1 Scope
This standard specifies the test method for coefficient of retroreflection of retroreflective sheeting utilizing the coplanar geometry.
This standard is applicable to the laboratory measurement of coefficient of retroreflection of retroreflective sheeting for highway, and the laboratory measurement of other retroreflective materials may be used for reference.
2 Normative reference
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition applies.
JT/T 688 Retroreflection vocabulary
3 Term and definition
For the purposes of this document, the terms and definitions given in JT/T 688 and the following apply.
3.1
coplanar geometry
retroreflection geometry condition in which the retroreflector axis, illumination axis and observation axis are located in the same plane
4 Instrument
Test instruments include: cast light source, receiver, goniometer specimen holder and receiver-light source holder.
4.1 Cast light source
The light source is of casting type and shall meet the following conditions:
Foreword i
1 Scope
2 Normative reference
3 Term and definition
4 Instrument
5 Sample
6 Test methods
7 Calculation
8 Test report
