Respirator
Filters
Respirator Filters
Certification requirements from NIOSH are about to
change
New rules will upgrade respirator
filters
and provide better protection
and provide better protection
The use of respiratory protection against airborne particles such as silica, asbestos, and lead is common in construction.
Currently the particulate filters used on half-mask and full-face respirators are broken down into dust/mist, dust/mist/fume, and HEPA cartridges.
This system is about to change. Until recently, certification requirements for respirator filters in the United States have been set by the National Institute for Occupational Safety and Health (NIOSH) and the Department of Labor/Mine Safety and Health Administration (MSHA). These standards have been referenced in Canadian codes and regulations.
NIOSH now has exclusive authority to test and certify respirators (except for certain mine emergency devices) and has revised the rules determining which types of filters manufacturers can have certified.
The new rules will upgrade respirator filters and provide better protection against all sizes of particulate in the workplace.
The new certification categories apply only to non-powered, air-purifying, particulate-filter respirators.
Filter series
Under the new particulate filter rules, there will be three series of filters: N, R, and P. The N filters are Not resistant to oil; the R filters are Resistant to oil; and the P filters are oil Proof.
The N series of filters is appropriate for airborne particles such as silica or lead, when there are no oil-based products also in the air.
For example, an N series filter would be recommended during the removal of old lead paint. However, for spraying an oil-based lead paint, an R or P series filter would be recommended as protection against the airborne mist of oil-based solvent.
The R series (resistant to oil) should only be used for a single shift when solvent or oil mist is present in the air. This filter resists oil but may break down in contact with oil or solvent over a long time.
When using P series filters, check the manufacturer's instructions to determine how long the filter can be used when airborne particles are present. NIOSH originally thought that P series filters were oil-proof but recent tests have found there may be some breakdown of the filter material with long-term oil exposure.
Note: N, R, and P filters do not provide protection against organic vapours.
Filter efficiency
N, R, and P series respirators have three levels of filter efficiency: 95%, 99%, and 99.97%.
The new filters will be identified by their series letter and by their efficiency percentage.
For example, the P series respirators include P95, P99, and P100 filters. The P100 filter is the same as a HEPA filter and is likewise coloured magenta.
Filter selection
How do these changes in classification affect the selection of respiratory protection?
For jobs involving airborne oil mist or organic solvent mist, R or P series filters should be used. For jobs such as the removal of asbestos or lead paint, where HEPA-filtered respirators are recommended, the 100 class should be used.
Generally, for toxic particulates in extremely fine particles, the 100 class of filter should be used.
NIOSH recommends the 95% efficient filters where dust/mist filters were formerly used; and the 99% efficient respirators where dust/mist/fume respirators were used.
For example, an N95 filter would provide adequate protection from fine particles such as wood dust and limestone dust in most applications.
For welding mild steel the N99 is recommended because the airborne particles are extremely fine but not too toxic.
Already available
Although the new classifications do not come into effect until July 1998, many manufacturers already have new certified filters on the shelves.
The new filters can be identified by the new lettering and number system (P95, for example) and by the replacement of the MSHA logo with the Department of Health and Human Services logo on the certification label.
The revised classifications provide a long overdue upgrading of the filter testing and certification process and should lead to improved respiratory protection for construction workers.
New Filter Classes certified
by NIOSH
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(% at .3 micrometer) |
Suitable for | ||
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All particulate (airborne solids) where no oil or solvent is in the air | ||
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Extremely fine and very toxic particles when no oil or solvent is in the air | ||
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Very fine particulate when no oil or solvent is in the air | ||
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Fine particulate when no oil or solvent is in the air | ||
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Resistant to oil but should not be used more than one shift. (Note: these filters do not provide protection from organic vapours) | ||
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Extremely fine and very toxic particulate when oil or solvent is also in the air | ||
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Very fine particulate when oil or solvent is also in the air | ||
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Fine particulate when oil or solvent is also in the air | ||
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Oil-Proof. However, check manufacturer's recommended service life when oil aerosols are present. Long-term exposure to oil may lead to degradation. (Note: these filters do not provide protection from organic vapours) | ||
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Extremely fine and very toxic particulate when oil or solvent is also in the air | ||
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Very fine particulate when oil or solvent is also in the air | ||
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Fine particulate when oil or solvent is also in the air | ||
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