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Re: VOC content/photochemical reactivity

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Date: Wed Feb 16 2000 - 08:23:21 CST

Brian -

I must have missed the initial message is that you are responding to,
so I do not know the original question; but here is a partial response.

1) Heptane is a VOC. It is photochemically reacitve. It has not been
deemed negligibly reactive by EPA and is not in the list of "exempt
compounds" in the VOC definition in 40 CFR 51.100. No one has
ever petitioned EPA to consider heptane as negligibly reactive.

2) Acetone and methyl acetate have been deemed negligibly
reactive by EPA. They are on the list of "exempt compounds" in
the VOC definiton in 40 CFR 51.100. I believe that most (perhaps
all, but I am not certain) states also consider these compounds
negligibly reactive.

3) There is a portion of method 24 that deals with quantifying
"exempt compounds" and subtracting them from total (weight
fraction) volatile matter content to get weight fraction VOC. See
section 5.1.3 and equation 24-5 in method 24. (This section of
method is very similar to the preceding section which deals with
quantifying water content and subtracting it from total volatile matter
content.) The language is not perfect, but the intent of this section is
to provide a way to not count "exempt compounds" as VOC. The
only references in method 24 to methods for quantifying "exempt
compounds" are to the ASTM methods for methyl chloroform (1,1,1
trichloroethane) and methylene chloride. These were two of the
earliest "exempt compounds". Methylene chloride was never used
much in coatings. It is frequently used as a paint stripper. Methyl
chloroform was used in a lot of coatings in the 1980's (and maybe
into the 1990's), but it is no longer used because it is a stratospheric
ozone depleter. There are also ASTM methods for acetone and
methyl acetate, but they are not yet referenced in method 24. There
is also an ASTM method under development for quantifying tertiary
butyl acetate. This compound was proposed to be deemed
negligibly reactive by EPA on September 30, 1999; but final action
has not yet been taken.

Dave Salman
Coatings and Consumer Products Group
MD - 13
RTP NC 27711
(919) 541-0859

>>> Brian Grochowski <> 02/16/00 01:05am

VOC content determination is probably one of the simplest but most confusing
issues. It seems that everybody and their brother has their own definition
of what is a VOC. Certainly Method 24 is the standard in determining
volatile content, but isn't VOC content based on the volatile content
and it's classification under 40 CFR 51.100? 40 CFR 51.100 specifically
defines a VOC as a volatile organic compound (as defined by Method 24)
which is photochemically reactive. Am I wrong to state that a product
like heptane which is volatile according to Method 24 is
not a VOC since it is not photochemically reactive?
Don't chemicals like acetone and methyl acetate become delisted as VOC's
because of their negligible photochemical reactivity? Methyl acetate and
acetone are clearly still volatile compounds according to Method 24,
but they are not VOC's due to negligible photochemical reactivity?

Is my logic incorrect?

Brian Grochowski

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