Water Line Pipe Corrosion

Try www.insituform.com for thier piping lining products.

Please be respectful and complete this thread.....tell us of your final decision and how you came to it

Hi,

One method of extending the life of corroded pipelines is to line it with HDPE high density polyethelene. More info is required in order to justify this procedure.

chama2633

Well -recommended removing the corroded areas by grinding/sand blasting,first of all !! But it is a tough job,and enviromentally difficult for the worker !!( How long is your pipe ? )

... Than using anticorrosive inhibitors on inside all over the pipe !!

NB

Using the UT Test on 0.5" thick tube/plate - is quite difficult to assume a good results,due to the existing surface quality, cautioning that 1/4" thick region on each side of the tube diameter,test results not recomended formally ( See UT Standards !)

Recomended check with magnetic /radiographic NDT tests after cleaning the pipe's corroded region (preferred the whole section !!)

This is a cost consuming procedure -you should compare to removing the whole section....

Run a sleeve up it only if dig and replace is a total cluster cuss.

What is the total length that needs to be repaired? How accessible is the total length?

About 30'. The replacement is going to be difficult as there are tight clearances between the pipe and the upper floor. I believe the pipe was installed then the flooring was placed.

Ron

There is a company located somewhere along the East Coast, I believe in New Jersey, which is in the business of cleaning and lining waterlines with a cementitious material. I believe that they use rotary pigs to abrade and remove the scale deposits and then they apply the cementitious liner. For your situation, I believe that this method is the most appropriate one. Many municipal water system operators chose this method and, providing there is still sufficient wall thickness to sustain the operating pressure, it is very effective.

You really have NOT provided us enough information to allow us to form an effective recommendation for you to utilize. DATA DATA DATA!

You denote that this main conveys water. But, is it untreated water or treated water?

Is the water chlorinated? What is the pH? From the photo that you have provided, as well as the current pipe wall thickness, I am presuming that the pH is relatively low due to the observable corrosion seen along the pipe barrel. OTHER WATER CONSTITUENTS?

Did you or somebody else take "coupon" samples of the pipe wall in several locations? Were any tests, including tensile stress tests performed on the samples? What is the mean wall thickness? Was that the 0.235-inch wall thickness that you have stated?

With a Working Pressure (WP) of 225 psig I have strong reservations against rehabilitation of this water main given the 0.235-inch wall thickness. The corrosion appears to be deeply pitted. InsituForm water main products are all good and well, but they do have an upper maximum Working Pressure (ie, Allowable Working Pressure) of around 150 psi for a water main this large (170 psi for mains up to 8-inch in diameter).

Is this a Ductile Iron or steel water main? Also, was there any evidence of an asphalt coating and cement coating? This is typically referred to as "Double-Cement Coating" in water industry parlance.

What is the MAXIMUM OR PEAK Water Pressure that the main sees? I ask this because surge pressures and main testing pressures can far exceed the Working Pressure due to a host of factors, including fast valve open and closings, and pumps cycling on and off......"water hammer".

Maximum Working Temperature of the conveyed water? This is a critical data point you need to investigate. Typically high water temperatures can induce secondary thermal stresses in and along the pipe barrel and any connections, including fittings and valves, etc.. Also, a high temperature coupled with a high WP may limit or negate the utilization of thermal plastic liners such as HDPE and the like. NOTE: BE VERY CAREFUL IN YOUR SYSTEM ANALYSIS IN THIS REGARD BECAUSE CHOOSING THE WRONG MATERIAL/SYSTEM MAY LEAD TO PREMATURE FAILURE OF SUCH.

Frankly, for safety reasons alone, based on the given WP I would recommend replacement of this main if it is economically and construction feasible. In the long run it may make more sense since the typical water main/transmission main lifespan of this size Ductile Iron Pipe is anywhere from 50 years to 75 years, all dependent on a number of factors such as: pipe zone bedding type & configuration, backfill type and configuration, depth of bury, highway loadings if applicable (including pavement type and thickness).

In the end, it is absolutely essential that you perform a structural analysis of this pipe barrel, both while in the pressurized and unpressurized operating states, all in accordance with American Water Works Association (AWWA) and the Ductile Iron Research Products Association (DIPRA) guidelines and Standards, together with performing the necessary calculations in accordance with established engineering methodologies (namely ASCE Standards).

If you are not familiar with either the AWWA, DIPRA, and ASCE Standards and analysis methodologies nor familiar how to perform the calculations then I strongly suggest that you obtain the services of a Licensed Professional Engineer (Civil Engineer) in your state who can provide the answers that you require + give you the necessary professional advice. I can post links for each if you do not have them already or can obtain them on your own.

