A. Utilization of Reflective Sheeting.
Unless otherwise specified, all signs with white background shall use Type III or IV retroreflective sheeting.

1. Permanent Signs and Devices.
Unless otherwise specified, all signs with yellow, green, or red, blue or brown background shall use Type III or IV retroreflective sheeting. The legend on white and yellow signs shall be accomplished with black nonreflective sheeting that is direct applied, or silk screened with black opaque ink. The legend on green signs shall be accomplished with white Type III or IV retroreflective sheeting that is direct applied. The legend on red signs shall be accomplished using either transparent red ink that is reverse silk screened on white Type III or IV sheeting, or with white Type III or IV retroreflective sheeting that is direct applied on a red Type III or IV retroreflective sheeting background. The legend on blue or brown signs shall be accomplished using either transparent ink that is reverse silk screened on white Type III or IV sheeting, with white Type III or IV retroreflective sheeting that is direct applied.

Type III or IV retroreflective sheeting shall be used for permanent road closure barricades.

2. Work Zone Signs and Devices.

a. Interstate and Primary Highways.
All rigid signs with orange backgrounds shall use Type VII (Iowa) retroreflective sheeting. The legend shall be accomplished with black nonreflective sheeting that is direct applied or silk screened with black opaque ink. All flexible roll-up signs with orange backgrounds shall use Type VI (Iowa) retroreflective sheeting. The legend shall be accomplished by silk screening with black opaque ink.

STOP/SLOW paddles shall use Type VII (Iowa) retroreflective sheeting. The black legend shall be accomplished with black nonrefelctive sheeting that is direct applied or silk screened with black opaque ink on orange Type VII (Iowa) retroreflective sheeting. The white legend shall be accomplished with transparent red ink that is reverse silk screened on white Type VII (Iowa) retroreflective sheeting.

Type VII (Iowa) non-fluorescent retroreflective sheeting shall be used for barricades, vertical panels, and all other work zone traffic control devices that use premanufactured barricade sheeting. Type VII (Iowa) fluorescent orange and Type III or IV white retroreflective sheeting shall be used for drums, 42 inch (1050 mm) channelizers, tubular markers, and all other work zone traffic control devices that use horizontal sheeting. Reboundable traffic control devices shall use Type III or IV or Type VII (Iowa) sheeting that is designed for such devices.

b.  Other Highways.
Unless otherwise specified, all rigid post mounted signs with orange backgrounds shall use Type III or IV retroreflective sheeting. Unless otherwise specified, all skid mounted signs with orange backgrounds shall use Type I or II retroreflective sheeting. The legend shall be accomplished with black nonreflective sheeting that is direct applied or silk screened with black opaque ink.

STOP/SLOW paddles shall use Type I or II retroreflective sheeting. The black legend shall be accomplished with black nonreflective sheeting that is direct applied or silk screened with black opaque ink. The white legend shall be accomplished with transparent red ink that is reverse silk screened on white retroreflective sheeting.

Type III or IV retroreflective sheeting shall be used for barricades and vertical panels. Reboundable drums, tubular markers, and other reboundable markers shall use Type III or IV retroreflective sheeting that is designed for reboundable devices.

At the Contractor's option, work zone signs and devices using retroreflective sheeting in accordance with Article 4186.03, A, 2, a above, may be used on all other highways.

B. Durability of Reflective Sheeting.
White, Yellow, green, red, blue and brown reflective sheeting used for permanent signing and traffic control devices shall be subject to a 3 year outdoor Iowa exposure at 45 degrees facing south. Orange and white reflective sheeting used for temporary traffic control signing and traffic control devices shall be subject to a 1 year outdoor Iowa exposure at 45 degrees facing south. At the end of the testing period, the reflective sheeting shall meet the requirements for artificial weathering specified in ASTM D 4956 Section 7.4 and 7.5. In addition, the reflective sheeting shall show no evidence of mildewing or similar disfigurement after the testing period.

4186.04 NONREFLECTIVE SHEETING.
Nonreflective sheeting shall conform to the same adhesive and physical requirements as for reflective sheeting found in ASTM D 4956. The colors for nonreflective sheeting shall conform to the same color requirements as for Type III reflective sheeting found in ASTM D 4956.

