400 Commonwealth Drive, Warrendale, PA 15096-0001
SURFACE VEHICLE RECOMMENDED PRACTICE
Submitted for recognition as an American National Standard
REV. MAY1997
J845
Issued Revised
1963-01 1997-05
Superseding J845 MAR92
(R) OPTICAL WARNING DEVICES FOR AUTHORIZED EMERGENCY, EMERGENCY, MAINTENANCE, AND SERVICE VEHICLES
1.
Scope—This SAE Recommended Practice provides test procedures, requirements, and guidelines for single color, optical warning devices.
2.
Ref Referen erence ces s
2.1 2.1
Appl Applic icab able le Pub Publi lica cati tion ons— s—The The following publications form a part of this specification to the extent specified herein. The latest issue of SAE publications publications shall apply. apply.
2.1.1
SAE PUBLICATIONS —Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001. 15096-0001. SAE J575—Tests J575—Tests for Motor Vehicle Lighting Devices and Components SAE J576—Materials for Use in Optical Parts Such as Lenses and and Reflectors of Motor Vehicle Lighting Devices SAE J578—Color Specification of Electric Signal Lighting Devices SAE J759—Lighting Identification Code
3.
Def Defini inition tions s
3.1 3.1
360 360 Degr Degree ee Opt Optic ical al War Warni ning ng Dev Device ice— —A device that projects light in a horizontal 360 degree arc. It will appear to project a regularly repeating pattern of flashes to an observer positioned at a fixed location. Its function is to inform other highway users to stop, yield right-of-way, or indicate the existence of a hazardous situation.
3.2 3.2
Zona Zonall O Opt ptic ical al Warn Warning ing Devic Device— e—A A device that projects light in a defined horizontal arc of less than 360 degrees. It will appear to project project a regularly repeating repeating pattern of flashes to an observer observer positioned at a fixed location within the arc of coverage. Its function is to inform other highway users to stop, yield right-of-way, right-of-way, or indicate the existence of a hazardous situation.
3.3 3.3
Prim Primar ary y Opt Optic ical al War Warni ning ng Devi Device ces— s—Devices Devices or groups of devices that are intended to provide the primary visual optical warning signal as called out in each service service class. Unless prohibited by law or regulation, a Class 1 device may be used in place of Class 2 device and a Class 1 or 2 device may be used in place of Class 3 device.
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 arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. QUESTIONS REGARDING THIS DOCUMENT: (724) 772-8512 FAX: (724) 776-0243 TO PLACE A DOCUMENT ORDER; (724) 776-4970 FAX: (724) 776-0790 SAE WEB ADDRESS http://www.sae.org Copyright 1997 Society of Automotive Engineers, Inc. All rights reserved.
Printed in U.S.A.
SAE J845 Revised MAY1997 3.4
Secondary Optical Warning Devices—Devices or groups of devices of lower performance that can be used to provide supplemental optical warning to that provided by the primary optical warning device or devices.
3.5
Class 1 Optical Warning Devices—Primary optical warning devices for use on authorized emergency vehicles responding to emergency situations. These devices are utilized to capture the attention of motorists and pedestrians and warn of a potentially hazardous activity or situation.
3.6
Class 2 Optical Warning Devices—Primary optical warning devices for use on authorized maintenance or service vehicles to warn of traffic hazards such as a lane blockage or slow moving vehicle.
3.7
Class 3 Optical Warning Devices—Primary optical warning devices for use on vehicles authorized to display an optical warning device for identification only.
3.8
Light Pulse—A single, continuous emission of optical energy.
3.9
Flash—A light pulse or a train of light pulses, where a dark interval of at least 0.160 s separates the light pulse or the last pulse of the train of light pulses from the next pulse or the first pulse of the next train of light pulses. To be considered a train of light pulses, each pulse in the train must begin within 0.100 s after the end of the preceding light pulse.
4.
Lighting Identification Code, Markings, and Notices— The optical warning device may be also identified by the codes: a. W3-1, Class 1 b. W3-2, Class 2 c. W3-3, Class 3 in accordance with SAE J759. If the optical warning device is a zonal device covering less than 360 degrees, the angle of coverage may be indicated in parentheses. For example, a Class 1 device providing 120 degrees of signal may be marked W3-1 (120).
5.
Tests
5.1
SAE J575 is a part of this report. The following tests are applicable with the modifications as indicated. All tests are to be made at 12.8 V dc for devices intended for operation on 12 V systems and 25.6 V dc for 24 V systems using the wiring supplied by the manufacturer or wire of the minimum size recommended by the manufacturer. The voltage shall be measured at 12 in ± 1 in from the point at which the wiring exits the device.
