Prepared by CPWR the Center for
Construction Research and
Training
An Overview of Air-Purifying Respirators
CPWR research project
The hierarchy of controls has underpinned industrial hygiene control efforts for a long timeElimination
Substitution
Modification
Containment
Ventilation
Work Practices
PPE
More reliance on workers
Is there an OSHA standard for respirators?• Yes!• General Industry 29 CFR 1910.134• Construction: 29 CFR 1926.103• Respiratory regulation may be
contaminant specific
What is required in a written respiratory protection program?• Respirator selection• Medical evaluation• Fit testing• Proper procedures for routine and
emergency use• Proper inspection, cleaning,
maintenance, and storing• Training• Program evaluation
Full-face half-face
Respirators can be divided based on facial coverage
A key difference is the pressure inside the mask when inhaling
Negative pressure Positive pressure
Powered air purifying respirators filter air, but keep a positive pressure in the face-piece
PAPRs with tight fitting facepiece PAPR with loose fitting hood
PAPR with loose fitting facepiece
for welding
Air purifying respirators filter out dusts AND vapors
Must have the correct color-coded cartridge and
it must be NIOSH-approved
Cartridges to protect against silica exposures are magenta
Color Type Protection against
Magenta, purple
High Efficiency Particulate Air (HEPA)
Silica dust, asbestos fibers, lead particles
BlackOrganic vapor Solvents
YellowOrganic vapor and acid gases
Brick cleaners
NIOSHs categories of particulate filters are based on oil mist degradation
•Not resistantN•ResistantR
•Protective against P
Particulate filters are further classified base on efficiency• 95 percent, designated 95• 99 percent, designated 99• 99.97 percent, designated
100 (HEPA filter)
This gives 9 categories of particulate respirators
N R P100 100 10099 99 9995 95 95
Method of particle capture
Courtesy Roland Berry Ann, NIOSH
What is the most penetrating particle size?
Particle diameter
Effi
cien
cy
Courtesy Roland Berry-Ann, NIOSH
OSHA requires that workers pass a fit test before wearing a respirator
PortaCount Quantitative Fit Testing SystemCourtesy TSI, Inc.
Quantitative Qualitative
Allegro Complete Smoke Fit Test Kit Photo Courtesy Gempler’s
User seal checks must be performed before each use
Negative pressure check Positive pressure check
Image courtesy IUOE Hazmat Program and Robert Harrold
Storage and maintenance of respirators are often neglected
• Follow manufacturers recommendations• Use warm water and mild soap• Air dry
Cleaning is important and easy
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