CFC's and Wei To

I received a private posting regarding my last (public) posting
regarding the subject of non-aqueous deacidification.  That posting
encouraged me to tread this path with caution, given that many readers
of this list are not conservators, or are not well read in the field and
might, thus, give my opinion, as a conservator, more credence than the
data allows. It was not, and is not, my aim to support any particular
chemical or technological solution to the manifest problem of
deteriorating collections.
  
However, there are questions which I would like an answer to with regard
to this matter. Approx. three weeks ago, on public television, there was
a program which raised some questions which may be of interest to this
group. According to that program, the ozone hole was in existence in
1948, the year that the spray can nozzle was introduced.

During this same program, it was stated that there is a lag time of
approx. 50 years between the time that CFC's are released into the
atmosphere and the time that they interact with the ozone.  I do not
know about this, but I wonder.

The question seems to be what happens with chlorine in the upper
atmosphere, in the ozone layer.

What is the effect of chlorine lifted from the sea?  What is the effect
of chlorine dioxide from paper manufacture (dioxin aside, for the
moment)?  The December, 1992, edition of _R&D_ magazine contains an
article entitled "CFC Replacement Technologies".  In the article various
representatives of the CFC producing industries state that the mandated
requirement of no CFC's by 1995 will be met, with limited exceptions.
HCFC's can replace CFC's in Wei T'o for single sheet treatment (as is
being tested in the Netherlands at this time), but at the moment, there
is no adequate substitute for CFC's as a mass non-aqueous
deacidification solution solvent.

DEZ was supposed to produce only ethane as a byproduct; it is now know
to produce butanol also (hence the persistent smell).  The efforts of
the Library of Congress, and AKZO to impress me with PR are almost as
depressing as the efforts of Wei T'o to flood me with data.  In the end,
I prefer data to PR.

I am not satisfied that the data we are given by our government(s) are
sufficiently unbiased to allow us to make completely informed decisions,
and I do not look to interested parties for unbiased data, so I look at
as large a data base as I can locate and make fluid decisions.  For the
past twenty years or so, the data has supported Wei T'o as a reasonable
solution when aqueous (yes!) treatments are not possible.
 
Jack C. Thompson
Thompson Conservation Laboratory
Portland, Oregon.

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                  Conservation DistList Instance 6:34
                  Distributed: Sunday, January 3, 1993
                        Message Id: cdl-6-34-009
                                  ***