1、Standard Specification for Retroreflective Sheeting for Flat and Vertical Traffic Control Applications AASHTO Designation: M 268-15 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-4d M 268-1 AASHTO Standard Specifi
2、cation for Retroreflective Sheeting for Flat and Vertical Traffic Control Applications AASHTO Designation: M 268-15 1. SCOPE 1.1. This specification covers retroreflective sheeting, translucent ink, and overlay film intended for traffic control applications. The sheeting serves either as the reflect
3、orized background for sign messages or for the legends and symbols applied to the reflectorized background. Messages may be applied in opaque black or transparent colors. This specification does not cover temporary retroreflective sheeting used during construction. Refer to other specifications for
4、these products. 1.2. All material furnished under this specification shall have been manufactured within 18 months of the delivery date. All retroreflective sheeting and process components on a single sign shall be supplied by the same manufacturer or approved by that manufacturer. 1.3. The values s
5、tated in inch-pound units are to be regarded as the standard. 1.4. This specification does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the
6、applicability of regulatory limitations prior to use. 2. REFERENCED DOCUMENTS 2.1. ASTM Standards: B209, Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate B209M, Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate (Metric) B449, Standard Specification for Chro
7、mates on Aluminum D523, Standard Test Method for Specular Gloss D2244, Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates D4956, Standard Specification for Retroreflective Sheeting for Traffic Control E308, Standard Practice for
8、 Computing the Colors of Objects by Using the CIE System E810, Standard Test Method for Coefficient of Retroreflection of Retroreflective Sheeting Utilizing the Coplanar Geometry E811, Standard Practice for Measuring Colorimetric Characteristics of Retroreflectors Under Nighttime Conditions E991, St
9、andard Practice for Color Measurement of Fluorescent Specimens Using the One-Monochromator Method E1164, Standard Practice for Obtaining Spectrometric Data for Object-Color Evaluation E1347, Standard Test Method for Color and Color-Difference Measurement by Tristimulus Colorimetry 2015 by the Americ
10、an Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4d M 268-2 AASHTO E1349, Standard Test Method for Reflectance Factor and Color by Spectrophotometry Using Bidirectional (45:0 or 0:45) Geometry E2152, Standard Practice f
11、or Computing the Colors of Fluorescent Objects from Bispectral Photometric Data E2153, Standard Practice for Obtaining Bispectral Photometric Data for Evaluation of Fluorescent Color E2301, Standard Test Method for Daytime Colorimetric Properties of Fluorescent Retroreflective Sheeting and Marking M
12、aterials for High Visibility Traffic Control and Personal Safety Applications Using 45:Normal Geometry G147, Standard Practice for Conditioning and Handling of Nonmetallic Materials for Natural and Artificial Weathering Tests G151, Standard Practice for Exposing Nonmetallic Materials in Accelerated
13、Test Devices that Use Laboratory Light Sources G155, Standard Practice for Operating Xenon Arc Light Apparatus for Exposure of Non-Metallic Materials 2.2. Federal Standard: Manual on Uniform Traffic Control Devices Standard Color Tolerance Charts, Federal Highway Administration, Washington, DC 2.3.
