Spray booths

We will be installing one 4 meter wide x 3 meter high spray booth
soon in an off site collections care area which will be used for
spray varnishing paintings for about 3 years, then will revert to a
general large project room where big items of any media are treated.
At that time we will move back into our present building and install
two similar spray booths in our newly renovated paintings and frames
labs.  The paintings lab will be spraying varnishes and adhesives in
flammable solvent mixtures (such as B-67 or MS2A in organic solvent
mix and BEVA adhesive in xylene mix.  In the frames lab it is likely
that gesso will be hot sprayed.

The consulting engineers are asking us to specify what we require
and are very concerned at the cost of the plant and ducting for such
a large booth.  I have emphasized that we are not requiring a huge
amount of air to be moved, but only need to contain overspray and
the volatiles within the room and gradually evacuate them.  In
comparison with light industry, we are dealing with very small
amounts of material and infrequent use- but it must still do the job
safely.  It is obviously difficult to design a spray booth in which
large flat paintings will no doubt be put in front of the air
exhaust and air must find its way around, taking the nasties with
it.

The engineers are considering a top down concept where temperature
and humidity controlled make up air is introduced at the top of the
booth and drawn through holes in the floor- essentially an air
curtain.  This means the floor of the booth has to be raised,
causing some inconvenience.

I will appreciate any experiences people can share on large spray
booths that work well.  Has anyone used a "top down" spray booth for
our purposes? Specifications and brand names would be especially
useful.

Tom Dixon
Chief Conservator
National Gallery of Victoria
Melbourne Australia

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                  Conservation DistList Instance 12:55
                Distributed: Tuesday, December 22, 1998
                       Message Id: cdl-12-55-012
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