498 SECTION 896
896.01 Rigid Conduit
A.Steel Conduit. Use steel conduit of corrosive-resistant material meeting the requirements in UL 6. Do not use aluminum conduit.
B.Nonmetallic Conduit. Use either polyvinyl chloride (PVC) or high-density polyethylene (HDPE) conduit for nonmetallic conduit.
1.PVC. Provide PVC conduit that meets the requirements of UL 651 suitable for direct burial applications and has a minimum wall thickness equivalent to Schedule 40 as defined by ASTM D 1785.
2.HDPE . Provide HDPE conduit that meets the requirements of UL 651 and ASTM D 3035 that is suitable for direct burial applications. Use HDPE conduit that has a minimum wall thickness equivalent to DR 15.5 as defined by ASTM D 3035. Install HDPE conduit when the conduit temperature and the ambient temperature is greater than minus 10°F.
896.02 Conductors
A.Feeders. If using conductors as feeders provide either a single conductor or multiple stranded conductors formed into a cable. Provide underground phase and neutral conductors that are insulated to meet the requirements for direct burial cable, rated at 600 volts, and that meet ASTM B 3 and B 8. Use single conductor marked with Style “RHW-USE” and the required AWG size on the sheath. Use stranded No. 6-AWG -Type THW or THHN/THWN for grounding conductor. Rubber insulation specifically listed for that purpose by UL does not require an outer cover.
B.Loop and Loop Lead-In Conductor. Provide a loop and loop lead-in conductor that meets one of the following:
1.Copper Loop Conductor. Use No. 14 AWG, Type XHHW or THWN or THHN single-stranded 600 volt conductor or as recommended by the detector manufacturer.
2.Polyethylene Conduit Pre-Wired. Provide a certificate of compliance stating that the 1/4 inch polyethylene conduit meets ASTM D 1248, Type III, E10, Category 5, Class C and Tables 896-01 and 896-02. Table 896 -01 Nominal Dimensions Of Polyethylene conduit (Inches) Duct Size 0.250 Outside Diameter 0.250 ± 0.010 Wall Thickness 0.032 ± 0.010 Nominal Inside Diameter 0.185 Minimal Bending Radius 1.00 Table 896 -02 Nominal Physical Properties Of Polyethylene Conduit Property Test Value ASTM Test Tensile Strength @ yield, psi 3,200 min. D 638 Ultimate Elongation, % 400 min. D 638 Melt Index, gms/10 min. 0.5 max D 1238 Carbon Black Content, % 2.00-3.00 D 1603 Density of Base Resin, gms/cc 0.941-0.959 D 1505 Brittleness Temperature, F 20 -75°C., max. D 746 Environmental Stress Crack Resistance, F 20 48 hrs. D 1693 Cond. B Use conduit that also meets or exceeds the performance tests as specified in NEMA Standards Publication No. TC7, Part 3 as follows:
a.TC7-3.01 Compressions and Recovery
b.TC7-3.02 Impact Test Use conduit that is permanently marked on the outside at regular intervals with the manufacturer’s name, trademark, nominal conduit diameter, Type III, and year of manufacture.
3.Copper Loop Lead-In Conductor. Use conductor that is a No. 14 AWG stranded polyethylene insulated twisted pair with a foil shield or as recommended by the detector manufacturer, and place it in a common conduit with power and control circuit cable without interference. Provide a jacket of HDPE with a nominal thickness of 0.032 inches.
4.Preformed Loop Detector. Construct Preformed Loop Detectors of PVC and loop conductor. Encase the loop detector in 1/2 inch schedule 40 PVC, with pipe fittings and glue. Terminate one corner with a 1/2 inch PVC tee fitting to provide an exit to the pull box conduit. Seal the PVC at the joints with water pipe fitting glue. Use a conductor of No. 14 AWG, Type XHHW or THHN or THWN, 600 volt s tranded single conductor. Do not splice the loop conductor. 500 Place three turns in the preformed loop. Twist the conductor from the loop to the pull box to provide a minimum of two to five turns per foot.
5.Microloop Probe. Construct microloop probes with the lead-in cables in 3/8 inch saw slot or in sand in the roadway base. The Engineer will allow microloop probes to be connected in series with other microloop probes or in conventional wire loops. Operate microloop probes under the following parameters: − Earth’s Vertical Magnetic Field (0.2 to 1.0 oersted); − Inductance (20 microhenries to 25 microhenries per probe plus 20 microhenries per 100 feet of wire); − DC Resistance (0.5 ohms per probe plus 3.2 ohms per 100 feet of wire) ; − Transducer Gain (typically 3.5 microhenries per oersted at 0.4 oersted ambient vertical field intensity); and − Sensitivity with two probes (7.0 microhenries per oersted at 0.4 oersted ambient vertical field intensity). Operate microloop probes at a temperature range of -35°F to 165°F. Construct microloop probes to detect all motorized vehicles.
