SECTION 638 - FLASHER ASSEMBLIES
638.01 Description. This work consists of furnishing all components and materials
required to assemble flasher assemblies and School Zone Flasher Beacon assemblies, including options for solar powered applications, in accordance to these specifications and the details shown on the plans.
638.01.1 Operational Specifications. The two flashers on the flasher assembly shall
alternate on and off when recei ving a signal from the traf fic controller. The flasher assembly shall have beacons that flash at a rate of not less than 50 or more than 60 times per minute. The illuminated period of each flas h shall not be less th an 50% of the dwell time. The yellow signals shall be flashed a lternately. The beacons shall have a night dimming feature. The School Zone Flasher Beacon assembly shall be activated by an integrated, programmable microcontroller (Time Switch Un it). The Time Switch Unit shall store at least 500 days of flash data.
638.02 Materials. Materials for the assembly shall meet the following
Sections/Subsections: Traffic Signs and Sign Posts .............................................................. 721 Pull Boxe s ..................................................................................... 722.06 Traffic Signal Heads ..................................................................... 722.14
638.02.1 Solar/Battery Unit. All solar/battery units associated with flasher assemblies
shall include two (2) 10-watt solar panels no larger than the footprint of the housing. The solar engine shall house two (2) field-replaceable, sealed lead-acid batteries no greater than 24 Ah each. The solar panel and battery system shall be 12 Volt DC. The solar panel shall meet the design qualification and type approval of photovoltaic modules in accordance with IEC 61215. This specification include s radiation testing, thermal testing, and mechanical testing for environmental conditions such as UV-exposure, thermal cycling, as well as degradation of maximum power output.
638.02.2 Solar Engine. All solar engine units associated with Flasher Assemblies shall
be constructed from powder coated aluminum. The solar panels shall be integrated into the solar engine. The solar engine shall have the provision to mount an external device for remote activation. The system shall have the capability to power such device. The solar engine must contain sufficient space to house a third party device inside a sealed enclosure located inside the solar engine.
638.02.3 Time Switch Unit . All time switch units associated with School Flasher
Assemblies shall be of solid state circuitry, continuous duty with a 7-day cycle clock operating from the 120 volt AC service line. Time switch unit shall automatically compensate for daylight savings time changes.
638.02.4 Hardwired option. Flasher assemblies shall have the option to operate on 120
volt AC electrical service. Flasher assemb lies operating on 120 volt AC shall be in accordance with Section 632.
638.03 Construction Requirements. Flashing Assemblies shall be installed at the
locations and as indicated in the plans and in conformance with the requirements herein.
638.03.1 Tests and Warranties. After completion of flasher units, the Contractor shall
demonstrate by tests to the Engineer's satisfaction that: All circuits are continuous and free from short circuits, That all circuits are free from unspecified grounds, That the resistance to ground of non-grounded conductors is at least one (1) megohm at 60°F measured with a 1000 ohms per volt megger, and That the ground resistances are not more than 25 ohms. The system, including battery packs, solar panel, LED modules and all components, shall be guaranteed for a minimum of three (3) years.
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