Interchanging air cylinders on emergency respirators

June 20, 1997

MEMORANDUM FOR: REGIONAL ADMINISTRATORS

FROM: JOHN B. MILES, JR., Director
[Directorate of Enforcement Programs]

SUBJECT: SCBA Cylinder Interchangeability

Recently it has come to our attention that some manufacturers are promoting their lower priced cylinders for use on other manufacturer's self-contained breathing apparatuses (SCBAs). They are also telling their customers that this practice is allowed by OSHA standards. This statement is misleading. Employers who use components from other manufacturers on respirator equipment are voiding the NIOSH approval for their respirators.
Two of OSHA's standards [1910.156(f)(1)(iv) and 1910.120(q)(3)(x)] do permit the use of other manufacturer's cylinders on self-contained breathing apparatuses (SCBA's), when deemed necessary to meet the tasks at hand. OSHA's concession to this practice is only intended to be granted in emergency, lifesaving situations.
An example of an allowed situation would be when several different emergency response organizations respond to a hazardous situation that requires the use of their SCBA's. As the cylinder supplies are depleted, the appropriate approved cylinder may not be available for a particular SCBA when a life-saving response is required. Rather than waiting until the appropriate cylinder is obtained, the responder is permitted to use another manufacturer's cylinder provided it meets the specifications of the respirator manufacturer and has the same capacity and pressure rating. Although this, temporarily, voids NIOSH approval, OSHA believes the interchangeability of air cylinders is important enough to life safety of fire brigade members to permit it. After the emergency, OSHA expects employers to return their SCBA's to their original NIOSH-approved condition.
In non-emergency situations, OSHA still expects SCBA's to be maintained and used in their approved condition.
I hope this clarifies OSHA's position on the interchangeability of cylinders on SCBA's. If you have any questions or concerns, please contact [the Office of Health Enforcement at 202-693-2190].
[Corrected 6/2/2005]