I need some help here gentlemen. I currently have three points in a primary/secondary that employ orifice devices for measuring chw flow. i am looking into buying a sq root extraction device to measure and report the flow automatically, however i am planning on installing a delta p gage in the mean time and as future back-up. do any of you have a formula for a standard orifice plate and gpm. i have looked every where and cannot find the typical sq root for chw. i.e. the sq root for air is 4005, with the density correction factor aplied for the temp and hum. But what is it for CHW? any help is great thanks.