This document provides design guidelines, test procedure references, and performance requirements for omni-directional and selective coverage, single color, optical warning devices used on authorized emergency, maintenance and service vehicles. It is intended to apply to, but not limited to, surface land vehicles.
Based on the results of demonstrations conducted over the last ten years by the Emergency Warning Lights and Devices Standards Committee and the Signaling and Marking Standards Committee, the following changes have been made to this document.
1. Various editorial changes were made to harmonize the language with that used in other warning lights and devices standards.
2. Multiple flash patterns and cyclic patterns have been added. End users have increasingly been requesting non repetitive flash patterns to prevent complacency.
3. Light Source definition has been added.
4. Light pulse and flash definitions have been revised.
5. Optical Power has been defined.
6. Multiple flash patterns that are user adjustable must be rated as the lowest performance mode.
7. Flash Rate was added to Section 5, "Tests".
8. Test Voltage - In conformance with other optical warning device reports, a tolerance has been added to the test voltages, and requirements added for 36 volt systems.
9. Environmental tests for flash rate were revised.
10. Photometric performance has been changed from flash energy to meeting a specified optical power and peak intensity. Advances in laboratory instrumentation have made it practical and cost effective to directly measure the optical power generated by any optical warning device. The direct measurement of peak intensity also is readily done with current technology.
11. The redefinition of the white boundary toward blue was added in anticipation of a change to the SAE J578 specification to harmonize color boundaries with the ECE standard.
12. New markings for selective coverage devices were added to provide a marking distinction between omnidirectional devices and devices with selective coverage.