Simultaneous Communication of Acoustic Data and Meter Readings Automatically

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1 Leakage Conference Proceedings Page 1 Simultaneous Communication of Acoustic Data and Meter Readings Automatically D Hughes, W Morgan, R Titus American Water Introduction In recent years, automatic meter reading (AMR) has become an increasingly reliable, cost effective method to convey customer meter readings with minimal error and personnel to utility billing and meter operations. Utilities recognize the increasing difficulty in accessing meters set inside of residential buildings with occupants working outside the home at a time of concerned about personal security. Utilities can also encounter hard to read and sometimes access meters set in pits. Even the remedy of walk by readings and efficient meter routing have significant costs for readers, their vehicles and their exposure to harm going from site to site. These factors are normally considered in deciding whether to proceed with an AMR program. What is often overlooked is the value of the communication network established by AMR that might be used to relay other information about the water system. With an innovative acoustical monitoring technology, American Water has not only found additional value of AMR but may have developed a revolutionary approach to maintaining minimal leak levels in a water system. This paper will examine a pilot program in Connellsville PA where relaying acoustic information from the system via such an AMR system and conveying daily results about possible system leakage is being tested. The Acoustic Monitor Photo Courtesy of Flow Metrix Several years ago, American Water approached well established leak detection companies in search of a low cost, permanent leak detection system that could be distributed throughout a water system and provide a leak analysis on demand. Flow Metrix, Maynard, MA responded with an effort culminating in the device known as MLOG. The MLOG leak detecting sensor can be strapped to active service pipes and is designed to monitor sound on a nightly basis. The range of the MLOG extends about 500 MLOG Acoustic Monitor strapped to water service feet for metal pipes, reaching into the distribution system and detecting noise from other nearby services. Because of the sensitivity of the sensor, only a small percentage of services must be equipped with the unit in order to monitor the entire distribution system. The percentage depends on the density of services, the pipe materials in use and the distribution system layout but is nominally 10%. Given the layout and the relatively low cost of the MLOG unit, the effective price of the equipment is less than $15 per connection. Pipe noise monitoring is programmed to occur frequently during a quiet time (12:30 AM to 4:30 AM). The monitor catalogs the data in 10 minute segments and selects the least noisy time period as a single data point for comparison with other MLOGs in the field. The original MLOG was designed for a walk-by meter reader to collect. The unit had its own radio transmitter that could transmit stored files of information. The data would be effectively communicated to the meter reader as he collected meter readings.

2 Leakage Conference Proceedings Page 2 Battery life for the MLOG is projected at over 10 years for a walk-by/drive-by AMR application. Automatic Meter Reading The parallels with the proposed walk-by collection of acoustic data and meter reading operations led to an examination of applying the fixed network AMR technology. Current AMR technology for water meters are of two basic types: mobile or drive-by AMR and fixed network AMR. In the drive-by system, a vehicle passes by the customer premises at nominal speeds that can receive the meter reads from the meter transmitters. This is accomplished as the transmitter bubbles up every four to seven seconds during predetermined hours in anticipation of a receiving device passing by at virtually any time. The fixed network AMR uses data collection stations located throughout the system to pick up meter read data at regular daily intervals ranging from 1 to 12 times per day. To collect the MLOG data in a mobile AMR scenario, the AMR system is unchanged. A vehicle could drive by and collect meter reads with the AMR receiver. The MLOG data collector would be a separate receiving device placed in the common vehicle. In initial testing the extensive data stream from the MLOG does suggest a possible slowed rate of collection. In a fixed network, receivers or collectors are stationed Photo Courtesy of Hexagram throughout the meter zone to collect meter readings transmitted from each meter. The range of the collectors is a function of the strength and frequency of the signal, topography, the location of the receiver and obstacles, like meter pit lids that attenuate the transmission. The collectors are stationed on poles, rooftops or tanks to maximize reception. If power is not readily available for collectors, solar panels are typically used to power the receiver, the data processor and the forwarding communication. Cell phones, SCADA or other devices transmit the data onto the AMR control center that organizes the data, transmits to other locations and prepares reports. Hexagram Star Meter Transmitting Unit There are advantages and disadvantages to collecting data by a passing vehicle or the fixed network. The fixed network AMR normally has higher capital costs because of the data collection stations while the drive-by AMR has higher operating costs because of reader and vehicle expenses. The drive-by AMR system has the advantage of generating meter reads at any time and, in fact sends out readings every 4-7 seconds (often restricted to during business hours) as the system does not know when the vehicle will pass by to collect information. The fixed network transmitter sends out readings at predetermined times usually one to six times per day. The frequent transmission by the drive-by tends to reduce the battery life in the transmitter. The infrequent transmission by the fixed network normally requires access to the meter to acquire readings at non-scheduled times. Drive-by systems tend to have more two-way communication capability as they are nearly always on. There is a trend for fixed networks to develop some two way capacity but they are largely one way systems at the present time. For the proposed MLOG link, the fixed network AMR provides the opportunity to collect the acoustic information daily. This translates into near real-time evaluation of potential leaks as they grow. Conversely, the drive-by AMR would store a month of data unless supplemental trips were made. The vehicle and the MLOG receiver system must pass by slow enough to collect the data stream. Part of the goal of the pilot program is to

