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Particulate Respirators, 42 CFR Part 84

Air-purifying particulate respirators are currently being tested under the guidelines set forth in 42 CFR Part 84, which became effective July 10, 1995.

Filters that have been tested per 42 CFR Part 84 are recognizable by a sequence of approval numbers for non-powered particulate respirators.The approval number will be TC-84A-XXXX. All particulate respirators approved under Part 84 will have a certification label bearing the NIOSH and the Department of Health and Human Services (DHHS) emblems.

Prior to early 1995, HEPA filters were the only filters approved for protection against tuberculosis (TB), which was costly to the health care industry. With Part 84, industries are now able to choose a lower cost respirator which provides appropriate protection. Under the test guidelines, workers exposed to TB can use the N95 series which is more affordable and provides the necessary protection.

Particulate respirators fall into nine different classes. They have three levels of filter efficiency (95, 99 and 99.97%) and three categories of filter degradation (N, R and P). All nine classes filter the same particle size (0.3 micrometers aerodynamic mass median diameter).

The following chart shows the filter classes certified under 42 CFR Part 84.

¹NIOSH will be conducting and encouraging other researchers to conduct studies to assure that these service time recommendations are adequate. If research indicates the need, additional service time limitations may be recommended by NIOSH for specific workplace conditions.

²NaCI = sodium chloride

³Limited by considerations of hygiene, damage and breathing resistance.

⁴High (200mg) filter loading in the certification test is intended to address the potential for filter efficiency degradation by solid or water-based (i.e., non-oil) aerosols in the workplace. Accordingly, there is no recommended service time limit in most workplace settings. However, in dirty workplaces (high aerosol concentrations), service time should only be extended beyond 8 hours of use (continuous or intermittent) by performing an evaluation in specific workplace settings that demonstrates (a) that extended use will not degrade the filter efficiency below the certified efficiency level, or (b) that the total mass loading of the filter is less than 200 mg (100 mg per filter for dual-filter respirators).

⁵DOP oil = dioctyl phthalate

⁶No specific service time limit when oil aerosols are not present. In the presence of oil aerosols, service time may be extended beyond 8 hours of use (continuous or intermittent) by demonstrating (a) that extended use will not degrade the filter efficiency below the certified efficiency level, or (b) that the total mass loading of the filter is less than 200 mg (100 mg per filter for dual-filter respirators).

⁷The P100 filter must be color-coded magenta. The Part 84 Subpart KK HEPA filter on a PAPR will also be magenta, but the label will be different from the P100 filter, and the two filters cannot be interchanged.

Use Limitations

N, R and P designations dictate usage of the filter. N-series filters are "not resistant to oil," R-series filters are "resistant to oil" and P-series filters should be selected if there are oil aerosols (e.g. lubricants, cutting fluids, etc.) or non-oil aerosols in the workplace. N-series filters should be used only for non-oil aerosols (e.g. solid and water-based). The service life of all three filter categories (N, R and P) is limited by considerations of hygiene, damage and breathing resistance. All filters should be replaced whenever they are damaged, soiled or causing noticeable increased breathing resistance.

N-Series Filters
Generally, the use and repeated use of N-series filters is limited only by hygiene, damage and increased breathing resistance. However, when working in very dirty or dusty workplaces that may result in high filter loading (200 mg), service time should be limited to continuous or intermittent use of 8 hours unless an evaluation is done of the specific workplace setting to prove that extended use will not degrade the efficiency below the efficiency level of the specific respirator or that total mass loading of the filter does not exceed 200 mg.

R-Series Filters
The R-series should be only used for one working shift (or for 8 hours of continuous or intermittent use) when oil is present. Service time for R-series respirators can be extended using the same criteria as stated above (by doing an evaluation of the specific workplace setting and proving that extended use will not degrade the efficiency below the efficiency level of the specific respirator or that total mass loading does not exceed 200 mg).

These determinations for both N and R series would need to be repeated whenever conditions change or modifications are made to processes that could change the type of particulate being generated.

P-Series Filters
Use and reuse of the P-series filters is subject only to considerations of hygiene, damage and increased breathing resistance.

Selection

To select the correct respirator for protection against particulates, the following conditions must be known:

1. The identity and concentration of the particles in the workplace air.
2. The OSHA or MSHA permissible exposure limit (PEL), NIOSH-recommended exposure limit, or other occupational exposure limit for the contaminant.
3. The hazard ratio (HR) (i.e. the airborne particulate concentration divided by the exposure limit).
4. The Assigned Protection Factor (APF) for the class of respirator (the APF should be greater than the HR).
5. The immediately dangerous to life or health (IDLH) concentration, including oxygen deficiency (NIOSH 1994).
6. Any service life information available for combination cartridges or canisters.

Multiplying the occupational exposure limit by the APF for a respirator gives the maximum workplace concentration in which that respirator can be used. For example, if the commonly accepted APF for a half-mask respirator is 10 and the PEL is 5 milligrams per cubic meter, then 50 milligrams per cubic meter is the highest workplace concentration in which a half-mask respirator can be used against that contaminant. If the workplace concentration is greater than 50 milligrams per cubic meter, a more protective respirator (with a higher APF) should be used. In no case should an air-purifying respirator be used in IDLH atmospheres or in areas that are oxygen deficient, and you should never exceed the manufacturer's guidelines.

The selection flow chart below is from NIOSH:

Commonly Asked Questions

Sources for More Information

ISEA (Industrial Safety Equipment Association) User and Selection Guide

NIOSH Guide to the Selection and Use of Particulate Respirators Certified Under 42 CFR Part 84

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Please Note: The information contained in this publication is intended for general information purposes only. This publication is not a substitute for review of the applicable government regulations and standards, and should not be construed as legal advice or opinion. Readers with specific questions should refer to the cited regulation or consult with an attorney.