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1. Proprietary Notice The contents of this manual are proprietary to Heath Consultants Incorporated Reproduction of this manual in whole or in part is prohibited without the express written consent of Heath Consultants Incorporated Heath Consultants Incorporated operates under a continual product improvement program and reserves the right to make improvements and or changes without prior notification This manual supersedes all previous manuals for the Heath Aqua Scope HPN 2913769 Revision B COPYRIGHT 2001 Heath Consultants Incorporated AQUA SCOPE User Manual Heath Consultants Incorporated Houston TX 713 844 1300 Fax 713 844 1309 IN a NTS 1 80 0 H EAT H U S Heath Safety Leadership Innovation Performance www heathus com Then Now and Tomorrow INTRODUCTION Economy and hygiene demand the most expedient way to locate and repair water pipeline damage More extensive water leaks can also result in considerable danger to traffic by causing street flooding The best method to locate and pinpoint leaks in water pipelines is by means of electro acoustical detection The sounds made by water escaping from a water leak spread as spherical background waves in the ground The sounds are also transmitted by the metallic pipeline itself The use of suitable detecting devices enables us to determine the exact location of a leak by listening to the escaping water from a small hole in the wate2. XB 3 x 70 Yards 17 5 Yards IF Figure 16 The graphical as well as the numerical solution are only preliminary determinations The ideal case of two equal contact measurements is so remote that a check with the Ground Microphone is always recommended 28 Practical Examples Test probe measurement at valve is 40 units at valve 2 90 units at valve 3 10 units and at hydrant 4 zero units This indicates the leak should be between points 1 and 2 Using the Ground Microphone point 5 1s the strongest test A sewer is present at point 5 This noise could be the sound of water flowing in the sewer If this is the case tests at 6 7 and 8 the other sides of the sewer the same intensity of sound should be found The comparatives show at point 5 60 units and the other points 6 7 and 8 a decrease This confirms the leak is at point 5 The combination of the acoustical and numerical tests is conclusive in this instance Figure 17 Houses without curb valves in a leakage area should be tested with the Direct Contact Microphone directly on the service line in the basement Checking with the Ground Microphone at point 2 gives a very strong test At point 1 a weak test is noted The leak is at point 1 This is caused by surface proximity and increased pipe turbulence sound at a bend in the pipe It is necessary to know the location of bends as they will cause an error in pinpointing if they are not taken in
3. Leakage on Asbestos Cement and Plastic Pipe The very poor transmission of sound on this material will make other methods for detection necessary The efficiency of using the Direct Contact Microphone for the preliminary localization will be diminished by the lack of sound transmission through the line Also if testing fittings with direct contact with the Direct Contact Microphone no sound of flowing water is heard the presence of a leak cannot be excluded It is recommended in all cases to check over the mains with the Ground Microphone at distances of 3 to 6 feet Other Sonics Some highly sophisticated sonic instrumentation has been developed using sound delay techniques computer analysis and analysis of sound waves on the oscilloscope These methods are quite expensive but should be considered where conventional sonic methods are impractical G Alternate Methods of Leakage Detection Tracer Gases For situations where sonic testing is completely impractical the use of tracer gases should be considered There are several tracer gas systems available and the following is a brief synopsis of advantages and disadvantages of four of these systems 31 Nitrous Oxide with Infrared Detection One of the advantages of nitrous oxide is that it is water soluble and the line does not have to be dewatered prior to the test The infrared detector is very specific for nitrous oxide so that there is no need to worry about interfering g
