ASTM_E_1709_-_09.pdf

Designation:E170909Standard Test Method forMeasurement of Retroreflective Signs Using a PortableRetroreflectometer at a 0.2 Degree Observation Angle1This standard is issued under the fixed designation E1709;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers measurement of the retroreflec-tive properties of sign materials such as traffic signs andsymbols(vertical surfaces)using a portable retroreflectometerthat can be used in the field.The portable retroreflectometer isa hand-held instrument with a defined standard geometry thatcan be placed in contact with sign material to measure theretroreflection in a standard geometry.The measurements canbe compared to minimum requirements to determine the needfor replacement.Entrance and observation angles specified inthis test method are those used currently in the United Statesand may differ from the angles used elsewhere in the world.1.2 This test method is intended to be used for the fieldmeasurement of traffic signs but may be used to measure theperformance of materials before placing the sign in the field orbefore placing the sign material on the sign face.1.3 This test method covers measurements at a 0.2 degreeobservation angle.See Test Method E2540 for measurementsat a 0.5 degree observation angle.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and to determine theapplicability of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E284 Terminology of AppearanceE808 Practice for Describing RetroreflectionE809 Practice for Measuring Photometric Characteristics ofRetroreflectorsE810 Test Method for Coefficient of Retroreflection ofRetroreflective Sheeting Utilizing the Coplanar GeometryE2540 Test Method for Measurement of RetroreflectiveSigns Using a Portable Retroreflectometer at a 0.5 DegreeObservation Angle3.Terminology3.1 The terminology used in this test method generallyagrees with that used in Terminology E284.3.2 DefinitionsThe delimiting phrase“in retroreflection”applies to each of the following definitions when used outsidethe context of this or other retroreflection standards.3.2.1 annular geometry,nthe portable instrument retrore-flection collection method where an annular area 0.1 degreeswide around the illumination axis collects the retroreflectedenergy at an angle to the center of the annular area correspond-ing to a specific observation angle.3.2.2 coeffcient of retroreflection,RA,nof a plane retrore-flecting surface,the ratio of the coefficient of luminousintensity(RI)of a plane retroreflecting surface to its area(A),expressed in candelas per lux per square metre(cd lx1 m2).3.2.3 datum axis,na designated half-line from the retrore-flector center perpendicular to the retroreflector axis.3.2.4 entrance angle,nthe angle between the illumina-tion axis and the retroreflector axis.3.2.5 entrance half-plane,nthe half plane that originateson the line of the illumination axis and contains the retrore-flector axis.3.2.6 instrument standard,nworking standard used tocalibrate the portable retroreflectometer.3.2.7 observation angle,nthe angle between the illu-mination axis and the observation axis.3.2.8 observation half-plane,nthe half plane that origi-nates on the line of the illumination axis and contains theobservation axis.3.2.9 orientation angle,s,nthe angle in a plane perpen-dicular to the retroreflector axis from the entrance half-plane tothe datum axis,measured counter-clockwise from the view-point of the source.1This test method is under the jurisdiction of ASTM Committee E12 on Colorand Appearance and is the direct responsibility of Subcommittee E12.10 onRetroreflection.Current edition approved July 1,2009.Published February 2010.Originallyapproved in 1995.Last previous edition approved in 2008 as E1709 08.DOI:10.1520/E1709-09.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.10 portable retroreflectometer,na hand-held instru-ment that can be used in the field or in the laboratory formeasurement of retroreflectance.3.2.10.1 DiscussionIn this test method,“portable retrore-flectometer”refers to a hand-held instrument that can be placedin contact with sign material to measure the retroreflection in astandard geometry.3.2.11 presentation angle,nthe dihedral angle from theentrance half-plane to the observat