14、Other Documents: Commission Internationale de lEclairage (CIE) Standard Colorimetric System Commission Internationale de lEclairage (CIE) Standard Illuminant D65 3. DISCUSSION 3.1. The retroreflective sheeting classifications established in this specification are not intended to describe any specifi
15、c materials, but are instead intended to establish meaningful minimum retroreflectivity intervals. These intervals are correlated with human performance factors by which sheeting may be classified. 3.2. Classifications are provided as a means for differentiating functional performance based on minim
16、um retroreflectivity levels at standard combinations of entrance and observation angles. The combinations of entrance and observation angles shown in this specification provide a mechanism to categorize retroreflective sheeting materials into Type classifications. It should be recognized that perfor
17、mance characteristics outside these standard geometries cannot always be reasonably predicted, especially for retroreflective sheeting of microprismatic construction, and may vary between particular products meeting the same Type. It is the responsibility of the user of this specification to determi
18、ne the suitability of any reflective sheeting material for its intended application. 3.3. When tested in accordance with ASTM E810, the average coefficient of retroreflection (RA) for a set of three samples taken from the same roll must not vary more than 20 percent between RAmeasured at 0, 45, 90,
19、and 120 degrees of rotation in order to be considered rotationally insensitive. Other rotational angles can be specified for testing by the user. The test shall be conducted at an observation angle of 0.5 degrees and an entrance angle of 4.0 degrees. Other combinations of observation and entrance an
20、gle can be specified for testing by the user. Calculate the percent difference by dividing the absolute difference between RA(0) and RA(45) by RA(0). Repeat the calculation replacing RA(45) with RA(90) and RA(120). RA(0) is established with the sheeting aligned in its optimum rotation. 2015 by the A
21、merican Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4d M 268-3 AASHTO 3.3.1. For sheeting not meeting the 20 percent maximum rotational sensitivity requirement, the manufacturer must provide identification marks or ot
22、her features (such as a datum mark, tiles, or distinct seal pattern) in or on the sheeting face denoting the optimum orientation of the sheeting. The markings or features must be visible from a minimum distance of 2 ft and must be arrayed in such a manner that they will be readily distinguishable on
23、 cutout legends, symbols, or borders. The manufacturer must provide fabrication guidelines outlining optimum sheeting orientation upon user request. 3.3.2. When utilizing sheeting that does not meet the 20 percent maximum rotational requirement, fabricate signs by applying white sheeting for cutout
24、legends, symbols, borders, and route marker attachments within the parent sign face in the optimum rotation according to the identification markings; and apply all background sheeting uniformly oriented. 3.4. DelineatorsRetroreflective sheeting materials suitable for use on delineators are typically
25、 of microprismatic construction. The Type of retroreflective sheeting shall be specified by the user. 4. CLASSIFICATIONS 4.1. This specification establishes four types of retroreflective sheeting, with successively increasing minimum coefficients of retroreflection. Retroreflective sheeting material
26、s shall meet all of the performance requirements in Section 5 to qualify as a particular type under this specification. Minimum coefficients of retroreflection are shown in Tables 4, 5, 6, and 7 for retroreflective sheeting Types A, B, C, and D, respectively. The designated type is exclusive to the
27、highest specified minimum RAsatisfied at observation angle of 0.5 degrees and an entrance angle of 4.0 degrees. Using higher retroreflectivity sheeting to manufacture signs where lower retroreflectivity sheeting Types are specified must be approved by the end user. 4.2. The following are general des
28、criptions of the types of retroreflective sheeting established by this specification. These are provided for descriptive information only and are not intended to be limitations or recommendations. Note 1The Manual on Uniform Traffic Control Devices (MUTCD) requires that traffic control signs, unless
29、 illuminated, be retroreflective to show the same shape and similar color both day and night. Therefore, any retroreflective sheeting materials meeting this specification would satisfy that requirement. However, when determining the appropriateness of a particular type of sheeting for a particular a
30、pplication, consideration should be given to the pertinent highway characteristics where the materials will be installed, such as traffic volumes, traffic speeds, and roadway geometrics, as well as available resources. Brighter materials (meeting Type B, C, or D) should be considered for use on comp
31、lex roadway environments where the driving task may be more involved. 4.2.1. Type ARetroreflective sheeting materials meeting Type A are typically constructed of encapsulated microscopic glass bead lens construction. 4.2.2. Type BRetroreflective sheeting materials meeting Type B are typically constr
