Leak detection methods

[WaterGIS]

hi all, I need information about Leak detection methods for plastic water distribution pipes, I'm planning to have a team for leak detection for ( DI,GI,PE), I need to know more about the required equipments , working procedures and other things related to this topic,many thanks.
Regards,

 

[PUMPDESIGNER]

Methods vary widely based on system criteria, give us more.
Pipe Sizes
Pressures
Depth of burial
Elevations
Fitting Types

If I knew of overall paper or book I would give you that reference.

PUMPDESIGNER

 

[WaterGIS]

the pipe size are varied from (0.5,075,1.0,2,6 in) and (300,400,500,700,800 mm) pressure in the networks are varied from 35 to 5 bar) , depth of burial are from (0.5 , 1.0 , 2.0 m), elevations ( did you mean from sea level?) it is from 0 to 600 m over the sea level. The fittings are (DI, GI, and PE). We are planning to have a team for small town that has it is own recourses (100Km). The high pressure is in the converting line.

 

[PUMPDESIGNER]

OK, here is what I know.

All persons involved should know the following:

On plastic pipe lines leaks tend to grow quickly in soil with any abrasives in it such as sand, quartz, etc. As water escapes a jet of water “roils” the abrasives in the soil which in turn eat away at the plastic so that the plastic is in effect “sand blasted”. By our experience small leaks will open up to a sizeable leak within 2-3 months maximum. CONCLUSION – Be patient, walk the line looking for evidence of leak (see below).

Become aware of and train yourselves about the evidence of leaks on soil. Make your own photographs and make sure your people are always on the lookout for the following:

1. Water rising to the surface and then moving downhill takes lighter materials and organic detritus away leaving heavier materials near to the point of exit such as a whitish or clean looking sand.
2. Leaks carry materials away so there are almost always depressions left.
3. Water flows downhill so inspect low lying areas carefully. Do not assume pooling water is from lawn sprinklers, agricultural watering, or rain. You must walk through the puddles to see if there is a continuous flow from some direction, follow the flow to find the source.
4. Become aware of things that leak by nature and enact program to eliminate those frequent sources of leaks. Largest villain is gate valves. Simple cheap gate valves are intended for service only, not on/off service for which you need a soft seating type valve. All knife gates will leak if used for on/off service, you must eliminate them and any other fitting or valve that tends to start leaking quickly.
5. Leaks on hard ground with very slow percolation rates show up on the surface quickly.
6. Leaks in soft ground with high percolation rates can hide for long, very long periods of time.
7. Leaks under roads, concrete, and other hard surfaces travel the route of least resistance, not the shortest path. In other words, it may be 10 feet from the edge of a road to the leak, but that leak may travel 100 feet downhill through a porous area before going to the edge of the road.
8. Loose asphalt indicates a leak. Asphalt will seal off water very effectively. A leak will separate the asphalt from the rock base causing a bubble in the road that moves when pressure is applied. Some very thick rooting grasses will do the same. So look for high spots that move.
9. Some leaks are just buggers, especially if they are aimed downwards and in loose soil. In those cases there may be no depression, no whitish sand, and no other simple evidence giving visual clues.

Now, as far as tools:
Use a stethoscope or small piece of tubing or pipe to check valves for internal leakage. Any leaking valve will make a hissing sound. I believe rubber is the best transmitter of sound from an object to the ear.

Scan the internet doing a search for the keywords. You will find many great claims so be careful but ultrasound and infrared are good tools. I especially like the infrared.

Best tool will always be an observant careful and patient person walking or driving the line. Not all people are suited for this.

Read everything at this link:

http://irc.nrc-cnrc.gc.ca/leak/leakdetect.html

PUMPDESIGNER

 

[HydroJo]

This is a huge area- difficult to answer in a few lines.
Are you planning a long term, on-going leakage detection policy over a wide area - if so leakage management with water metering and zoning will be needed to identify the worst areas for leakage - before localised leak detection.
If you have zones set up, then step testing will guide you to the worst affected streets.
If you are just trying to locate individual leaks in suspected areas accoustic methods are popular - using listening sticks and/or noise correlators.
There are many consultants in UK with great experience following the clamp down on leakage of the 1990's. I cant tell you who - just go on the internet.
Your best bet is to set up a small team and then get one of these companies to come in an provide some training - experience is everything as PUMPDESIGNERS has demonstrated I'm affraid you wont get far just by buying equipment. ALTERNATIVELY - advertise for a leakage guy !

 

[KRSServices]

I have a good deal of experience in municipal leak detection. Is this situation municipal or other areas such as a processing plant or the like?

KRS Services

http://www.krs-services.com

 

[camabee]

There are a number of acoustic data collection and leak detection products out there. One of the bestis described at:

http://www.radcom-usa.com/soundsens.htm

 

[KRSServices]

I agree with camabee, but be very careful in rushing out to either purchase or hire leak detection firms. The costs can mount very quickly with the results being indeterminate. You firstly need to have a good understanding of the system, and similar to a detective, spend some time to review the evidence.

Your team should also be experienced and knnow what to look for.

Secondly, you then need to systematically begin measuring leakage in suspected areas, factoring in such things as minor service leaks, weeping gaskets and valve packing faults. This systematic review will not cost much, but will save you considerable time in "chasing ghosts" with detection equipment. That is of course unless you have an unlimited budget.

As I stated previously, I have years of experience in this field and have saved myself (and my clients) time and money by not running out to hire leak detection equipment right away. You will be amazed at how many leaks can be tracked down with a little detective work and good system records.

If you would like to speak to me further on this, please contact me at (780)537-1884.

KRS Services

http://www.krs-services.com

 

[WaterGIS]

Hi all
Many thanks for all of u, we are trying to establish a new leak detection unit, we are working for Water Company that is responsible for a wide area. We have wide rang of pipe types and diameters.
The UFW in our system is over 40% .