1、 SURFACE VEHICLE RECOMMENDED PRACTICE J1174 APR2015 Issued 1977-10 Revised 2015-04 Superseding J1174 MAR1985 Operator Ear Sound Level Measurement Procedure for Small Engine Powered Equipment RATIONALE This document was revised to allow the use of sound level meters and data acquisition systems confo
2、rming to current ANSI and SAE Standards. The updated standard includes the option for testing on an artificial surface or natural turf. 1. SCOPE This SAE Recommended Practice establishes the instrumentation and procedure to be used in measuring the operator ear sound level for engine powered equipme
3、nt under 30 kW (40 bhp). The sound levels obtained by using this procedure are representative of the sound levels generated by the equipment under typical operating conditions. It is intended to include equipment such as lawn mowers, snow blowers, and tillers. It is not intended to include equipment
4、 designed primarily for operation on highways or within factories or buildings, or vehicles such as motorcycles, snowmobiles, and pleasure motorboats that are covered by other SAE Standards or Recommended Practices. This procedure does not cover handheld equipment such as chainsaws, leaf blowers, an
5、d trimmers. This SAE Recommended Practice may also be used when measuring the operator ear sound level of similar equipment powered by electricity or other power sources. 2. REFERENCES 2.1 Applicable Documents The following commonly referenced publications form a part of this document as listed belo
6、w. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing
7、in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1.1 SAE Publication Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www
8、.sae.org. _ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement ari
9、sing therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2015 SAE International All rights reserved. No part
10、 of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 7
11、24-776-4970 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J1174_201504 SAE INTERNATIONAL J1174 Revised APR2015 Page 2 of 6 SAE J1
12、84 Qualifying a Sound Data Acquisition System 2.1.2 ANSI Publication Available from American National Standards Institute, 25 West 43rd Street, New York, NY 10036-8002, Tel: 212-642-4900, www.ansi.org. ANSI/ASA S1.4 American National Standard Electroacoustics - Sound Level Meters ANSI/ASA S1.40 Amer
13、ican National Standard Specifications and Verification Procedures for Sound Calibrators ANSI/ASA S1.1 Acoustical Terminology ANSI/ASA S1.13 Measurement of Sound Pressure Levels in Air 2.1.3 ASTM Publication Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, P
14、A 19428-2959, Tel: 610-832-9585, www.astm.org ASTM C423-09a Method of Test for Sound Absorption of Acoustical Materials in Reverberation Rooms 2.1.4 ISO Publication Available from International Organization for Standardization, ISO Central Secretariat, 1, ch. de la Voie-Creuse, CP 56, CH-1211 Geneva
15、 20, Switzerland, Tel: +41 22 749 01 11, www.iso.org. ISO 3744 Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Engineering methods for an essentially free field over a reflecting plane ISO 11094 Acoustics - Test code for the measurement
16、 of airborne noise emitted by power lawn mowers, lawn tractors, lawn and garden tractors, professional mowers, and lawn and garden tractors with mowing attachments ISO 3411 Earth-moving machinery - Physical dimensions of operators and minimum operator space envelope 2.1.5 IEC Publication Available f
17、rom IEC Central Office, 3, rue de Varembe, P.O. Box 131, CH-1211 Geneva 20, Switzerland, Tel: +41 22 919 02 11, www.iec.ch. IEC 60942 Electroacoustics - Sound calibrators 3. INSTRUMENTATION The following instrumentation shall be used for the measurement required. 3.1 A sound level meter meeting the
18、Type 1 or Type S1A requirements of ANSI/ASA S1.4 3.1.1 As an alternative to making direct measurements using a sound level meter, a microphone or sound level meter may be used with a recorder or other indicating instrument, provided the system meets the requirements of SAE J184. 3.2 A sound level ca
19、librator with an accuracy of 0.5 dB conforming to IEC 60942 Class 1 and/or ANSI S1.40. 3.3 If a microphone windscreen is used, it shall not affect the overall reading by more than 0.5 dB(A) for the sound source that is being measured (see 5.4). 3.4 An anemometer with steady-state accuracy of 10% at
20、9 m/s (20 mph). 3.5 An engine speed indicator (accuracy 1% of full range). SAE INTERNATIONAL J1174 Revised APR2015 Page 3 of 6 3.6 A thermometer for measurement of ambient temperature. 4. PROCEDURE 4.1 Test Site When testing outdoors the test area shall consist of a flat open space free from the eff
21、ects of signboards, buildings, or hillsides for at least 15 m (50 ft) from the center of the measurement zone. Two alternative test surfaces are available as specified in ISO3744 and ISO11094. This standard allows for hemi-anechoic chamber measurements using an artificial surface. The minimum dimens
22、ions of the measurement zone are 1.0 m (3.3 ft) wider on all sides of the equipment being tested. (See Figure 1.) Figure 1 - Test site 4.1.1 Artificial Surface SAE INTERNATIONAL J1174 Revised APR2015 Page 4 of 6 When testing indoors an artificial surface may be used in place of natural turf. The ent
23、ire measurement zone surface shall be covered with the artificial surface. The acoustical properties tested per ASTM C423-09a of the artificial surface shall meet the specifications shown in Table 1. An example of this type of surface can be found in Annex A of ISO 11094. Table 1 - Acoustical proper