32、ucted of unmetallized microprismatic optics. These triangular microprismatic materials do not have a significant 1-degree observation angle performance. 4.2.3. Type CRetroreflective sheeting materials meeting Type C are typically constructed of unmetallized microprismatic optics. These triangular mi
33、croprismatic materials have a significant 1-degree observation angle performance. 4.2.4. Type DRetroreflective sheeting materials meeting Type D are typically constructed of unmetallized microprismatic optics. These materials have 0.5- and 1-degree observation angle performance approximately two tim
34、es greater than Type C materials. 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4d M 268-4 AASHTO 4.3. Adhesive Backing ClassesThe adhesive backing classes shall be specified by the end user and sha
35、ll be classified as follows: 4.3.1. Class 1The adhesive backing shall be pressure-sensitive and require no heat, solvent, or other preparation for adhesion to smooth, clean surfaces. 4.3.2. Class 2The adhesive backing shall be activated by applying heat and pressure to the material. The temperature
36、necessary to form a durable permanent bond shall be a minimum of 66C (150F). Reflective sheeting materials with Class 2 adhesive shall be repositionable under normal shop conditions and at substrate temperatures up to 38C (100F) without damage to the sheeting. Reflective sheeting materials with Clas
37、s 2 adhesive may be perforated to facilitate removal of air in heat-vacuum laminators, but the perforations must be of a size and frequency such that they do not cause objectionable blemishes in the finished sign. 4.3.3. Class 3The adhesive backing shall be a positionable low-tack pressure-sensitive
38、 adhesive that requires no heat, solvent, or other preparation for adhesion to smooth, clean surfaces. Reflective sheeting materials with Class 3 adhesive shall be repositionable up to a temperature of 38C (100F) without damage to the sheeting. 4.3.4. Class 4The adhesive backing shall be a low-tempe
39、rature pressure-sensitive adhesive that permits sheeting applications down to 7C (+20F) without the aid of heat, solvent, or other preparation for adhesion to smooth, dry, and clean surfaces. 5. SHEETING PROPERTIES 5.1. Test ConditionsUnless otherwise specified in this specification, condition all a
40、dhesively bonded and unbonded test samples and specimens at a temperature of 73 3F (23 2C) and 50 5 percent relative humidity for 24 h prior to testing. 5.2. Panel PreparationUnless otherwise specified in this specification, when tests are to be performed using test panels, apply the specimens of re
41、troreflective material to smooth aluminum cut from Alloy 6061-T6 or 5052-H38, in accordance with ASTM B209 or B209M. The aluminum substrate thickness shall be between 0.060 in. (1.52 mm) and 0.100 in. (2.54 mm). See Note 2. The retroreflective sheeting area shall be a minimum of 48 in.2with a minimu
42、m dimension of 4 in. and a maximum dimension of 12 in. Prepare the aluminum in accordance with ASTM B449, Class 2, or degrease and lightly acid etch before the specimens are applied. See Note 3. Apply the sheeting specimens to the panels in accordance with the recommendations of the retroreflective
43、sheeting manufacturer. Note 2It is recommended that the thicker aluminum sheeting (0.0800.100 in.) be used for outdoor weathering to aid in mounting and to minimize warping over time. Note 3It has been determined that cleaning the aluminum surface with isopropyl alcohol aids in the adhesion of the s
44、heeting. 5.3. Chemical ResistanceThe surface of the sheeting or the face of a completed sign must be chemically resistant to the extent that there will be no detrimental effects to the surface when wiped with a soft, clean cloth dampened with mild detergents or cleaners supplied or recommended by th
45、e sheeting manufacturer. 5.4. AdhesiveApply 4 in. (102 mm) of a 1-in.-by-6-in. (25-mm-by-152-mm) reflective sheeting specimen to a test panel. Condition as specified in Section 5.1. Suspend the panels in a horizontal position with the specimen facing downward. The adhesive backing of the retroreflec
46、tive sheeting shall produce a bond that will support a 13/4-lb (0.79-kg) weight for adhesive classes 1, 2, and 3 or a 1-lb (0.45-kg) weight for adhesive Class 4 for 5 min, without the bond peeling for a distance of more than 2 in. (51 mm). The test panel must have a minimum thickness of 0.040 in. (1
47、016 mm). 2015 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-4d M 268-5 AASHTO 5.5. Liner RemovalThe liner, when provided, shall be easily removed without soaking in water or other solutions, and shall n
48、ot break, tear, or remove adhesive from the sheeting. The protective liner, if any, shall be easily removed following accelerated storage for 4 h at 160F (71C) under a weight of 2.5 psi (17.2 kPa). 5.6. Daytime ColorDetermine the chromaticity and luminance factor percent Y for CIE Standard Illuminan
49、t D65 and the 1931 CIE (2-degree) standard observer in accordance with ASTM E308, E991, E1164, E1347, E1349, E2152, E2153, and E2301, as applicable. The luminance factor is the sum of the reflectance luminance factor and the fluorescence luminance factor. Bispectral measurement provides the individual factors, while measurement with simulated CIE Standard Illuminant D65 provides their sum. For fluorescent specimens, it is necessary either that the physical illumination of the specimen be a goo
