scope:

This standard describes the various classes of cold-water turbine meters in sizes ¾ in. (20 mm) through 20 in. (500 mm) for water supply customer service and the materials and workmanship employed in their fabrication. The turbine meters described in this standard are divided into class I and class II meters. Both classes of meters register by recording the revolutions of a turbine set in motion by the force of flowing water striking its blades.

Class I. Class I meters are the vertical-shaft and low-velocity, horizontal-shaft models.

Class II. Class II meters are the in-line, horizontal-axis, high-velocity-type turbines characterized by lower head loss and a wider normal operating flow range than class I models.