1、SURFACE VEHICLE STANDARD J994 SEP2014 Issued 1967-07 Reaffirmed 2014-09 Superseding J994 MAR2009 AlarmBackupElectric Laboratory Performance TestingRATIONALE J994 has been reaffirmed to comply with the SAE five-year review policy. _ SAE Technical Standards Board Rules provide that: “This report is pu
2、blished 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 arising therefrom, is the sole responsibility of the user.” SAE reviews each techni
3、cal 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 2014 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmit
4、ted, 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: +1 724-776-4970 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WE
5、B ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J994_201409 FOREWORD This document has been modified to include additional system voltages and reduce the upper limit of the acceptable frequency range
6、. Additional modifications have been made to clarify ambiguous sections of the Standard. Rationale for the modifications is included at the end of this document. 1. SCOPE The scope of this SAE Standard is the definition of the functional, environmental, and life cycle test requirements for electrica
7、lly operated backup alarm devices primarily intended for use on off-road, self-propelled work machines as defined by SAE J1116 (limited to categories of (1) construction, and (2) general purpose industrial). 1.1 Purpose The purpose of this document is to define a set of performance requirements for
8、backup alarms, independent of machine usage. The laboratory tests defined in this document are intended to provide a uniform and repeatable means of verifying that a test alarm meets the stated requirements. For on machine requirements and test procedures, refer to SAE J1446. 2. REFERENCES 2.1 Appli
9、cable Publications The following publications form a part of the specification to the extent specified herein. Unless otherwise indicated, the latest revision of SAE publications shall apply. 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001,
10、Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. SAE J184 Qualifying a Sound Data Acquisition System SAE J1116 Categories of Off-Road Self-Propelled Work Machines SAE J1446 On-Machine Alarm Test and Evaluation Procedure for Construction and General Purpose Indust
11、rial Machinery 2.1.2 ANSI Publications Available from ANSI, 25 West 43rd Street, New York, NY 10036-8002, Tel: 212-642-4900, www.ansi.org. ANSI S1.4 Specification for Sound Level Meters ANSI S1.40 Specification for Acoustical Calibrators 2.1.3 ASTM Publication Available from ASTM International, 100
12、Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM B 117 Method of Salt Spray (Fog) Testing 2.1.4 Mil Specification Available from Defense Printing Service, Detachment Office, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094. MIL-STD
13、-810B Environmental Test Methods 510 and 514.1 2.2 Related Publications The following publications are provided for information purposes only and are not a required part of this document. 2.2.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel:
14、 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. SAE J1105 HornForward WarningElectricPerformance, Test and Application SAE J1211 Recommended Environmental Practices for Electronic Equipment Design SAE J1455 Recommended Environmental Practices for Electronic Equipmen
15、t Design in Heavy-Duty Vehicle Applications SAE J1849 Emergency Vehicle Sirens SAE INTERNATIONAL J994 Reaffirmed SEP2014 Page 2 of 15_ 2.2.2 ANSI Publications Available from ANSI, 25 West 43rd Street, New York, NY 10036-8002, Tel: 212-642-4900, www.ansi.org. ANSI S1.1 Acoustical Terminology ANSI S1.
