April 24, 1986
Mr. G.T. Slay
Martin Marietta Energy Systems, Inc.
Post Office Box P
Oak Ridge, Tennessee 37831
Dear Mr. Slay:
This is in response to your letter of March 12, concerning air line
couplings used in a supplied air respirator (SAR) system.
The Occupational Safety and Health Administration (OSHA) respiratory
protection standard states that
"Air line couplings shall be incompatible with outlets
for other gas systems to prevent inadvertent service of air line
respirators with nonrespirable gases or oxygen,"
(Correction 11/24/98) ["The employer shall ensure that breathing air
couplings are incompatible with outlets for nonrespirable worksite air or other gas systems.
No asphyxiating substance shall be introduced into breathing air lines,"] 29 CFR 1910.134[(i)(8)].
The intent of this standard is to prevent the inhalation of gases other than
breathing air by the
SAR wearer. If there is a likelihood that the breathing air may be contaminated or replaced
with toxic gases, a separate air line for transporting breathing air is required.
There would be a violation of the standard if the breathing air and other
toxic gases are transported through with the same system.
We hope we have addressed your concern.
Edward J. Baier
Directorate of Technical Support