ANULAB Retroreflective Sheeting Testing (Traffic Sign) as per ASTM D 4956 скачать в хорошем качестве

ANULAB Retroreflective Sheeting Testing (Traffic Sign) as per ASTM D 4956

Scope: This test method covers measurement of the retroreflective properties of sign materials such as traffic signs and symbols (vertical surfaces) 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 sign material to measure the retroreflection in a standard geometry. The measurements can be compared to minimum requirements to determine the need for replacement. Entrance and observation angles specified in this test method are those used currently in the United States and may differ from the angles used elsewhere in the world. This test method is intended to be used for the field measurement of traffic signs but may be used to measure the performance of materials before placing the sign in the field or before placing the sign material on the sign face. Procedure: This test method involves the use of commercial portable retroreflectometers for determining the retroreflectivity of highway signing materials. The entrance angle shall be --4°. The observation angle shall be 0.2°. The portable retroreflectometer uses a instrument standard for standardization. After standardization, the retroreflectometer is placed in contact with the sign to be tested, ensuring that only the desired portion of the sign is within the measurement area of the instrument.The reading displayed by the retroreflectometer is recorded. The retroreflectometer is then moved to another position on the sign, and this value is recorded. A minimum of four readings shall be taken and averaged for each retroreflective color on the sign to be tested.