Estimates of Victim Surface Area and Associated Extraction Force for Partial Entrapment in Grain

Abstract

HighlightsEight selected anthropometric landmarks were useful for estimating victim surface area and entrapment depth.Surface area estimates for a partially entrapped male victim ranged from 0.0716 to 2.7296 m2.Partial extraction force estimates for a male victim ranged from 0.29 to 3,693 N.Partial extraction force estimates were 18% greater on average when including the arm surface area than when not including the arms.Abstract. A prediction model for estimating extraction forces on entrapped victims was enhanced and modernized in 2018 from the original 1985 model. The prediction model was divided into two conditions based on the victim’s relative position to the grain surface. The first condition was when the victim is completely below the grain surface. The second condition was when the victim’s shoulders are above the grain surface; this condition is the focus of this research. A variable in the prediction model that changes with the depth of entrapment is the surface area of the victim. A sample of 60 male models was used to approximate the human surface area at optimal discrete positions selected based on visually identifiable anthropometric landmarks. The surface area estimates for those 60 partially entrapped male models ranged from 0.0716 to 2.7296 m2. Extraction forces for twelve partially entrapped male body types with various combinations of stature and body mass index were calculated. The extraction forces were calculated for conditions when the victim’s arms were raised (above the grain) and lowered (in the grain). Results from the prediction model showed that surface area contributed less to the partial extraction force for short underweight bodies than for tall extremely obese bodies. At the lower landmarks, i.e., medial malleolus (MM) and knee crease (KN), surface area did not contribute noticeably to the partial extraction force. The contribution of surface area was not noticeable until the victim was buried up to the crotch (landmark CR). Keywords: Farm safety, Grain entrapment, Prediction model, Rescue, Safety.