16、13 Methods for the Measurement of Sound Pressure Level 3. DEFINITIONS 3.1 Free Field A free field, for the purposes of this document, is defined as a space with no reflecting surface within 15 m of the sound source in any direction. 3.2 Horizontal Reflecting Plane A horizontal reflecting plane is de
17、fined as flat ground with a surface no rougher than an asphalt road. A paved parking lot with no reflecting surfaces within 15 m would be an acceptable horizontal reflecting plane for the tests outlined in this document. 3.3 Zero Degree Axis A line known as the “zero degree axis” is defined to corre
18、spond to the centerline of the sound producer, perpendicular to and extending outward from the output face of the alarm. 3.4 Sample Alarm A sample alarm shall consist of an alarm randomly drawn from the production population. 3.5 Predominant Sound Frequency The predominant sound frequency of the ala
19、rm shall be defined as the frequency that produces the highest A-weighted sound pressure level. This frequency may or may not correspond to the fundamental frequency produced by the alarm. 3.6 Test Voltages The nominal, extreme low and extreme high system test voltages are defined for each system vo
20、ltage in Table 1. All voltages are 0.2 V, measured at the input terminals of the alarm when the alarm is operating. 3.6.1 Test Voltage Table NOTE: On multi-voltage alarms, use the extreme low system voltage from the lowest system voltage included in the multi-voltage range, and the extreme high syst
21、em voltage from the highest included voltage range, and all included nominal voltages, unless otherwise specified. SAE INTERNATIONAL J994 Reaffirmed SEP2014 Page 3 of 15_ TABLE 1 - TEST VOLTAGES System Voltage(1) Nominal System Voltage Extreme Low System Voltage Extreme High System Voltage 12 (IC) 1
22、4.0 9.0 16.0 24 (IC) 28.0 18.0 32.0 36 (E) 42.0 27.0 42.0 42 (IC)(2) 49.0 32.0 56.0 48 (E) 56.0 36.0 56.0 72 (E) 84.0 54.0 84.0 80 (E) 94.0 60.0 94.0 1. IC Internal Combustion E Electric (Battery Powered) 2. New European Electrical SystemThe Extreme High System Voltages for System Voltages of 36, 48
23、, 72, and 80 volts are equal to the Nominal System Voltages because these are battery powered (e.g., fork lifts) and will not be subjected to possible alternator failures causing excessively high voltages as in the 12, 24, and 42 volt internal combustion electrical systems. 3.7 Test Sequence All fun
24、ctional and performance tests shall be conducted in the order in which they are presented. The same sample alarm shall be used for all of the Functional, Environmental, and Life Tests. 4. INSTRUMENTATION Persons technically trained and experienced in current techniques of sound measurement should se
25、lect and operate the equipment. Sound Engineering judgment, including an assessment of the “state-of-the-art” with respect to test equipment, facilities, and test personnel, should be used when establishing specific test procedures used to verify compliance with the requirements of this standard. Wh
26、en single-sided test parameters are specified, such as “minimum”, “maximum”, and “at least”, it is intended that the required specific parameter be met, with the constraint that deviations from the nominal parameter value (on the open-ended side) be minimized. When non-specific parameter tolerances
27、are used, such as “approximately”, it is intended that deviations from the nominal parameter be minimized. 4.1 A sound level meter which meets the Type I requirements of ANSI S1.4. 4.2 As an alternative to making direct measurements using a sound level meter, a microphone or sound level meter may be
28、 used with a magnetic tape recorder and/or a graphic level recorder or indicator meter, provided the system meets the requirements of SAE J184, for the frequency range that is of primary concern. The deviations in the magnetic tape recorder frequency response from flat response, especially at lower
29、frequencies, must not affect the overall reading by more than 0.5 dB. 4.3 A sound pressure level calibrator meeting the requirement of ANSI S1.40 (accuracy within 0.5 dB). 4.4 A temperature measuring system accurate to 0.5 C over the range of 40 to +85 C. 4.5 A voltage measuring system accurate to 1
30、00 mV over the range of extreme system voltages for the tested system voltage(s). 4.6 Vibration apparatus. 4.7 Environmental chamber. 4.8 Dust chamber. 4.9 Rain, steam, and corrosion chamber. SAE INTERNATIONAL J994 Reaffirmed SEP2014 Page 4 of 15_ 5. SOUND PRESSURE LEVEL TEST SETUP Sound pressure le
31、vel Test - Two acceptable test methods will be described for measuring alarm sound pressure level. 5.1 Test Method 1 The alarm is located in a free field or an equivalent fully anechoic room. The microphone is directed toward the alarm sound output opening along the zero degree axis and at the dista
