A Mixed-Gas Control System for an Environmental Chamber
Abstract
In order to simulate the expected environmental conditions in a submarine that has become disabled (i.e., loss of electrical power and subsequent inability to control temperature, humidity, and oxygen and carbon dioxide levels), a system was created to control the oxygen and carbon dioxide concentration of an environmental chamber. The study protocol called for a baseline testing period of ambient environmental conditions for 2 days (20 deg C, 50% RH, 20.93% O2, 0.04% CO2), followed by a 24-hour transition phase to the disabled conditions (4 deg C, 80% RH, 16.75% O2, 2.50% CO2), which where maintained for 5 days. Due to numerous design factors, the hypobaric chamber facility was chosen to conduct this study, since the facility met all of the needs of the study except for the ability to control oxygen and carbon dioxide levels, which none of the institute's chambers are normally capable of. Reduced oxygen content was achieved by displacement with nitrogen, and increased carbon dioxide content was achieved by injection of 100% carbon dioxide and metabolic carbon dioxide production. The oxygen and carbon dioxide content of the chamber was continually monitored and controlled by a custom designed software system. During the 5 day 'disabled' portion of the study, chamber conditions were as follows: temp 4.51 +/- 0.56 deg C; relative humidity 80.48 +/- 5.27% RH; oxygen 16.73 +/- 0.06% and carbon dioxide 2.49 +/- 0.04%. Variations in temperature, oxygen and carbon dioxide levels, as indicated by the standard deviation, were all within desired limits (+/- 1.0 deg C; +/- 0.10% concentration). Relative humidity was outside the desired limit of +/- 3.0% R.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2001
- Accession Number
- ADA390457
Entities
People
- David W. DeGroot
- Laurie A. Blanchard
Organizations
- United States Army Research Institute of Environmental Medicine