4. Detection with the Direct Contact Microphone Preliminary Detection with the Direct Contact Microphone The Direct Contact Microphone is used for preliminary detection in direct contact with an accessible part of the main hydrant curb valves or directly on the service in the house etc The intensity of this direct contact is always in direct relationship to the distance of the leak from the point of measurement and indicates where the leak might be By acoustic comparison of the noise heard in the Headset and by visual observation of the noise strength with the aid of the optional meter readout module at one or more points of measurement the leak can be approximately located 19 Figure 10 As you can see from Figure 10 in preliminary detection the Direct Contact Microphone is connected with the Amplifier Module and the Headset is plugged into the jack on the Amplifier Module The Volume is then turned clockwise and the amplification is turned up enough so that the sound of a leak is recognizable The position of 4 to 6 on the volume control is recommended for best sound intensity Procedure of Preliminary Detection The point of the Direct Contact Microphone is placed on the part of the line which is to be checked The point should be abraded and firmly held against the line to insure good contact When the Direct Contact Microphone is firmly placed on the line the Listen control switch on the Amplifier Module is depres
5. is necessary to observe the sound over a period of time to determine an average value it the reading is changing For this method we assume that the product of sound intensity and distance is a constant Therefore for two points A and B and distance XA and XB from a leak IA XA IB XB Where IA and IB are the values for intensity at points A and B respectively and the total distance between test points is XA XB X 26 This gives two simultaneous equations IA XA IB XB O XA XB X O IB X j IBX Se IA IB IA IB 1 1 AO 1X AX eS IA IB IA IB 1 1l Example Making contact measurements using the Magnet Attachment we check two hydrants separated by a distance of 70 yards At hydrant A we read 30 units and at hydrant B we read 90 units We plot this graphically by first laying off the X axis as the total distance between hydrants or 70 yards We now mark off the value of intensity for hydrant A along the positive Y axis LABEL THIS POINT B At distance X from the origin draw a perpendicular Starting at X and moving in the negative Y direction lay off the value of intensity for hydrant B LABEL THIS POINT A Draw a straight line from point B to point A Where this line intersects the X axis is the point of leakage Note the inversion of points A and B 27 By the numerical technique the distance from test point A to the leak 1s XA 9 x 70 Yards 52 5 Yards 9 3 Similarly
6. valve present nor is there any accessible contact point on the service to the house Therefore a direct contact inside the house is necessary At hydrant 8 the noise is also very much smaller This acoustical preliminary detection can be accomplished with far more ease by using the meter on the optional Meter Readout Module At this time by listening to the loudest noise that has been detected a medium reading of the scale is to be set In this example at measurement point 5 a reading of 60 units is set on the scale by turning the Meter Readout Control Knob clockwise while a test is being taken This setting is recommended to be able to see an increase or a decrease of the reading on the instrument at the different test points For all further comparative measurements the setting of intensity of sound and meter are not to be changed as any change during comparisons will affect the uniformity of the test If a change in setting is necessary all comparative tests must be repeated at the new setting Meter reading at point 4 gives a decrease of reading down to 15 units which would substantiate the acoustical result On the other hand the meter reading at point 6 shows an increase to nearly 70 units This indicates further search towards point 7 is necessary The test in house 7 is conducted with an unchanged setting of the instrument It gives another decrease in instrument reading of 30 units But we are to keep in mind that the length of the
7. 15 361 8651 Western Region 4100 S Fremont Avenue Suite 150 Tucson AZ 85714 Phone 520 790 4971 Fax 520 790 5016 Heath Consultants Incorporated operates under a continual product improvement program and reserves the right to make improvements and or changes without prior notification Heath Consultants Incorporated Houston TX 713 844 1300 HEATH Fax 713 844 1309 CONSULTA NTS 1 800 H EATH US Heath Safety Leadership Innovation Performance WWW heathu s com Then Now and Tomorrow
8. References 22cc 0vaceceretatenaderre eae 14 B Relating Sound Principles to Leakage Detection sc ccseaeanatedarsenanceanacunn ame 17 CHAPTER THREE AQUA SCOPE OPERATION A APPR AOU a acca EEA ER 19 B Leakage Detection with the Direct Contact Microphone a taccapeatercheassectntsiclnndendcn 19 C Pinpointing with the Ground Microphone 0 22 D Exercises with the Direct Contact Ground Microphones ccccccsscesseeeesees 25 E Graphical and Numerical Determination ofthe Pointof Leakage as vecesacscatannyecstsureriononsssaseetian 26 F PEACH Call Te MONS Sigs G soceciererdeaarasenoconensceaieswmscaenee 29 G Alternate Methods of Leakage Detection 04 31 CHAPTER FOUR SERVICE INFORMATION A Warranty and Warranty Repallr ccccecceessseesreeeees 33 Customer Assistance Manufacturing and SN e LOCOS e E asia Back Cover CHAPTER ONE I AQUA SCOPE SYSTEM COMPLETE Figure 1 AQUA SCOPE Basic System part No 2903768 1 Direct Contact 5 Ground Microphone Microphone w ext w Handle Part No 2916428 Part No 2916427 2 Amplifier Module 6 Microphone Cables 2 Part No 2916426 Part No 2916411 3 Headphones 7 Carrying Case Part No 2911352 Part No 2913767 4 Instruction Manual Part No 2913769 II 8 10 11 AQUA SCOPE SYSTEM COMPLETE W OPTIONAL ACCESSORIES Figure 2 AQUA SCOPE System with Optional Accessories Meter Modu
