An EBA system is provided which includes a primary source of pressurized air, a secondary source of pressurized air, hoses leading the primary and secondary sources of pressurized air to an EBA valve, and two hoses for directing pressurized air to the interior of a protective suit for over-pressurization...http://www.google.com/patents/US5293864?utm_source=gb-gplus-sharePatent US5293864 - Emergency breathing apparatus
