Real Estate Journal — Multifamily — May 10 - 23, 2019 — 11D


M id A tlantic


By Nicole Paul, Energy Management Systems, Inc. Combatting reduced recovery rates based on water meter degradation

place exist- i n g wa t e r meters with new meters due to under- reporting of actual tenant consumption and l owe r flow rates as- W

ater meter degrada- tion can be defined as the need to re-

different flow rates which can be costly or rely on statistically representative samples of each type of meter. It is also impor- tant to determine water meter weighted accuracy with the average water consumption pattern, which gives informa- tion about how much water is used at different flow ranges. The weighted accuracy is the parameter used to estimate the total unmetered water volume over time and the optimal re- placement frequency of meters (Residential Water Meter Re- placement Economics). One excellent example of water meter degradation

would be when EMS replaced the water meter set at a prop- erty for a national REIT. The national REIT water meters were experiencing exceptional recovery rates in the two months after meter replacement and exceeded the two months prior to meter re- placement by an outstanding 37%! This example further reinforces the idea that water meter degradation occurs and that there are benefits in cost recovery when the meters are replaced. In addition, it sup- ports the assertion that this national REIT has an opportu- nity to greatly increase its re-

coveries through water meter replacement, in addition to the operational benefits of a con- version to full AMR readings. In conclusion, building owners should pay close attention to the age of their meter, and get them replaced with newmeter equipment or read with AMR to avoid inaccuracy of meter reads and tenant consumption later down the line. Nicole Paul is a market- ing communication special- ist with Energy Manage- ment Systems, Inc.  References: Allendar, Hans, Dr. Determining the Economic Optimal Life of Residen-

tial Water Meters, Water Engineering and Management Journal, 1996 Arregui, F.; Cabrera, E.; Cobacho, R.; & Garci-Serra, J., 2005. Key Fac- tors Affecting Water Meter Accuracy. Proc. Leak- age 2005, Davis, S.E., Residential Water Me- ter Replacement Economics, Leakage 2005 Conference Proceedings, 2005 1 In 2001, the Water Research Foundation (WRF) published the results of an extensive four year a re- search study, “Accuracy of In-Service Water Meters at Low and High Flow Rates” 2 Noss, R.R.; Newman, G.J.; & Male, J.W., 1987. Optimal Testing Frequency for Domestic Water Me- ters. Jour. Water Resources Planning &Management Div.—ASCE. 113:1:1.

Nicole Paul

sociated with the meter types aging. Rapid amortization of the investment is based on the advanced age of the target water meters and the propen- sity for older meters to degrade over time. Studies date back to 1987 by G.J, Newman, when the water utility industry began to document the suscep- tibility for older water meters to suffer degraded accuracy and under-reporting of actual consumption. Water meters are not able to exactly register the total amount of water consumed since they have a limited range of operation. Its performance normally diminishes at low flow rates, which are in most cases due to leaks in the us- er’s facilities. This problem increases with water meters aging since the accuracy curve decays over time. For instance, a study done by the Water Engineering and Management Journal, explains that meter accuracy degrades rapidly on average after 20 years, falling from a real meter accuracy of 99% down to 82% by year 30. In addition, the size of the meter in relation to aggregate flow-through volume can cause problems, as smaller meters with low flow rates result in the highest degrees of inac- curacy. There are three specific fac- tors to focus on when analyzing meter degradation and the rea- soning for this occurring: Age, Rate of Degradation and Low Flow Rates. Accuracy degrada- tion only in low flow scenarios for a 20-year-old meter ac- cording to Dr. Hans Allender, P.E., may be as high as 40% degradation or the meter may be only 60% accurate. In addi- tion, there is also the issue of renewing the meters too often that will produce economical losses caused by the fixed costs of the investment. To solve this issue, you must either test ev- ery single water meter in the system, to exactly determine the average performance at

Improve Sustainability, Energy Benchmark Your Property New York, Philadelphia, Washington, D.C. Contact us: 202-525-8475 » www.ems3.com

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