A respirator that provides breathing air from a source independent of the surrounding atmosphere. There are two types: air-line and self-contained breathing apparatus
US Department of Labor, Glossary of Terms - Occupational Safety & Health Administration, OSHA Office of Training and Education, Construction Safety and Health Outreach Program, Washington, D.C., USA 1996. https://www.osha.gov/doc/outreachtraining/htmlfile s/hazglos.html, (OSHA/ Const - Amer) {614}