4186.05 INKS, CLEARS, AND THINNERS.
Inks, clears, and thinners shall be used in accordance with the recommendations of the sheeting manufacturer.

4186.06 SIGN FABRICATION.
Fabrication of all sign blanks and panels shall be accomplished in a uniform and high quality manner. All fabrication, including shearing, cutting, and hole punching or drilling, shall be completed prior to metal degreasing and application of reflective sheeting. Sign blanks and panels shall be cut to size and shape and shall be free of buckles, warp, dents, cockles, burrs, and defects resulting from fabrication.

Type B signs shall be assembled using a maximum number of structural panels of 12 inch (300 mm) width dependent upon the dimensions shown in the contract documents, in order to keep the number of sign joints to a minimum. If a 6 inch (150 mm) panel is required, it shall be the top panel of the completed sign.

The finished signs, both Type A and B, shall be smooth and flat. The signs shall be free from blisters, wrinkles, cracks, tears, and delaminations. All letters shall be clean cut and sharp.

A. Application of Sheeting.
Sheeting, reflective and nonreflective, shall be applied mechanically with the equipment and in a manner specified by the manufacturer of the sheeting or by a method which will produce an equivalent result.

On extruded aluminum or formed steel sign panels, the sheeting shall lap over the longitudinal edges of each panel a minimum distance of 1/4 inch (6 mm) and shall be bonded to the panels by means of an accessory tool recommended by the manufacturer of the sheeting or by a tool which will produce an equally satisfactory result.

Whenever a sign face comprises two or more pieces or panels of reflective sheeting, they must be carefully matched for color at the time of sign fabrication to provide uniform appearance and brilliance, both day and night. Signs with background color of adjacent sheets or panels not properly matched will be rejected.

At splices, sheeting with pressure sensitive adhesive shall be overlapped not less than 3/16 inch (5 mm). Sheeting with heat activated adhesive may be spliced with overlap not less than 3/16 inch (5 mm) or butted with a gap not to exceed 1/32 inch (1 mm). Only butt splices shall be permitted on signs screen processed with transparent color.

B. Intentionally left blank.

C. Letters, Numerals, Symbols, and Borders.
Letters, numerals, symbols, and borders shall be in accordance with the details shown in the contract documents.

The border strip on the left and right edges of each sign shall be set in far enough from the edge to accommodate installation of the required trim molding without reducing the border width.

D. Other Details.
Any gaps on the edges of plywood signs shall be filled with a waterproof putty.

Signs shall be slip sheeted and packed in such a manner as to insure arrival at their destination in an undamaged condition. Packaged signs shall not become wet.

4186.07 SIGN IDENTIFICATION.
The Contractor shall mark the back of all finished signs with an identification sticker at the bottom edge of the sign that is visible when the sign is erected. The sticker shall be a piece of nonreflective sheeting approximately 3 by 4 inches (75 mm by 100 mm) with the following information: the contractor's name, type of sheeting, and name of sheeting manufacturer. Type A signs shall also have the erection date on the sticker. In addition to the sticker, Type B signs shall have the following information on the back of the sign in 1 inch (25 mm) letters: the sign number, and the erection date. The 1 inch (25 mm) letters may be painted or stenciled on with black exterior grade paint, or printed on a sticker.

4186.08 FINISHED SIGN INSPECTION.
Finished signs shall be visually inspected upon receipt for correct message, and conformity to the contract documents. Non-complying signs shall be replaced by the Contractor at no additional cost to the Contracting Authority.

4186.09 FASTENING ACCESSORIES.
Unless otherwise stated, dimensions and tolerances for all bolts, nuts, and washers shall be in accordance with ANSI standards for the size required. The threads of all fastening accessories shall meet the requirements of ANSI B1.1, National Coarse Thread Series. Fastening accessories shall comply with the following requirements:

A. Type A Signs.
Type A sign fasteners shall be as follows:

1. Bolts.
Bolts shall be 3/8 inch (9.5 mm) in diameter with a hexagonal head. Thread fit shall conform to ANSI Class 2A. The length required shall be dependent upon the type of post supplied by the Contractor (wood, steel, or aluminum). The minor thread diameter shall be used in determining stress area.