5.1.1
VIBRATION TEST
5.1.2
MOISTURE TEST
5.1.3
DUST TEST
5.1.4
CORROSION TEST
5.1.5
WARPAGE TEST FOR PLASTIC COMPONENTS
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SAE J845 Revised MAY1997 5.1.6
FLASH RATE AND PHOTOMETRY —In addition to the test procedures in SAE J575, photometric performance shall be determined by measuring flash energy. The flash rate shall be measured and recorded at the end of the test. Photometric measurements shall be made with the device mounted in its normal operating position and all measurements shall be made with the light source of the device at least 18 m from the photometer. The device shall be mounted so that the horizontal plane through the photometer axis passes through the center of light source. The vertical axis through the center of the light source shall be perpendicular to this horizontal plane. The device shall be turned about its vertical axis within its defined arc of coverage until the photometer indicates minimum reading. This shall be the H-V point.
5.2
Color Test—SAE J578 is a part of this report.
5.3
Additional Tests
5.3.1
HIGH TEMPERATURE FLASH RATE TEST —The device shall be subjected to an ambient temperature of 50 °C ± 3 °C for a period of 6 h. The device shall be off (not operating) during the first hour and shall operate continuously for the next 5 h of the test. The flash rate shall be measured before the test, not less than 3 min nor more than 4 min after the beginning of the second hour of the test, and not less than 3 min nor more than 4 min after the end of the test.
5.3.2
LOW TEMPERATURE FLASH RATE TEST —The device shall be subjected to an ambient temperature of −30 °C ± 3 °C for a period of 6 h. The device shall be off (not operating) during the first 5 h and shall operate continuously for the last hour of the test. The flash rate shall be measured before the test, not less than 3 min nor more than 4 min after the beginning of the last hour of the test, and not less than 3 min nor more than 4 min after the end of the test.
5.3.3
DURABILITY TEST —The device shall be operated continuously for 200 h at an ambient temperature of 25 °C ± 3 °C in cycles consisting of 50 min on and 10 min off. The flash rate shall be measured before the test and not more than 3 min after the last off period at the end of the test.
5.4
Materials Test—SAE J576 is a part of this report.
6.
Performance Requirements
6.1
Performance Requirements—A device, when tested in accordance with the test procedures specified in Section 5, shall meet the following requirements.
6.1.1
VIBRATION —SAE J575
6.1.2
MOISTURE —SAE J575
6.1.3
DUST —SAE J575
6.1.4
CORROSION —SAE J575
6.1.5
WARPAGE —SAE J575
6.1.6
PHOTOMETRY —The device shall meet the photometric requirements contained in Tables 1, 2, or 3, and Tables 4, 5, or 6, Photometric Requirements and their footnotes. The summation of the flash energy measurements at the specified test points in a zone shall be at least the value shown. The flash rate for devices shall be at least 1 Hz and not more than 4 Hz.
6.2
Color—The color of light emitted shall be white, yell ow, red, or signal blue as specified in SAE J578.
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SAE J845 Revised MAY1997 6.3
Additional Requirements
6.3.1
HIGH TEMPERATURE —There shall be no evidence of operating conditions which would result in failure to comply with Section 6 of this document. Operation of the device shall begin and continue within 5 s of the beginning of each operating cycle and the flash rate at each of the required measurements shall be not less than 0.8 Hz nor more than 133% of the flash rate measured per 5.1.6.
6.3.2
LOW TEMPERATURE —There shall be no evidence of operating conditions which would result in failure to comply with Section 6 of this document. Operation of the device shall begin and continue within 5 s of the beginning of each operating cycle and the flash rate at each of the required measurements shall be not less than 0.8 Hz nor more than 133% of the flash rate measured per 5.1.6.
6.3.3
DURABILITY —There shall be no evidence of operating conditions which would result in failure to comply with Section 6 of this document. Operation of the device shall begin and continue within 5 s of the beginning of each operating cycle and the flash rate at each of the required measurements shall be not less than 0.8 Hz nor more than 133% of the flash rate measured in 5.1.6.
6.4
Material Requirements—Plastic materials used in optical parts shall meet the requirements of SAE J576.
7.
Guidelines
7.1
Photometric Guidelines
7.1.1
FLASH ENERGY —The Photometric Design Guidelines are contained in Tables 4, 5, or 6.
7.1.2
OPTICAL WARNING DEVICES CONTAINING MULTIPLE LIGHT SOURCES —The photometric performance of individual light sources contained in light bars and similar optical warning devices can be determined by testing each source independently over the specified arc of coverage.