9. ases One of the real disadvantages of this system is that nitrous oxide is heavier than air so that holes must be probed to approximately the depth of the main Two other disadvantages are that heavier than air gases are more difficult to pinpoint than lighter than air gases and the infrared detection equipment is very expensive 10 Helium 90 Air With this system the line must be dewatered before the helium air mixture is inserted Helium has the advantage of being an extremely small molecule and very light Detection is by Thermal Conductivity or Comparative Sonics Methane Nitrogen A mixture of 2 1 2 methane balance nitrogen utilizing flame ionization as the detector is an extremely effective method Methane being lighter than air requires no test hole placement However the line does have to be dewatered Flame ionization detection of methane is in the low parts per million ranges so that even small amounts of methane are readily detectable Methane Argon This mixture takes advantage of both a heavier and a lighter than air gas with the methane being detected by flame ionization and the argon acting as a confirming gas being detected by comparative sonics The helium and methane tracers require a pre survey of the area before insertion of the tracer They can all be interfered with by natural gas leaks or naturally occurring methane Tracer Gas Surveys are extremely expensive compared to Sonic Surveys and sho
10. e some idea about the efficiency of amplification the Direct Contact Microphone should be tried with different positions of intensity while in contact with a mechanical type watch Due to the high amplification the sound of the watch which is normally not heard is as audible as the noise of a small leak The third exercise 1s the amplification of a typical noise of water usage This is especially true on metallic lines For this purpose a Direct Contact Microphone will be with the position of Volume set from 4 to 6 placed in contact with a curb valve and one of the faucets in the house and also some faucets of houses in the neighborhood opened Open and close each of these outlets in the sequence of several seconds Exercises on different types of pipe material will give some idea on transmission of sound Exercises with the Ground Microphone Listening to background sounds using various sensitivities is necessary For example check to hear the sound of a walking pedestrian Become acquainted with the change of background noise when you are placing the Ground Microphone over different surfaces such as pavement sod or other types of surfaces With the Ground Microphone directly at the curb wall over a service line valve water flowing through the service might be heard Opening and closing the outlet also is recommended as an exercise Type of Leak and Different Types of Leak Noises The experienced listener will know from the type
11. e Plunger Bar is driven to the depth desired The Plunger Bar is utilized as a sub surface probe which provides additional listening points when used with the Direct Contact Microphone For unpaved areas the Plunger Bar is driven to the depth desired The Plunger Bar is utilized as a sub surface probe which provides additional listening points when used with the Direct Contact Microphone 13 CHAPTER TWO HI PRINCIPLES OF SOUND A Engineering References This section will cover the basic physics of sound Section B will attempt to relate a few of these principles to the field of underground leak detection and pinpointing Wave motion of which sound is but one example is classically regarded as either transverse or longitudinal In transverse wave propagation the wave travels perpendicular to the motion of the source a plucked string is an example Longitudinal waves progress along the axis or body of the media listening for a train on its tracks is an example The audible limits of sound frequency for people are approximately from 20 to 20 000 hertz The human ear responds to sound pressures from 0 0002 to 2000 dynes cm seven orders of magnitude Sound intensity is generally expressed ona logarithmic scale Decibels or dB with the reference intensity taken to be 10 16 watt cm so that lobserved erved E E eference INTENSITY LEVEL IN DECIBELS 10 log In addition the sound pressure with the reference pre
