Asbestos Cement Sanitary Sewer

[cb1331]

Does anyone have an idea on the typical lifespan of an AC sanitary sewer. Sewer is 6" and has been in service since 1974. Any good publications on this issue?

Thanks in advance.

 

[cvg]

you can speculate, or you can run a camera down the line which might be more useful way to evaluate the remaining life

 

[SlideRuleEra]

Cement-asbestos is made from naturally occurring minerals that do not rot or decompose while buried. Also, it has high resistance to wear from normal flow. No reason to define a maximum life based solely on age.

Therefore, I agree with cvg; make an inspection of the interior. If it is in good condition leave it alone. If not, perhaps it can be relined in place.

If relining is not practical, I suggest abandoning it in-place with a replacement line installed nearby (if possible).

Because of the necessary and expensive procedures needed to handle asbestos based products safely, disturbing or removing it should be a last resort, IMHO.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[bimr]

Rather than focus on the age of the pipe, one should consider that the installation methods and pipe materials that were used in 1974 are typically no longer used and are obsolete.

A sewer service that was built that long ago probably has numerous leaking joints and is probably in need of repair/replacement.

As CVG posted, the best method to inspect the pipe is to use a remote camera at a cost of several humdred dollars.

If the service is not extensively damaged, then you may line it or replace it.

 

[dicksewerrat]

I would TV the line. Then line with Cured in Place Pipe liner if the internal corrosion had taked more than 25% of the pipe wall.
BIMR, I was inspecting clay and PVC pipe for sanitary lines in the 70's. Never saw one installed made of AC. That is not 'along time ago'. The pipes I worked on that were installed in 1880's was a long time ago.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[cvg]

as far as I can remember, I have never seen an AC sewerline either in the field or on a set of plans. Most of the AC waterlines were installed between about 40 - 80 years ago and while they are no longer installed due to the potential liability, there are apparently 400,000 miles of the pipe in service in the US alone. AC pipe is highly resistant to corrosion and most sewer service is not highly erosive. However, anectdotal evidence suggests that AC pipe is "brittle" and difficult to tap, connect or repair. These pipes are generally being replaced these days do to the age and liability associated with them. Bursting or internal lining would be a preferred method to rehab this type of pipe.

 

[bimr]

http://news.google.com/newspapers?i...9&dq=asbestos+cement+water+pipe+history&hl=en

AC pipe was first used in the 1930's. In the mid 70's about a third of the pipe being installed was AC pipe. AC pipe was never banned, people just stopped using it.

http://books.google.com/books?id=bi...q=asbestos Cement water pipe history&f=false

dicksewerrat: If you were truly installing pipe in the 1880's, one would have to agree that was "along time ago", not "that long ago".

 

[dicksewerrat]

I wasn't installing it then. I was fixing the stuff installed in the 1880's from 1960's till 2001 when gave up that job. Now I just line them. But I neve saw any installed during that time in Minnesota. All the old stuff was cement or clay.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[rconner]

Per the latest figures I've seen from EPA circa 2009, asbestos cement pipe (ACP) makes up a rather small percentage now of the wastewater piping infrastructure in the USA (I believe something on the order of 3%-5% or so of both gravity sewers and forcemains). [As there is however a tremendous length of such service pipelines out there, this nevertheless could still be a good many sticks of ACP in some local areas.]

 

[cb1331]

Thanks for the responses guys. I did have the sewer videod and have reviewed teh CCTV dvds. The pipe seems fine to me and i am comfortable commenting on the remaining lifespan. However what I am not sure of are the service connections which have severely rusted. I am hesitant to comment on what type of material it is but it is certainly not stainless. Does anyone have any experience with this? What was the standard type of service Tee connection with AC pipe installed in the 70's.

You commments are appreciated.

Cheers, Chris.

 

[bimr]

Mechanical couplings made of cast iron or ductile iron are typically used on asbestos cement pipe.

 

[rconner]

I don't have detailed knowledge of local practices for service connections to ACP; however, I have heard in the sewer industry in general that this has varied some, all over the map depending on local codes and extent of inspection etc. Furthermore, while video inspections are indeed helpful in many cases, it is probable that not all 100% of videographers have the experience or guidance to appropriately identify and know the significance of everything they are looking at on the record. "Stainless" many not necessarily mean stain(or corrosion)-free. Finally, I believe it has been reported, particularly where somewhat brittle pipes are involved, that some installers have even used rather crude installation procedures in some areas e.g. beating a hole as best they could in the pipe with a hammer etc. and then basically sticking the end of the service pipe (with various pemnetration depths) in, with or without mortar or mastic in the annular space.

 

[bimr]

In addition to rconner's comments, you should note that inflow/infiltration would not necessarily be witnessed with a video inspection unless it was raining at the same time of the inspection.