C.Traffic Signal and Flashing Beacon Control Circuits. Use cables that are rated for 600 volts and meet IMSA 19-1 or 20 -1. Use conductor consisting of Class B or Class C stranded copper. Insulate each conductor with 25 mils of polyethylene insulation. Use fillers of a moisture- resistant material, and do not use jute. Use moisture resistant binder tapes. Provide color coding of conductors that meets Table 5.1 of IMSA 19-1.
896.03 Saw Slot Sealant
Use an effective joint sealer that: - Forms a resilient and adhesive compound capable of sealing the saw slot; - Protects against infiltration of moisture and foreign material throughout repeated cycles of expansion and contractions with temperature changes; - Uses a sealing compound that does not flow from the joint or will be picked up by vehicle tires at summer temperatures; - Is of material that is capable of being brought to a uniform pouring consistency for completely filling the saw slot without large air holes or discontinuities and without damaging the material; and - Is not an epoxy -type sealant.
896.04 Feed Points
A.Traffic Signal. Include the following on a traffic signal feed point: 501 1. A 60 ampere size switch box.
2.One manually operated weatherproof switch, two-pole, single throw, 125/250 volts with 45 ampere breakers.
B.Flashing Beacon. Include the following on a flashing beacon feed point:
1.A 60 ampere size switch box.
2.One manually operated weatherproof switch, two-pole, single throw, 125/250 volts with 15 ampere breakers.
3.A Radio Interference Filter (RIF) and a Surge Voltage Protector (SVP) on the AC 120 volts supply. Each rated at nominal 120 volts, 60 hertz, and a minimum of 30 amperes and not less than the current rating of the circuit breaker protecting it. There may be one RIF and one SVP protected by a common main circuit breaker before the AC 120 volts supply is split into the automatic and flash circuit breaker branch circuits, or a separate RIF and SVP may be used after each pole of the automatic and flash circuit breakers.
4.A solid state flasher meeting NEMA Standards Publication No. TS 2, latest edition, Traffic Controller Assemblies with NTCIP Requirements, Section 6.
5.On flashing school crossing beacons install a time clock with the following capabilities:
a.Automatic daylight savings time and leap year compensation.
b.A minimum of 48 hour battery or capacitive backup-memory and timing maintained in event of power loss.
c.A minimum of six program steps programmable to one minute intervals.
d.Operate on a line voltage of AC 95-135 volts, 60 hertz.
e.Temperature range of -22°F to 165°F
f.Liquid crystal display.
g.Single Pole, Double Throw output relay rated 10 ampere, AC 115 volt resistive load.
h.Terminal block for electrical connection that will accommodate wire sizes #16, #14 and #12-AWG.
6.If the flasher is not placed in a feed point cabinet, place it in a weatherproof cabinet with a lock and two keys, of adequate size to mount the flasher and circuit breakers, on- off switch, time clock, and all necessary wiring.
896.05 Traffic Signal Standards
A.Design. Design traffic signal standards to meet the requirements of AASHTO publication, Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals . Use a wind velocity of 90 mph with the following height and exposure correc tion factor: − If the traffic signal is less than 33 feet use a K za of 1.00; or − If the traffic signal is greater than 33 feet use the K za found in Table 3.8.4-1 “Height and Exposure Factors, K za”. Design each structure component using the requirements of Table 11.6-1, “Fatigue Importance Factors, I F.” Design the components for the total deflection, with galloping, at the free end of the traffic signal arm is limited to less than 8 Inches. Furnish all the necessary calculations and drawings used in the design of poles with the shop drawing submittal. A Professional Engineer duly registered in the State of North Dakota must sign, seal, and date the calculations and work drawings used in the design of lighting standards.
B.Type II Standards.
1.Shaft. Use a shaft constructed of: - standard steel seamless pipe meeting ASTM A 36 or ASTM A 53; or - standard aluminum pipe meeting ASTM B 429, Alloy 6061 T6, or 6063 T6. Use a pipe that is 4-1/2 inches in outside diameter, with one end threaded for connection to the base. Calculate the design stresses for the shaft at the root of the thread.