12. ension rods Rods are 5 16 diameter All threaded sections are 10 32 thread Poured in place the urethane core suspends the sensor shaft in the body for acoustical isolation Each Direct Contact extension is 24 long Piezo Ceramic resonant at approximately 3000 Hz Approximately 300 6000 Hertz The Direct Contact Microphone microphone tip optional magnet and two extensions are depicted in Figure 5 All threaded joints are stainless steel on the Direct Contact Microphone probe tip and the extensions The 1 4 plug mates with the 1 4 jack labeled M on the Amplifier Module via one of the two Microphone Cables D Headphones part No 2911352 Figure 6 1 General Specifications Weight Approximately 0 94 Lbs 425 Grams Impedance 600 Ohms DC resistance Frequency Response 40 18 000 hertz Output 105 db Type Dynamic dual mono The Headset used with the AQUA SCOPE is depicted in Figure 6 The ear pads provide comfort to the user and minimize the reception at the ear of unwanted noises adjacent to the work area The 1 4 monaural phone plug mates with the 1 4 phone jack labeled H on the Amplifier Module 10 E Meter Module part No 2923754 Figure 7 1 General Specifications Weight Approximately 1 2 Lbs 545 Grams Size Same as Amplifier Module Battery General Electric GC 9 Nickel Cadmium Battery Life Approximately eight hours after a complete char
13. fic heat at constant pressure to the specific heat at constant volume ns the universal gas constant T Absolute Temperature degrees Kelvin m Gram Molecular Weight of the gas Therefore the Velocity of Sound in Air 1s yen ft T metera sec Velocity 331 l At 68 F the velocity 1125 ft sec The resonant frequency of rods plates pipes strings etc is a function of the shape density elastic properties and boundary conditions defining the object s In the case of a string the fundamental resonant frequency is proportional to the Transverse Velocity and inversely proportional to length Sound dissipation along a fixed length of rod or pipe will be effected by transit time constraining forces along the wall perimeter and the media in the pipe Discontinuities may drastically reduce sound transmission Point source sound propagating in a spherical pattern dissipates with no consideration of losses due to absorption reflection or interference in sound pressure per unit area as the square of distance This means a pressure decrease of 12 decibels each time the distance traveled doubles Sound waves like other forms of energy experience reflection and refraction at the boundary between two media Interference can occur when two waves from the same source travel different path lengths and reunite 16 Absorption of sound by materials is a science in itself Terms often stated by acoustical
14. ge Charge time is sixteen hours Nominal overall life is 1000 complete discharge cycles Meter 0 1 milliamp ere D C Amplifier Gain 200 volts volt maximum Meter response is matched to the Amplifier Module output 11 Figure 7 illustrates the Meter Readout Module an accessory item with AQUA SCOPE The charger plug jack system differs from the plugs and jacks used with other AQUA SCOPE components to minimize error A rechargeable nine volt battery internal to the Meter Readout Module powers the instrument BATTERY TEST The internal battery may be tested by depressing the square button Battery Test switch shown in Figure 7 while observing the Meter the instrument must be turned ON The Meter must read a minimum of 0 7 If a lower reading is obtained a complete recharge is required F Resonant Plate part No 2921326 Figure8 l General Specifications CONSTRUCTION 1 8 steel octagonal plate Approximately 6 1 2 diameter maximum WEIGHT Approximately 2 5 Lbs 1135 Grams The Resonant Plate shown upside down with the contact rod and thumbscrews not assembled in Figure 8 is used to enhance water leak detection in unpaved areas The Ground Microphone rests on top of the Plate during use 12 G Plunger Bar Figure 9 1 General Specifications Weight 13 Lbs 5 9 Kg Length 62 assembled Bar Length 40 Bar Standard Steel Tempered For unpaved areas th
15. le w Battery 12 Charger 110 VAC Part No 2923754 Resonant Plate 13 with 18 Spike Part No 2921326 Magnetic Tip used with 14 The Direct Contact Microphone Part No 2923776 Plunger Bar w Insulated Handle Not Shown Good Vibrations VHS Video Training Present tation Not Shown Part No 7106653 Meter Module w Battery Charger 220 VAC Not Shown Part No 2923698 Ear Pad Cover used w Headset Not Shown Part No 2927414 A Amplifier Module Part No 2916426 Figure 3 1 General Specifications Weight 1 37 Ibs 620 grams including batteries Size 5 deep x 3 7 wide x 4 thick 12 7 x 9 40 x 6 096 cm including all projecting knobs clips and jacks Batteries Requires 2 alkaline 9 volt batteries Eveready 522 Mallory MN1604 or any NEDA 1604A type is recommended Battery Life Approximately 30 hours Amplifier Gain Approximately 3 x 10 volts volt maximum Storage Temperature Limited to the specifications on the batteries used Figure 3 depicts in two views the Amplifier Module with all hardware in put output jacks and controls Battery access is gained by removing the Battery Access Plate exposing the two nine volt batteries which power the instrument The battery adjacent to the input jack should be removed first The second battery may require lateral movement toward the input jack end to clear the opening Replacement and inser tion should be
