7-77 manual operation. Contacts shall be silver alloy enclosed in an arc quenching chamber. Overload tripping of breakers shall not be influenced by an amb ient temperature range of from 0 to +158°F.
718.12 Conductors The number and size of conductors required in each cable is
indicated on the plans. All conductors shall be stranded coppe r conductors. Multiconductor cables shall conform to the latest revisions of IMSA Specificat ion Number 19-1 or 20-1. The service ground rod shall be 8 foot by ⅝ inch copperclad rod . The service wiring shall be single conductor number 6 AWG THW stranded copper black insulated and number 6 AWG THW stranded copper white insu lated rated 600 volts. All circuits for the timer and each auxiliary control unit sha ll terminate in a multiple contact connector. Conductors shall be attached to all pins of the connector and cabled. Conductors of the cable, except spares, shall be fitted with te rminal ends compatible with the terminal block and shall have identifying bands. The ends of all spare conductors shall be taped. SECTION 719 - SIGNING MATERIAL
719.01 Reflective Sheeting The reflective sheeting shall cons ist of a retro-reflective
lens system having a smooth outer surface. The sheeting shall have a precoated adhesive on the back side, protected by an easily removable liner. The reflective sheeting and its components shall be NTPEP test ed and conform to all the requirements of FHWA ASTM D4956, Standard Specification for Retroreflective Sheeting for Traffic Control, i ncluding supplementary requireme nts. Engineering grade reflective sheeting shall meet the reflective intensity require ments of ASTM D4956, Standard Specification for Retro reflective Sheeting for Traffic Control, including supplementary requirements Type II sheeting. High intensity pr ismatic reflective sheeting shall meet the reflective requirements for ASTM D4956 Type III prismatic sheeting. Reflective sheeting, used in sign construction, shall be from the Department’s Qualified Products List and have been manufactured within the s ix months immediately prior to fabrication of each sign. Upon delivery at the job si te of each shipment of signs, a letter of certification shall be provided by the Contractor tha t the reflective sheeting conforms to the requirements contained herein. Super high intensity fluorescent retro-reflective sheeting, AST M D 4956 - Type VIII, or Type IX (prismatic), is required for all construction signs. Example Table Engineering Grade Type II High Intensity Type III 7-78 Work Zone Type VIII or Type IX (prismatic) For Type I Guide Signs, all reflective sheeting shall be color matched on each sign unit.
719.02 Demountable High Intensity 719.02 Demountable High Inte nsity Prismatic
Reflectorized Letters, Numerals, Symbols and Borders Demountab le reflectorized letters, numerals, symbols and borders shall consist of cut out high int ensity prismatic sheeting, be NTPEP tested and, conforming to FHW A, "Standard Specifications for Construction of Roads and Bridges on Federal Highway Projects", 2014 FP-14 718. 0.
719.03 Aluminum Extrusions The extruded aluminum planks shall be bolted type
with dimensions, holes, lengths, and cross sections as detailed on the plans. The extruded aluminum molding for edging of the extruded aluminum sign panel s shall be of the cross section as detailed on the plans. Extruded aluminum planks sha ll conform to ASTM B 221, 606-T6, 6005-T5, or 6061-T6. The extruded aluminum planks and molding shall be free from all corrosion and dirt and the face and edges shall be tru e, smooth, and free from burrs and breaks.
a.Degreasing Required on aluminum plank by either of the foll owing methods:
1.Vapor Degreasing shall be by total immersion of the plank in a saturated vapor of trichloroethylene or perchloroethylene. Trademark pri nting shall be removed with lacquer thinner or controlled alkaline cleaning system.
2.Alkaline Degreasing - Planks shall be immersed in a tank containing alkaline solutions, controlled and titrated to the solution man ufacturer's specification. Immersion time shall depend upon the amount of soil present and the gauge of the metal.
b.Etching
1.Alkaline Etch The pre-cleaned aluminum surface shall be w ell etched in an alkaline etching material that is controlled by titration, use time, temperature and concentration specified by the solution manufacturer and rinsed thoroughly. Smut shall be removed with an acidic, chromium compound type solution as spec ified by the solution manufacturer and then thoroughly rinsed.
2.Alodine 500 or 1,200 is acceptable.
c.Drying Material may be air-dried or oven dried. Metal shal l not be handled between all cleaning and etching operations and the application of Refl ective Sheeting, except by devise or clean gloves. There shall be no opportunity for meta l to be exposed to grease, oils, or other contaminants before application of Reflective Sheeting .
d.Fabrication All fabrication shall be completed before met al degreasing. 7-79
719.04 Aluminum Sheets All blanks shall be made of 5052-H38 o r 6061-T6
aluminum. The Contractor shall guarantee the material to be fr ee of buckles, warp, dents, cockles, burrs and defects resulting from fabrication.
a.Degreasing Required on sheet aluminum by either of the foll owing methods:
1.Vapor Degreasing Sign blanks shall be totally immersed in a saturated vapor of trichloroethylene or perchloroethylene. Trademark printing sha ll be removed with lacquer thinner or controlled alkaline cleaning system.
