[Strawbale] OSB in detail

asbn asbn at baubiologie...
Tue Dec 7 20:06:20 CET 2010

Dear OSB-Pros & Cons

I would like to have a completely natural structural board instead of OSB,
but we didn't find a board with the same advantages and a similar price.

But we tried to look very carefully on OSB, avoided it in the beginning, but
as the OSB Top 4 boards came on the market with emissions just 1/10 of OSB
3, we decided to use it, until we have a better material.

There are a lot of tests made for Egger Eurostrand OSB (Top 4) by serious
institutes, which show, that... (if you want all the details, the complete
document is available on the net):

* For the production of OSB EURO TOP only raw materials are used which
correspond to the recommendation of the Commission of BFR plastics for food
packaging: XLV, "Networked polyureas as binders for wood chips, etc."
* The PUR glue in OSB Top 4 is completely formaldehyde-free.

* yet, there is (natural) formaldehyde in the wood.

* Emission standards EURO OSB 4 TOP and OSB 8000 are below 0.05 ppm
formaldehyde (= equilibrium concentration in the test area) and are
harmless for health.
Formaldehyd measuring point: WKI Fraunhofer Wilhelm-Klauditz-Institut,
Prüf-, Überwachungs- und Zertifizierungsstelle, Braunschweig
-  OSB/2: 6,4 mg/100 g atro (10 mm) + 6,5 mg/100 g atro (15 mm)
-  OSB/3 : 3,9 mg/100 g atro (10 mm) + 3,1 mg/100 g atro (18 mm)
-  OSB TOP: 0,4 mg/100 g atro (12 mm) + 0,3 mg/100 g atro (22 mm)
-  OSB 8000: 0,5 mg/100 g atro (25 mm) + 0,2 mg/100 g atro (30) mm

* MDI and other isocyanates:
measuring point: Wessling - Beratende Ingenieure GmbH, Altenberge
Results: in accordance to RAL UZ 76 and NIOSH (P & CAM 142).
The emissions of MDI and other isocyanates were below the detection limits
of analysis. The requirements of RAL-UZ 76 for MDI emissions are fulfilled.

* Smoke toxicity [ in case of fire or burning the boards ]
Measuring point: University of Osnabrück, Prof. Dr. Lechner IMFE Materials
Results: The results after DIN 53 436 show that the boards are practically
free of chlorine compounds and sulfur compounds. Hydrogen cyanide, HCN, was
below the detection limit. The gaseous emissions when burned correspond
largely to the emissions caused by burning natural wood.

And so on...

The German magazine Ökotest (which is a relyable ressource, I think), stated
in 2001 for OSB-boards (at this time OSB Top 4 didn't exist, so the results
for OSB Top 4 are again much better):

"In general, OSB keep, what is promised by them. Five out of seven tested
products are "very good" or "good", in only two products of the manufacturer
Kronospan we found several shortcomings.

The result of the sawing tests were encouraging: In no case isocyanates were
found. The consumer can be certain that the PU glue does him no harm. For
the environment, it is still not without problems.

Good news also at the formaldehyde measurement. Only one product outgassed
after three days more than 0.05 ppm of the the classical pollutant. After 28
days all products were well below this limit and thus fulfill the
requirements of the environmental label Blue Angel - for low emissions. This
proves that OSB panels have a significantly lower pollution potential.

Mit lieben Grüßen
Herbert Gruber
asbn - austrian strawbale network
Österreichisches Netzwerk für Strohballenbau
3720 Ravelsbach, Baierdorf 6
Email: asbn at baubiologie...

> --On Tuesday, December 7, 2010 10:11 AM +0100 Kurt235 at yahoo... wrote:
>> Formaldehyd is a naturel product contained in wood.
>> There are no formaldeyd free OSB´s (wood).
>> After "they" found out how bad formaldehyd is, "they" changed the clue
>> to PU-clue. But this clue contains isocyanate... THat PU-clue is
>> worse...but most people just don´t know! As a building biologist i
>> wouldn´t use OSB´s in my home!
> I haven't been able to find any references to formaldehyde in (natural)
> wood.  In all the regulatory documents that I looked at, formaldehyde
> was only discussed as an additive to wood products.  Can you tell us
> more about the concentrations in natural wood, Kurt?  From my searches,
> it looks like the researchers considered the naturally occurring levels
> of formaldehyde in wood, if any, to be too low to mention.  In
> contrast, there is much discussion of the amount of formaldehyde added
> to wood products, and the health risks that might be associated, even
> at very low concentrations.  There are also a number of composite wood
> products labeled as "formaldehyde-free", which may contain other
> dangerous chemicals.
> Derelict
> Derek Roff
> Language Learning Center
> Ortega Hall 129, MSC03-2100
> University of New Mexico
> Albuquerque, NM 87131-0001
> 505/277-7368, fax 505/277-3885
> Internet: derek at unm...
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