2.Transformer Base. Tighten the shaft securely in the base. Provide the base with holes to receive the anchor bolts, a handhole, and a grounding l ug on the inside of the shaft or base. Place the grounding lug opposite the handhole and include a locking device for the handhole cover. Calculate the design stresses at the root of the thread or thinnest wall section. Use materials that meet ASTM A 27 Steel, or ASTM B 26, or B 108 Alloy 356 16 Aluminum.
C.Type IV, V, VI, and VII Standards and Combination Signals and Light Standards.
1.Shaft. Provide a steel shaft that has a minimum yield strength of 48,000 psi after fabrication. Provide a combination light and signal shaft that is of two-piece construction. Use a wall thickness of a minimum of 0.179 inch for Types IV, V, VI, and VII shafts, and
0.239 inch for the combination light and signal shaft.
Taper the shafts with top and bottom di ameters large enough to withstand their design load. Construct the Type V, VI, and VII shafts with a top outside diameter of 4-1/2 inches for a post top slipfitter.
2.Mast Arm. Construct the truss mast arm with both lower and upper members securely joined by vertical struts. Use members with a minimum wall thickness of 0.119 inch, and minimum yield strength in excess of 48,000 psi after fabrication. 503 Construct the monotube mast arm with a minimum wall thickness of 0.179 inch and a minimum yield stress of 48,000 psi after fabrication. Only use one longitudinal weld and no transverse welds in fabricating the monotube mast arm. Design the signal mast ar m to be rotated away from the roadway without disconnecting signal circuits or removing the mast arm.
3.Anchor Base. Construct the anchor base as a one-piece steel casting or hot-rolled carbon steel plate. Use a steel casting that meets AASHTO M 103, Grade 65-35. Secure the anchor base to the lower end of the shaft by two continuous welds. Place one weld inside the base at the bottom of the shaft, and the other on the outside of the shaft at the top of the anchor base. Provide a grounding lug on the insid e of the base.
4.Transformer Base. Construct the steel transformer base to the size specified by the manufacturer to support the shaft and mast arm. Fabricate the transformer bases to have a minimum yield strength of 33,000 psi. Fasten the transformer base to the shaft anchor base with galvanized hex - head machine bolts and nuts meeting ASTM F 3125 Grade A 325, galvanized according to AASHTO M 232. Install a door opening opposite the street side of the transformer base, secured in place by an approved lock ing device. Provide a grounding lug on the inside of the base.
5.Luminaire Extension. Design the shaft extension for mounting the luminaire the same as the rest of the shaft. Construct the galvanized steel extension with a minimum wall thickness of 0.119 inch and a minimum yield strength of 48,000 psi after fabrication. Galvanize the extension and hardware according to Section 854, “Galvanizing” . Construct the stainless steel extension with a minimum wall thickness of 0.721 inch and a minimum yield strength of 60,000 psi. Use stainless steel that meets the requirements of ASTM A 666, Type 201. Provide a tapered shaft that has a bottom and top diameter of sufficient size to withstand the design loads.
896.06 Traf Fic Signal Heads
A.Standard Units.
1.General. Use an anti -seize lubricant when installing stainless steel screws into an aluminum alloy material.
a.Use circular signal heads with Light Emitting Diodes (LED) that conform to ITE Standards. Use 1808, Type 304 stainless steel for exposed screws and fasteners.
b.Use Circular Signal Head LED Modules that fit into traffic signal housings built to the Vehicle Traffic Control Signal Heads (VTCSH) Standard, or use stand-alone units that incorporate a housing meeting the performance requirements of the VTCSH Standards. Connect the module directly to the existing electrical wire system. 504 c. Use a vehicle arrow traffic head that conforms to VTCSH “Part 3: Light Emitting Diode (LED) Vehicl e Arrow Traffic Signal Modules” of the ITE. Use modules that fit into signal housings built to the VTCSH Standard. Design retrofit replacement modules for existing signal lamps to not require special tools for installation. Provide modules that install into the existing signal housing, only require the removal of existing optical components, that are weather tight, fit securely in the housing, and connect directly to existing electrical wiring.
2.Housing.
a.General. Provide a one-piece aluminum alloy die casting housing, or a one-piece polycarbonate resin material housing. Provide a housing door made of the same material as the housing. Install reinforcement plates to reinforce the bottom of the signal head when it is mounted on a pedes tal-type signal standard. Provide two sets of internal bosses in each section for horizontal mounting of a terminal block. Construct the top and bottom exteriors flat to align the assembled sections. Fasten individual signal sections together either with machine screws between each section or by the three- bolt and two-washer method.
b.Polycarbonate Housings. Use a polycarbonate housing that is at least 0.090 inch thick, and is ribbed with at least two vertical ribs in addition to ribs on the top and bottom surfaces.
