IEC 60534-2-4:2009 applies to all types of industrial-process control valves. It defines how to state typical control valve inherent flow characteristics and inherent rangeabilities. It also defines how to establish criteria for adherence to manufacturer-stated flow characteristics. This edition constitutes a technical revision. The main changes with respect to the previous edition are:
- update the normative references,
- delete the terminology included in IEC 60534-1,
- transform the previous Note 1 in Clause 6,
- redraw the graphics,
- delete the previous Figure 3.