The April 2015 issue of Valve World contains an excellent article by the well-known consultant Mr E.W.Singleton (Koso Kent Introl). In that article, Mr Singleton discusses the sizing of control valves for nonturbulent flow by means of the loss coefficients K and KL. For reasons of space we were unable to include the Appendix. However, readers can find both the original article as well as the Appendix attached here in PDF format.