3.Module. Use a Circular Signal Head LED Module that: - Is suitable for replacement into an existing signal housing; - Only requires the removal of the existing optical unit components; - Is weather tight and fit securely in the housing; - Connects directly into the existing wiring; and - Does not require special tools for installation. - Is hard coated or otherwise made to comply with material exposure and weathering effects requirements of the Society of Automotive Engineers (SAE) J576. Provide retrofit modules that install into an existing signal housing, only require the removal of existing optical components (i.e. lens, lamp module, gaskets, refractor), that are weather tight and fit securely in the housings, and connect directly to existing electrical wiring.
4.Visors. Use visors of aluminum alloy or polycarbonate resin and of the tunnel type. Include anti - sun phantom feature on signal heads. 505 5. Surface Finish. Finish all surfaces with two coats of baked enamel. Oven bake the finish coat and ensure it meets Federal Specification TT-E -489. Paint the door and visors dull black. Mold the required color in the polycarbonate units.
B.Programmed Units.
1.Signal Visibility. Erect and place the lens’s color position to meet the requirements of the MUTCD, and provide signal colors that meet the ITE Transmittance and Chromaticity Standard. Provide a signal unit that projects the desired signal so it can be seen only by the lane of traffic it controls and permits the projected image to be seen, or veiled from view anywhere in an area up to 15 degrees on either side of the centerline of the projected image.
2.Optical Limiter. Use an optical limiter that projects the signal image to a distance of 900 to 1,200 feet, and provides a veil or mask that can be applied to limit visibility of the image to a specific lane of traffic. Construct the limiter of heat resistant glass.
3.Intensity Controller. Construct the intensity c ontroller: − With an integrated, directional light-sensing and regulating device interposed between lamp and line wires; − To be compatible with the 60 hertz input and responsive within the range of 105 to 135 volts; and − To provide a nominal terminal impedance of 1,200 ohms open circuit and corresponding holding current, and phase controlled if desired.
4.Material Composition. Use die cast aluminum parts that meet ITE alloy and tensile requirements and have a chromate preparatory treatment. Use sheet metal parts including visors and backplates that meet ITE material requirements, and include a chromate preparatory treatment. Furnish the exterior of the signal case, lamp housing, and mounting flanges with high quality baked enamel prime and finish paint. Provide an optical black lens holder and case interior. Predrill the signal case and lens holder for backplates and visors. Paint the backplates, visors, and batten plates dull black. Provide hinge and latch pins that are stainless steel. Seal all access openings with weather -resistant rubber gaskets.
5.Installation. Equip the signal to mount to standard 1-1/2 inch fittings. Provide the signal section with an adjustable connection that permits incremental tilting from 0 degree to 10 degrees above or below the horizontal while maintaining a common vertical axis through couplers and mounting. Construct the terminal connection to permit external adjustment about the mounting axis in 5 degree increments. 506 Use attachments such as visors, backplates, or adapters that conform and that readily fasten to existing mounting surfaces without affecting water and light integrity of the signal.
896.07 Pedestrian Signals
A.Two-Piece Pedestrian Signals.
1.Housings. Use a pedestrian signal with a two section UPRAISED HAND symbol (symbolizing DON’T WALK) and WALKING PERSON symbol (symbolizing WALK). Use filled symbols and do not use the outline-symbol type indication. Construct the signal so the upper section displays the UPRAISED HAND symbol and the lower section displays the WALKING PERSON symbol. In pedestrian heads, use LED module conforming to the ITE “Pedestrian Traffic Control Signal Indications – Part 2: Light Emitting Diodes (LED) Pedestrian Traffic Signal Modules”. Use manufactured pedestrian signal housings that conform to the ITE “Pedestrian Traffic Control Signal Indications”. Provide a dust-free and weather -tight si gnal with molded gaskets between all component parts. Use stainless steel for all screws, fasteners, and metal parts. Fit the two sections rigidly and securely together without a spacer. Make all sections identical and interchangeable. Mount the signal on 1-1/2 inch signal brackets. Make each rectangular section a one -piece: − Aluminum alloy die casting; or − Polycarbonate resin material. Provide two sets of internal bosses in each section for horizontal mounting or terminal strip facilities. Provide each section with an integrally -cast, serrated locking ring that will permit the rotation of the signal head in five degree increments. Locate two hinge pin openings on the left side of each housing, and two noncorrosive inserts internally on the right side of each housing.
