Escape from a submersible vehicle simulator wearing different thermoprotective flotation clothing.

BACKGROUND

Winter road workers, who drive heavy vehicles on ice-covered waterways, are at risk for ice failure and subsequent drowning in frigid water. Some workers who are recommended to wear thermoprotective flotation clothing are concerned that buoyancy or bulk may impede underwater exit.

METHODS

Using a simulator, 10 volunteers (2 women) compared everyday winter clothing (Control), a flotation Jacket and Overall, and an inflated inflatable personal flotation device (Inflated Vest). On each study day, all clothing conditions were tested in either Cool (20 degrees C) or Cold (8 degrees C) water conditions using a randomized balance design. After each trial, subjective ratings for thermal sensation and exit tasks along with exit task times were determined.

RESULTS

Exit task times were unaffected by clothing or water conditions. Compared to Control, the Inflated Vest was rated with higher exit task difficulty and impedance, while the Jacket and Overall were not (ratings for exit task difficulty and impedance in cold water were: Control, 'a little' and 'none'; Jacket, 'a little' and 'a little'; Overall, 'a little' and 'moderate'; and Inflated Vest, 'moderate' and 'moderate - a lot'). Finally, there was a training effect, with total exit times improving by 20% from trials 1-8 (12.3 to 9.8 s).

CONCLUSIONS

Results suggest that, compared to Control clothing, flotation Jackets and Overalls do not increase exit time or impede exit during egress from a submerged vehicle while providing thermoprotection and buoyancy in 20 degrees C and 8 degrees C water. The Inflated Vest created the most perceived exit impedance in comparison to Control.