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Water Loss and Acoustic LeakTechnologies – Then and Now

Name: James FisherManager Non Revenue Water Services(770) 547-4829Jfisher@echologics.com

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Journals of the AWWA Conventions – Proceedings and Papers1887 to 1936 – Leakage – Then and Now

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1887 1901

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NEW YORK – 1900’s

FIRE HYDRANT FLOW TO KEEP COOL

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CYPRUS WATER MAINS HAND LAYED WATER MAINS

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NEW YORK - 1901

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IN the 1900’s LEAKAGE IS LABELED “WASTE”

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1907 – BURSTING WATER MAINS

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Water Loss has Always and Always Will Be With Us

From the Journal of the AWWA – Vol. 24, No.11 November 1932

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Leak Listening Methods

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NITROUS OXIDE INJECTION – LEAK DETECTION

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Geophones

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Listening for Leak Sounds

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Listening for Leak Sounds

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Then and Now• Unamplified Listeners

▸ Have no batteries▸ Cheaper▸ Easier to Repair and Maintain

• Amplified Listeners▸ Can hear quieter leaks and 

further away leaks▸ Can isolate external noise▸ Filters can remove unwanted 

noise

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Wavelength & Frequency

Short wavelength means lots of waves; high frequency, high sound

Long wavelength means fewer waves; low frequency, low sound

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Typical Frequency Ranges

Human male voice

Human female voice

Music – middle C note

Music – middle A note

Typical 6” cast iron pipe

Typical ¾” copper pipe leak

Typical 6” PVC pipe

125 – 2000 Hz

250 – 5000 Hz

256 Hz

440 Hz

200 – 800 Hz

400 – 2000 Hz

5 – 30 Hz

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How Far Can I HearGeneral Distance Sounds Travel for 2 GPM

Leak at 60 PSIPipe Size & Material Distance _• 6 inch Cast Iron Pipe - 600 to 1,000 feet• 12 inch Cast Iron Pipe - 400 to 800 feet• 24 inch Cast Iron Pipe - 200 to 400 feet• 6 inch AC Pipe - 400 to 800 feet• 12 inch AC Pipe - 300 to 500 feet• 24 inch AC Pipe - 100 to 300 feet• 6 inch PVC Pipe - 200 to 300 feet• 12 inch PVC Pipe - 100 to 200 feet• 24 inch PVC Pipe - 50 to 100 feet

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Rate the Loudness

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Ground Microphone Instruments

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PITOMETER DISTRICTS

WASTE METER AREAS

DISTRICT METERED AREAS

SUB-DIVISION

STEP TESTING

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PHOTO PITOMETER RECORDER

Measuring Water Flow to Identify WATER WASTE

1903

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Pitometer District 1924 – District Metered Areas (DMA)

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Pictured is a DMA from 1924

The theory and process has not changed, but the instrumentation to measure flow and pressure has advanced.

DMA’s Are Not New

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Mobile WASTE METER – 1974 UK

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Mobile WASTE METER Chart

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DMA Development

District Metered Area (DMA) – 1990’sA DMA is just a smaller geographic area within the distribution system that can be temporarily isolated by closing valves.

An instrument capable of measuring flow into and out of the area is temporarily inserted into the main for 24-48 hours.

InsertionMeter

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DMA/District Measurements are Indicators of Leakage Potential (Real Losses)

Lower night time flow rate is an indicator of minimal leakage

Unavoidable Leaks

Undiscovered Leaks

Meter Error

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LEAK CORRELATORS

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Correlators I Have Used

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Leak Correlators – My First One

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Correlation Theory• Leaks make noise• Time of flight technology• Correlation function:

▸ Leak bracketed with 2 Sensors▸ Leak noise takes longer to arrive at Sensor 1 than Sensor 2▸ Correlator measures time difference to identify exact leak location

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Know Pipe Construction

• The use of non-metallic flexible pipe can lead to incorrect distance measurements that result in an incorrect location of a leak correlation

• A 22 degree bend in a pipe segment not shown on a map may cause incorrect length measurement

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Frequencies – Pipe Material

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Mixed Pipe Materials

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Plastic Mains – PVC HDPE• Leak detection on plastic and large diameter mains does take longer to complete.

• Multiple leak shots normally have to be taken at different filter settings to dial in the best setting.

• Out of Bracket or In-bracket velocity calibrations have to be conducted to identify the correct velocity input

• The frequencies where leaks on plastic pipe and large diameter concrete pipes are identified are extremely low and in a narrow band.

• It takes time, much more time than leak detection on metallic mains, consequently the amount that can be completed in a day is much less and the cost is higher

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Leak Noise LoggersThese Instruments Provide an Indication of leak noise and confidence• Provides for sounding investigations before leak correlation• Can be Permanently Installed or Moved around the system• Data interrogation can be accomplished with: Drive‐by Radio, SMS Text Message Communication or, Connected 

to an AMR system

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Network of interconnected nodes monitors a service area

Mi.Hubdata collector unit

System comprised of a series of nodes and radio infrastructure:

Mueller Data Center

Mi.Net RF

Mi.Host customer interface

Cellular Network

Fire Hydrants as Permanent Leak Detectors

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Processor & Comm.

Hardware

Power Source

Hydrophone

Antenna

Node 1 Node 2 Node 3

MonitoredTransmission Main ½ mi. ½ mi.

Permanent Transmission Main Monitoring

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Current AWWA M36 Manual Water Audits and Loss Control 4th Ed.

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AWWA-IWA Water Balance

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THREE TYPES of LEAKAGE

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Previous Definition of Unavoidable Leakage

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Unavoidable Leaks – Best Case - UARLInfrastructure Component Background 

(Undetectable) LossesReported Breaks Unreported Breaks

Mains 8.5 gal/mi/hr. 0.20 breaks/mi/yr.@ 50 gpm for3 days duration

1 breaks/mi/yr@ 25 gpm for50 days duration

Service linesMain tap to curb stop(Company responsibility)

0.33 gal/service line/hr. 2.25/1,000 service lines/yr.@ 7 gpm for 8 days duration

0.75/1,000 service lines/yr.@ 7 gpm for 100 days duration

Service LinesCurb Stop to meter(For 50 ft. avg. length)

0.13 gal/service line/hr. 1.5/1,000 service lines/yr.@ 7 gpm for 9 days duration

0.50/1,000 service lines/yr.@ 7 gpm for 101 days duration

Infrastructure Component

Background (Undetectable) Losses

Reported Breaks

Unreported Breaks

UARL Total

Units

Mains 2.87 1.75 0.77 5.41 Gallons/mile of mains/day/psi of pressure

Service linesMain tap to curb stop(Company responsibility)

0.112 0.007 0.030 0.15 Gallons/mile of mains/day/psi of pressure

Service LinesCurb Stop to meter

4.78 0.57 2.12 7.5 Gallons/mile of mains/day/psi of pressure

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Leak Run Times Not all leaks surface and many can run for many months or years before identification if an aggressive leak program is not active. For this reason we modified the run times to create several scenarios firstbeing that all leaks had ran for 30 days then all leaks ran for 60 days.

Water Loss Value.

� Current Estimated Run Time 105.780 MG $ 24,383� All at 30 Days 309.010 MG $ 71,230� All at 60 Days 618.019 MG $142,460

The current AWWA free software does not have cells that let you account for this but if these leaks are discovered during the audit period the volume and values should be taken into consideration in a water audit.

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THANK YOU

QUESTIONS