7.2
Installation Guidelines—The following guidelines apply to optical warning devices as used on the vehicle and shall not be considered part of the requirements.
7.2.1
MOUNTING —The devices shall be installed within the guidelines provided by the manufacturer of the device.
7.2.2
VISIBILITY —Visibility of the optical warning device should be unobstructed by any part of the vehicle from 5 degrees above to 5 degrees below the horizontal. Multiple optical warning devices may be required to obtain 360 degrees of coverage. If a zonal device is used, the optical warning device shall be oriented to provide the desired coverage.
7.2.3
INDICATOR —There should be a visible or audible means of giving a clear and unmistakable indication to the driver when the optical warning devices are energized.
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SAE J845 Revised MAY1997
TABLE 1—PHOTOMETRIC REQUIREMENTS—CLASS 1 WARNING DEVICES ZONE TOTALS(1)(2)
Zone
1
Test Points Degrees 5U-V 2 1/2U-V H-V 2 1/2D-V 5D-V
Minimum Flash Energy Candela Seconds White
Minimum Flash Energy Candela Seconds Yellow
Minimum Flash Energy Candela Seconds Red
Minimum Flash Energy Candela Seconds Signal Blue
400
200
100
100
1. A one-time adjustment in lamp orientation from design position may be made in determining compliance to Tables 1 and 4, provided each adjustment does not exceed 1 degree in any direction. The zone shall comply after this one time, final reaim. 2. The measured value at each test point shall not be less than 60% of the minimum values in Table 4.
TABLE 2—PHOTOMETRIC REQUIREMENTS—CLASS 2 WARNING DEVICES ZONE TOTALS(1)(2)
Zone
Test Points Degrees
Minimum Flash Energy Candela Seconds White
Minimum Flash Energy Candela Seconds Yellow
Minimum Flash Energy Candela Seconds Red
Minimum Flash Energy Candela Seconds Signal Blue
100
50
25
25
5U-V 2 1/2D-V 1
H-V 2 1/2D-V 5D-V
1.
A one-time adjustment in lamp orientation from design position may be made in determining compliance to Tables 2 and 5, provided such adjustment does not exceed 1 degree in any direction. The zone shall comply after this one time, final reaim. 2. The measured value at each test point shall not be less than 60% of the minimum values in Table 5.
TABLE 3—PHOTOMETRIC REQUIREMENTS—CLASS 3 WARNING DEVICES ZONE TOTALS(1)(2)
Zone
Test Points Degrees
Minimum Flash Energy Candela Seconds White
Minimum Flash Energy Candela Seconds Yellow
Minimum Flash Energy Candela Seconds Red
Minimum Flash Energy Candela Seconds Signal Blue
40
20
10
10
5U-V 2 1/2U-V 1
H-V 2 1/2D-V 5D-V
1.
A one-time adjustment in lamp orientation from design position may be made in determining compliance to Tables 3 and 6, provided such adjustment does not exceed 1 degree in any direction. The zone shall comply after this one time, final reaim. 2. The measured value at each test point shall not be less than 60% of the minimum values in Table 6.
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SAE J845 Revised MAY1997
TABLE 4—PHOTOMETRIC DESIGN GUIDELINES—CLASS 1 WARNING DEVCIES
Zone
1
Test Points Degrees
Minimum Flash Energy Candela Seconds White
Minimum Flash Energy Candela Seconds Yellow
Minimum Flash Energy Candela Seconds Red
Minimum Flash Energy Candela Seconds Signal Blue
5U-V
20
10
5
5
2 1/2U-V
90
45
22.5
22.5
H-V
180
90
45
45
2 1/2D-V
90
45
22.5
22.5
5D-V
20
10
5
5
TABLE 5—PHOTOMETRIC DESIGN GUIDELINES—CLASS 2 WARNING DEVICES
Zone
1
Test Points Degrees
Minimum Flash Energy Candela Seconds White
Minimum Flash Energy Candela Seconds Yellow
Minimum Flash Energy Candela Seconds Red
Minimum Flash Energy Candela Seconds Signal Blue
5U-V
5
2
1
1
2 1/2U-V
22.5
12
6
6
H-V
45
22
11
11
2 1/2D-V
22.5
12
6
6
5D-V
5
2
1
1
TABLE 6—PHOTOMETRIC DESIGN GUIDELINES—CLASS 3 WARNING DEVICES
Zone
1
Test Points Degrees
Minimum Flash Energy Candela Seconds White
Minimum Flash Energy Candela Seconds Yellow
Minimum Flash Energy Candela Seconds Red
Minimum Flash Energy Candela Seconds Signal Blue
5U-V
2
1
0.5
0.5
2 1/2U-V
9
4
2
2
H-V
18
10
5
5
2 1/2D-V
9
4
2
2
5D-V
2
1
0.5
0.5
8.
