This document provides design guidelines, test procedure references, and performance requirements for directional, single color, flashing optical warning devices used on authorized emergency, maintenance and service vehicles. It is intended to apply to, but not limited to, surface land vehicles.
The definition of LIGHT SOURCE was renamed to EWD LAMP ASSEMBLY.
Test voltages were added to accommodate the electrical system voltages of industrial vehicles.
The flash rate limits were revised from "at least 1 Hz and not more than 4 Hz" to "at least 1.0 Hz and not more than 4.0 Hz" to eliminate rounding errors.
References to SAE J2139 were added as an alternative to SAE J575 to accommodate devices intended for vehicles wider than 2032mm.
A requirement was added that test samples which exhibit a partial outage of non-filament EWD lamp assemblies must still comply with the photometric requirements upon the completion of any of the required tests.
The photometric test procedure was revised to ensure that sources whose output increases prior to stabilizing will still comply with the photometric requirements at their lowest output levels.
The definition of pseudo-random flash pattern was added.
Requirements for pseudo-random flash patterns were added to section "FLASH RATE AND FLASH PATTERNS".
Sections 5.7 and 6.7 were renamed "FLASH RATE AND FLASH PATTERNS".
Added the "optical power" to the list of characteristics to be measured in Section 6.7 in order to be all inclusive. It is unknown why it was left out of earlier versions.
The characteristics, including optical power, peak intensity, flash rate, period, number of pulses per flash, on time (electrical), off time (electrical) and pulse separation, shall be measured and recorded. If the flasher or power supply/flasher has more than one flash pattern, the characteristics shall be measured and recorded for each pattern.