Is it a real problem or is it just easier to blame China than to actually solve a problem in a home. Have you noticed that the “Chinese” drywall problems are mostly coming from Florida. And whats so special about Florida.. Its very humid. And what are the problems people are complaining about. corrosion on metal and possible sickness in the home among others. Well need i go on or have i already given the clues necessary to begin a diagnosis on this home. I am wiling to explain some ways to diagnose health issues, corrosion issues and efficiency issues in a home but i would welcome some suggestions and see if someone can point us in the right direction. The clues are “Florida” “corrosian on metal” sickness reported in home” “humidity” and “china” any takers. Rodney
Chinese Drywall is it real
November 24, 2009
Uncategorized chinese drywall sickness indoor health asthma 7 Comments
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Nov 24, 2009 @ 20:09:28
Hi Rodney – High speed blowers strip the water off the AC coil. When water is stripped from the coil, it is catapulted down the duct work. Thus, a good portion of the water that the AC system has collected is re-evaporated and/or sits in the ductwork which is the perfect breeding place for mold
Water’s adherence to an AC coil is inversely related to the temperature of the coil. i.e. the warmer the coil the less adhesion the water has to the coil. The faster the air’s speed over a coil, the warmer the coil becomes. The AC coil is designed to operate at a temperature and air flow that is cold enough and slow enough to hold the water to the coil long enough for it to drain all the way down the coil and reach the drain pan. Many systems are poorly designed and/or installed.
Bypass dampers in zoned systems are the worst offenders because the face velocity imposed on the AC coil goes way over 500 ft/min.
I’ve wondered, for years, why the insurance companies have not picked up on this situation.
My solution is to modulate the blower’s speed in direct relation to the temperature of the delivered air. It works!
Nov 24, 2009 @ 21:42:54
Dick:
thanks for a good lesson on one of the real problems in our industry. If air conditioning coils cant get rid of the water, then they allow it to blow or evaporate right back into the home. I have more to say on this subject but first are there any more who will step up with Richard and give solutions to the mystery. Rodney Koop
Nov 25, 2009 @ 19:29:53
Rodney,
Dick’s response is right on the money but from my point of view, that’s only part of the problem. Let’s start with a couple of facts we already know and build form there.
1) The problem with Cninese drywall is an out gassing problem.
2) The sulfur gasses from the drywall mix with water vapor and oxygen in the air to form a corrosive gas.
3) When this gas comes in contact with metalic surfaces, especially damp surfaces, it then becomes a hungry corrosive compound.
4) Houses have been built for the past several years so “Energy Efficient” that they no longer breathe. It’s like living in a plastic bag.
5) Even minor quantities sulfur gasses can be a health risk to some people.
Other folks can keep adding on from here but I think you get the idea. In the case of Chinese drywall I see 3 options:
1) Bitch and moan, blame it on “somebody else”, and do nothing (the most prevelant today).
2) Gut the house, remove all the drywall and drywall dust then rebuild. (Who pays for it?)
3) Ventilate the house to reduce the concentration of sulfur gas in the air of the non-breathing house. Tight houses need to be put on a respirator, i.e.: VENTILATION.
This is something that we as “AIR” Conditioning and IAQ professionals should be providing to our customers to resolve or at least reduce their problem until something else can be done. Eventually the drywall should complete it’s outgassing process but so far I don’t think anyone can calculate how long this will take. Almost all products used to buuild or rebuuild and furnish a home will outgas compounds to a point of equalization. Mother Nature says so! At the present time I suggest and ERV (Energy Recovery Ventilator) or, if there is enough slush built into the load calc., inject a controlled volume of outside air into the return air system. This will dilute the concentration of VOC’s in the home in most cases to a minimal or less objectionable state.
These are a few things that my dad was able to cram into my hard head since he started me in this industry at the age of 12.
The first word in “air conditioning” is AIR. We must work with it and control it.
