Survival suit volume reduction associated with immersion: implications for buoyancy estimation in offshore workers of different size.

AbstractRationale: It is currently unknown how body size affects buoyancy in submerged helicopter escape. Method: Eight healthy males aged 39.6 ± 12.6 year (mean ± SD) with BMI 22.0–40.0 kg m−2 wearing a standard survival (‘dry’) suit undertook a normal venting manoeuvre and underwent 3D scanning to assess body volume (wearing the suit) before and after immersion in a swimming pool. Results: Immersion-induced volume loss averaged 14.4 ± 5.4 l, decreased with increasing dry density (mass volume−1) and theoretical buoyant force in 588 UK offshore workers was found to be 264 ± 46 and 232 ± 60 N using linear and power functions, respectively. Both approaches revealed heavier workers to have greater buoyant force. Discussion: While a larger sample may yield a more accurate buoyancy prediction, this study shows heavier workers are likely to have greater buoyancy. Without free-swimming capability to overcome such buoyancy, some individuals may possibly exceed the safe limit to enable escape from a submerged heli...