16. nting Situation Figure 14 In the example of the preliminary detection Figure 14 a leak near the point of measurement number 6 was anticipated For final pinpointing with the Ground Microphone the section between points 4 and 7 will be checked at close intervals 3 to 6 and near point 6 you will find a very strong noise This is the source of the leakage When doing such examinations with the Ground Microphone you should extend the test pattern as the leak may cause false noises Some examples from practical use are detailed later in this Guide 23 Influence of the Leak Noise Material of the Lines You should know the material of the line being tested as the sound transmission of leak sounds vary greatly from cast iron to steel to asbestos cement and PVC A simple example to clarify this Ifa steel line suspended from a cable is struck with a hammer it will sound like a gong A plastic or asbestos cement line would give a thumping noise on impact but it wouldn t resonate the sound at all Pressure in the Lines The pressure in the line is also a very important factor High pressure normally gives a loud noise a high frequency and good sound characteristics for localization It generally can be said that a pressure of twenty pounds per square inch PSI is sufficient enough to locate leaks Under twenty PSI it may be necessary to use auxiliary means Special Circumstances Encountered The conditions of the cover
17. of noise which type of leak 1s present the distance of the leakage location and also the type and amount of leakage Small holes especially in steel lines under high pressure will give very high frequency sounds A total breakdown of the line with a large amount of water leaving the line will produce a typically deep roaring sound 25 If you are inspecting an intersection with several valves these results may be predicted 1 Using the Direct Contact Microphone at point 3 a leaking valve packing will give a very high pitched sound Using the same amplifier intensity at points 1 2 and 4 will result in much lower sound readings on the meter 1 d Figure 15 2 A total break of the line at point 3 will give nearly similar values on the meter at all four test points However a slight increase at point 3 will indicate the direction for further search E Graphical and Numerical Determination of the Point of Leakage The reading of the exact measurement of sound intensity with the instrument allows the graphical or the numerical determination of the location of the leak The procedure therefore is controlled measurement with the Direct Contact Microphone at two points on the same line at two valves two hydrants two curb valves or at two direct contacts if the line is exposed For these measurements it is recommended to use the optional Magnet Attachment which will provide uniform contact and will give very constant values It
18. over the main will especially influence the detection of the leak noise A very hard ground has a better efficiency for sound transmission and 1s of higher resonance than muddy ground or sod Sand and compact sand and stony grounds are very efficient sound transmitters On the other hand the transmittance of sound under frozen ground may be so excellent that it is very difficult to locate the maximum Loudest Point since a large section of the frozen earth will be vibrating Surface The surface in the environment can greatly influence the detection It is necessary when pinpointing to consider the surface on which the Ground Microphone is placed A change in the kind of surface from sod to asphalt for example from one medium to the other may cause a very contradictory test value This can sometimes cause so many differences of noise that a real comparison of noises for the leak detection may be difficult Time of Work The choice of day or night testing is very dependent on the local situation In rural or residential areas work during the day is possible In areas with heavy traffic noise loud machines and or factories work during evening or night hours may be necessary 24 D Exercises with the Direct Contact Ground Microphone Initially it is necessary to become acquainted with the background noise of the instrument under different positions of intensity Beyond positions 6 and 7 the Amplifier noise is easily heard To hav
