U.S. Department of Labor
Process: Surface Preparation and Preservation
Respirators protect the lungs and upper respiratory track from dust, mists, fumes, and vapors that are associated with cleaners and residues. Worker illness may result from:
- Inhalation exposure to toxic or corrosive chemicals.
- Exposure to oxygen-deficient atmospheres.
- Exposure to dust (such as silica, lead, and chromate).
There are two major classes of respirators:
- Air-purifying, which remove contaminants from the air.
- Atmosphere-supplying, which provide clean, breathable air from an uncontaminated source. As a general rule, atmosphere-supplying respirators are used for more hazardous exposures.
Air-purifying respirators use filters or sorbents to remove harmful substances from the air. They range from simple disposable masks to sophisticated devices. They do not supply oxygen and must not be used in oxygen-deficient atmospheres or in other atmospheres that are immediately dangerous to life or health (IDLH).
Atmosphere-supplying respirators are designed to provide breathable air from a clean air source other than the surrounding contaminated work atmosphere. They include supplied-air respirators (SARs) and self-contained breathing apparatus (SCBA) units. The breathing air must meet at least the requirements for Grade D breathing air described in ANSI/Compressed Gas Association Commodity Specification for Air, G-7.1-1989, to include: oxygen content of 19.5-23.5%; hydrocarbon (condensed) content of 5 milligrams per cubic meter of air or less; carbon monoxide (CO) content of 10 ppm or less; carbon dioxide content of 1,000 ppm or less; and lack of noticeable odor (1910.134(i)(1)(ii)(A) through (E)).
Choosing the right equipment involves:
- Determining what the hazard is and its extent.
- Considering user factors that affect respirator performance and reliability.
- Selecting an appropriate NIOSH-certified respirator. Equipment must be used in accord with specifications accompanying the NIOSH certification.
When selecting respirators, employers must consider the chemical and physical properties of the contaminant, as well as the toxicity and concentration of the hazardous material and the amount of oxygen present. Other selection factors include the nature and extent of the hazard, work rate, area to be covered, mobility of the worker, work requirements and conditions, as well as the limitations and characteristics of the available respirators.
The time needed to perform a given task, including the time necessary to enter and leave a contaminated area, is an important factor in determining the type of respiratory protection needed. For example, SCBAs, gas masks, or air-purifying chemical-cartridge respirators provide respiratory protection for relatively short periods. On the other hand, an atmosphere-supplying respirator that supplies breathable air from an air compressor through an air line can provide protection for extended periods.
If the total concentration of atmospheric particulates is low, particulate filter air-purifying respirators can provide protection for long periods without the need to replace the filter. Where there are higher concentrations of contaminants, however, an atmosphere-supplying respirator such as the positive-pressure SAR offers better protection for a longer period. SARs eliminate the need for concern about filter breakthrough times, change schedules, or using end-of service life indicators (ESLI) for airborne toxic materials, factors that must be considered when using air-purifying respirators.
Another factor to consider when using respirators is the air-supply rate. The wearer’s work rate determines the volume of air breathed per minute. The volume of air supplied to meet the breathing requirements is very significant when using atmosphere-supplying respirators such as self-contained and airline respirators that use cylinders because this volume determines their operating life.
For additional information on respiratory protection program requirements; use of respirators; air monitoring for exposures; selection of respirators; employee training; fit testing of respirators; inspection and maintenance of respirators; medical evaluation of workers using respirators and breathing air requirements, see the following:
To prevent the inhalation of hazardous substances, respirators must form a complete seal. A complete seal prevents airborne contaminants in the work environment from seeping into the mask around the edges and being inhaled or contacting the skin.
Facial hair can break the respirator seal, allowing hazardous material to enter the respirator where it may be inhaled or make contact with the skin. Full beards and goatees are not the only facial hair that can create this risk. Even a single day of facial hair growth can create gaps in the respirator seal.
Workers assigned to perform tasks requiring full- or half-face respirators must be clean shaven in order to have an effective seal.
Seal areas must be free of hair
Seal areas must be free of hair
F-38, F-39, F-40