665 HAZWOPER for General Site Workers VI

Combination SCBA/SAR

A relatively new type of respiratory protection is available which uses a regulator to combine the features of an SCBA with an SAR. The user can operate the respirator in the SCBA or SAR mode, through either the manual or automatic switching of air sources.

The Combination SCBA/SAR respirator allows entry into and exit from an area using the self-contained air supply, as well as extended work periods within a contaminated area while connected to the air line.

The Combination SCBA/SAR respirator is appropriate for sites where workers must travel an extended distance to a work area within a hot zone and remain within the area for relatively long work periods (e.g., drum sampling). In these situations, workers enter the site using the SCBA mode, connect to the air line during the work period, and shift back to the SCBA mode to leave the site.

The combination SCBA/SAR should not be confused with an SAR with escape provisions. The primary difference is the length of air time provided by the SCBA;

• the combination system provides up to 60 minutes of self-contained air, whereas
• the escape SCBA contains much less air, generally enough for only 5 minutes.

NIOSH certification of the combination unit allows up to 20 percent of the available air time to be used during entry, while the SAR with escape provision is certified for escape only.

Questions to ask. Key questions to ask when considering SAR use are:

• Is the atmosphere IDLH or likely to become IDLH? If yes, an SAR/SCBA combination or SCBA should be used.
• Will the hose significantly impair worker mobility? If yes, the work task should be modified, or other respiratory protection should be used.
• Is there a danger of the air line being damaged or obstructed (e.g., by heavy equipment, failing drums, rough terrain, or sharp objects) or permeated and/or degraded by chemicals (e.g., by pools of chemicals)? If yes, either the hazard should be removed, or another form of respiratory protection should be used.
• If a compressor is the air source, is it possible for airborne contaminants to enter the air system? If yes, have the contaminants been identified and are efficient filters and/or sorbents available that can remove those contaminants? If no, either cylinders should be used as the air source or another form of respiratory protection should be used.
• Can other workers and vehicles which might interfere with the air line be kept away from the area? If no, another form of respiratory protection should be used.

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