19. performed in the opposite sequence Be careful not to cross thread the access plate retaining screw when securing the battery access plate The push button LISTEN control switch should only be depressed after the ground microphone has been firmly placed on a solid surface and one to two seconds Sensor Settle Time elapsed When using the direct contact microphone be certain that the tip is in firm contact with the pipe valve box etc before depressing the LISTEN control switch Ground Microphone Part No 2916427 Figure 4 l General Specifications Construction Acoustically suspended variable reluctance sensor Impedance 380 Ohm DC resistance Frequency Response 10 300 Hertz Weight Approximately 2 Lbs 5 Oz 1049 grams Figure 4 illustrates the Ground Microphone with the Ground Microphone Handle The shock insulator minimizes sound coupling through the handle The foam rubber sound seal restricts ambient noises which may be pres ent in the work area The internal sensor is suspended and magnetically shielded to improve the signal to background noise ratio The 1 4 plug mates with the 1 4 jack labeled M on the Amplifier Module via one of the two Microphone Cables C Direct Contact Microphone Part No 2916428 Figure 5 1 General Specifications Construction Sensor Frequency Response Cold rolled steel case Stainless steel sensor shaft probe tip and ext
20. quately insured Return shipping charges and insurance will be paid by Heath warranty expense We do not assume liability for indirect or consequential damage or loss of any nature in connection with the use of any Heath product 33 There are no other warranties expressed implied or written except as listed above The following suggestions will expedite the repair of your instrument Package carefully using the original shipping carton if available return all components Specify your complete shipping and billing addresses Specify the instrument or product name model number and serial numbers on all correspondence Include a brief description of the problem you are experiencing and specify person to be contacted for information 34 CUSTOMER ASSISTANCE MANUFACTURING AND SERVICE LOCATIONS CORPORATE HEADQUARTERS Heath Consultants Incorporated 9030 Monroe Road Houston Texas 77061 Phone 713 844 1300 Fax 713 844 1309 MANUFACTURING AND WARRANTY SERVICE CENTERS Heath Consultants Factory Service Center 9030 Monroe Road Houston Texas 77061 Phone 713 844 1350 Fax 713 844 1398 DIVISION OFFICES Northeast Region 1051 Garden Street Greensburg PA 15601 Phone 724 836 7830 Fax 724 836 7835 Central Region 9030 Monroe Road Houston Texas 77061 Phone 713 844 1300 Fax 713 844 1309 Southeast Region 1645 Murfreesboro Road Suite E Nashville TN 37217 Phone 615 361 8306 Fax 6
21. r pipeline The sounds made from such leaks provide a good condition for electro acoustical water leak detection FUNCTION The Heath Consultants Incorporated AQUA SCOPE System is an advanced state of the art electro acoustical water leak locator designed to provide the operator with the means for efficient locating and pinpointing of water pipeline leaks The instrument amplifier receiver unit provides a wide range of clarity simplicity and ease of control The ground and hand microphones have good wind immunity for outdoor use A removable handle and extension rods are handy for compact storage TABLE OF CONTENTS INTRODUCTION sos areata scence ata EERE E EE A ET PONC TION e E A E E A E E l T BEFOFCONTE NI E EO 2 CHAPTERI I AQUA SCOPE SYSTEM COMPLETE II HI AQUA SCOPE Basic System Figure 1 c cccsscesssseeeseees AQUA SCOPE SYSTEM COMPLETE W OPTIONAL ACCESSORIES AQUA SCOPE System with Optional ACESSO C5 1 CUTS Z e E E EES 5 A Amplifier Module Figure 3 a canvarsearssenndeettesslacecanses 6 B Ground Microphone Figure 4 ss nnesonesnoseeesne0se0s0 7 C Direct Contact Microphone Figure 5 ccccseseee 9 D Headphones Figure G sccrecectscecastseeeustutastieovneaeesesceeus 10 E Meter Module FISULS T arscnseianosea 11 F Resonant Plate Pie ure S seen cssehcteunsvrissanvcineastavastenae 12 G Pluie et at PU O eeen ra 15 CHAPTER TWO PRINCIPLES OF SOUND Engineering
22. s clay can create special problems Any soil which has a rubber like consistency will greatly attenuate sound The actual contact area of the Ground Microphone with a surface is quite small Ifa hard surface even frozen earth will help is unavailable the use of a resonant plate may help Any solid structure penetrating or covering the earth can be used to advantage Sound may be induced on a pipe by secondary noises such as leaking water filling a cavity Once the cavity fills this source of noise vanishes 18 CHAPTER THREE IV AQUA SCOPE USER S GUIDE A Application The pinpointing of unknown water leakage can be accomplished by the use of a combination of components which make up the kit By using different microphones and by amplification with a solid state receiver the sounds of water leaking from the line can be localized and pinpointed The type or pitch of the sound varies from the deep roaring of a main up to a very high whining of leaking valve packing It is necessary to differentiate these sounds from the other normal background noises Auxiliary Means Plunger Bar Useful when searching for leaks on soil or sod covered pipes Surfaces of this nature are poor sound transmitters and require the use of a bar as an auxiliary sounding Resonant Plate The Resonant Plate is a specially machined plate which improves the sounding qualities The Plate is designed to accept the Ground Microphone Leakage
