Respiratory Protection
Respirators protect your lungs from dust, fumes, vapors and gases, but only when they are the right type, fit your face, and are part of a proper respiratory protection program.
- Construction
- General Industry
Common respirator types
| Type | Good for | Notes |
|---|---|---|
| Filtering facepiece (N95, P100 disposable) | Dusts and particles | No protection from gases or vapors |
| Half-face elastomeric with filters or cartridges | Particles, and with the right cartridges, some vapors and gases | Reusable; must match cartridge to hazard |
| Full-face elastomeric | Higher protection; also protects the eyes | Higher assigned protection factor |
| PAPR (powered air-purifying) | Long wear, hot conditions, some workers with beards (loose-fitting hoods) | Battery-powered blower |
| Supplied-air or SCBA | Oxygen-deficient or immediately dangerous atmospheres | Special training required |
Assigned protection factors
An assigned protection factor (APF) tells you how much a properly fitted respirator reduces exposure. An APF of 10 means the air inside should have no more than one-tenth of the contaminant outside.
| Respirator | APF |
|---|---|
| Filtering facepiece (N95) or half-face elastomeric | 10 |
| Loose-fitting PAPR hood or helmet | 25 |
| Full-face elastomeric | 50 |
| Half-face PAPR | 50 |
| Full-face PAPR | 1,000 |
| SCBA, pressure-demand, full face | 10,000 |
Some substance rules, like silica, lead and asbestos, also say which respirators to use at which exposure levels.
Filters and cartridges
- Particle filters are rated N, R or P (N = not resistant to oil, R = oil-resistant, P = oil-proof) and 95, 99 or 100 (percent of particles filtered). A P100 filter (usually magenta) is common for silica, lead and asbestos.
- Gas and vapor cartridges must match the chemical, such as organic vapor (often black), acid gas (often white) or ammonia (often green). Combination cartridges cover several hazards.
- Cartridges don’t last forever. Follow the change schedule your employer sets. Don’t wait until you smell the chemical.
Danger: Air-purifying respirators (N95s, cartridge respirators, PAPRs) do not supply oxygen. Never use them in oxygen-deficient atmospheres or confined spaces with unknown air. See Confined Spaces.
When a respirator is required
When your employer requires respirators, it must have a written respiratory protection program that includes:
- A medical evaluation before you are fit tested or use a respirator
- A fit test before first use, whenever you change models or sizes, and at least every year
- Training on use, limitations, inspection, cleaning and storage
- The right respirator and cartridges for the hazard, and a cartridge change schedule
User seal check: every time you put it on
- Negative pressure: cover the cartridges or filter inlets and inhale gently. The facepiece should collapse slightly and stay that way.
- Positive pressure: cover the exhalation valve and exhale gently. The facepiece should bulge slightly without air leaking around the edges.
- If it leaks, adjust the straps and try again. Don’t use a respirator that won’t seal.
Facial hair: Tight-fitting respirators cannot be worn if facial hair (including stubble) comes between the seal and your face. Loose-fitting PAPR hoods may be an option.
Care and storage
- Inspect before each use: facepiece, straps, valves, gaskets and cartridges.
- Clean reusable respirators after use, following the manufacturer’s instructions, and let them dry.
- Store in a clean bag or container, away from dust, sunlight, heat and chemicals, so the facepiece doesn’t get deformed.
- Throw away disposable respirators that are damaged, dirty, wet or hard to breathe through.
- Don’t share respirators.
- Don’t hang it around your neck or toss it on the dashboard between uses.
- Don’t tape over leaks or modify the straps.
Voluntary use
If you choose to wear a dust mask when it isn’t required, your employer must give you the information in Appendix D of the respirator standard. For voluntary use of an elastomeric respirator, a medical evaluation is still required.
Standards & references
- 29 CFR 1910.134: Respiratory protection (also applies to construction via 1926.103)
- 1910.134 Appendix D: Information for voluntary use
- NIOSH: Respirator approvals (NPPTL)
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