Re: HEPA filters

[John livingston <jlivgstn@execpc.com>]

At 10:45 AM 6/4/96 -0500, you wrote:
>I am writing a procedure on use of HEPA filtered vacuum cleaners and I need 
>references for the performance criteria.  I have a copy of MIL-F-51068 but I 
>don't think what we are using meets the letter of the document.  There are 
>requirements for the filter housing to be constructed of certain materials 
>and plastic is not one of them.  Does anybody know of another document I can 
>reference
>
>Kim D. Merritt
>kdmerri@sandia.gov
>
Dear Kim,
It has been years since I built HEPA vacuum machines (big ones doing
2000+CFM @ 15"hg).  I am sure a lot has changed since then, but as I recall
we had to provide DOP testing ports, and independently certify that the HEPA
installation met the smoke test.  Quite frankly, I thought the specs were
loose - especially when considering what we were putting the HEPA's through.
I can't imagine why anyone would care what the HEPA housing was made of if
the temperature or chemical attack of the air going through the filter was
not too aggressive and it didn't leak.  Thinking about it while key
boarding...some of the better sealing surfaces are made of plastic.  They
are easier to manufacture and much less likely to leak.  I personally would
want to examine the clamping/gasketing mechanics to see if they were adequate.  

Come to think of it there is a set of standards...I think put out by the
ASME or some such organization, but they are so insignificant that I would
be embarrassed to make a product that was built to them.

I know this has been next to useless, but "Whatever"