Re: Fume hood in HP Labs

["David Bromwich" <davidb@plato.ens.gu.edu.au>]

I'm a Health Physicist turned hygienist, will a long time interset in
Industrial Ventilation (including fume hood design).  Some of my 2c
worth.

If you use unsealed sources YES, you must have a hood. However most
hood deigns are very poor. Look for good aerosdynamics on the front
lip. This means no lip and a false floor to collect spills if it is a
conventional type of hood.

Look out for poorly designes handles on the sash. This may be a 
moulding along the length of the sash. Smoke tube tests with smoke on
the inside of the sash and lip on the fron t of the cupboard using
will show reverse air fows and subsequent loss of containment into the
swirling air in front of you and consequent tracking to the air you
breath.

Stear clear of tiled surfaces  and fittings like taps from the working
surface. These cannot be de-contaminated adeqautely.

If you are using shielding, this will interfere with the smooth 
airflow away from you.  A downdraft cupboard may be more suitable.
Downdraft cupboards are genrally superior if you are using samll
vessels and decating between them (eg isotopes, pharmaceuticals). 

Get a copy of Don Hughes books on Fume Cupboards. Write to Science 
Reviews (the publishing arm of the British Occupational Hygiene
Society) and ask for their catalogue. The books are small, but packed 
with useful information.

Titles include

A literature Survey and Design Study of Fumecupboards and 
Fume-disperal Ssytems

Health Physics Aspects of the Use of Tritium

A guide to the Safe Use of Tritium

Phosphorus 32

Radiation Protection in x-ray optics

The Peformance, Installation , Testing and Limitations of 
Microbiological Safety Cabinets.

Fume Cupbaords Revisited

Discharging to Atmosphere from Laboratory Scale Processes.

Controlling Airbourne Conatminants in the Workplace (This complemenst 
the ACGIH "Industrial Ventilation Manual")

Science Reviews Ltd
28 High Ash Drive
Leeds LS17 8RA
UK

Hope this helps

> Question: Do you use a fume hood as part of your health physics operations?
>  Is the fume hood part of your "health physics" lab or do you use a fume hood i
> n another facility?
>  Reason: For years our operation has had the use of our own fume hoods because
> we took over lab space previously occupied by a research group that needed the
> fume hoods. Now we are moving to a new facility without a fume hood and need ju
> stification for spending the money to install a hood.
>   New question: How do you as a health physicist feel about the need for a fume
>  hood as part of your own health physics facility? If you can find the time to
> respond send the response to me at  milwicz@princeton.edu    Thanks
> 

David Bromwich, CIH           D.Bromwich@ens.gu.edu.au
Lecturer, Occupational Hygiene     tel (+617) 38757487
Faculty of Environmental Sciences  fax (+617) 38757459
Griffith University, Nathan Q 4111 AUSTRALIA
http://plato.ens.gu.edu.au/hygiene/db.htm