Re: Re: testing copper for sulfur-related corrosion

[Guest guest]

Henry

On your comment about the airtightness of the houses, natural ventilation is only related to air leakage is a very sporadic way and, if the time of the year was wrong (little wind and small temperature differences for weeks on end), the actual air exchange rates of houses with high tightness can bee almost too small to measure. I have been in a number of houses under those conditions and they really smell of occupancy. Under those conditions a small source rate leads to very high indoor concentrations.

I have been noted to be strongly against "natural" ventilation and any supposed safety of air exchange and that is true; there is no reliable correlation for days if not weeks on end and people do NOT open their windows (not that an open window helps ALL of the time) so the actual ventilation rate is really small under those conditions.

Those who say that leaky houses are well ventilated have not done enough field tests; some rooms can be poorly ventilated even in cold and windy weather.

The point of all of this is that, without a working ventilation system that is virtually continuous, some house can have very low pollutant removal rates for extended periods of time; it is likely in those houses that the sulphur compounds got into the high concentrations and the corrosion occurred.

Real house ventilation does not respect consensus standards that say houses can be properly cleared of pollutants by natural ventilation alone. They just react to the real pressure differences across/along real flow pathways. When the pressure differences are low for long periods of time, the indoor concentrations are large for much of that period.

To bad we did not get funded to do enough real-time monitoring of ventilation rates in rooms of a significant number of houses; then the standards would not say that leakage area and natural forces make for adequate/reliable ventilation.

Jim H. White SSC

Re: testing copper for sulfur-related corrosion

Y'all -Florida Department of Health sponsored a Technical Symposium on ImportedCorrosive Drywall in November 2009. Most of the papers on tests andtesting are available athttp://www.drywallsymposium.com/blind/index.html .The true test to see if drywall is corrosive is the put a sample in ajar with a piece of copper and a source of moisture (damp sponge) andwait. The reaction proceeds faster at elevated temperatures. Somepresentations state that XRF technology could be used to identifydrywall that was imported.The free sulfur reacts with hydroxyls, CO, and HCHO (formaldehyde) tocreate H2S, CS2, and COS, which then react with copper wherever it maybe. Measured levels measured of these gases were extremely low (ppb)when compared to industrial levels (ppm) at which health effects havebeen documented. Interestingly, many homes were very tight (as low as0.1 ACH, if I remember correctly), and only half met ASHRAE-recommendedminimum levels of ventilation.Also, http://www.cpsc.gov/info/drywall/index.html has the Federalresponse, and recommendations (in short, replace the drywall and thecopper). They have received around 3,6000 reports from 38 differentstates,Henry Slackslack,henry@...U.S. EPA Region 4

[Guest guest]

Try electron microscopy with ED X-Ray spectrometry. I had a materials lab do that to identify copper sulfide corrosion products.

 

Don Schaezler, Ph.D., P.E., CIH

ETC Information Services, LLC

Cibolo, Texas

 

 

Steve, 

 

To my understanding there is no definative lab test (that looks at drywall chemisty) to prove that a specific piece of drywall is reactive.  ASTM recently said that looking at strontium levels with FTIR gun can result in both false positive and false negative results (mainly due to surface coatings of drywall).  Sulfur levels in drywall also are not a indicator if a piece of drywall is reative or not.  I have a client that is a large condo association with obvious results of defective drywall and we are trying to find the most useful lab data that can be used for possible future litigation or insurance claim.   I would like to have the copper cooling coil corrosion tested and proved that it is related to sulfur compound corrosion.

 

Sherry, CMC Environmental Scientist / Certified Microbial Consultant

Southern Sciences, Inc. 3600 Mystic Pointe Drive, Suite 1403Aventura, Florida 33180www.southernsciences.comrsherry@...

ph) , fax)

To: iequality

Sent: Sat, September 25, 2010 6:32:50 PMSubject: Re: testing copper for sulfur-related corrosion

 

,I hate to go way outside my expertise to state the obvious, but the gypsum part of wallboard is supposed to be calcium sulfate (dot 10H2O, that is, in a matrix with a lot of water). So there's supposed to be lots of sulfate there, and water is supposed to migrate through it, albeit slowly. My recollection was it was sulfide and not sulfate which caused the corrosion. There have also been anecdotal mentions of metals other than calcium found in the offending wallboard.

Steve Chalmers(computer type who hasn't studied or used chemistry in 35 years...)

>> Thanks Chuck -  that is a good idea...but I am trying to be non-destructive for > the time being and am really trying to show that the corrosion itself is related > to sulfuric acid.>  

> Sherry, CMC > Environmental Scientist / Certified Microbial Consultant> Southern Sciences, Inc. > 3600 Mystic Pointe Drive, Suite 1403> Aventura, Florida 33180> www.southernsciences.com

> rsherry@...> ph) ,fax) > > > > > ________________________________> > To: iequality

> Sent: Thu, September 23, 2010 6:20:47 PM> Subject: Re: testing copper for sulfur-related corrosion> >   > ,>  > I suggest that you secure several relatively small (+/- 2-3 sq.in.

> ea.) sheetrock samples from different locations from within the site in > question, and place them in identical, separate, clear glass, air tight jars > w/plastic lids, with a couple of inches of new medium gauge copper wire with the

> insulation removed.  Wear gloves while stripping the insulation from the wire so > to not contaminate it with skin oils/acids while handling it.  Label each jar > accordingly so that you know the source location of each sheetrock sample.

>  > Wait several days to perhaps a couple of weeks and see if corrosion appears on > the wire in each jar.>  > If time is a factor, you may want to photograph each every couple of days to

> compare photos, as this may allow you to detect slight changes in the condition > of the copper wire more readily.  Consistency in lighting, distance, location, > etc., when photographing will be very important in allowing the most accurate

> comparison of slight short term changes in characteristics.> > In a perfect world, you would be able to also secure a sample of known corrosive > drywall, treat that identically to the others, and use that one as a control. 

> Although the composition isn't likely to be the same, it's better than no > control at all in helping to make some preliminary determinations.>  > I imagine that you could accomplish this for very minimal expense, and use your

> results to send additional sheetrock samples from locations that indicate a > positive result to a lab for definitive analyses, which would be more > financially efficient than simply sending all of the samples to a lab initially.

>  > Let us know how this works out, please.>  > Chuck Reaney CIEC, CIAQP>  > Alpha Environmental, Inc.> Media, PA>  > testing copper for sulfur-related corrosion

>   > I am trying to find a lab that can test blackened copper to determine if > corrosion is related to surfuric acid (chinese drywall project).  I have found > many labs that can put the copper under the microscope and describe the pitting

> and other characteristics but cannot state if the corrosion is from sulfuric > acid.  Oh yeah, budget is an issue.>  > Sherry>