Development of a speech amplifier system for use with the Navy A4 oxygen breathing apparatus and a proposed firefighting instructor's breathing device

The purpose of the program was to design, develop and fabricate a mask communication system for use with the A4 Oxygen Breathing Apparatus (OBA) and a modified Bio-Pak 45 Breathing Apparatus. The latter device has been proposed as a Navy Firefighting instructor's breathing apparatus. Firefighters and other Navy Damage Control personnel, who are required to wear breathing devices, are severely limited in their work effectiveness due to inadequate communications. The masks they are required to wear degrade the speech to such an extent that it is unintelligible, especially in the high ambient noise environments inherent with their work. In these high noise levels, the voicemitters in the masks are completely ineffective. A communication system was developed that gives a speech projection capability to the wearer, permitting a high degree of aural intelligibility over extended distances, in high ambient noise environments.