24、ties Hz Sound Absorption Coefficient 125 0.00-0.20 250 0.20-0.40 500 0.40-0.60 1000 0.60-0.80 2000 0.70-0.90 4000 0.80-1.00 4.1.2 Natural Turf The entire surface of the measurement zone shall consist of a high quality natural grass. The surface should be free of moisture, frost or snow. The height o
25、f cut should be set closest to 30mm as possible but not lower than 30mm. The height of cut shall be adjusted with the equipment resting on a hard, flat surface. 4.1.3 The observer reading the sound level meter shall be at least 2 m (6.6 ft) from the equipment being tested and not affect the measured
26、 sound level. One other person may be directly behind the observer reading the meter. All others, except the operator of the equipment being tested, shall be at least 7 m (23 ft) from the equipment. 4.1.4 The A-weighted sound level, (including wind effects) due to sources other than the equipment be
27、ing measured, shall be at least 10 dB lower than the level of the equipment being measured. 4.2 Equipment Operation All equipment shall be tested in stationary mode as specified in 4.2.1 to 4.2.5. Tests in the stationary mode shall be made at the center of the measurement zone. Then engine(s) or mot
28、or(s) shall be set at the equipment manufacturers maximum specified rpm. Then all mechanisms necessary for the equipment to perform its intended function shall be engaged. 4.2.1 Mowing Equipment The cutting height of the blade shall be set at the closest available position to 30 mm. 4.2.2 Walk-Behin
29、d Tillers Test in a stationary mode those units that are intended to be propelled by the tines. 4.2.3 Walk-Behind Snow Blowers Test in a stationary mode. 4.2.4 Garden Tractors with Attachments Other than Mowers These shall be tested in the stationary mode as stationary equipment. 4.2.5 Miscellaneous
30、 Equipment Test in a stationary mode according to its intended use. SAE INTERNATIONAL J1174 Revised APR2015 Page 5 of 6 4.3 Measurements 4.3.1 The sound level meter or data acquisition system shall be set for slow response and the A-weighted filter. 4.3.2 The ambient wind speed relative to the sourc
31、e and microphone, ambient temperature, equipment manufacturers maximum specified engine rpm, engine rpm at test condition, and ambient A-weighted sound level shall be measured. 4.3.3 Equipment Type 4.3.3.1 Walk-Behind With an operator present, the microphone shall be supported independent of the equ
32、ipment being tested. The microphone shall be located 1.7 m (66 in) above the test surface, 250 mm (10 in) to the right and left of the centerline of the operators position, and 200 mm (8 in) to the rear of the rear-most point of the handle, with the handle in the forward-most position. 4.3.3.2 Ride-
33、On With an operator present, the microphone shall be supported independent of the equipment being tested. The microphone shall be located 760 mm (30 in) above the loaded seat, 250 mm (10 in) to the right and left of the centerline of the operators position, and 100 mm (4 in) forward of the seat back
34、, with the seat adjusted to its center position. 4.3.3.3 Stationary Stationary equipment normally requiring an operator shall be tested with an operator at the normal operator station. If the operator is standing, the microphone shall be located 1.7 m(66 in) above the test surface and 460 mm (18 in)
35、 from the outer-most vertical surfaces of the equipment being tested, and 250 mm (10 in) to the right and left of the centerline of the operator. If the operator is seated, locate the microphone as in 4.3.3.2. Record the exact microphone position relative to the equipment. 4.3.4 The sound level mete
36、r or data acquisition system shall be observed for a minimum of 5 s or until a stabilized reading is obtained. Record the maximum sound level to the nearest 0.5 dB(A) and document the microphone position. The reported sound level shall be the highest repeatable sound level observed during the test.
37、5. GENERAL REQUIREMENTS 5.1 It is recommended that the equipment operator size be within the ISO 3411 dimensions for 5-95 percentile man. 5.2 It is strongly recommended that persons technically trained and experienced in the current techniques of sound measurement select the equipment and conduct th
38、e tests. 5.3 Proper use of all test instrumentation is essential to obtain valid measurements. Operating manuals or other literature furnished by the instrument manufacturer, should be referred to for both recommended operation of the instrument and precautions to be observed. Specific items to be c
39、onsidered are: 5.3.1 The type of microphone, its directional response characteristics, and its orientation relative to the noise source. 5.3.2 The ambient weather conditions (temperature, humidity, and barometric pressure) can affect the performance of all instrumentation. Care should be taken to fo
40、llow the instrumentation equipment manufacturers recommendations. Proper acoustical calibration procedure shall include the influence of extension cables. Field calibration shall be made immediately before and after each test sequence. Internal calibration means is acceptable for field use, provided
41、 that external calibration is accomplished immediately before and after field use. SAE INTERNATIONAL J1174 Revised APR2015 Page 6 of 6 5.4 It is recommended that measurements be made only when wind speed is below 19 km/h (12 mph). 5.5 It is recommended that care be taken in selecting a test site and
42、 placing the artificial test surface so that test surface vibrations do not contribute to the sound level readings. 6. NOTES 6.1 Marginal Indicia A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have be
43、en made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only. PREPARED BY THE SAE SMALL ENGINE AND POWERED EQUIPMENT COMMITTEE