23. sed This will complete the electrical contact between the microphone and the amplifier The switch should not be depressed before or while making contact as the noise of making contact is unpleasant to the ear Tests are made in this manner and sound levels for the tests compared see Figure 11 Figure 12 is an example of the above technique in a field situation The Direct Contact Microphone should not be immersed in water If a test must be taken in deep water use the extensions or contact the line or desired test point with a rod or key The tip of the Direct Contact Microphone is then used on the rod or key 20 SOUND LEVEL INTENSITY AT DIFFERENT TEST POINTS Figure 11 Example of a Preliminary Detection Figure 12 After opening valve boxes on the main at 1 2 and 3 the valve stems are checked with the Direct Contact Microphone At all three valves a small noise is recognized The noise at valve 2 1s a little bit louder but it is not enough louder to determine a difference in the intensity of sound To decide the further direction of examination take comparative measurements at curb valve 4 at hydrant 9 and at curb valve 10 While the noise at point 4 is louder no noise is heard at point 9 and 10 The search is continued in the direction of point 4 Further listening at points 5 and 6 shows a small increase of intensity of sound and a slight decrease at point 7 Figure 12 21 At point 7 there is no curb
24. service the test was taken in the house might influence the result of the test The final measurement at hydrant 8 is less than 10 units Following this preliminary detection the leakage should be near point 6 Pinpointing is now conducted with the Ground Microphone Pinpointing With The Ground Microphone The Ground Microphone is exchanged for the Direct Contact Microphone The Listen Control switch at the upper left of the instrument is the interface between the Microphone and the Amplifier and should only be depressed when the Ground Microphone is placed in a test position In working with the Ground Microphone use a setting of 4 to 6 units of amplification Using higher sensitivity by opening the sensitivity volume control will also give an amplification of background noises 22 SOUND LEVEL INTENSITY AT DIFFERENT TEST POINTS LaK ae ay eo i is 1 i Figure 13 For the pinpointing of the leak the Ground Microphone will be placed as exactly as possible over the water main or service with test points a maximum of 6 apart All noises received are to be compared with each other The approach to the leak will be recognized by a higher intensity and increase of the noise Above the point of leakage the intensity will reach a maximum As you pass the leak the intensity will decrease The meter reading will show the same result as the Audio test Example of a Pinpoi
25. ssure taken as 0 0002 dyne cm is given by Observed F Reterence SOUND PRESSURE LEVEL IN DECIBELS 20 log An upper limit exists for this sound pressure depending on the media involved For air the upper limit is approximately 191 dB At this level rarefaction of the wave causes cavitations and the wave breaks down since the media can no longer support it The pain threshold for audible sound is at an intensity level of 120 Decibels 14 The Transmission Velocity of Sound in an extended solid is given by VELOCITY Longitudinal EB 413235 af P Where EB The Bulk Modulus Rigidity of the Solid ES The Shear Modulus Resistance to Deformation of the Solid p Density In the case of a transverse wave in an extended solid the Velocity is determined by the Shear Modulus alone and is expressed as VELOCITY Transverse J3 F If we now divide the Longitudinal Velocity by the Transverse Velocity in an extended solid we note that VL _ B 4 TT Es Or that the Longitudinal Velocity always exceeds the Transverse Velocity This fact is used in Seismology to determine the point or origin of earthquakes Since a fluid cannot sustain a shear ES O no Transverse Wave can be transmitted in a fluid and the Longitudinal Velocity is given by r Ep i f a Where EB is the Adiabatic Bulk Modulus 15 The Velocity of Sound is given by W mT Y Where V Velocity y the ratio of the speci
26. ted more likely in a transverse mode Now no sound can be transmitted through the fluid or gas in the pipe in a transverse mode based on the previous section This means that the pipe wall must carry any transverse sound transmission alone 17 The frequency and velocity of the sound induced on the pipe by a leak will be a function of pipe size thickness material and boundary conditions Quite important is the rigidity of the pipe Metal pipe has a high modulus Therefore we will hear the characteristically higher frequency pipe noise generated by a leak Also the velocity will be high or the transit time is short and minimum attenuation of the sound will result Plastic pipe has a much lower modulus and for similar conditions of pipe size and boundary conditions the frequency will be lower with much higher transit time attenuation Other sounds may also be generated by restrictions within the system such as a partially closed valve a reduction coupler a booster pump etc These devices will cause turbulence along the pipe wall and will emit a detectable sound similar to that of a leak Do not be mislead by this effect If these sounds are of sufficient magnitude you may be incapable of distinguishing the existence of a leak in the immediate vicinity Soil is basically a non homogeneous material Generally the soil will be layered except directly over man implanted objects such as pipe Fluidic type soils such a
