5.1 This test method provides a standard for comparison of rotating type anemometers, specifically cup anemometers and propeller anemometers, of different types. Specifications by regulatory agencies (4-7) and industrial societies have specified performance values. This standard provides an unambiguous method for measuring starting threshold, distance constant, transfer function, and off-axis response.

1.1 This test method covers the determination of the starting threshold, distance constant, transfer function, and off-axis response of a cup anemometer or propeller anemometer from direct measurement in a wind tunnel.

1.2 This test method provides for a measurement of cup anemometer or propeller anemometer performance in the environment of wind tunnel airflow. Transference of values determined by these methods to atmospheric flow must be done with an understanding that there is a difference between the two flow systems.

1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.

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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.