Replies

1. 
   AndyEngel | Sep 24, 2003 04:59pm | #1

   You'll see an article on the stuff in issue 161. Bottom line -- It's more corrosive. At a minimum, use hot-dipped galvanized fasteners, not electro-galvanized. Stainless is better. Use copper for flashing, not aluminum. If you can't find hot-dipped joist hangers (They are out there, Simpson and others make them, but you might have to ask), then paint regular hangers w/ Rust Oleum or the like.

   Andy Engel, The Former Accidental Moderator
1. 
   CAGIV | Sep 25, 2003 05:55am | #4

   If you can't find hot-dipped joist hangers (They are out there, Simpson and others make them, but you might have to ask), then paint regular hangers w/ Rust Oleum or the like.

   We just talked about this at our weekly meeting, I guess it would be easy enough to look up myself, but.well, I'm feeling lazy.

   Any idea on the difference in price between Hot-Dipped and Electro, and will the hot-dipped corrode eventually or is it immune to the ACQ

   and will the ACQ break down the paint?

   Guess these questions are better for simpson.

   The Count-Down begins, 82 days left

1. 
   AndyEngel | Sep 25, 2003 05:45pm | #5

   Everything breaks down eventually. If you want to be sure, use stainless, or paint the hot-dipped. No idea if the paint is more likely to fail sooner. The issue springs from the fact that essentially, the arsenic in the old PT has been replaced with higher levels of copper. I don't have a periodic table of the elements in front of me, but if memory serves, copper is a more active metal than arsenic, and is therefor more corrosive to other metals in the presence of an electrolyte. If the longevity of paint is affected by galvanic corrosion, then yes, the ACQ may shorten its life.Andy Engel, The Former Accidental Moderator

1. 
   UncleDunc | Sep 25, 2003 07:03pm | #6

   If extra copper is the problem, then no doubt somebody will soon be offering bronze joist hangers, eh?

1. 
   AndyEngel | Sep 25, 2003 07:04pm | #7

   Ooh, decorative, too.Andy Engel, The Former Accidental Moderator

2. 
   CapnMac | Sep 25, 2003 08:52pm | #8

   the difference in price between Hot-Dipped and Electro

   I always preferred elctroplated over hot dipped for fasteners.  The hot dipped nails would have clumps & lumps, which might or might drop off durring, or after driving.  Hot dipped lags never seemed to "thread" right when run into PT. 

   Ok, buying a higher quality fastener meant a better (or more uniformly coated) fastener--but that only worked when I was the one buying the fasteners.

   I'm glad I don't have a trailer full of ring shanks, or EP deck screws, or fencing nails--now facing incompatibility with ACQ treated lumber.  Which just caused me to wonder about "J" bolts & Hilti/Ramset fasteners run through PT bottom plates--will we have to "upgrade" those fasteners, too?  And all this to lower the exposure of the workers pressure treating lumber to arsenic by a whopping 0.5% or so.  (Don't rub peach juice on the wood--you'll need a HazMat team.)

1. 
   CAGIV | Sep 25, 2003 10:35pm | #9

   Capn,

     Come on it's so little kids don't get cancer and us lumber butchers don't get brain damage while handling the stuff.

   To bad all it really is, is a costly PR move, unless someone can show me differently with actual hard un-biased scientific data and research.The Count-Down begins, 81  days left

1. 
   caseyr | Sep 25, 2003 11:51pm | #10

   It's not just a PR move.  Most of the big producers of pressure treated lumber were opposed to the removal of arsenic based treatments.  However, while the risk appears to be real, it is not an overwhelming threat.   You are far more at risk of death each time you step into your car to go to the store than if you injested a modest amount of arsenic. 

   The impetus for removal of arsenic in treated lumber seamed to come from a study in Florida which found that children playing on pressure treated playground equipment had measurable amounts of arsenic on their hands. 

   Most of the evidence for an arsenic and cancer link comes from southeast asia where certain areas have elevated levels of arsenic in the drinking water.  In those areas with high level of arsenic, high rates of bladder, urinary, and other cancers were found.  I have not seen anyone attempt to project cancer deaths in the US based on the amount of arsenic that children get on their hands and put into their mouth from playing on arsenic based pressure treated structures. 

