Craig Hannah, P.E., is the Engineering Manager for Johnson Controls’ Water Infrastructure Technology Team. He is Vice-Chair of the AWWA Metering Standards committee and a George Anderson Award recipient. He also serves on both the AWWA Water Loss Control Committee and Customer Metering Practices Committee, the latter of which he was a former Chair. Craig is a co-author of the AWWA M6, M22, and M36 Manuals. He earned a BS in Aerospace Engineering from Texas A&M University and an MA from Texas Tech University. He has 21 years of experience in the water industry.

The author recently completed a water loss optimization project for a medium-sized utility in the Midwest.  The utility had over 400 large water meters in service, and every one of those large water meters was of the horizontal turbo type—regardless of the application.  Consequently, the utility was losing nearly $630,000 annually in unbilled water and sewer revenue because those horizontal turbo type water meters were never designed to accurately measure usage at low flow rates.

Turbo type water meters are very accurate measuring devices at both intermediate and high flow rates, but they are not intended to be used at services that experience much usage at low flow rates.  Installing the correct type of water meter for each application is a critical component in reducing apparent water loss and increasing billable revenue.

To further complicate the situation, two-thirds of those horizontal turbo water meters were not installed correctly.  Horizontal turbo water meters must have a turbulent flow profile entering the measuring chamber.  Any disturbances in the flow profile as it enters the measuring chamber may cause the water meter to either over-register or under-register usage.  The presence of elbows, reducers, butterfly valves, couplers, and other devices near the measuring chamber often create disturbances in the flow profile that adversely affect turbo water meter accuracy.

Some of the large water meters were field tested for accuracy.  To illustrate the importance of having a turbulent flow profile entering the measuring chamber, those horizontal turbo water meter measuring chamber assemblies that were tested and found to be inaccurate were then removed from service and then bench tested in a new setting that eliminated the disturbed flow profile.  Wherever possible, the author and his colleague redesigned those large water meter settings to better condition the flow.

Meter data loggers were installed at each service that appeared to be improperly typed, and the flow data was analyzed to determine the percent of flow that was not being measured with any degree of accuracy.  The analysis also determined the financial benefit to be realized by the utility from large water meter typing.

The goal of this presentation is to conclusively prove that water meter selection and installation matters using actual examples and data from the field.