PVC pipe corrosion 2

[madmarv]

I have a drainage force main that will carry vehicle wash water and possibly oils or fuel mixed in the water. It's also likely that the pipe will be installed in fuel contaminated soil. My memory is a bit fuzzy at the moment but I thought PVC has issues with corrosion in this kind of an environment. Is this true or is my memory playing tricks on me again?

 

[ctmtwilliams]

I install PVC monitoring and extraction wells into hydrocarbon impacted soil on an everyday basis as part of remediation of contaminated soils & groundwater. We pump everything from gasoline and waste oil to chlorinated solvents through these wells for years with little to no impact to the PVC.

 

[bimr]

You may be thinking of a situation where it is possible to contaminate drinking water when the pollutants will permeate through the pvc pipe. That would not apply here and it is doubtful that the concentration of the pollutants are strong enough to harm the pvc pipe.

 

[rconner]

Contrary to some perceptions (as evidenced by this thread) and industry claims all materials including pvc pipe have exposure limitations, as is evidenced by the pvc industry site on the bottom of pg 1 at

http://www.vinidex.com.au/vinidex/l...02UseofPVCsewersforindustrialapplications.pdf

and on pg 4 of a plastic competitor's site at

http://www.concrete-pipe.org/buried_facts/plastic_pipe.pdf.

You may wish to get the opinion of the specific pipe manufacturer for the specific service/exposure conditions you envision.

 

[bimr]

rconner,

Madmary said that the pipe in question will carry vehicle wash water and possibly oils or fuel mixed in the water.

Here is a direct quote from the article that you quoted:

"No material which is acceptable under authority regulations for transmission to their sewers will have any detrimental effect whatsoever on PVC pipe."

It is doubtful that there will enough pollutants in permitted wastewater or stormwater to harm PVC pipe.

 

[ctmtwilliams]

I made the assumption that the discharge was going to meet permitted guidelines and I saw the post more from the standpoint of the pipe being placed in hydrocarbon impacted soils. My comment is based on standard industry practice working with hydrocarbon impacted sites and was intended to show that no physical evidence of degradation has been apparent (in my experience) after years of exposure. Keep in mind that the screened portions of the wells are also composed of PVC, and that the slots used to create the screening, adds a tremendous amount surface area for possible interaction to occur.

Perception, after all, is reality ;-)

 

[rconner]

Just happened to see the following verbiage on page 25 of the current May 2005 AWWA "Opflow" publication (in an article it appears from Uni-Bell) concerning and otherwise promoting pvc pipe,

"...the pipe should not be installed in areas where there is known soil contamination by high concentrations of low molecular weight organic solvents or where potential exists for high concentrations of organic solvents to leach into the soil, because the solvents could permeate the pipe, contaminating the water, and eventually soften the plastic pipe. Pipe gaskets are also vulnerable to high-concentration organic solvents."

 

[bimr]

rconner,

I would agree with your logic if you are installing and guaranteeing a 150-psig rated potable water line through a site with a high concentration of organics.

However, it sounds like madmarv is working on a site drainage issue at a fuel depot with de minimus fuel spillage.

There is little or no concern for internal degradation of the PVC pipe as your first reference points out:

"No material which is acceptable under authority regulations for transmission to their sewers will have any detrimental effect whatsoever on PVC pipe."

As to the external pipe degradation, that is an old-fashioned spitting contest as to how much contamination exists. Madmarv has not specified the level of contamination. However, if a significant spill of organics into the soil had already occurred, madmarv would be investigating remediation rather than drainage.

 

[rconner]

ok. I don't believe I have attempted to impose any sort of "logic" other than that shown in the references provided, nor have I attempted to deny the utility of any sort of piping in any specific application (I apologize if this is the effect). However, I am not sure that the integrity of plastic piping systems for any sort of application, drainage/sewer, potable or otherwise, would be aided IF the material is "softened" by whatever contaminant or cocktail of contaminants may be present in an exterior or interior environment (again, I did not see the specific soil contamination and concentrations of same identified in the original inquiry). Likewise, I am not sure if the various structural moduli used/assumed to design the plastic piping for long-term service are unaffected by said softening, if/when same occurs. I have happened to notice also some guidance from a state regulatory agency on pg 4 at

http://dnr.wi.gov/org/aw/rr/archives/pubs/RR649.pdf

that could be interpreted by some as applying to more sorts of utilities than permeation in potable water piping. That is why I thought it might be a good idea to communicate with the pipe manufacturers and/or any other pertinent authorities about the specific conditions.
I guess the only other thing I would say concerning these matters is that all prudent safety precautions (regarding breathing atmosphere et al) should be employed when installing or otherwise working around any sort of piping in contaminated soil areas.