2.LED Module. Install LED modules into pedestrian -signal housings that fit securely in the housings and connect directly into the existing wiring. Provide a LED module that is weather tight. Provide a LED module for installation into an existing pedestrian-signal housing that: − Only requires the removal of the existing optical unit components; − Is weather tight; − Fits securely in the housing; and − Connects directly into the existing wiring. 507 For new installations, determine the minimum size of the message-bearing surface of a module by the length of the intended crosswalk, but in no case shall it be less than 9 inches by 9 inches. Size the message bearing surface in accordance with the minimum dimensions given in Table 1, ITE Pedestrian Traffic Control Signal Indications, “Part 2: Light Emitting Diode (LED) Pedestrian Traffic Signal Modules”. Use an LED Signal Module capable of replacing the optical components of the pedestrian indication. Design the configurations of the walking person icon and the hand icon in accordance with Figure 1 and Figure 2, respectively, of ITE Pedestrian Traffic Control Signal Indications, “Part 2: Light Emitting Diode (LED) Pedestrian Traffic Signal Modules”, latest edition.
3.Visors. Use aluminum alloy or polycarbonate resin tunnel type visors. Use signal heads that contain an anti -sun phantom feature.
4.Surface Finish. Finish all surfaces with two coats of oven-baked enamel. Paint the final coat of the door and visors dull black. Use paint that meets Federal Specification TT-E-489. Do not paint fastening devices. Mold the required color in the polycarbonate units.
B.Single Piece Pedestrian Signals.
1.Housings. Provide pedestrian signal heads that consist of a single piece cast aluminum housing and door. Provide a LED module with minimal sun phantom that gives a clear, unmistakable message to the pedestrians using the crosswalk area. Provide a system that only gives a limited view of the signal message to pedes trians outside the crosswalk area or a system that does not allow pedestrians outside the crosswalk area to view the signal message.
2.Visors. Use tunnel type visors made of aluminum alloy or polycarbonate resin or fabricate visors from 0.040 inch thick black polycarbonate strips to form a geometric grid consisting of 1 inch bisected diamond patterns. Construct the visor so the message surface of the lens is totally shaded when the sun is more than 22 degrees above horizontal and at least 50 percent shaded if the sun is 8 degrees or more above horizontal. Use stainless steel screws when attaching the visor to the signal.
C.Pedestrian Countdown Signal Head. Furnish and install an LED pedestrian signal meeting the requirements of Light Emitting Diodes (LED) Pedestrian Traffic Signal Modules of the ITE. Furnish and install a countdown timer module. Use a filled-symbol type pedestrian signal. Do not use the outline-symbol type. Use one of the following models of pedestrian signal or an approved equal:
1.GE Lighting Solutions, GT1 LED Countdown Pedestrian Signals, 16 inches by 18 inches. 508 2. National Sign and Signal Co., Inc., 16 inches by 17-3/4 inches LED Pedestrian Signal and Count Down Timer Kit-16-inch Hand Man With 7 inch numerals.
896.08 Pedestrian Push Button Post and Button
Use a steel post that meets AASHTO 270, Grade 36. Use die-cast aluminum for the push button housing. Provide a push button assembly that is tamperproof and weatherproof to prevent electrical shock to the user under any weather conditions. Provide a pedestrian push button that can be raised from or flush with its housings and is a minimum of 2 inches in the smallest dimension. Use a push button that requires no greater than 5 pounds to activate.
896.09 Surg E Protection
A.Feed Point. Install a lightning protection device on the feed point incoming lines to prevent lightning surges entering through the wiring from damaging electrical wiring and control equipment in the controller cabinets. Use a weatherproof lightning protection device that immediately drains lightning surges harmlessly to ground without maintenance. Install the lightning protection device in the knockout on the switch box. Use a lightning protection device that is a two-pole, three -wire device designed for single- phase 120/240 volt three -wire grounded neutral service. Use tinned copper No. 14 AWG for all leads. Provide a lightning protection device capable of:
1.Limiting the surge voltage to 3 kilovolt peak;
2.Conducting sur ge currents of at least 10 kiloamperes with an 8 by 20 microseconds (time to crest by time to second half- crest) waveform; and
3.Recovering to its former state after the surge is over, when the device is receiving power. Provide an AC suppressor that meets ANSI C 621.1/IEEE, Standard 28, paragraphs 7.1 and 7.6, and that has a peak voltage that will not exceed 3 kilovolt when tested according to paragraphs 7.3 and 7.5 of the ANSI/IEEE Specification. Install the AC line surge protector on the load side of the circuit breaker. Provide a circuit breaker that opens to give maximum protection if the protector should fail and short the circuit. Give the AC neutral the same protection as the AC load. Keep the arrester leads as short as possible. Make grounds directly to the cabinet wall or ground plate as near as possible to the object being grounded. The Engineer will allow bringing the AC power into the cabinet via an underground conduit. 509 Make connections from the ground rod to the objects inside with AWG No. 8, or larger, copper wire.