2.Alkaline Degreasing Sign blanks shall be totally immersed in a tank containing alkaline solutions, controlled and titrated to the solution man ufacturer's specifications. Immersion time shall depend upon the amount of soil present and the gauge of the metal.
b.Etching
1.Alkaline Etch The pre-cleaned aluminum surface shall be w ell etched in an alkaline etching material that is controlled by titration, use time, temperature and concentration specified by the solution manufacturer, and rinse d thoroughly. Smut shall be removed with an acidic, chromium compound type so lution as specified by the solution manuf acturer and then thoroughly rins ed.
2.Alodine 500 or 1,200 is acceptable.
c.Drying Material may be air-dried or oven dried. Metal shal l not be handled between all cleaning and etching operation and packaging, except by dev ice or clean gloves. There shall be no opportunity for metal to come in contact with greas e, oils, or other contaminants prior to application of the packaging and shipping.
d.Fabrication All fabrication, including shearing, cutting, a nd punching of holes, shall be completed before metal degreasing. Fabrication of all metal parts shall be accomplished in a uniform and skillful manner. The surface of all sign pane ls shall be flat. The minimum sheet thickness shall be 0.08 inches for signs of a n area of 12 ft² or less and shall be 0.125 inches for signs over 12 ft² unless otherwis e specified.
e.Chromate Treatment Treatment shall be in accordance with AS TM B 449 Class I.
719.05 Plywood The plywood shall conform to the following req uirements:
a.Face stock Face veneers shall be Grade A.
b.Core and Cross Veneers Core and crossband veneers shall be Grade B or better and shall be solid jointed. 7-80
c.Glue The entire area of each contacting veneer surface shal l be bonded with a waterproof adhesive that meets the test requirements for exteri or type.
d.Overlay The overlay shall be of the high-density type. It shall be a minimum of 60 lb/1,000 ft² surface, shall be at least 0.009 inches thick, and have a minimum resin content of 40 percent based on the dry weight of the impregnated fiber. It shall consist of at least 2 sheets of resin-impregnated fiber of sufficient resin content t o bond itself to the plywood. Manufacturing precautions shall be taken to prevent overlay sur faces from coming into contact with any substance that would inhibit adhesion of paint or reflective sheeting. The overlay shall be natural color.
e.Thickness The thickness of plywood shall be ⅝ inch.
f.Testing The plastic overlay shall not delaminate from the p lywood after being subjected to the exterior boiling test for glue line durability .
719.06 Demountable Reflectorized Delineators Delineators shal l be diamond
reflectors approximately 3 inch square or shall be rectangular, adhesive coated reflective sheeting permanently adhered to a sheet aluminum backing. All delineators on a project shall be the same type. Single delineators shall be clear or si lver-white; double and triple delineators shall be amber.
a.Single delineators shall have one ¼ inch square hole for cen ter mounting. Double and triple delineators shall have two ¼ inch square mounting ho les on the vertical centerline. Single delineators shall be 3 by 3 inches diamonds with ¾ inch radius corners and two ¼ inch square mounting holes, 3 inches on center. Double delineators shall be 3 by 6 inch rectangles with ¾ inch radius corners and two ¼ inch square mounting holes 5 inches on center. The aluminum shall be 6061-T6, ASTM B 209 or 6063-T6 or 6005-T5 0.063 inches thick sheet properly degreased and etched or treated with a lig ht, tight amorphous chromate type coating. The reflective sheeting shall be applied to properly treated ba se panels with mechanical equipment in a manner specified by the sheeting manufacturer.