2. Nuts.
Nuts shall be finished, finished thick, regular, or heavy, hexagonal, self locking nuts for 3/8 inch (9.5 mm) bolts, but all nuts shall be of the same type. The axial tensile strength at room temperature shall be not less than 4,730 pounds (21 kN).

3. Self Locking Nuts.
Self locking nuts shall be approved by the Engineer. Thread fit shall be as recommended by the manufacturer.

4. Washers.
Washers shall be made of a quality of material approved by the Engineer. The washers shall be 3/8 inch (9.5 mm) I.D. x 1 3/8 inch (35mm) O.D. x 0.125 inch (3mm). A thickness tolerance of ± 0.006 inch (0.15 mm) will be allowed.

Neoprene washers shall be 3/8 inch (9.5mm) I.D. x 15/16 inch (24mm) O.D. x 1/8 inch (3 mm) thickness. (Neoprene washers are required when treated wood posts are used). Durometer hardness shall be 60 to 70 with a tolerance of ± 5.

5. Other Details.
Other details, including post clips on I-beam posts, etc., are shown in the contract documents.

Hardware may be furnished in stainless steel or galvanized steel as approved by the Engineer. Galvanizing shall meet requirements of ASTM A 153, Class D, or ASTM B 633, Class Fe/Zn 12, Type 1.

B. Type B Signs.
Post clip bolts shall have a square or rectangular head, shall be 3/8 inch (9.5 mm) in diameter and 1 3/4 inches (45 mm) in length, and shall be manufactured in accordance with the dimensions and details shown in the contract documents. Panel bolts shall have a hexagonal head and shall be 3/8 inch (9.5 mm) in diameter and 3/4 inch (19mm) in length. Both bolts shall be made from aluminum wire or rod meeting requirements of ASTM B 211, Alloy 2024-T4. Thread fit shall conform to ANSI, Class 2A. The minor thread diameter shall be used in determining stress area.

Nuts for Type B signs shall be manufactured from any aluminum alloy listed in ASTM B 211 or from stainless steel. Post clip nuts shall be finished, finished thick, regular, or heavy, hexagonal, self locking nuts for 3/8 inch (9.5 mm) bolts, but all nuts shall be of the same type. Nuts shall withstand a proof load, at room temperature, of 4,730 pounds (21 kN). Self locking nuts shall be approved by the Engineer. Thread fit shall be as recommended by the manufacturer.

Panel bolt nuts shall be finished hexagonal nuts for 3/8 inch (9.5 mm) bolts. Nuts shall stand a proof load of 4,200 pounds (18.7 kN). Thread fit shall conform to ANSI, Class 2B.

Washers shall be made of a quality of material approved by the Engineer. Post clip washers and panel bolt washers shall be flat 7/16 inch (11 mm) I.D. x 1 inch (25 mm) O.D. x 0.078 inch (2 mm). A thickness tolerance of ± 0.006 inch (0.15 mm) will be allowed.

Post clips shall be aluminum castings and shall be manufactured in accordance with the details and dimensions shown in the contract documents. The clip shall be able to withstand the load requirements of the bolt specified.

Edge trim molding shall be attached to the signs by means of self tapping, 300 series, stainless steel, machine screws, Size 8-32. The screen shall have a pan head, binding head, or truss head. A screw shall be installed 1/2 inch (13 mm) from the end of each section of molding, and intermediate screws shall be not more than 12 inches (300 mm) apart.

The fittings herein described shall, when combined with the aluminum sections and posts, form a complete, assembled sign unit that will meet the specified strength requirements. Though aluminum hardware is specified, equivalent hardware may be furnished in stainless steel or galvanized steel as approved by the Department. Galvanizing shall meet requirements of ASTM A 153, Class D, or ASTM B 633, Fe/Zn 12, Type 1.

