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 time

Elimination

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 resistant

N

•Resistant

R

•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 100 100

99 99 99

95 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

Bruce Lippy, Ph.D., CIH, CSPCPWR’s Director of Safety Researchblippy@cpwr.com301-495-8527 (direct line)

Questions?