3 Leakage Conference Proceedings Page 3 evaluate the value of assessing data on a daily or weekly basis as opposed to examining data on a monthly basis. Combining Technologies Hexagram, Inc was among the AMR companies approached to investigate and pilot a system using the fixed network AMR and the MLOG. They accepted the challenge and began discussions with Flow Metrix. Because Flow Metrix had devised a communication link that was in meter (Sensus) format, a fundamental issue was already addressed. Hexagram obtained an MLOG prototype and successfully transferred the data stream through an AMR system in its Ohio factory. Since the MLOG generates its daily reports in 4 packets, it was necessary to increase the daily transmissions from the originally proposed twice daily transmission to four times per day. The dual port Hexagram AMR transmitter unit, designed for compound meters, used one port for the meter (encoder) signal and one port for the acoustic device. For installation purposes both units had waterproof connections installed to their devices with an agreed waterproof connector to be linked in the field. The connections and the transmitters needed to be tested in both pit and indoor environments. More importantly, the untested MLOGs needed to be evaluated as a leakage monitoring tool Piloting Program Installation The site for the fixed network piloting program selected was a system in and around the small city of Connellsville in western Pennsylvania. The system is modestly sized at 5000 customers with a water need of about 1.3 MGD. Connellsville was selected because its Non-Revenue Water (NRW) exceeds 25% and the cost of water purchased for the system is $1.90 per thousand gallons, providing a strong financial driver for effective leakage reduction. The Connellsville distribution system dates back to the 1800 s. The city sits along hillside adjoining the Youghiogheny River where leaks might easily flow unseen into the water table. In 2004, there were 35 main or service break repairs. An old distribution system such as that in Connellsville offered high potential for a payback of the investment in leakage equipment if it proved successful. Connellsville, PA and vicinity Hexagram engineers evaluated the service area of nearly 9 square miles with 400 feet differentials in topography and identified 9 proposed locations for data collection (receivers) units. Following negotiations with the local power company, 6 locations using existing support (guide) poles were secured for a modest one time payment. Hexagram installed poles in the remaining 3 locations. Following a public notification campaign, the effort to install the meter transmitter unit and the MLOG throughout the system began. Installation was straightforward for the 450 locations inside the buildings once access was secured. Care was taken to space the units (MLOGs) to get acoustic coverage of the system. Corner locations were preferred as the range would extend in four directions for mains connected there. Two installers from American Water s meter staff carried out installation following a brief training period.

4 Leakage Conference Proceedings Page 4 Installers placed approximately 10 units per day per installer. This modest figure was largely attributed to problems of access. About 50 meters were proposed at meter pit locations. Pits were small and a challenge to attach the MLOGs securely. Hexagram trained the installers and their supervisors on how to install the AMR system to obtain the most reliable signals. The Network control center was installed in American Water s nearby office in Uniontown, PA and readied to receive signals. For meter pits, composite lids were special ordered and installed with the installation of the AMR and MLOG. With each day s installation, the Hexagram unit transmissions were confirmed. Cost Analysis The pilot work was performed in parallel with a cost analysis to assess whether the acoustic monitor is a viable addition to AMR network installation. The cost model is rooted in the analysis of the AMR system where the bulk of the cost and long-term savings are expected to occur. An exhaustive investigation was made to evaluate significant costs and savings using AMR. This included looking at the obvious impacts of meter reading labor, transportation and supplies. But it also included a careful examination of workman s compensation claims by meter staff and a variety of impacts on customer service costs. For example, a quick examination of PUC complaints revealed that 35-50% of claims related to estimated, misread, or inaccurate meter readings. In a similar way, calls into customer service frequently referenced this category of call. In some cases, the MLOG addition provides an immediate payback on the overall investment making the combination more attractive. In a case like Connellsville, the additional installation costs of the MLOG are minimal and the detection of leaks will pay for the MLOG portion of the investment (largely the MLOG equipment itself) within a twofour years. The program would be even more cost effective if scheduled coincidentally with a meter change-out program. The economic effectiveness of the acoustic monitor will be dependent on four elements: The potential for non-revenue water (NRW) reduction. For systems with low NRW, the monitors may not be cost effective. The cost of the non-revenue water that is reduced. If the cost of producing finished water now lost to leakage is significant, the savings could be significant. The amount of reduction in non-revenue water that the MLOG system (and subsequent analysis of data and main break repair effort) can achieve. The MLOG will not totally eliminate NRW but is expected to reduce leakage significantly. Results from the piloting of a system with an NRW in excess of 25% will help determine the acoustic monitor effectiveness. The number of MLOG s (expressed as a percentage) required in a system. A system with a low density of properties per area or having pipe with poor acoustic capacity may require a higher concentration of MLOGs, increasing initial costs. In addition to reducing the NRW and saving expenses for water production or purchase, the MLOG should impact other expenses as it sustains NRW at lower levels. The early identification of leaks, will allow repairs to be scheduled on a routine rather than emergency basis in some instances. Damage from a quickly discovered leak will be less than when it would normally be found coming to the surface. This will impact liability claims for property damage and restoration costs.

