Leak Detection Methods in a Water Pipeline

you will need to watch the pressure drop on the pipeline after pressurizing it, the drop in pressure means you are having a leak some ware , the leak has to be found visually, if not possible, you may need some coloring substance added to the water of the pipeline

Fluorescence + Ultraviolet lamp! Commercially availble in tablet or liquid form.

Excellent and simple suggestion.

Water soluble Fluorescein sodium is commonly used to detect water seepage under Ultraviolet light.

Questions to be answered -

- is the pipe buried, underwater, how deep ?, under concrete ?

- can both ends of the pipe be capped or flanged ?

- can repairs be made from the outside or must repairs be made inside the pipe ?

- a leak locating dye would require circulating to disperse the dye in the liquid in the pipe ( a second pipe or hose within the pipe) pressurizing to force the dye from the pipe.

Dye is one way, an alternative would be to listen for it either from the surface if it is buried in the ground or to fly a hydrophone through it and you would hear the leak due to the turbulence.

If the leak is in an awkward location check out platlet technology from Brinker - they use it for sealing pipelines in the oil & gas industry just like your body heals cuts.

Hi,

Many years ago they used wooden rods with a flatten end
as an ear piece. (forget what the "tool" was officially called)

Using the old 1/2 of a 1/2 method in just a few "ear" tests
they could easily pin point the leak. i.e. they would listen on
the pipe and then go half way; then half of the half, again,
then half again and so on towards the leak. In about 7 (or
less) "listening" they would know exactly where is the leak.

Very cost effective; just a wooden stick with ear piece!
No electronics or technology. (great!) Hope this helps.

jt.

Love thy neighbour; but chose your neighbourhood carefully.

I am curious if by any chance the "submerged" pipeline was designed/installed e.g. with weighting etc. that would safely keep things in place if it did not have hydrostatic testing water inside same?

Usually sub sea pipelines are designed either heavy enough (increased Wall thickness) to stay submerged, or else have a concrete weight coat applied to provide negative buoyancy. the concrete weight coat will not keep the contents inside, it only helps to confuse the location of a leak as a "hole" can leak contents (fluorescent dye as suggested above) which will then travel under the coating to a field joint.. you fix the field joint (pipe section to pipe section weld), then the pipe fails the hydro test again... For leak detection - fill it with water and do a hydro-test to confirm if it holds pressure, if the answer is no, add fluorescent dye to the pipe during daylight in calm weather - run a survey boat on top of the pipe path - when you see "pink water" you have found the area - then it gets expensive - ROV or side scan sonarto pinpoint the leak, divers to confirm, crane barge to pick it up, or install a repair clamp... happy hunting..

Did you install air release valves to allow any trapped air to escape. If you didn't, you will never be able to pressure test the pipe, because the water and air compress at different rates. To find a leak, there are a number of tools that can be used. Get a subscription to one of the water efficiency or AWWA Opflow magazines, and there will be ads for dozens of companies, all trying to sell their latest leak detector. Look for an acoustic leak detector. These types of devices can detect even the smallest of leaks. You have to place them in contact with a valve, hydrant or the pipe itself. An added bonus, they will tell you where the leaks are in relatioin to their location. Also, look up subsurface leak detection.

chuksizuoqu,

I assume that you are filling this line for a hydrostic test. If so, it is not a good idea to try to fill a closed pipeline. To fill a pipeline for a hydrotest you should use batching pigs ahead of the water to insure that all the air is driven out of the pipeline. If you did this you require a pig trap of some sort to receive the pigs on arrival. If the pigs dont arrive after pumping the required volume to fill the pipeline you are in trouble as this would indicate a serious leak. Assuming they do arrive it is then necessary to allow the temperature of the fill water to stabilize with the water it is submerged in.

After temperature stabization it would be required to start the pressurization. The amount of water added should be measured and ploted against the increase in pressure. From this plot you can determine if there is air trapped in the pipeline. If it is indicated that there is no air in the pipeline you can proceed to the required test pressure. The pipeline shall then be sealed and a plot of pressure against time made.

If the pressure drops more that a determined allowable, you have a leak.

Finding it and repairing it is a different question with good suggestions already made.

Chama

Thanks for the replies here, they've helped me greatly.

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water leak detection