[The MA 1 B respirator. Apropos of an experiment involving 91,300 hours of function]

Description of the working principle and the characteristics of the Bennet MA 1 B respirator, which is of the release of volume type with electro-mechanical functioning. Study of the advantages and drawbacks. During an experiment involving 91,300 hours of utilization of 21 sets of apparatus, 12 breakdowns concerning a mechanical or electrical component were recorded. No incident in the functioning of the electronic part of the system of control or of surveillance was noted. The reliability of the apparatus appears on the whole to be satisfactory, taking into account its remarkable working posibilities.