Re: Fume Hoods in Rad Labs

[jgbarnes@ix.netcom.com (JAMES BARNES)]

Dear Denny,

I am digging back into the cobwebs for this one, so bear with me:

The best manual for this type of stuff was a book called "Industrial 
Ventilation."  I think it was published by the American Conference of Industrial 
Hygienists (I recall it being brown in color, about 250 handlettered pages.)  It 
was widely distributed, so a good technical library should have a copy.

Also, you might check out ANSI Z9.2-1979 (or later), "Fundamentals governing the 
design and operation of local exhaust systems."

Several points:

1)  You may have to get a NESHAPS permit for your hood exhaust; you may have to 
set up a monitoring point on the exhaust stack.

2)  You may want to install a HEPA scrubber filter in the hood intake plenum.  It 
is more expensive as you will need a larger air mover and HEPA mounting cabinet.  
The payback is that it will reduce deposition and plating on vent ducting; which 
pays benefits when it comes time to decontaminate and decommission.

3)  While stainless steel seamless construction has always been touted as "easy 
to decontaminate," my experience has been that it is rarely releasible after 
several years of use.  You may be able to use a plastic or fiberglass hood; 
realizing that it will be radwaste when you're done with it.  Herculite or 
plastic covering (or decon paint) can be used to protect surfaces to keep 
contamination and dose rates under control.  (It looks shabby, but it works 
well).

Jim Barnes, CHP
RSO
Rockwell International, Rocketdyne Division


You wrote: 
>
>Good morning all,
>
>I am becoming involved in the set up of my first lab here at CMU.  New
>professor is renovating spaces for his new lab.  The architect is
>inquiring about specs for the fume hood, primarily material of the
>surfaces and ductwork.  My thinking is sheet metal of the normal
>thickness for ductwork.  Seamless would be great, but I don't whether
>that is cost effective or not.
>
>Any thoughts?
>
>Thanks in advance,
>
>Denny
>CMU, RSO
>