ASTM E1809-01

Measurements made by this test method are related to the night time brightness of retroreflective marking materials approximately facing the driver of a mid-sized automobile equipped with tungsten filament headlights at about 200 m distance.

Retroreflective marking material used for pedestrian safety can degrade with time, exposure to sunlight, wear and cleaning, and the material requires periodic measurement to ensure that the performance of the retroreflective material provides adequate safety to the wearer.

This test method is not intended to be used for the measurement of retroreflective marking material for pedestrian safety at observation and entrance angles other than those specified herein.

5.3.1 For most materials, the values for the coefficient of retroreflection obtained at −4° entrance angle and 0.2° observation angle using this test method will be nearly the same as the values corresponding to +5° entrance angle and 0.2° observation angle, a geometry that is specified in some high-visibility clothing standards.

1.1 This test method covers the measurement of the retroreflective properties of high visibility pedestrian garments, such as vests, using a portable retroreflectometer that can be used in the field. The portable retroreflectometer is a hand-held instrument with a defined standard geometry that can be placed in contact with retroreflective marking material to measure the retroreflection. The measurements can be compared to minimum requirements to determine the need for replacement of the retroreflective material.

1.2 This test method is designed for measuring retroreflective marking materials that have an area equal to or greater than that of the aperture of the retroreflectometer.

1.3 This test method is intended to be used for field measurement of retroreflective marking materials, but may be used to measure the performance of materials before placing the clothing in use.

1.4 This standard 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 applicability of regulatory limitations prior to use.