Correction factors for assessing immersion suits under harsh conditions

Area of Science:

• Marine safety
• Protective clothing technology
• Human physiology

Background:

• Immersion suit standards often use calm water testing, which doesn't reflect real-world harsh conditions.
• Suits may underperform in challenging environments, posing risks to users.
• Realistic testing is expensive and logistically difficult.

Purpose of the Study:

• Develop correction factors for immersion suit insulation testing.
• Enable accurate assessment of suit protection in calm water for harsh conditions.
• Ensure adequate thermal protection for users in adverse marine environments.

Main Methods:

• Conducted two immersion studies: one dry and one with 500 mL of water inside the suit.
• Simulated harsh conditions using wind and waves to measure insulation changes.
• Calculated minimum required thermal insulation based on physiological limits and suit insulation.

Main Results:

• Wind and waves significantly reduced immersed insulation compared to calm water.
• Identified multiplicative correction factors: 1.37 for wind/waves, 1.25 for wetness, and 1.72 for combined conditions.
• Established an equation for minimum in-situ suit insulation in dry, calm conditions.

Conclusions:

• Calm water certification needs to account for real-world conditions.
• Correction factors are essential for realistic minimum insulation requirements in harsh environments.
• Applying these factors ensures immersion suits provide sufficient thermal protection during cold water emergencies.