Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Agricultural and Biological Engineering

First Advisor

William E. Field

Committee Chair

William E. Field

Committee Member 1

Klein E. Ileleji

Committee Member 2

Eric A. Nauman

Committee Member 3

Charles V. Schwab

Committee Member 4

Richard L. Stroshine


Grain entrapments and engulfments are one of most common hazards associated with grain storage facilities. Since the 1970’s over 1,880 incidents have been documented in agricultural confined spaces of which 65% of all recorded incidents were grain entrapments and engulfments. There have been several studies conducted on the contributing factors behind these incidents; however, there have been very few attempts to understand the environmental, physiological or psychological factors the victims experience while entrapped, engulfed, or extricated. This includes understanding how secondary injuries are caused by grain or during extrication by first responders. The research effort was divided into three segments. The first segment is a literature review to identify and better understand the environmental, physiological and psychological stresses that an individual might be exposed to during grain entrapment, engulfment or extrication. The second segment expands upon previous studies that involved vertical pull tests (Schwab, Ross, Piercy, McKenzie, & B.A, 1985; Roberts, Field, Maier, & Stroshine, 2015) by testing forceful extrication attempts under a wider set of variables, including different types of grains (corn, popcorn, wheat, oats, soybeans, canola seeds and sunflower seeds), depths of entrapment, pull angles (15°, 30°, 45°, 60°, and 75°), limb placement and grain moisture content (corn only). With the exception of the pull angle test, these experiments were conducted only in a small scale setting. Pull angle tests were conducted in a full scale setting using a full sized mannequin (185 lb) in corn and soybeans. This is an important study since grain bin roofs are not generally designed for 5,000 lb anchor points. In addition, the tensile force limits of a sheep spine were tested and compared to the force needed to extricate a mannequin. The third segment focused on measuring the actual pressure that a victim might experience by pushing wooden plates against grain (simulating a rib cage pushing against the grain) and measuring the force. These experiments also focused on localized forces on the spine and limbs and estimating forces generated when a test mannequin is extricated at different angles. The literature review provided a total of eleven factors that negatively impact a victim’s ability to survive a grain entrapment. The most important factor was asphyxiation (which includes aspiration, crush asphyxiation and postural asphyxiation). In 33 cases where the cause of death was medically reported, 63% cited asphyxiation. Another factor of notable importance is psychological, where it was found that stress could cause shortness of breath and chest pain and thus could be a contributing factor in death. In the extrication segment of the research, it was found that high moisture content could increase extrication forces by 39%. In addition, while shallow angles of pull did not significantly impact extrication force, pulling a victim at angles sharper than 45o degrees increased extrication forces by 22-44%. Lastly, the author found that the maximum tensile force that a spine can handle (1.65-2.48 kN) was in the same range of forces required to extricate a victim from between waist and shoulder depth. In the third segment of research, the author found that passive pressure on the victim was about four times larger than active pressure, thus a victim will experience four times more pressure in grain (while attempting to breath) than what a load cell measures. In conclusion, the best strategy to prevent or reduce the severity of injuries associated with grain entrapments remains prevention through compliance with accepted best workplace practices and current workplace safety regulations. It was determined that 94% of all grain entrapment and engulfment incidents were preventable. Regarding methods of victim extrication from grain entrapment it was concluded that there is a real and possible risk of causing secondary injuries, including spinal injury, if force is used to pull the victim from the grain. Reducing the pressure on the victim by removing the grain from around the victim is strongly recommended unless there are other significant medical issues that might reduce the likelihood of survival if extrication is not expedited.