B.Controllers. Install a lightning protection device at each interconnect wire terminal connection on the cabinet terminal strip. Install a lightning protection device on the incoming power lines to prevent lightning surges entering and damaging electrical wiring and control equipment. Use a lightning protection device that does the following:
1.Clamps the surge to as low a voltage as possible, ideally to about twice the peak operating voltage of the circuit being protected.
2.Capable of conducting a surge current of at least 1,000 amperes at an 8 by 2 microseconds waveform without damage to itself.
3.Capable of dissipating at least 40 joules of energy without damage to itself.
4.Capable of suppressing six surges in rapid (1 second) succession as described in 1, 2, and 3 above without degradation of performance. Install the interconnect line suppressors as close as possible to the point where the lines enter the controller cabinet. The Engineer will allow the use of surge suppressors packaged in one unit if the suppressors meet the performance requirements listed above. Keep the suppressor leads as short as possible.
896.10 Controller Cabinet
Provide a control cabinet that meets the requirements of NEMA TS 2 Traffic Controller Assembly with NTCIP Requirements Section 7, except as follows:
1.Provide cabinets that are constructed entirely of aluminum. Ensure all hinges, lock nuts, and any other moving parts, are free and operate easily without damage to the gasketing.
2.Size the base mounted cabinet to provide space for the housing of all equipment specified as well as future coordination equipment. Construct the cabinet to be a minimum of 52 inches high, 44 inches wide, and 24 inches deep.
3.Provide a metal weatherproof cover that blocks air flow in cold weather, and adequately covers the fan vent assembly and the louver on the door. Install a gasket to the cover and attach the cover to the inside of the cabinet. Construct the cover of the same material as the cabinet. Provide a weep hole in the bottom loop on each end of the cabinet full -size door. Build the cabinet to contain the following items: − All items of control equipment specified in these Specificatio ns. − Provide a thermostatically -controlled minimum 250 watt strip -type heater mounted on the full -size door cover with a protective wire- mesh shield installed around the heater. Use a heavy -duty thermostat capable of being set within a temperature 510 range of 30°F to 90°F. Activate the power to the fan and to the heater using a three-position toggle switch located on the auxiliary switch panel. Use a switch that operates vertically up and down with the: o Up position being FAN (power to the fan on and power to the heater off); o Center position being OFF (power to both the fan and the heater off); and o Down position being HEATER (power to the heater on and power to the fan off). Provide an electrical three-prong twist lock -type plug between the switch and the heater. Mount the heater thermostat on the auxiliary switch panel. Make the connection to the heater with stranded copper wire having 200°C insulation and non-insulated, solderless term inals. − Provide three duplex receptacles with ground fault interrupter. Fuse the receptacles ahead of the main circuit breaker. − Provide a switched lamp socket, fuse the lamp socket ahead of the main circuit breaker. − Include the following in the maintenance switches inside the cabinet: o Stop time control. o Timer power. o Flash. o Vehicle detector input for each phase in use and all future phases. o Pedestrian input for each phase in use and all future phases.
4.Use load switches and flasher with sockets that meet the requirements of NEMA TS 2 Traffic Controller Assembly with NTCIP Requirements Section 6 and include switches and flashers for future phases.
5.Two radio interference filters with surge protectors, each rated at nominal AC 120 volts, 60 hertz, and minimum 30 amperes or greater based on load, with one filter and surge protector in the main automatic operation circuit and the other in the main flashing operation circuit.
6.In addition to the number of solid -state load switch units required to operate the intersection, provide one spare solid-state load switch unit, separately packaged and marked, and stored in the cabinet.
7.Provide pushbutton detector test switches in the controller cabinet for placing calls for vehicular and pedestrian phases for testing purposes.