Please get back to us with some valuable data/information so that we can steer you in the right direction. Good luck!

Let me have my tech do a XRF PMI. The water is filtered in our system. The main purpose of the line is to feed the De scale pump to blow down the primary scale on a rolling mill which operates at around 100 bar.

We just had to cut a window to repair a leak and i don't believe it was successful. I am use to working with ASME and ASTM of the standards you mentioned i have never worked to them.

A pig would have to be installed using a window , i really don't believe it is feasible.

Ron, here's a link to the DIPRA website that may help you determine the adequacy of the pipe wall thickness:

http://www.dipra.org/programs/

The programs are free to download. You can also download handbook e-files, as well as pipe lining literature and other information from this site.

My recommendation, based on what information has been presented so far, is to replace that pipe......cutting windows into the pipe barrel will induce serious weak points and may overstress the material. Field welding steel reinforcement plates at these windows may not be possible. The 225 psig internal Working Pressure is pretty high. If the pipe bursts the resulting water leakage may severely undermine the concrete floor slab and any nearby structural foundations. In the long run, it may make better economic sense to do a replacement, especially if the main is roughly 30 feet in length and not too deep.

http://www.bing.com/search?q=pipe+lining+systems&src=IE-Address

Miners in my Country are using HDPE liners which are installed inside the pipe during it's construction. It will require from you to cut the line in order to install the liner, and reweld it.This is done to carry corrosive and abrasive copper concentrate or pulpe from the mine to the smelters. Personally, I wouldnt do this. Your pipeline paid for itself, and now is at half wall thickness which means half mechanical sterngth or less.The photo shows deep corrosion. Even though your pressure is relatively low it will evantually cause leaks or worse.

How about a different approach all together which will be a LOT cheaper...Why not install an advanced leak detection system that can give you a very early warning incase of leaks, and LOCALIZE the leak (plus minus 30') long before it becomes a catastrophy.

To really help you I will need more information. You can send me a private msg.

Wangito.

Well the repair did not work as expected. There is still a minor leak, i really don't see saving the line and i will have to come up with an alternative.

Ronclarke, I'm offering some sage advice here. If possible, in the event that you decide to replace the aforementioned water main place it's replacement above the floor slab for ease of future maintenance. That is, if there's room for it and no interference with other process piping, equipment and machinery, electrical , as well as structural walls, columns, foundations, and what have you.

If needed, you can put it in a below-floor concrete lined trench topped with removable steel or HDPE grating selected for it's rated strength and chemical resistance. Of course, this will involve some construction inside your plant.

Whenever I engineer any type of plant I aim to have process piping located above the floor or in service trenches. I eliminates a lot of future headaches for the owner and their maintenance staff.

BTW, lining such a well degraded water main pipe with HDPE, epoxy, and other thermal-setting liners maybe a total waste of money. The combination of high hydraulic pressures and temperatures may negate their use and be unacceptable. You must look at both factors together, not seperately. Also, after installing any of these types of liners it may become almost impossible to weld a new steel plate at the 'window', as the extreme heat from the arc welding may ignite the liner. Most people forget this very important fact.

Good luck!

the aforementioned water main place it's replacement above the floor slab for ease of future maintenance.
My thoughts exactly. I will have to re-route the pipe above the roll line , but with insulation it will work.Thanks all.Ron

This is not 24" ductile iron pipe, as 24" ductile iron pipe was not manufactured ~40 years ago with "24"OD" (like steel in that size); also, 25.8" O.D. (nominal 24" size) ductile iron pipe is normally furnished standard for water service with a rich cement mortar lining, that is typically VERY effective in preventing any meaningful loss of wall thickness due to corrosion in normal, very long-term water service. Looking at the pictures, I suspect this is steel pipe that was either installed bare or with some other lining that was obviously not effective for such long term service (users of steel pipe in particularly the smaller sizes have been tempted to use such as small steel cement mortar lined pipes may not be stocked as widespread around the country (as standard cement mortar-lined ductile iron pipes).

In doing any repair/alteration works for a corroded pipeline, don't forget to use the code ASME B31G which is a good reference used for Determining the Remaining Strength of Corroded Pipelines.

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I have already crunched the numbers and the pipe has to be replaced. Its odd that the elbow shows little internal corrosion but the straight run has depleted over 50% wall. Its difficult to get an accurate ultrasonic Tgage reading due to the internal surface condition.