External Work of Breathing of Demand-Air Underwater Breathing Apparatus

Underwater breathing apparatus can be effectively evaluated by measuring the external work of breathing. This paper reviews the existing and the proposed standards for demand-air breathing apparatus and recommends improvements to the Bentley-Reimers criterion. An automated method of collecting data on the external work of breathing is also described along with test results of various demand-air breathing apparatus. The test and evaluation data in this paper support the proposed, modified Bentley-Reimers criterion.