We are not just wrench turning mechanics. We must know, understand, and work with the laws of physics.
Open your eyes, take the blinders off, observe EVERYTHING that could affect the problem at hand and learn to think outside the box.
And finally, if you can’t buy what you need, build it.
Sorry for the rant, but I see too many people stuck on “Option 1″ above and not looking at the “AIR” problem at hand. If anyone else can put more light on the subject and come up with a better or different solution, please let me know because we have the same problem here in south Louisiana since the rebuilding from hurricanes Rita and Katrina.
Thanks
Kenny Robért
Nov 25, 2009 @ 19:41:24
Kenny: Wow thanks so much. very good information. So we agree that A. humidity can and must be controlled no matter who made the drywall. and B. Introduce enough fresh clean air to dilute the offgassed chemical compounds. This is very good and as you are suggesting all homes need this no matter who made the drywall. so this is good and lets here from more. By the way Kenny: i’d like to ask you how long you have been looking outside the box. and question #2. are other hvac contractors in your area also willing and able to look outside the box for solutions. Rodney Koop
Nov 25, 2009 @ 21:31:53
Rodney,
In response to your questions:
1) I think I finally took thinking outside the box seriously about 25 years ago when my dad retired and it was either sink or swim. Obviously the lessons worked because we’re still here.
2) If I had to guess, I’d say that there are no more than a half dozen other HVAC contractors able and willing to look outside the box. The rest, I believe, are either afraid to look over the edge, too lazy to try something new, or as Rhett Butler said “just don’t give a damn”.
Happy Thanksgiving and God bless,
Kenny
Nov 25, 2009 @ 23:41:23
Hi Rodney,
(I sent this to SRT this AM but just cjecked your blog and thought would be good to post it here too!)
Of course I agree there’s probably more to it all than many think. Building science is all about looking at the building as an interactive system.
Understanding the role of high humidity is a BIG part of that, also has a lot of impact on materials science and corrosion.
In the drywall controversy case, it seems that our tax dollars are hard at work figuring this out. A new web site has been put up that is a great resource:
http://www.cpsc.gov/info/drywall/index.html
Everyone should browse that site and get familiar with the problem. Great pics and video of nasty corrosion of copper. I wouldn’t want my family living in one of those houses!
Bottom line is that high levels of hydrogen sulfide have been measured in these 2006-2008 new homes.
Sure high humidity and low air exchange rates will likely contribute to the corrosion and odors etc, but at this time the presence of something nasty in this imported drywall seems to be the dominant factor.
I haven’t read all the detailed reports yet, but my best guess is that short of rebuilding the houses the best remedy will be:
- sealing air leaks that allow the offgassing corrosives to get into the house (exterior walls and all interior partitions),
- sealing all other air leaks in the home to enable a positive pressure to be obtained with minimal cfms
- creating positive pressure with supply only ventilation,
- installing supplementary high efficiency dehumidification (e.g. Thermastor, Air & Energy, Aprillaire etc).
Classic example of controlling pollutant pathways by sealing leaks and controlling pressure and airflow direction … IAQ 201
I don’t know if a couple of coats of latex paint is enough to stop the offgassing off the visible/living area side surfaces, my guess is probably but not my area of expertise. Just need to find an extra few hours to read the CPSC reports ….
Brendan Reid
President
cell: (360) 420-5049
fax: (360) 656-0001
http://www.ciinfo.org
breid@comfortinstitute.org
Nov 27, 2009 @ 15:18:33
Brendon, thanks for the great info. and also the resource link. I appreciste Comfort Institute going the extra mile to research. Your reference to IAQ 201, where should we look for this information. Also is this something that Heating/Cooling Contractors should become familiar with. I see that the government info link suggests that homeowners call their insurance agents or builders. I think HVAC contractors need to educate themselves and help the homeowners assess whats really going on. By the way, as a building science professional, do you think this would have become a problem if the humidity had been controlled in the home? Rodney Koop