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Subject: Nitrate


From: Walter Henry <whenry>
Date: Friday, July 27, 1990

I haven't had much time to devote to your question, but it is really
intriguing.  I think (but have not worked it out in any detail) that it
might be possible to model the behaviour of your building rather neatly.
A few questions that you might or might not have answers to:

1.  What did the health-safety people tell you?

a.  Did they give you any information about the air-exchange rate in
your building (ie exchanges with outdoors)?

b.  Or about the air-exhange rate within the building (ie how quickly
air in the film storage area dissipates into the rest of the building
and how quickly the air in the storage area is diluted by air from the
rest of the building).

c.  What do you have in the way of air filtration?

2.  What is the volume of nitrate material?
What stage of deterioration?

3.  What is the volume of the nitrate storage area?
of the whole building?

The reason Im asking these particular questions is that it seems like we
ought to be able to treat this matter in sort of the same way
health-safety people would treat a volatile toxics problem. viz

i. we can tell from the literature what the degradations products
ought to be [I will see what I can dig up]

ii. we have (at least some) standards for maximum
allowable concentrations in library collections (I'm not certain
there are actually published standards for nitro(etc) products, but
we could probably browbeat someone like paul into giving us a target
figure)).  [If Im overoptimistic here and this stuff isnt available,
then this whole exercise is going to be futile].

iii. we ought to be able to figure out what rate of gas production
would exceed that maximum given the particular air exchange rate/
building volume at HRHRC.

iv. given (iv) we ought to be able to get a statement from one of
the photo folks about whether the materials in your place could
generate degradation products at a rate >= maxrate.  (Based on
volume of nitrate material, stage of deterioration, temp and rh in
storage area).


                  Conservation DistList Instance 4:15
               Distributed: Saturday, September 22, 1990
                        Message Id: cdl-4-15-005
Received on Friday, 27 July, 1990

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