5 Leakage Conference Proceedings Page 5 Since the initial analysis, American Water has found several special cases where the MLOG may prove valuable. In at least one California system there are substantial penalties if the NRW exceeds 10% and lesser penalties if the value exceeds the current low value of 7% NRW. In several Ohio systems there is a PUC order to bring NRW below 15% or absorb the chemical and electrical costs for NRW in excess of the 15%. Preliminary Pilot Results The initial results of the MLOG were critical to give the utility confidence in the MLOG system. With about 40% of the MLOGs installed (effectively covering about 25% of the system), the MLOGs suggested 26 locations where acoustic values suggested a high to moderate probability of a leak. The highest 11 rated sites were examined and 6 leaks were found. A second review and leak investigation made for a fully deployed system identified 26 probable locations. An additional 12 system leaks and one customer leak were found. Pinpointing leak detected by MLOG Many of the leaks were located on the smaller galvanized mains, but there were also hydrant leaks and service line leaks. Repairs are being made on these leaks. It is anticipated that the system noise will be reduced by repairs, enabling the MLOGs to continue to look with greater sensitivity for more leaks. There are several indications that point to the value of the long term deployment of devices like the MLOG. At least one leak actually began during the overnight monitoring and the start of the leak was literally captured by the MLOG. Several leaks have been found in the 300 foot range and it is expected that the MLOGs range will increase as the leaky system is repaired. Finally, two MLOGs captured an acoustic signal in June that became a real main break several weeks later. Leak found with MLOG system One important cost and operational factor is the time invested in pinpointing a leak after an MLOG suggests an area of probable leak. It is vital that the personnel assigned to pinpoint leaks have sufficient training and equipment to efficiently pinpoint leaks or identify the cause of non-leak noise. The MLOG is highly sensitive and listens for leaks at times thought to be optimum. In the early morning hours, not only is system noise minimized, leak sound may be maximized as tanks fill and lower demands to maximum pressures. American water is testing both highly sensitive manually operated leak noise correlators during the daytime but data

6 Leakage Conference Proceedings Page 6 logging leak noise correlators to work at night to find the most effective pinpointing techniques. Initial Conclusions and Future Outlook It appears that the combination of AMR and acoustic monitoring can provide an effective network for system leakage monitoring. Although the value of the daily monitoring for system leakage is still being assessed, preliminary data strongly suggests that NRW will be significantly reduced. Only when the pilot program in Connellsville progresses to bring leaks to minimal levels, the full capability of the acoustic monitoring and companion pinpointing tools will be evaluated. As a result American Water will continue to study the pilot program with a broader research effort is contemplated. Part of the research will look at other cost savings that might be realized. By identifying leaks in the early stages, repairs can be conveniently scheduled. Cost savings per repair should be reduced as the extent of damage to the pipe and the environment around the pipe will be less severe. If most leaks are arrested before the pipe fully fails, the extent of damage to other infrastructure and private property will be reduced. The research effort will target broader infrastructure analysis of leaks. Do most severe breaks begin as slow leaks that can be caught to reduce the consequence of pipe failures? The indication may come this winter if the number of surfacing breaks is reduced. Is the leak monitoring effort identifying a family of leaks that do not manifest in large breaks but rather remain largely unidentified for extended periods of time? It is expected that the identification of previously undiscovered leaks will trigger a more effective assessment of the company s main renewal program. American Water is looking forward to learning and reporting further on the evolution of a truly innovative leak monitoring effort. Acknowledgements The AMR/MLOG project in Connellsville was funded by American water and its subsidiaries. The staff of PA American in the Connellsville area, notably Tom Barozzini, were instrumental in implementing this innovative project. Flow Metrix and Hexagram provided the technical knowledge and skill to make the interface between technologies effective. And Flow Metrix continues to provide extraordinary support with analysis of the data produced by the acoustic monitoring.