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Re: GBlist: GB List: OSB question



Hi, Hal--

Point taken. It did seem that the incorrectly stated emissions rate was
still very low. What is your understanding of the formaldehyde emissions
from phenolic resins in boards?

Best, Mike


>Gentle friends:
>
>Please excuse a rant, but a very hot button of mine has been pushed. I have
>worked for 14 years to establish standard methods for sampling and analysis
>of indoor air so that measurements from various labs and buildings could be
>compared. One of the most important standards applies to emisssions testing,
>since we need to know source strengths (contributors to contaminant loads)
>to design buildings reliably and effectively.
>
>So......PPM, or parts per million, is not an emission rate, it is a
>concentration. The wood products industry has reported emissions this way
>for some time - back into the early 80s at least - but, to my knowledge,  it
>is unique, with the possible exception of Underwriters Laboratory, which
>reports ozone emissions from photocopiers in ppm or (ppb) also. This sort of
>reporting simply does not tell the users of the test results what the
>emission rate is. You must know the loading factor - in the case of
>composite wood products, the area of the emission source per volume of the
>test chamber - and the ventilation rate to be able to calculate an emission
>factor or emission rate. In the case of a machine such as a photocopier, you
>must know the copy rate and air exchange rate in the test chamber.
>
>An emission rate must be stated in mass units per unit of time. For sheet
>materials such as composite wood panels, a unit of area should also be
>given. This might be called an area specific emission rate, or a normalized
>emssion rate. So, the formaldehyde  emission rate from composite wood
>products would be stated in micrograms or milligrams of formaldehyde per
>square meter per hour -- µg/m^2-h. If you are interested in the details of
>>emissions testing and the reporting and meaning of results, consult ASTM
>Standard D5116-90. Although it has been revised recently and the revision is
>currently being balloted, the original standard is the most authoritative
>guide to emissions testing available. Copies can be obtained from ASTM at
>610 832 9500.
>
>For the computationally inclined lister, the formula is
>
>EF = C(Q)/A
>
>where
>EF = emission factor, mg m^-2 h^-1,
>C = equilibirum changer concentration, mg/m^3,
>Q = flow through chamber, m^3/h, and
>A = sample area, m^2.
>
>An equivalent expression is also used:
>
>EF = C(N/L)
>
>where
>N = chamber air exchange rate, h^-1
>L = chamber loading, m^2/m^3.
>
>Note that N = Q/V, where V = chamber volume, m^3.
>
>An emission rate would involve multiplying the area of source material times
>the emission factor, and would be stated in units of mass per unit time.
>
>
>
>At 10:50 AM 5/8/97 -0700, you wrote:
>>Hi, Chris
>>
>>John A. Emery of the American Plywood Association wrote a paper on
>>formaldehyde in composite wood panels made with phenolic resin, "Structural
>>Wood Panels and Formaldehyde", that you can request from APA at
>>(206)565-6600. It reports on formaldehyde emission levels found using a
>>test chamber procedure. The test procedure seems reasonable, except for the
>>fact that the ventilation rate was somewhat high. Allowing for that, the
>>emissions levels reported from new boards was under 0.1 ppm.
>>
>>Best, Mike
>>
>>
>>(snip)
>>
>>>Can anyone provide accurate information regarding the harmfulness of
>>>phenol formaldehyde in building materials?
>>>
>>(snip)
>>
>>O'Brien & Associates
>>Environmental Building Consultants
>>Portland General Electric Earth Smart program
>>obrien@hevanet.com
>>
>>
>>__________________________________________________________________
>>This greenbuilding dialogue is sponsored by Oikos (www.oikos.com)
>>and Environmental Building News (www.ebuild.com). For instructions
>>send e-mail to greenbuilding-request@crest.org.
>>__________________________________________________________________
>>.-
>>
>>
>
>Hal Levin         <hlevin@cruzio.com>


O'Brien & Associates
Environmental Building Consultants
Portland General Electric Earth Smart program
obrien@hevanet.com


__________________________________________________________________
This greenbuilding dialogue is sponsored by Oikos (www.oikos.com)
and Environmental Building News (www.ebuild.com). For instructions
send e-mail to greenbuilding-request@crest.org.
__________________________________________________________________


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