C. Delineators, Milepost Markers, and 6 Inch by 6 Inch (150 mm by 150 mm) Route Markers.
Delineators shall be fastened to the post by a blind, pull through, aluminum rivet and washer. The rivet shall have a diameter of 3/16 inch (5 mm), with a suitable grip range. Washers shall be made of a quality of material approved by the Engineer. The washer shall have dimensions of 0.193 inch (4.9 mm) I.D. x 3/4 inch (19 mm) O.D. x 0.091 inch (2.3 mm) with a thickness tolerance of ± 0.006 inch (0.15 mm).

Milepost markers and 6 inch by 6 inch (150 mm by 150 mm) route markers shall be fastened to the post as shown in the contract documents.

4186.10 SIGN POSTS.
Sign posts shall be of the following types for the sign or signs specified:

A. Wood Posts for Type A or B Signs.
Wood posts for Type A or B signs shall be of the type and size shown in the contract documents.

Wood sign posts shall meet requirements of Section 4164.

B. Steel Breakaway Posts for Type A or B Signs.
Steel breakaway posts for Type A or B signs shall be of the size and type shown in the contract documents. Unless otherwise specified, steel shall meet requirements of ASTM A 36/A 36M. Fabrication shall be in accordance with Section 2408. Posts shall be galvanized after fabrication except as noted. The coating shall be applied by the hot dip process, in compliance with ASTM A 123, Grade 85. Posts shall be cleaned and pickled before such application.

Fasteners for breakaway sign posts shall be high strength bolts, nuts, and washers meeting requirements of Article 4153.06, B.

Washers shall meet requirements of ANSI B18.22.1 for the bolts specified, shall be made of steel, and shall be capable of withstanding the specified minimum load of the bolt on which they will be used without sign of failure. Washers with dimensions other than those specified may be approved by the Engineer.

Heavy hexagonal, semi-finished nuts and jam nuts shall be used on the anchor bolts. Nuts shall meet requirements of ANSI B18.2.2. Nuts may be tapped oversize only enough to product finger free fit. Regular hexagonal jam nuts may be used when approved by the Engineer.

Bolts (including the entire length of the anchor bolts), nuts, and washers, shall be galvanized according to ASTM A 153, Class A coating.

Holes in the fuse plates and splice plates shall be drilled. Notches in the base plates and fuse plates shall be provided so that no metal projects beyond any face of the plate and the edges of the notches are smooth and true. All bearing surfaces of base plate and fuse plate assembly shall be smooth and free of beads or runs.

For the fuse plate assembly, the post cut shall be accomplished by either sawing or flame cutting, and may be made either before or after galvanizing of the post. If the cut is made after galvanizing, the damaged area shall be repaired by painting or smoldering.

Before fabrication, shop drawings for the steel breakaway sign posts shall be submitted in accordance with Article 1105.03 for review.

C. Posts for Delineators, Milepost Markers, and 6 Inch by 6 Inch (150 mm by 150 mm) Route Markers.
These posts shall be of the type and length designated in the contract documents.

1. Type 1 Posts.
Type 1 posts shall be galvanized steel. The nominal weight of the posts shall be 2.00 pounds (3 kg) or more per foot (meter), before punching, although a variation of 3% under the specified weight (mass) will be permitted.

Posts shall be U-shaped with flat flanges at the front or open end of the "U". The faces of the flanges shall be flat and in the same plane. The back of the posts shall be reasonably flat or ribbed or shall otherwise provide for suitable sign or delineator bearing to a width of at least 1 1/8 inches (28 mm) parallel to the front flanges. The front of the post shall have a width of 3 inches to 3 1/2 inches (75 mm to 90 mm). The overall depth of the section shall be 1 13/32 inches to 1 17/32 inches (35 mm to 40 mm). The cross section of the posts shall be symmetrical about the center axis perpendicular to the front and back, and the thickness of metal shall be reasonably uniform. Minor deviations may be allowed by the Engineer.

Posts shall be punched on center line with holes 7/16 inch (11 mm) in diameter on 1 inch (25 mm) centers. The posts shall be punched the entire length of the post. The top hole shall be 1 inch (25 mm) from the top of the post. Spacing and alignment of holes shall be within 1/16 inch (2 mm) of correct center line and distance. Punching shall be done so that there will be no cracks radiating from the holes. The posts may be furnished pointed for driving.

