Flow rates (a) and leakage volumes (b) for the 3M Breathe-Easy PAPR shown in the previous figure. The time scale has been compressed to show effects of blower and breathing machine activity. The blower was turned on at the 10-second mark, the breathing machine was turned on at 20 seconds, and the blower was turned off at 40 seconds. The negative blower flow before and after the blower was turned off demonstrates that air was being forced backward through the blower and filter. No clay was used to seal the periphery.
