Service Life 4 : The (SAR) or airline respirator means an atmosphere-supplying respirator for which the source of breathing air is not designed to be carried by the user
University of California (Environmental Health & Safety), Safety & Industrial Hygiene Glossary of Terms, Riverside, CA, USA 2010. http://ehs.ucr.edu/safety/glossary.html, (IndHygS - Amer) {500}