b.General Requirements and Packaging. The finished delineator s shall show careful workmanship, be free of burrs, scratches or damaged reflective surface. Delineators shall be packaged in such a manner as to insure the ir arrival at destination in undamaged condition. Delineators shall not become wet in stora ge or shipment. 7-81
719.07 Assembly and Mounting Hardware - General The attachment of signs shall be in
accordance with the contract documents and the appropriate hard ware prescribed in this Section. Requests for substitution for all specified material shall be submitted in writing with full documentation, including but not limited to specifica tions and mill certification reports, enabling the Department to evaluate the proposal promp tly. 719.071 Aluminum Planking The bolt assembly required to fasten the extruded aluminum planks together shall conform to the designs used in s tandard commercial processes for the selected type of extruded aluminum panels. G uidance for bolt hole punching and typical plank-to-plank attachment is provided in t he contract documents. 719.072 Overhead Signing Sign panels mounted to independent si gn support structures and support structure components mounted to bridges passing ove r the highway are considered to be overhead signing. Overhead signing shall be m ounted on W6 by 9 steel beams conforming to the requirements of ASTM A 992/A 992M, galv anized in accordance with AASHTO M 111, or the same size aluminum beams conforming t o ASTM B 221M, alloys and tempers of 6061-T6, 6063-T6 or 6005-T5. These compo nents shall be horizontally spaced a maximum of 5¼ feet on center, extending f rom the bottom of sign panel to the top. If supplemental signs are included in the co ntract, these beams will extend from the bottom of the main si gn panel to the top of the supple mental sign panel. The maximum distance from the edge of the sign to the center of the W6 by 9 shall not exceed approximately 3¼ feet. On independent sign support structures, these W6 by 9 beam comp onents shall be fastened to chords with a pair of appropriately sized U-bolts o n each side of the web at each fastening location. A similar pair of U-bolt assemblies s hall be used in attaching each chord of an overhead component to upright supports. U-bol ts for steel support structures shall conform to ASTM A 449, Type 1 or 2. The U-bol t hardware, which includes nuts, flat washers and helical lock washers, shall be galvanized in accordance to AASHTO M 232 (ASTM A 153 or B 695, Class 50, Type 1). Washers shall conform to the requirements of ASTM F 436. The U-bolt material for alumin um support structures, or a combination of steel and aluminum structural components, s hall be stainless steel conforming to the requirements of ASTM F 593, alloy group 1, wi th a minimum yield strength of 45 ksi. Steel support structures may also utilize stainless steel hardware assemblies as an alternative to galvanized steel. Nuts shall b e of the locking type with nylon inserts. Washers shall conform to the requirements of AS TM A 276, Type 302. Flat washers, without helical lock washers, will be acceptable in this stainless steel assembly. On bridge mounted structures, the fastener configurations shall be depicted in the contract documents. 719.073 Post Clip Hardware For Overhead Signing Signs mounted steel or aluminum W shape beam components shall be attached using post clip hardwar e as described in this Section as well as the contract documents. Overhead signing sh all have post clip assemblies fastened in pairs, one on each side of the web of the W shape b eam, at all locations on the 7-82 backside of the extruded plank panels that provide a groove acc ommodating a post clip bolt and assembly. Post clips shall be 356-T6 aluminum conforming t o the requirements of ASTM B 108. The post clip bolt material for overhead signing s hall be stainless steel conforming to the requirements of ASTM A 193/A 193M, AISI Type 304, Grade B8. The post clip bolt nut shall be stainless steel material con-formin g to the requirements of ASTM A 194/A 194M, AISI, Type 303, Grade 8F and of the locknut type with nylon inserts. Flat washers of these assemblies shall be stainless steel material c onforming to the requirements of ASTM A 276, Type 302. 719.074 Post Clip Hardware For Roadside Signing Signs mounted on other than overhead locations may be mounted using aluminum hardware. The aluminum post clips shall be 356T-6 aluminum conforming to the requirements of ASTM B 108. The post clip bolts, washers and nuts shall conform to the requirements of al uminum alloy 2024-T-4 (bolts and washers) and alloy 6061-T6 or 6262-T9 (lock nuts). 719.075 Roadside Signing Aluminum signs mounted on U-channel p osts shall be fastened with 5/16 by 1½ inch stainless steel bolts, washers, and self-locking ty pe nuts. The bolts shall conform to the requirements of ASTM F 593. A washe r, either a white nylon or neoprene or stainless steel ASTM F 593 shall be used between th e head of the bolt and the face of the sign. Plywood signs mounted on U-channel posts shall be fastened with 5/16 by 2½ inch stainless steel cap screws and hex nuts conforming to ASTM F 59 3, and a washer either white nylon or neoprene or stainless steel ASTM F 593 shall be used between the head of the bolt and the face of the sign. Delineator assembly hardware shall consist of ¼ by 2¼ inch stai nless steel bolts, washers, and self-locking type nuts. The bolt assembly shall c onform to the requirements of ASTM F 593. SECTION 720 - STRUCTURAL SUPPORTS FOR HIGHWAY SIGNS, LUMINAIRES AND TRAFFIC SIGNALS
720.01 Aluminum Supports Extrusions for aluminum supports sha ll conform to
ASTM B 221 or ASTM B 429, Alloy 6061-T6 or 6063-T6. Castings f or use with aluminum supports shall conform to ASTM B 26or B 108, Alloy 356.0-T6, ex cept that castings for parts having a non-structural application, such as pole caps or bolt covers, may be temper F. The T6 tempers specified for Alloys 6063 and 356.0 shall be obt ained by the proper heat treatment of the assemblies after all welding for the base and if required, for the handhole reinforcement has been completed. No welding will be allowed o n the shaft other than as required for the attachment of the shoe base, handhole reinforc ement and bracket arm. All welding for aluminum shall conform to the current edition of AW S Structural Welding Code - Aluminum D1.2 (AWS D1.2).
Source: Maine Standard Specifications for Road and Bridge Construction, 2020 Edition. Pages 782–787 of 817.