Posts shall be galvanized after fabrication. The coating shall be applied by the hot dip process at a rate of not less than 2.0 ounces per square foot (610 g/m²) of actual surface as provided in ASTM A 123.

Posts for permanent roadside delineators shall be Type 1 Posts. Posts for temporary delineators shall be either Type 1, Type 2, or Type 3 Posts.

2. Type 2 Posts.
Type 2 posts shall be galvanized steel. The nominal weight of the posts shall be 1.12 pounds (1.67 kg) or more per foot (meter), before punching, although a variation of 3% under the specified weight (mass) will be permitted.

Posts shall be U-shaped with flat flanges at the front or open end of the "U". The faces of the flanges shall be flat and in the same plane. The back of the posts shall be reasonably flat or ribbed or shall otherwise provide for suitable sign or delineator bearing to a width of at least 11/16 inch (18 mm) parallel to the front flanges. The front of the post shall have a minimum width of 2 inches (50 mm). The overall depth of the section shall be at a minimum of 7/8 inch(22 mm). The cross section of the posts shall be symmetrical about the center axis perpendicular to the front and back, and the thickness of metal shall be reasonably uniform. Minor deviations may be allowed by the Engineer.

Posts shall be punched in accordance with Paragraph 1.

Posts shall be galvanized after fabrication. The coating shall be applied by the hot dip process at a rate of not less than 1.0 ounce per square foot (305 g/m²) or actual surface as provided in ASTM A 123.

3. Type 3 Posts.
Type 3 posts shall meet requirements of Paragraph 2, except they may be painted in lieu of galvanizing. When painted, the posts shall be painted with a prime coat and with a final coat of aluminum or green paint. The posts shall be thoroughly dry before being bundled for shipment.

4186.11 DELINEATORS.
Delineator reflectors shall be circular, hermetically sealed, prismatic reflectors with a sealed optical system. Permanent roadside delineators shall have an aluminum housing of 0.020 inch (0.508 mm), ASTM B 209, Alloy 5052. Temporary delineators may have either aluminum or plastic housing.

The delineator shall have a central mounting hole with a 3/16 inch (5 mm) diameter. Delineators with aluminum housing shall have an aluminum grommet expanded within the mounting hole. Delineators with plastic housing shall have a molded one piece reinforced plastic sleeve extending the thickness of the delineator. The central mounting hole shall withstand the pressure of fastening without cracking or damaging the reflective surface.

The delineator shall consist of a clear and transparent face of methyl methacrylate compound meeting requirements of ASTM D 788, Grade B, with a reflective lens area of approximately 7 square inches (4500 mm²), and a backing fused to the lens under heat and pressure around the entire perimeter of the lens and the central mounting hole. The backing shall be aluminum foil or a white, opaque compound of the type specified for the face. The foil backing will be acceptable only when the delineator has an aluminum backing. The reflector shall be colorless or yellow, as specified.

The lens shall consist of a smooth front surface, free from projections or indentations affecting reflectance other than a central mounting hole and identification, with a rear surface bearing a prismatic configuration so that it will effect a total internal reflection of light. The manufacturer's trademark shall be molded legibly into the face of the lens.

The optical performance of each delineator reflector when tested in accordance with Iowa DOT Materials Test Method 905 shall be equal to or exceed the following minimum values:

Observation Angle Degrees	Entrance Angle Degrees	Specific Intensity Candle Power Per Ft.-Candle (Candela Per Lux)
		White	Yellow
0.1 0.1	0 20	120 (11.0) 50 (4.6)	75 (7.0) 30 (2.8)
Five test specimens shall be selected for the specific intensity test. If all five specimens exceed the minimum values, the reflectance will be considered acceptable. If one of the five specimens fails to meet the minimum values, an additional ten specimens shall be selected for test, all of which must meet the minimum values. If two of the original five specimens fail to meet the minimum values, the lot shall be rejected.

Delineator reflectors shall be tested for proper sealing against dust and water in accordance with Iowa DOT Materials Test Method 907. Not more than 2% of the specimens tested shall show sealing test failure.