8.Include two surface-mounted main circuit breakers with no back wiring in the cabinet. Use one breaker to carry the load during automatic operation and the other breaker to carry the load during flashing operation. Use single pole, 120/240 volt, 60 hertz, and 30 maximum ampere based breakers on the load. If the signal circuit load during automatic operation exceeds 30 amperes, use a three- pole common trip circuit breaker with 30 ampere rating for each pole or a s ingle 60 amp 511 breaker on that circuit. Split the signal bus load and equally divide it between the two poles. If the flash load exceeds 30 amperes, use a 30 ampere two-pole breaker with split flash on that circuit. Clearly mark each circuit breaker with “ON ” and “OFF” positions and identify with the load which it is carrying (“AUTO” or “FLASH”).
896.11 Controller
Use a solid state controller with front panel access to display cycle length, offset, and internal timing values. Provide access to these timing functions by keyboard entry as an integral part of the controller. Use a controller that meets NEMA environmental and electrical performance standards and has a liquid crystal display with: − A minimum of 4 lines with 40 characters per line; − A 16 range adjustment of contrast control; and − A backlight that automatically turns off 10 minutes after the last key is pressed. Use a display and keyboard that are functional over the temperature range of -34°F to 165°F.
1.Equip the controller with solid state signal load switching devices meeting NEMA requirements. Furnish load switches with indicator lights on the front panel.
2.Furnish each controller with a malfunction manager unit conforming to NEMA performance standards.
3.Furnish the controller with extra feature wiring to provide for remote flashing. Provide each wire with its own terminal connection. Use a flash control circuit to ensure that remote transfer to flashing from normal stop and go operation occurs during the No. 1 interval in the cycle. Provide a signal switching mechanism that is inoperative when the controller is in flashing condition.
4.Use load switches for pedestrian indications. Include cabinet wiring, load switch sockets, and connection facilities for pedestrian movements permissible. Provide a technician trained in the operation of the controller to provide training at the time of signal activation for a minimum of two consecutive days. Furnish a controller that meets current NEMA TS 2 Traffic Controller Assemblies with NTCIP Requirements.
896.12 Loop Detector Amplifiers
Provide loop detector amplifiers that meet NEMA TS 2 Traffic Controller Assemblies with NTCIP Requirements. Provide a self -tuning loop detector amplifier meeting Section TS 1-15.2.20.2 of NEMA Standards,
Part 15 — .
896.13 Railroad Pre- Emption
Include all equipment and material required for railroad pre-emption in the controller cabinet. Use a rack switch for activating the railroad pre-emption that is normally closed. 512 896.14 EMERGENCY VEHICLE PRE- EMPTION
A.General. Design the system to consider all possible conditions of priority control. Make software and hardware changes in the traffic controller if neces sary. Design the controller so the indicator light is not illuminated until both conditions are met: − Emergency phase is green; and − Phase selector has registered a pre-emption call.
B.Certificate of Compliance. In addition to the requirements in Section 106.01 C, “Certificate of Compliance” , submit a certification from the manufacturer of the pre-emption system components that includes the following:
1.Acquire all relevant controller information.
2.The number of vehicle phases (greens).
3.The desired greens for priority approaches.
4.The ring configuration of each controller.
5.The established pedestrian phase timing requirements.
6.The established minimum green times for non-priority phases.
7.The established manipulation method of each controller type.
8.A copy of the interface information that was supplied to installer.
9.A copy of the system checkout that the supplier assisted with prior to purchas er’s acceptance by: − Verifying proper installation per recommended interfaces; − Verifying that optical ranges are properly set; and − Verifying that phase selector timings or controller software timings are properly set. Include a certification in system checkout requirements when using the plug‐ in version of phase selector that when two plug‐ in units are used, the controller must recognize high frequency over low frequency and first‐ come, first‐ served. Include a certification from the manufacturer of the pre-emption system components that the optical system cable has been tested and meets matched component system performance.
C.Optical Detector. Provide a weatherproof optical detector capable of sensing and transforming pulsed optical energy into electrical signals usable by the phase selection equipment that: − Is of high-impact polycarbonate construction with non-corrosive hardware; 513 − Is designed for mounting at or near an intersection on mast arm, pedestal, pipe, or span wire; − Allows aiming of the two optical sensing inputs for skewed approaches or slight curves; − Has a built-in terminal strip to simplify wiring connections; − Receives power from the phase selector and is operational from 16 to 40 unregulated DC volts; − Is responsive to the optical emitter at a distance of 1,800 feet; − Is capable of providing the necessary electrical signal to the phase selector through up to 1,000 feet of optical detector cable; and − Employs a replaceable circuit board assembly and photocells to facilitate repair.
D.Optical Detector Cable.
