School Zone Beacon Assembly

School zone beacon assemblies shall consist of a three section, twelve inch traffic signal having 12” diameter round yellow lenses, located one above and one below a nominal 12” square, illuminating, speed limit indication; a twelve foot tall, aluminum pedestal; a time switch operated flasher controller; a sign with message reading “SCHOOL SPEED LIMIT WHEN FLASHING” and mounting brackets to allow all of the various components to be assembled. Components of the school zone beacon assembly shall be in accordance with the following specifications.

Signal Heads

Each signal housing shall be screw injection molded of polycarbonate. The top and bottom shall include mounting holes sized to accommodate standard 1 ½ inch signal mounting hardware. Each mounting hole shall be surrounded with molded in serrations to provide a positive lock between the signal and mounting brackets. The serrations shall provide 5 degree increments of adjustment to allow proper aiming of the signal. The inside surface of each body end shall be essentially smooth and flat. Any webbing or other protrusions which prevent the use of standard signal mounting hardware or which obstruct the use of normal installation tools shall be cause for rejection.

The signal doors shall be screw injection molded of polycarbonate resin. The doors shall be hinged to the body section on the left side via stainless steel hinge pins and shall be equipped with a substantial screw or wing nut type fastener of stainless steel material on the right side to provide a secure closure means. Both the hinge and closure device shall be internal to the signal body and shall not protrude from the body side in any way. Both the hinge pins and the closing fasteners shall be held captive to the door for ease of maintenance. In the closed position, the hinge pins shall be positively locked in place to preclude their falling out due to vibration. Each door shall be equipped with a molded lip, which the visor shall fit over in such a way as to prevent any possibility of light escaping between the door and the visor.

The door of the round signal sections shall be fitted with a tunnel type visor which shall, at its base and extending approximately 1” from the door surface totally surround the lens to provide strength. Beyond this strengthening ring, the bottom portion of the visor shall be removed to form a “tunnel”. All visors shall be of polycarbonate resin and shall be molded with four ribs extending outward from the door surface for added rigidity. Tabs shall protrude at right angles to the side of the visor to provide attachment to the signal door, and to allow their easy removal or replacement. All visor mounting hardware shall be of stainless steel. Signal head assemblies shall be supplied with all visors attached. The door of the square illuminating speed limit section shall also be fitted with a tunnel type visor which shall surround three sides of the door, and shall be held in place with stainless steel hardware.

Round lenses shall be molded of polycarbonate material and shall conform to the specifications of the INSTITUTE of TRANSPORTATION ENGINEERS. Square lenses shall be molded of polycarbonate material and shall present a smooth front to reduce the potential for dirt to accumulate. Each lens shall be gasketed to prevent the entrance of dust or moisture into the optical portion of the signal. All gaskets shall be neoprene. Round lenses shall be yellow. Square lenses shall be Portland orange with all but the numerical speed indication covered with an opaque coating so that the speed message will appear Portland orange when illuminated.

Each signal shall be equipped with a highly polished, parabolic reflector manufactured of “ALZAK” material. The reflector shall be mounted to a one piece die cast aluminum component which shall hinge to the body section in such a manner as to be positively located when the signal door is in a closed position but yet shall allow easy access to the reflector and lens for cleaning. Reflectors which mount to the door assembly are specifically prohibited. The reflector shall accommodate a lamp receptacle meeting the specifications of The INSTITUTE of TRANSPORTATION ENGINEERS and shall be arranged such that proper lamp filament rotation shall be easily accomplished. Signals shall be designed to accommodate lamps having a light center length of 3 inches. The optical portion of the signal head shall be designed as a unit to prevent sun phantom.

Each signal head shall be equipped with a terminal block for electrical hookup. All terminal blocks shall be separate and removable components which shall provide minimum 8 - 32 screws for all wiring connections. No “Fast-On” terminals shall be permitted.

The color of each component of the signal head assembly shall be as specified on the bid document and shall be molded throughout the thickness of each part. The underside of each visor shall be dull black. No painting shall be allowed except in the case of visors which are specified to be of a color other than black. In this instance, the outer color of the visor shall be molded throughout the material thickness and the underside shall be finished with a dull black paint specifically designed to be applied to polycarbonate material.

