LEC8: Thermal Countermeasures Flashcards
Generally, countermeasures try to
- Reduce core temperature
- Reduce skin temperature
- Reduce heart rate
- Reduce the perception of fatigue
- Increase tolerance time
Pre-Cooling
Definite ↑ tolerance time
– Water-perfused suits
– Phase change vests
– Cool shower / baths
– Cool fluid ingestion
Pre-cooling
Cold water immersion is the (blank) method of pre-cooling
most effective
Pre-cooling
Ice slurry injestion has shown (blank) initial results
good
Pre-cooling
Cooling garments appear of (blank) efficacy, but this finding may be the result of suboptimal cooling protocols or inadequate study power.
limited
Cooling During Work Bouts
Microclimate Cooling Systems: Cooling systems under clothing
- Conductive cooling
- Liquid coolant
- Phase change materials
Microclimate Cooling Systems: Body Ventilation System
- Spacer garment + battery-powered blower
- ~ 2.3 kg extra mass, 2.33 m/s flow rate
Cooling During Work Bouts
Cool Vests
- Weight is approximately 5 kg
- Use water-based or phase-change cooling packs
- Effective time is up to 3 hr depending on environment and physical activity
Cooling During Work Bouts
Auxiliary cooling
Counteracting thermal strain with auxiliary liquid cooling
- work well
- cumbersome and require a power supply
Counteracting thermal strain with auxiliary air cooling
- less effective unless air flow is very high
- require power supply
Some cooling systems have very limited utility: phase-change systems: materials and fabrics
Cooling During Rest Pause
Types of Cooling Measures
- fan + water cooling (systems or “mister” devices for rehab in firefighting)
- Forearm Immersion
- Cranial cooling
Cooling During Rest Pause
Cranial Cooling
Practical, accessible, good blood flow, good option when it is not feasible to remove clothing
