AC ( Asbestos Cement) Water Piping 1

[5wp]

My concern is trying to figure out a method of determining the degree of AC piping degradation prior to a complete failure. Does AC pipe shed asbestos at given rates vs age, or are there other factors that accelerate degradation? Will NTU units rise as the pipes shed?
Not my area so I have a lot of questions, hoping I can get some advice, thanks.

 

[coloeng]

I worked for a system that had 50 to 60 year old AC pipe. I never saw a failure that was caused by deterioration of the piping material. The only failures I saw were from beam breaks due to uneven settlement or from tree roots that grew adjacent to the pipe and put unequal pressure on the pipe. Not to say there isn't degradation of the pipe, I just never experienced it.

 

[fel3]

I remember reading--sometime in the mid-1980s, IIRC--that one of the byproducts of the acid rain phenomenon (

https://www.usgs.gov/special-topics/water-science-school/science/acid-rain-and-water)

was the degradation and even failure of AC pipes in and downwind of the industrial areas in the northeastern US. The acids in the rainwater lowered the pH of the surface waters that many municipal water systems used as sources. So, if a surface water treatment system didn't also adjust pH, this more acidic water entered the distribution system. The low-pH water had a tendency to leach cement out of the pipe wall, leaving a spongy asbestos matrix with less cement than it started with. Too much leaching and the pipe would fail. I don't know if this also lead to shedding asbestos, but I'm sure it eventually would.

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"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill

 

[5wp]

Thanks Coloeng for your response. Interesting to hear that the roots can be causing failures.
Did your area ever test for asbestos fibre in the tap water as part of their protocol?
There seems to be a few documentaries out suggesting asbestos in water can to linked to various cancers. WHO says otherwise in 2021 report on asbestos.
My take on this is if the pipes were shedding asbestos then the water NTU(turbidity) number should rise. Not sure if that thinking is correct or not.
Thanks again for your reply.

 

[5wp]

Thanks fel3, their should have been higher turbidity readings in their tap water system, no?
Any idea what ph levels they were experiencing?
Thanks again.

 

[fel3]

I don't remember much about the details. The USGS page I referenced above mentioned pH values in the acid rain as low as 4. I don't know what pH values the water systems saw. At the bottom of the USGS page are a couple of links to the USEPA. I didn't look at them, but they might have the info you are looking for.

============
"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill

 

[bimr]

Go to the Water Research Foundation:

WERF

 

[5wp]

Thanks bimr.

 

[swazimatt]

NZ water

another useful document.

general consensus is to not touch it unless you have to

 

[ashtree]

Early in my career i worked for a Utility that had a whole lot of AC pipe breaks in one part of a city. The breaks were often complete burst where the top of the pipe would blow out. It was not my operational area so i never got directly involved but i can remember the guys involved saying it was some cheap grade stuff made in Europe after WW2. The pipes were slightly corrugated on the outside and i think they used to say the AC had gone soft. That is probably an exaggeration more meaning that it had lost structural integrity. The situation got so bad that they accelerated a pipe replacement program that fixed the problem.

Otherwise beam breakages seem to be the most common problem and are related to soil movement.

I doubt that you would detect an increase in ntu of sufficient magnitude to use as a indicator of degradation or impending failure.

Regards
Ashtree
"Any water can be made potable if you filter it through enough money"