   I did a quick scan and here are a few articles and bibliographies (there are lots more out there) that relate to the dangers of arsenic ingestion.  Some of them even appear to have been based on a scientific study:

   http://www.who.int/inf-fs/en/fact210.html

   http://www.aig.asn.au/arsenic_cancer_link.htm

   http://www.cancerpage.com/cancernews/cancernews2413.htm

   http://www.awwa.org/communications/waterweek/index.cfm?ArticleID=63

   http://www.nrdc.org/water/drinking/arsenic/biblio.asp

   http://www.mercola.com/2001/mar/24/arsenic.htm

   and for a somewhat contrarian organization's view:

   http://www.heartland.org/Article.cfm?artId=846

2. 
   CAGIV | Sep 26, 2003 02:22am | #12

     I heard about the study in Florida, but I also read that there was no link to kids playing on a playground and thus becoming more prone to cancer or the like.  I can't remember where I read that though.

   Not to say that arsenic is not or can not be detrimental or even fatal to ones health, but I've yet to see anything to substantiate the risk associated with the levels in CCA lumber to a person's health.

   The levels in drinking water I can't say to know much about, but I think that is a separate issue from arsenic in CCA lumber.  Water is taken internally, the CCA is only through touch.  Unless someone is claiming that arsenic is leaching from CCA into the water supply, which I have not seen..

   And from what I read above, the difference will only be 5%,  I'm not a chemists but that just doesn't seem substantial to me. 

   The only thing that really bothers me about the whole deal is the way, in general, the media jumped on it and made the facts sound worse then they were.

   I may be a cynic but with out the government stepping in, I can see no reason why the lumber treatment companies would self impose a deadline to switch over to ACQ if not for the main purpose of calming the general public concern.

   One of the proprietary names is even Naturewood....  sounds a lot like a PR move right there lol.

   The Count-Down begins, 81  days left

3. 
   CapnMac | Sep 26, 2003 10:28pm | #13

   I may be a cynic

   Nothing inherently wrong with that.  While there may be health risks associated with arsenic, the linkiage between CCA as a source for the arsenic in people/environment is not real "provable."  Supposed to be all number of health risks from creosote--a naturally occuring chemical, i.e. "organic"--but this has not slowed utility usages of the material.  I have heard that the small shop glass blowers are about to be regulated for arsenic exposure--in amounts real similar to that found in CCA.

   My problem is that I've witnessed more than a decade's change in workplace (non-agricultural) standards for all sorts ofchemicals.  Every year, the exposures are ratched down.  Yet the proportions of people suffering from alleged work exposures seems to be the same.  Underthe current TNRCC rules, raw peach juice, spilled in a non-ag workplace would represent a high enough exposure to require a HazMat team & remediation.  That's how low, "having the half" has pushed the exposures.

   For a real contrarian outlook, google "hormesis."  Hormesis says that there are certain levels of exposure to vvarious things in life that are needed for good health.  In other words, a zero exposure to some things may actually be bad for you. 

2. 
   BossHog | Sep 24, 2003 05:09pm | #2

   There's a PDF document from Simpson here:

   http://www.woodtruss.com/images/acq/simpson.pdf?PHPSESSID=64d6b0e3659fe79b21bd63a9fad052e4

   "In America, the demand for power to compel is a confession of incompetence to lead." [Eugene E. Wilson]

1. 
   ProBozo | Sep 25, 2003 05:39am | #3

   So, will the ACQ last as long as what we've been using?

3. 
   Megunticook | Sep 26, 2003 12:22am | #11

   Osmose is a chemical manufacturer that makes one of the ACQ treatments used by wood preservers (they've branded it "Nature Wood"--pretty silly, huh?)

   They've got a sheet with fastener recommendations, which I presume resulted from lab testing with different fastener materials. The link to the PDF is on this page: http://www.osmose.com/wood/usa/preserved/naturewood/product/

   The other company making an ACQ treatment solution, Chemical Specialties, also has some info. on fasteners here:  http://www.treatedwood.com/products/preserve/

   And if you're interested in how why things are moving in this direction, you can read about it directly from the horse's mouth: http://www.epa.gov/pesticides/factsheets/chemicals/residential_use_cancellation.htm

   Basically it's a push by the EPA to limit arsenic exposure. Can't argue with it in principle, but you have to wonder whether there are other, more urgent environmental health issues to deal with.

   For what it's worth, I built a timber bridge using some ACQ treated 6x14 beams, and all fasteners were hot-dipped. Too early to tell how things will last long-term, but seemed like the best choice for the application. Of course stainless would've been better, but these were some monster fasteners (60d spikes, 3/4 inch bolts, etc.).