescribed microphone positions in the proximity of the machine under test while the machine is sta- tionary or in motion. From these values the A- weighted so
15、und power level of the machine may be calculated. It defines acoustical requirements for measure- ments in an essentially free field over a partially re- flecting plane, covered with a specified official absorbing material or natural grass (see 4.1). The operating and mounting conditions of the mach
16、ine under test are described in detail. NOTE 1 For noise control purposes, for example in the development of quieter machines, other methods em- ploying frequency analysis are usually applied. This International Standard applies to the following types of mower designed for private or professional (c
17、ommercial) use in recreational, decorative and domestic areas: - powered lawn mowers: walk-behind mowers, self-propelled mowers and riding mowers with, for example, rotary- and reel-mowing systems, and with reference to the power source such as mains-powered electric mowers, battery- powered electri
18、c mowers and internal com- bustion engine-powered mowers; - lawn and garden tractors or other multi-purpose gardening machines with attachments for mowing, with mowing systems as for powered lawn mowers being powered by electric batteries and/or internal combustion engines; - professional (commercia
19、l) mowers and turf-care equipment. It does not apply to the following: - towed machines with mowing systems which are not powered by the machine but powered by a gearing mechanism from the wheels of the ma- chine; -. agricultural and forestry machines for grass- cutting or grass-harvesting. This Int
20、ernational Standard does not describe the following: - measurement of sound pressure levels at the operators position (i.e. at the ears of the oper- ator); - determination of the directivity characteristics of the emitted noise and of the content of impulsive noise since these quantities are irrelev
21、ant; - determination of frequency characteristics, for example, for noise control purposes in the de- velopment of quieter machines, where frequency analysis in octave bands or one-third octave bands is usually applied. NOTES 2 A-weighted sound power levels determined in accord- ance with this Inter
22、national Standard tend to result in re- peatability standard deviations of approximately 1 dB. provided that the noise spectrum does not contain pro- nounced discrete frequencies. If it does, the magnitude of the repeatability standard deviations may be larger than 1 dB. The repeatability standard d
23、eviation of 1 dB reflects the cumulative effects of all causes of measurement un- certainty, excluding variations in the noise emission from machine to machine in mass or quantity production and from test site to test site. 3 For different test sites, the reproducibility standard deviation may be 2
24、dB. Artificial test site surfaces will 1 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 10:14:16 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 11
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