Physiological Responses to Wearing the Helicopter Aircrew Integrated Life Support System (HAILSS) in Hot Environments
Abstract
Individuals wearing encapsulating garments require auxiliary cooling systems to sustain physical and cognitive performance when exposed to high temperatures or workloads. The Helicopter Aircrew Integrated Life Support System (HAILS S) is designed to minimize thermal problems by incorporating normal flight suit functions with protective functions (fire, chemical and biological warfare (CBW), and cold water immersion) in a single, integrated clothing ensemble. This study evaluated the effectiveness of the HAILSS cooling concept by comparing heat loads incurred while performing up to 6 hi of physical work in either HAILSS or the current A/P22P-9(V) CBW protective ensemble. This study exposed seven test subjects (six male, one female) to six experimental trials each. Subjects wore the HAILSS (h20, h75) and CB (m20, HAILSS% N" 75" 35" a) Need for head ventilation b) Airflow though breathing valve adequate but saliva a problem, "mouth too were M.L.nt moderate physical work (40% of an individual's maximum oxygen uptake) and cognitive tasks. In addition, each subject had one exposure using HA%S without the chemical protective AR-5 hood (h75n) and another employing HAILSS with cooled ventilation air (24C inlet air temperature) (h75c) in the hot/humid condition. Test results indicated 20% RH trials lasted significantly longer (p<O.Ol) and were significantly less stressful (p<O.O5) than 75% RH trials based on various physiological parameters. Increasing heat removal by ancillary cooling brought the level of heat strain experienced in the HAILSS assemble at 75% RH to roughly that of Mk 1 or HAILSS at 20% RH. HAILSS or Mk I without ancillary cooling was demonstrably more stressful to wear at 75% RH than at 20% RH. Operational mission performance would likely degrade at this higher RH without active cooling. These results demonstrate that ambient relative humidity significantly affects heat removal even in totally encapsulated protective clothing ensembles.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 08, 2000
- Accession Number
- ADA381402
Entities
People
- B. S. Shender
- G. K. Askew
- J. W. Kaufman
- K. Farahmand
- L. Schaaf
Organizations
- Naval Air Warfare Center