32、nce specified by the test requirements. 5.2 Test Method 2 This is an alternative method for testing an alarm sound pressure level without the aid of an anechoic room. The alarm is located in a free field except for a horizontal reflecting plane and an acoustical barrier partition. The acoustical bar
33、rier partition must be constructed. 5.2.1 Required Materials for Acoustical Barrier Unless otherwise specified, all dimensional tolerances are 10 mm. a. Two pieces of particle board 900 mm x 1200 mm x 16 mm 2 mm thick b. Two Tripods adjustable to 1200 mm high c. Three each 200 mm x 200 mm x 90 degre
34、e sheet metal shelf brackets. d. Two sections of sound absorbing foam of dimensions 1200 mm x 1350 mm and a thickness of 50 mm or greater. The sound absorbing foam should have an absorption efficiency of at least 50% at 50 Hz rising to at least 75% at 1000 Hz and greater. 5.2.2 Construction of Acous
35、tical Barrier Using the three 200 mm shelf brackets and screws, center and attach one of the 900 mm x 1200 mm particle boards perpendicular to the other 900 mm x 1200 mm base board to yield a 900 mm high wall as shown in Figure 1. Two brackets should be located 150 mm from the outside edge on one si
36、de of the upright board. The third bracket should be mounted in the center on the other side of the upright board. Cover the exposed particle board with the sound absorbing foam as shown in Figure 1. 5.2.3 Alarm and Microphone Locations Secure the alarm and microphone to their tripods. Position the
37、alarm and microphone on opposite sides of and equidistant from the sound barrier at a height of 1200 mm 10 mm above the horizontal reflecting plane. The distance between the two devices is specified in 6.3 of the Functional Test Requirements. 5.3 Allowable Background Noise Level While the sound pres
38、sure level test is in progress, the sound pressure level due to all sources other than the alarm device shall be at least 15 dB (A) lower than the sound pressure level of the alarm. This precaution reduces the effect of background noise on the sound pressure level test results. 5.4 Sound Level Meter
39、 Settings The sound level meter shall be set for fast response or equivalent and have the A-weighting network installed when checking sound pressure levels. SAE INTERNATIONAL J994 Reaffirmed SEP2014 Page 5 of 15_ FIGURE 1 - ACOUSTICAL BARRIER DIMENSIONS FOR TEST METHOD 2 SAE INTERNATIONAL J994 Reaff
40、irmed SEP2014 Page 6 of 15_ 5.5 Instrumentation Precautions Proper usage 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 pr
41、ecautions to be observed. Specific items to review include: 5.5.1 The Microphone The type of microphone, its directional response characteristics, and its orientation relative to the ground plane and source of noise. 5.5.2 Calibration Field calibration should be made immediately before and after eac
42、h test sequence. Internal calibration means are acceptable for field use, provided that external calibration is accomplished immediately before or after field use. 5.5.3 Windscreens When using a windscreen, it should be calibrated for the type of noise source being measured and data corrected if nec
43、essary. It is recommended that measurements be made only when the wind speed is below 19 km/h. 6. FUNCTIONAL TEST REQUIREMENTS Unless otherwise specified, data measurements will be taken during a minimum test period of 1 min operation at ambient temperature of 25 C 11 C and nominal system voltage(s)
44、 (0.2 VDC) for the tested system voltage(s) in Table 1. 6.1 Predominant Sound Frequency Measure and record the predominant sound frequency of the alarm. The predominant sound frequency of the alarm shall be defined as the frequency that produces the highest A-weighted sound pressure level. The accep
45、table frequency range is 700 to 2800 Hz. 6.2 Cyclic Pulsation Rate and Duty Cycle Measure and record the rate of cyclic sound pressure level pulsations from the alarm and the duration of the “on” and “off” intervals. The cycles of sound pressure level pulsations from the alarm shall be 0.8 to 1.8 Hz
46、. The duration of the “on” interval shall be equal to that of the “off” interval within 20%, as defined by the formula: (“on” interval minus “off” interval) divided by (“on” interval plus “off” interval), multiplied by 100%. 6.3 Sound pressure level Measure and record the sound pressure level of the
47、 alarm at all nominal system voltages included in the voltage range of the alarm using the methods of 5.1 or 5.2. The microphone shall be placed on the zero axis of the alarm at a distance of 1.2 m 0.01 m from the front face of the alarm. The sound pressure level shall be any of the following: Type A - 112 dB (A) Type B - 107 dB (A) Type C - 97 dB (A) Type D - 87 dB (A) Type E - 77 dB (A) Type F - Other SAE INTERNATIONAL J994 Reaffirmed SEP2014 Page 7 of 15_