27. to consideration Difference in pipe location will influence the measurement In case of doubt drawings of local situations or a pipe locator should be used 29 t I a CECE ae a8 ae T 27 a T Figure 18 The noise of the leak should be checked with the Direct Contact Microphone at hydrant 4 and at valve 6 Pinpointing with the Ground Microphone will give a strong noise at point 5 However at bend points 1 2 and 3 a high level of sound may be found Please note the effect Different depths in the cover over the main can give a varying intensity of the sound It is always recommended to extend test areas and not dig at the first strong noise t 2 3 3 i Figure 19 A restriction or a reducer in the line or a partially closed valve may cause a false leakage indication Such cases seldom occur but you never can exclude them Such noises should be checked very carefully and then the restricted parts of the line should be eliminated if possible In checking the main a leak noise is found at point 1 The next test of the house connection results in a strong noise at 2 But here a steeply sloped drain for wastewater is running To eliminate this condition the Ground Microphone is placed at 3 and 4 If the noise at 2 3 and 4 yield the same instrument reading it must be assumed that the drain is causing the sound and the leakage is at point 1 30 1 I i 1 i i Figure 20
28. uld only be considered when sonics are completely impractical 32 CHAPTER FOUR V SERVICE INFORMATION A Warranties and Warranty Repair All instruments and products manufactured by the Heath Consultants Incorporated are warranted to be free from defects in material and workmanship for one 1 year from the date of shipment Furthermore the warranty on authorized repairs in Houston FSC and regions is ninety 90 days materials and thirty 30 days labor This repair warranty does not extend any other applicable warranties Our warranty covers only failures due to defects in materials or workmanship which occur during normal use It does not cover failure due to damage which occurs in shipment unless due to improper packing or failures which result from accident misuse abuse neglect mishandling misapplication alteration modification or service by anyone other than a Heath warranty repair location Battery and damage from battery leakage and all expendable items such as filters and Plunger Bar rods are excluded from this warranty Also O rings gaskets and seals for the Petro Tite product line are excluded from warranty coverage In addition wetted parts in various Petro Tite products are warranted for 30 days only Heath s responsibility is expressly limited to repair or replacement of any defective part provided the product is returned to an authorized warranty repair location shipping charges pre paid and ade
29. wall manufacturers are seal and absorption loss Seal refers to sweep strips used on doors to attenuate the transmission of higher frequencies Absorption loss or door rating in decibels tends to increase as the number of laminates metal wood fabric etc increases The higher frequencies are attenuated more dramatically than low frequencies Sheet lead is often used to reduce plenum crossover Finally the effect of paved surfaces on sound pick up should be discussed For lack of a better name let us call it the Diaphragm Effect Because of the large area and low modulus the resonant frequency will be low This surface therefore tends to amplify noises of low frequency occurring in the soil beneath the paved area and helps immeasurably in water leak location Relating Sound Principles to Leakage Detection The detection and location of underground leaks is implemented by a variety of instruments and numerous methods For the purpose of this section we will discuss the use of the AQUA SCOPE and some of the general conclusions we might draw from the previous section in that regard The Direct Contact Microphone is generally placed against the surface of a pipe in a position nearly perpendicular to the pipe direction The sensor responds to vibration along the axis of the Direct Contact Microphone Therefore the instrument is most sensitive to transverse sound waves on the pipe Likewise sound induced by leaks will be orien
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