Fluid replacement advice during work in fully encapsulated impermeable chemical protective suits

Area of Science:

• Occupational Health
• Environmental Physiology
• Protective Equipment Performance

Background:

• Responders to hazardous materials (HazMat) incidents face heat strain from impermeable protective suits.
• Dehydration is a significant health concern for HazMat responders due to fluid loss within these suits.

Purpose of the Study:

• To quantify fluid loss in HazMat responders wearing Level A suits under various environmental conditions.
• To assess the impact of different climates and walking speeds on thermal strain and dehydration.
• To establish hydration guidelines for HazMat responders to mitigate hypohydration risks.

Main Methods:

• Human subject trials involving 17 firefighters and 24 students (ages 25-51) were conducted.
• Six Level A HazMat suits were tested across moderate, warm-wet, and hot-dry climates.
• Subjects walked at speeds of 2.5, 4, and 5.5 km/hr, with weight loss data collected to determine fluid loss.

Main Results:

• Fluid loss ranged from 0.2 to 2.2 liters, with an average of 0.8 liters across all experiments.
• 56% of the data indicated fluid loss between 0.5 and 1 liter.
• Working times varied from 20 minutes (hot-dry) to 60 minutes (moderate climate).

Conclusions:

• Drinking 0.7 liters per hour is suggested to hydrate over 50% of responders after one work-rest cycle.
• Implementing this hydration strategy significantly reduces the risk of hypohydration compared to no fluid intake.
• These findings provide crucial data for developing effective hydration protocols for HazMat responders.