Dave Finkelnburg on tue 1 jun 04
Bob, to add to your knowledgeable post,
Even paper respirators will filter fine dust, what industrial hygienists
(scientists who study this) call "respirable" dust, the stuff that is fine
enough to get deep in our lungs and stay there and cause health concerns.
That is not the problem. The problem is how much dust a given respirator or
dust mask will handle. Paper respirators won't protect you from very much
fine dust. :-(
The quantity of dust a wearer is exposed to is not easy to measure. It
takes sophisticated sampling equipment that pulls a known volume of air
through a filter. Then a trained person weighs that sample and analyses it.
Not something we usually know how to do.
In general, paper respirators are rated for use with quantities of dust
that are very low. Basically, the air looks clean, even though you know
there is some particulate present.
If there are visible clouds of dust, then you absolutely need at least a
flexible-rubber type half-mask with dust cartridges. Fume cartridges are a
separate issue. Most of them also filter dust, or provide for dust filters
plus fume removal.
For very dusty situations you need a PAPR or Powered Air-Purifying
Respirator. It pumps air through a filter and into your mask.
In the most extreme dust, you need a Supplied Air Respirator--clean
breathing air pumped into the face mask. Sand-blasters and spray-painters
usually use such breathing protection.
I think, cynically, that some manufacturers tout the fine-particle
removal capabilities of their respirators or dust masks, but intentionally
gloss over the importance of understanding the quantity of dust you are
exposed to.
I wish I knew more, specifically, about how respirators are rated and
how to select one for common studio jobs, say for clay mixing or glaze
spraying. Unfortunately, I only know enough about this to realize reading
the box labels in the store is not enough research to get adequate
protection for your lungs. Your mention of Monona's article is great! That
is a wonderful starting point.
Yours for studio safety,
Dave Finkelnburg
----- Original Message -----
From:
Sent: Tuesday, June 01, 2004 12:43 PM
Cindy Bracker:
> At any rate, the disposable masks are
> "NIOSH approved for particulates
under 42 CFR 84. Approved as an N95 -
> Particulate Filter (95% filter efficiency level)
effective against
> particulate aerosols free of oil;
John Hesselberth responds
//////////These masks are virtually useless
against silica particles (probably
the biggest in-studio hazard potters face).
I don't know if they are
adequate for ceramic fiber dust or not.
One with a P100 rating is what
is needed for silica. The best articles
I have seem on this subject
were written by Monona Rossol in
Clay Times in the Nov/Dec 1999 and
Jan/Feb 2000 issues. P100 rated masks
are available for $30-$50 from
industrial supply or industrial safety firms,
e.g. Grainger and others.
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