720 DELINEATOR MATERIALS

720.01 Rectangular Reflectors. Furnish rectangular reflectors that are a minimum size of 3 ´ 6 inches (75 ´ 150 mm) and that consist of reflective sheeting conforming to 730.19 adhered to a flexible post or a rigid bracket. Furnish white, yellow, or red reflectors as specified, by day and when viewed by reflected light at night. Furnish the aluminum plate for rectangular reflectors made from 6061-T6 reflective sheeting and that is a minimum of 0.060 inch (1.5 mm) thick.

720.04 Barrier Reflectors. Furnish reflector body housings that are made of acrylic or polycarbonate plastic, or corrosion resistant metal. Ensure that the minimum reflective surface area of the reflector is 7 square inches (4400 mm²).

Furnish white reflectors that reflect the following minimum candela of light at the indicated observation angles for each 1 foot-candle (10.76 lx) of incident light at the indicated entrance angles. Furnish amber reflectors that reflect at least 60 percent of these values.

		Observation Angle (degrees)
		0.2	2.0
Entrance angle (degrees)	-4	62	0.25
Entrance angle (degrees)	15	52	0.18

The entrance angle is measured in the horizontal plane between the direction of incident light and normal to the face of the reflector. The observation angle is measured in the vertical plane between the observer’s line of sight and the direction of light incident to the reflector face.

A. General. Furnish round prismatic reflectors made of methylmethacrylate plastic. Ensure that the protected back of the round reflector is plastic-coated foil or methylmethacrylate plastic. Furnish reflectors that have a net reflective surface area of not less than 7 square inches (4400 mm²).

Furnish yellow or red reflectors as specified, by day and when viewed by reflected light at night.

Furnish reflectors with a smooth front surface free from projections or indentations other than for identification of orientation, and with a configuration on the rear surface such as to return light that conforms to the brightness specified under the Brightness Test. Test a sample of 5 units for each delineator reflector color for brightness. The following definitions apply:

1. Entrance Angle. The angle at reflector between axis of light incident on it and the reflector axis.

2. Divergence Angle. The angle at reflector between observer’s line of sight and the axis of light incident on reflector.

3. Brightness. The total candelas returned by a reflector, at the specified divergence angle, per foot-candle (10.76 lx) of light incident on the reflector.

Entrance Angle (degrees)	Divergence Angle (degrees)	Brightness
Entrance Angle (degrees)	Divergence Angle (degrees)	Yellow	Red
0	0.10	71	28.6
20	0.10	28	11.3
0	0.33	12	4.8
20	0.33	5	1.9

B. Tests. Ensure that the configuration surface is sealed against dust, water, and water vapor by means of a protective back fused around the perimeter of the reflector and around the central mounting hole where used with the following tests:

1. Seal Test. Submerge a sample of 50 reflector units per shipment in water at room temperature, and subject them to a vacuum of 5 inches (125 mm) gage for 5 minutes. After restoring atmospheric pressure, leave the units submerged for an additional 5 minutes. When examined for water intake, failure of more than one unit is cause for rejection.

2. Heat Resistance Test. Test 3 reflectors for 4 hours in a circulating air oven at 150 ± 5 °F (66 ± 3 °C). Place the test specimens in a horizontal position on a grid or perforated shelf allowing free air circulation. At the conclusion of the test, remove the samples from the oven, and allow them to cool in air to room temperature. When examined for significant change in shape and general appearance as compared with corresponding unexposed control standards, failure of any reflector is cause for rejection.