Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 9621, 1995 Dec; :1-8
The performance of the CSE SR-100, Draeger OXY-K-Plus, Mine Safety Appliances (MSA) Portal-Pack, and the Ocenco M-20 self contained self rescuers was compared. The CSE SR-100, Draeger OXY-K-Plus, and MSA Portal Pack are 60 minute, one use only, chemically based self rescuers containing an oxygen generation and carbon-dioxide (CO2) absorbent bed. The Ocenco M-20 is a 10 minute compressed oxygen device with a CO2 absorbent bed. Inhaled levels of CO2 and oxygen, inhaled wet and dry bulb temperatures, and breathing pressures were monitored. The CSE SR-100 and Draeger OXY-K-Plus had the lowest levels of inhaled CO2. The MSA Portal-Pack has the largest breathing bag volume, over 40% larger than the next largest. It also had the lowest average wet and dry bulb temperatures. The Ocenco M-20 had the highest average wet and dry bulb temperatures. The investigators note that large breathing bags with large surface areas can disperse heat well if the environment is cool. However, if the ambient temperature is high, this heat exchange mechanism can work in reverse. In addition, whereas large breathing bags enable to user to use more of the oxygen produced by the apparatus than would otherwise be purged in apparatus with smaller breathing bags, they increase the chances for the occurrence of hypoxia. Compressed oxygen apparatus are more susceptible to this phenomenon than pure KO2 apparatus which through overproduction of oxygen tend to purge the breathing circuit of nitrogen. The Draeger, MSA and Ocenco devices were also subjected to heat, cold, shock, and vibration to determine their survivability in the underground mining environment. No significant effects were observed.
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 9621