Each signal unit shall be furnished with a pair of polycarbonate, side of pole mounting brackets to rigidly mount the signal at both ends. Attachment to the pole shaft shall be accomplished using standard banding material. Signal mounting brackets have integrally molded banding guides to ensure that, once installed, the banding material does not slip out of place.

Sign

The signal indications shall be surrounded by a sign fabricated of 0.125” aluminum of 5052 – H38 alloy, and having overall dimensions of 36” X 72”. The sign corners shall be rounded. The sign shall have a cutout portion designed to fit tightly around the outer edges of the signal described above, and shall be fastened to the signal body with conventional signal backplate hardware.

Both sides of the sign shall be powder coated white. The upper portion of the sign shall have a yellow background, approximately 8”in height, and shall be silk screened with the word “SCHOOL” in black, 6” letters. Below the yellow portion, and above the signal cut out, the words “SPEED LIMIT” in black letters, 7” high shall be silk screened. On the lower portion of the sign face, below the signal cut out, the words “WHEN FLASHING” shall be silk screened in black letters, 4” high. The sign face shall have a 5/8”black border.

Pedestal

Each pedestal shall have an overall height of twelve feet. The shaft shall be a one-piece tube of 6063-T6 aluminum alloy with a minimum wall thickness of 0.237”. The shaft shall be of uniform diameter throughout its length. The shaft outside diameter shall be approximately 4.5”. The shaft shall have a satin brush finish. The shaft shall be threaded with a nominal 4” pipe thread and be threaded into the base. The shaft shall be secured to the base by a 3/8” bolt to prevent loosening of the shaft due to vibration, wind, etc.

The pedestal base shall be of cast aluminum and shall meet or exceed the requirements of all 1985 AASHTO breakaway standards and shall have been tested to withstand a bending moment of 10,750 Ft./Lbs. It shall be equipped with a hand hole and door for access to the interior of the base. The hand hole shall have a minimum dimension of 7-3/4” by 8”. The door shall be molded of ABS plastic to deter theft and shall be fastened in place by a single bolt which shall have an Allen head to discourage unauthorized personnel from gaining access to the wiring compartment in the pedestal base. The pedestal base shall be mounted to a poured concrete pad by means of four anchor rods set in a bolt circle of 13 ½” diameter.

Each pedestal shall be furnished with four anchor bolts and associated hardware. Anchor bolts shall be ¾” diameter by 27” long plated, and they shall be supplied with nuts, lock washers and flat washers.

The shaft shall be provided with a protective wrapper for shipment. Large scratches or gouges in the aluminum material shall be cause for rejection.

Flasher Controller

Each school zone beacon assembly shall include a flasher controller unit. The unit shall consist of a standard, two circuit, alternating, traffic signal flasher which shall be designed in accordance with NEMA requirements, latest version; a time clock capable of controlling the On – Off times of the signal, as well as a circuit breaker and terminal connections for all electrical wiring. The circuit breaker shall be rated at 15 Amps. All field hook up terminal blocks shall be equipped with minimum 8 – 32 screws. The controller shall also be equipped with a toggle switch, wired such that the outputs to the signal heads may be disabled while leaving power applied to the time clock.

The time clock shall be of all solid state construction except for the relay output. All components shall be warranty, or shall be so identified that they may be purchased from industrial electronics suppliers. The time switch shall have the ability to operate from either a 115VAC or 12VDC power source. It shall be installed in a case to protect it from dust. Interface to the power line and to the controlled device shall be provided by means of a terminal block capable of terminating wire sizes up to #10 AWG. The AC power input shall be protected with a fuse and MOV.

The time clock shall operate from a nominal 115 VAC, 60HZ power source, and shall operate satisfactorily between 95 and 135 VAC. The time switch shall also operate from a 12VDC, +/- 2VDC. The time switch shall operate satisfactorily between -30 and +74 degrees C. Timing shall be synchronous with the power line when such power is available. During a power failure, or when operating from a 12VDC power source, timing shall be quartz crystal controlled with an accuracy of +/-0.005% throughout its full temperature range. No time shall be gained or lost during changeover from 115 VAC to the back-up system and back to 115 VAC.

