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OSHA Hazard Information Bulletins
Concerning Portable Breathing Air Compressors


January 25, 1985

MEMORANDUM FOR:

REGIONAL ADMINISTRATORS

ATTN:

ARAs for Technical Support

THRU:

  • JOHN B. MILES
  • Director
  • Directorate of Field Operations

FROM:

  • EDWARD J. BAIER
  • Director
  • Directorate of Technical Support

SUBJECT:

  • Health Hazard Information Bulletin Concerning Portable Breathing Air Compressors

Recently, it has come to our attention that two respirator manufacturers are marketing approved supplied air respirators (SAR) equipped with portable air compressors as a source of air supply. These SARs are the Bullard "Free-air Air Pump" and the Willson "Ambient Air Breathing Apparatus" (information attached). They are used in many workplaces which do not have a compressed air supply.

Some questions were raised by our field offices concerning whether these air compressors would meet the requirements prescribed in the standard on respirator protection, 29 CFR 1910.134(d)(2)(ii). Since these devices have no air receiver to enable the respirator wearer to escape from a contaminated atmosphere in the event of a compressor failure, nor do they have an alarm to indicate compressor failure or overheating, or a high temperature alarm, they do not meet the requirements prescribed in the standard. If a receiver were installed in this type of compressor, the unit would lose its portability.

Under our current policy, supplied air respirators are not to be used in an atmosphere which is immediately dangerous to life or health (IDLH) unless it is equipped with a self-contained air supply for escape. If the use of these SARs is limited to non-IDLH conditions, the requirements for an air receiver and a compressor failure alarm may not be necessary, provided the wearer carries an escape respirator in the event of a compressor failure. Since these compressors are not oil lubricated, a high temperature alarm to indicate overheating or the presence of high levels of carbon monoxide may not be required.

In view of the fact that these SARS are operated in the positive-pressure mode, the portable supplied air respirator system could provide a high level of protection for employees engaged in operations such as asbestos removal or spray painting with isocyanate-containing paints. Use of these units should be encouraged despite the fact that they do not meet the requirements described above.

The Bullard "Free-air Air Pump" and the Willson "Ambient Breathing Apparatus" are acceptable provided the following requirements are met:

  1. These devices are not to be used in an atmosphere which is immediately dangerous to life or health.
  2. Air used for this equipment must be drawn from an uncontaminated air source. Suitable filters and sorbents shall be installed and maintained when the need arises.
  3. The air delivered by the compressor at the Breathing zone of the SAR wearer must meet the requirements of Grade D Breathing air as prescribed in 29 CFR 1910.134(i)(1)(ii).
  4. The respirator wearer must carry an additional air-purifying respirator (with appropriate sorbent or filter) for quick donning and escape from the contaminated atmosphere in the event of a compressor or SAR failure. Quantitative or qualitative fit testing shall be performed to select the facepiece which would provide adequate protection. The employee must be trained for quick donning of the escape respirator.
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