1.Provide a cable that delivers: − The necessary quality signal from the optical detector to the phase selector over a non-spliced distance of 1,000 feet; and − Sufficient power to the optical detector over a non-spliced distance of 1,000 feet.
2.Provide cable that can be installed by one of the following methods: − Direct burial; − Conduit and mast arm pull; and − Exposed overhead (supported by messenger wire).
3.Provide cable with the following characteristics: − Weight does not exceed 0.04 pounds per foot; − Outside diameter does not exceed 0.3 inches; − Insulation rating is a minimum of 600 volts; and − Temperature rating is a minimum of 80° C.
4.Provide cable that has three conductors of AWG No. 20 7/28 stranded, individually tinned, copper color coded as follows: − Orange for delivery of optical detector power (+); − Blue for optical detector power return (-); and − Yellow for optical detector signal.
5.Provide conductors that are shielded with aluminized polyester and have an AWG No. 20 7/28 stranded and individually tinned drain wire to provide signal integrity and transient protection.
6.Use a shield wrapping with a 20 percent overlap to ensure shield integrity following conduit and mast arm pulls.
E.Phase Selection Equipment. 1. Use a priority control system manufactured to interface with electromechanical controllers, solid-state controllers with or without internal priority control capability, and Type 170 controllers with internal priority control software.
2.If using internal pre-empt controllers, use phase selectors: 514 a. With a plug- in, two channel, dual priority device intended to be installed directly into the input file of internal preempt controller equipped with priority phase selection software;
b.That are powered from AC mains and contain an internal, regulated power supply to power optical detectors;
c.That ar e capable of recognizing the following pulse rates as delivered by the optical detectors: (1) Between 9.520 and 9.758 hertz as Frequency I; and (2) Between 13.780 and 14.290 hertz as Frequency II.
d.With primary optical detector inputs and power outputs on the card edge. Provide two additional detector inputs, per channel, via a front panel connector;
e.With an opto-isolated output that provides the following signals to the card edge: (1) Between 6.23 and 6.27 hertz pulse in response to a low frequency signal; and (2) A “Steady -On” in response to a high frequency signal.
f.That uses a crystal controlled timing and optical pulse rate recognition circuitry to ensure: (1) Accurate optical signal (dual frequencies); (2) Synchronous logic; (3) Precise output pulse; and (4) Accurate call drop-out time.
g.That has six recessed range controls per channel, three per frequency, to independently adjust optical sensitivity;
h.That has a solid-state “Power -On” indicator;
i.That has a “Frequency I” and “Frequency II” solid -state indicator for each channel that performs as follows: − Flashing during call validation; and − Be steady -on when processing a valid call and during test switch operation.
j.That has a test switch for each channel to deliver Frequency I or Frequency II signal pulse rates to verify proper function at both optical emitter flash rates, first- come, first- served operation, and Frequency II override capability;
k.That can be set to a call dropout time of either 5 or 10 seconds. The call dropout time tolerance shall be at least the selected time and up to 2.5 percent longer than the selected time.
l.That will identify a Frequency II demand with any combination of up to 10 high and low priority emitter signals being received simultaneously and asynchronously on either channel; and
m.That does not exceed the following dimensions: − Length including handle 7.91 inches; − Width 1.11 inches; and − Height 4.50 inches.
F.Reliability. Supply equipment for the optical priority remote traffic control system intended for use in the controller cabinet that meets the electrical and environmental specifications in the NEMA TS 2 Traffic Controller Assemblies with NTCIP Requirements.
G.Training. Provide a technician trained in the operation of the priority control systems to provide training at the time of activation and available for a minimum of two consecutive days. Provide training to the emergency vehicle operators in the operation of the system that includes introductory training, periodic training updates, and a leave-behind audio visual self- instruction course for on -going training. Provide training in routine maintenance of the system. Provide manufacturer’s technical support that includes techni cal service, design engineering, manufacturing engineering, and research engineering for system development, process management of priority control components, and in-depth training of system users.
896.15 Span Wire
Use a span wire that is a double galvanized seven-strand steel wire cable not less than 3/8 inch in diameter meeting ASTM A 475.
896.16 Stabilization Wire
Use a stabilization wire that is a double galvanized seven-strand steel wire cable not less than 1/8 inch in diameter meeting ASTM A 475.
896.17 Service Pole
Treat Class II wood service poles as specified in Section 846, “Preservatives and Pressure Treatment Processes for Timber”.
Source: North Dakota Standard Specifications for Road and Bridge Construction, 2022 Edition. Pages 533–550 of 550.