RE: Dust Masks

["McDonald, Michael P" <mpmcdon@sandia.gov>]

Paul,

Thanks for your detailed response to the dust mask question.  Two questions
for you:

How would a facility perform quantitative fit testing on these filtering
facepieces, if a true quantitative fit test is required?  Will the
manufactures be producing a "fit testing" model, one with a sample port
manufactured into the facepiece?  Just wondering.

Thanks

Michael McDonald, CHP, RRPT
Sandia National Laboratories, NM
mpmcdon@sandia.gov

-----Original Message-----
From: K P Steinmeyer [mailto:publish@gyral.com]
Sent: Tuesday, April 27, 1999 9:48 AM
To: Multiple recipients of list
Subject: Dust Masks 


Joe Archer asked about the use of dust masks.


NRC is in the process of amending its regulations (10 CFR 20 Subpart H
and Regulatory Guide 8.15) to (among other things) permit the use of
filtering facepieces (i.e., "dust masks").  Under NIOSH's relatively new
certification system for negative-pressure air purifying respirators (42
CFR 84), all such filtering facepieces are at least 95% efficient,
although non-NIOSH-certified "comfort masks" of uncertain efficiency are
still available.  A thorough explanations of this certification system
can be found in Steinmeyer, K. Paul. "NIOSH Approval Requirements for
Respiratory Protection Equipment."  <italic>Radiation Protection
Management</italic> Vol. 15, No. 5, Sept/Oct 1997.


NRC is considering treating filtering facepieces in two groups, which
I'll refer to here as upper division and lower division.  Upper division
filtering facepieces have adjustable straps AND a rubber (or plastic)
seal-enhancing material applied to the entire face-sealing surface. 
Also, most of the upper division devices have an exhalation valve, but
the presence of one of these is not considered critical.  All other
filtering facepieces would be considered to be in the lower division. 
NRC would consider the upper division devices to be half facepieces with
APF = 10, as recommended by ANSI, as long as all other program
requirements are met (medical screening, training, fit testing, etc.). 
Lower division facepieces would not be given an APF but could be used
with an APF = 10 if all the program elements, including fit testing, are
in place.  


Licensees, however, will be able to use lower division facepieces (NOT
upper division) on a VOLUNTARY BASIS without medically screening or fit
testing the volunteer users, as long as they are provided with a very
brief and basic training program (possibly 5 minutes long).  This
practice is also permitted by OSHA.  Respirator use is voluntary when one
is not required, but workers request a device.  It sounds like carrying a
filtering facepiece for ALARA reasons in case an unexpected release were
to occur would be an appropriate application for these devices.


In your case, a NIOSH-certified device should be used.  While it may cost
a bit more than 50-cents, it is a real respirator designed to fit well
and to remove a large percentage of airborne particulate contaminants. 
Don't use a medical or surgical mask since there is no requirement for
these to be NIOSH certified, and they are just not designed for an
industrial environment.  All NIOSH-certified filtering facepieces are
REAL RESPIRATORS, and will be much more effective than a surgical mask or
a shirt wrapped around a person's face.


These filtering facepieces are designed to be reuseable, within
reasonable limits, so a new one would probably not be required each day
or each shift.  The carrying of such devices by workers, to be used in
case of a release, is certainly ALARA, and the upcoming revision of
Subpart H would require that ALARA be the determining factor for
assigning (or not assigning) respirators to workers.  Professional
discretion would also be given a lot of weight in NRC's new scheme.


As a point of clarification, the term HEPA is not and never was applied
to respirator filters.  Under NIOSH's old rule (30 CFR 11) dust-fume-mist
respirators were required to be 99.97% efficient at collecting 0.3 micron
particles generated by hot DOP, but the term HEPA is not found.  NIOSH
now permits the use of NaCl and non-thermally generated DOP to test
filter media, since hot DOP presents an exposure problem to the test
equipment operators.


The NRC's proposed new table of assigned protection factors (APFs) are
consistent with those listed in ANSI Z88.2-1992.  While these may be
conservative, there is potentially a vast difference between quality of
fit obtained during fit testing and average quality of fit maintained in
the workplace.  The efficiency of the filter medium isn't the problem. 
It's the face-to-facepiece seal that is the weak link, and in the
workplace average fit factors (when they can be measured) are often
dramatically lower than those obtained during fit testing.  NRC's new
rule would contain clear guidance on what constitutes an acceptable fit
before the APF can be applied in the field.


Further input from Radsafers on this and related topics would be most
welcome.


K. Paul Steinmeyer, RRPT

Senior Health Physicist


************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html
************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html