The time clock shall be programmed via a 16 key positive action push button keyboard that is an integral part of the unit. Prompt messages shall be displayed during the programming process to guide the operator as the data is being entered. It shall be possible to set to an accuracy of one second. Time of day, day of week, date, year and the operation of the relay output shall be able to be easily set from the integral keyboard. The functions of the keys shall be clearly marked on the keypad. Prompt messages shall be displayed during the programming process to guide the operator as the data is being entered. All data required to properly set and program the unit and review the stored program shall be clearly displayed without the use of auxiliary devices.

Changeover from standard time to daylight savings time or vice versa shall be accomplished automatically. The operator shall have the capability of entering the daylight savings time information from the keyboard thus eliminating the need for a PROM change should the current U.S. law change. The daylight savings time feature shall be capable of being defeated from the keyboard. Leap year compensation shall be automatic. When the user is programming the unit, the display shall provide for verification of each piece of data prior to its being entered. Provision shall be made for correction of any incorrect data prior to entering it. It shall be possible to alter any individual program step without disturbing any other step in the program.

When an instruction is given to turn the output on or off, that instruction time shall be able to be set to one minute, and change shall take place at the zero second of that minute. The time switch shall be capable of initiating a minimum of 16 program steps. A program step is defined as the time of day and the day or days of the week at which the output shall be turned on or off. The time switch shall have the capability of a pulsed output adjustable from 1 to 99 seconds in one second increments. A set of clear operating instructions shall be furnished with each time switch.

The time switch shall be capable of executing ten (10) separate skip plans programmable to any year in advance. Programming for the skip plans shall be accomplished through the integral keyboard. Each plan shall be programmed by entering the beginning date (month/date/year) and the ending date for which the output of the time switch will not be activated. The time switch shall be capable of skipping as short a duration as one (1) day or as long as six (6) months. It shall be possible to begin a skip plan in one calendar year and end that same plan in the next consecutive year. It shall not be necessary to enter the skip plan program in chronological order.

A means shall be provided to review the skip plan program without affecting the normal operation of the time switch. The display shall include the skip plan number, the beginning date and the ending date.

A means shall be provided to maintain timekeeping and the program when the line power source (120VAC) is not available or when the time switch is operating from a 12VDC power source. This back-up system shall maintain timekeeping and all programmed steps intact for not less then 48 hours at 25C when fully charged, and shall go on line automatically upon failure of the line power. Upon resumption of the line power, the unit shall automatically resume normal operation and begin recharging the back-up system. Should the program of the time switch be erased during an AC power outage, the unit shall display an indication of the program loss. The display shall be an easy to read LCD and shall be able to be reset from the integral keyboard. The device used for the back-up system shall be a rechargeable capacitor. Batteries will not be allowed. When the time switch is operating on the back-up system, the displays shall be blanked and the output disabled to conserve back-up power.

Integral with the time switch shall be an easy to read 16 character alphanumeric liquid crystal display (LCD). This display shall provide a clear indication of the time of day, day of week, date and the condition of the output relay. If time is kept on a 12-hour format, provision shall be made to display AM/PM. The unit shall have the ability to switch to an alternate display of time that includes seconds. A means shall be provided to review the program in the clock’s memory, and such means shall be integral with the unit. Such program review shall not affect the current operation of the time switch.

The display of the time switch shall automatically blank after five minutes of keyboard inactivity. To reactivate the display, the operator simply presses any key on the keyboard. This feature shall be able to be defeated from the time switch keyboard.

The time switch shall have a single-pole, double-throw relay output with a contact rating of at least 15 amps at 120 VAC resistive load.

The flasher controller shall be enclosed in a rugged, cast aluminum cabinet having approximate dimensions of: Height – 16”: Width – 12”: Depth – 5 ¾”. It shall have a door which shall represent essentially the entire front of the cabinet and shall be fitted with a standard “police door’ lock. Two keys shall be supplied with each cabinet. The cabinet shall have an internal, neoprene gasket, which shall mate tightly to the door to prevent the entry of dirt, dust and moisture.

The cabinet shall include a cast aluminum mounting bracket suitable for attachment to a pedestal pole with standard banding material.