Notes
8.1
Marginal Indicia—The change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions have been made to the previous issue of the report. An (R) symbol to the left of the document title indicates a complete revision of the report.
PREPARED BY THE SAE LIGHTING COORDINATING COMMITTEE AND THE SAE EMERGENCY WARNING LAMP AND DEVICES STANDARDS COMMITTEE
-6-
SAE J845 Revised MAY1997 Rationale—Based on the results of demonstrations conducted over the last ten years by the Emergency Warning Lights and Devices Standards Committee and the Signalling and Marking Standards Committee, the following changes have been made to this document. a. Elimination of steady-state measurements to estimate the performance of flashing optical warning devices. Advances in laboratory instrumentation have made it practical and cost effective to directly measure the flash energy generated by any optical warning device. There is no longer a need to use indirect measurement techniques, and the Alternative Method of Measuring Photometric Performance has been eliminated. b. Elimination of the definitions of various types of 360 degree optical warning devices. In the revised report, all devices can be tested following the same procedures and the definitions are no longer needed. c.
Addition of a definition of zonal optical warning devices. Zonal optical warning devices have the same requirements as 360 degree devices but are designed to provide protection throughout an arc of less than 360 degrees. Such devices, i.e., the inboard elements in light bars, have been in common use for many years but were not covered by any report.
d. Establishment of new performance requirements for use of the color blue. The use of blue as a signal color for emergency vehicles has steadily increased until now approximately one half of such vehicles employ blue either alone or in combination with red or white. It is apparent that the operators of emergency vehicles have determined that the spectacular performance of blue at night outweighs the very poor performance of this color during the day. At the present time, most devices being manufactured use the same light source for all colors. The color temperature of the light source determines the relative amounts of red and blue energy. Typically a halogen light source will provide greater amounts of red light and a gaseous discharge light source more blue light. For users operating a combination of such devices in red and blue, the primary optical warning device may be red or blue depending on the light source. The weaker color may be a secondary optical warning device to supplement the stronger color. This is an acceptable arrangement and is addressed in 3.4. For example, if blue signal devices using halogen light sources are employed and a Class 1 device is mandated, a higher wattage lamp may be required. Conversely, in a red gaseous discharge system, the same issues must be considered. Such sources are available but require more energy to operate and may require some design modifications to dissipate the increased heat associated with the higher light output. e. Flash Rate—The results of numerous demonstrations strongly imply that a signal of adequate conspicuity requires the flash energy levels called for in Tables 1, 2, or 3. Increasing the flash rate without a corresponding increase in photometric energy lowers the flash energy. However, if the flash rate is increased and the photometric energy is maintained above the minimum requirement, the conspicuity of the signal is improved. From a practical stand point, higher flash rates reduce the travel distance between signal flashes and promote earlier recognition of a hazardous condition. For example, for an emergency vehicle approaching another vehicle with each traveling at 30 mph, the closing distance between flashes is:
SAE J845 Revised MAY1997
Flash Rate—Hz
Closing Distance—Ft
1
88
2
44
4
22
This document increases the allowable flash rate maximum to 4 Hz, so long as the flash energy content of the signal is not reduced below the required tabulated values. It is important to note that the energy to operate such devices may have to increase with the flash rate. f.
Test Voltage—In conformance with other optical warning device reports, the test voltage is changed to 12.8 V for 12 volt systems and 25.6 V for 24 volt systems instead of “the voltage recommended by the manufacturer.”
g. Miscellaneous Editorial Changes—The word “device” is used to indicate the assembly of components which is tested. The previous edition used both the words “lamp” and “device” for this purpose as well as referring to light sources as “lamps.” The typographical errors created when the photometric performance tables were typeset have been revised to their original values. Relationship of SAE Standard to ISO Standard—Not applicable. Application—This SAE Recommended Practice provides test procedures, requirements, and guidelines for single color, 360 degree and zonal optical warning devices. Reference Section SAE J575—Tests for Motor Vehicle Lighting Devices and Components SAE J576—Materials for Use in Optical Parts Such as Lenses and Reflectors of Motor Vehicle Lighting Devices SAE J578—Color Specification of Electric Signal Lighting Devices SAE J759—Lighting Identification Code Developed by the SAE Emergency Warning Lamp and Devices Standards Committee Sponsored by the SAE Lighting Coordinating Committee
