Dirk E. Maier

Review of Entrapments in Bulk Agricultural Materials at Commercial Grain Facilities

Abstract Seventy-one cases of entrapment in various bulk agricultural materials at commercial grain facilities were identified during the period from 1969 through 1995 in 25 states and the province of Ontario. The present annual rate of five fatal entrapments in the commercial grain industry is estimated to be 4.3 per 10,000 facilities. While fatal entrapments appear to be relatively rare events compared to other work-related fatalities associated with the grain-handling industry, the morbidity of entrapment victims is extremely high. In fact, 92% of the complete entrapments identified resulted in a fatality. As with farm-related grain entrapments and suffocations, entrapments in commercial facilities tend to occur in the Corn Belt and involve out-of-condition grain, primarily corn. The data gathered in this study also suggest that employees become entrapped when they are circumventing safe work practices and that an employee working alone is unlikely to survive the entrapment. It is also clear that current injury surveillance mechanisms do not provide adequate information to develop comprehensive prevention and first response strategies for the commercial grain industry.

Summary of fatal entrapments in on-farm grain storage bins, 1966-1998.

For over 30 years, Purdue University has maintained a national database of agriculture-related entrapment cases that have occurred in loose agricultural material. At present, 391 documented fatal and non-fatal entrapments from the U.S. and Canada make up the Purdue University Agricultural Entrapment Database. In order to specifically study fatal cases of entrapments in grain bins located on farms, the database was reviewed, 181 cases were identified using specific criteria, and the results were summarized. Approximately five cases per year were identified between 1966 and 1998, representing 18 states and one Canadian province. Entrapments were generally reported more often in the top corn-producing states and during the months of November, December, January, March, and June. In 24% of the cases in which the victims age was known, the victims were younger than 16. Children and adolescents younger than 16 were more often fatally entrapped in June than in any other month. For cases in which the product was known, corn was the agent of injury in 53% of the cases and was frequently found to be out-of-condition. At the time of entrapment, victims were involved with bin unloading activities in 76% of the cases in which the activity was identified. These findings are being used to design new injury prevention strategies, including educational materials and recommendations for engineering controls that focus on primary causative factors.

Summary of Prior Grain Entrapment Rescue Strategies

Entrapment in flowable agricultural material continues to be a relevant problem facing both farmers and employees of commercial grain storage and handling operations. While considerable work has been done previously on the causes of entrapment in grain and possible preventative measures, there is little research on the efficacy of current first response or extrication techniques. With the recent introduction of new grain rescue equipment and training programs, it was determined that the need exists to document and summarize prior grain rescue strategies with a view to develop evidence-based recommendations that would enhance the efficacy of the techniques used and reduce the risks to both victims and first responders. Utilizing the Purdue University Agricultural Entrapment Database, all data were queried for information related to extrication of victims from grain entrapments documented over the period 1964-2006. Also analyzed were data from other sources, including public records related to entrapments and information from onsite investigations. Significant findings of this study include the following: (1) between 1964 and 2006, the number of entrapments averaged 16 per year, with the frequency increasing over the last decade; (2) of all cases documented, about 45% resulted in fatality; (3) no less than 44% of entrapments occurred in shelled corn; (4) fatality was the result in 82% of cases where victims were submerged beneath the grain surface, while fatality occurred in 10% of cases where victims were only partially engulfed; (5) the majority of rescues were reported to have been conducted by untrained personnel who were at the scene at the time of entrapment; and (6) in those cases where the rescue strategies were known, 56% involved cutting or punching holes in the side walls of the storage structure, 19% involved utilizing onsite fabricated grain retaining walls to extricate partially entrapped victims, and the use of grain vacuum machines as a rescue strategy was on the increase. Among the recommendations growing out of the study are these: (1) conduct further tests on the efficacy of grain rescue strategies, including the use of recently introduced grain rescue tubes and grain vacuum machines; (2) incorporate the findings into future first responder training programs; and (3) enhance the first response skills of personnel working at grain storage facilities, both on-farm and at commercial operations.

Quantifying feedstock availability using a geographical information system.

The feasibility of utilizing cellulosic biomass such as corn stover as an energy feedstock is dominated by factors such as facility location, feedstock availability, and transportation logistics. This study compares two methods to quantify feedstock availability given a facilitys location using a geographical information system (GIS). The purpose is to highlight the advantages of using the proposed method (method 2) compared to a previously developed method (method 1). Method 1 is a straightforward approach in which the distance from the facility to the farm fields is first estimated and then hectare availability per service area is calculated using USDA-NASS statistics. Method 2 determines hectare availability by using geospatial images from which a service area is created based on a detailed road network dataset and a crop data layer. This method proved to be more accurate because it calculates the distance from the facility to the farm fields using a real road network and uses hectares of crop-specific fields in a given service area based on crop season-specific satellite images. Method 1 overestimated hectare availability per service area by 14,374 ha (35,518 ac; a factor of 1.45) on average, giving the false impression that a facilitys annual feedstock requirement can be met within a shorter distance and with presumably lower transportation costs. The proposed GIS-based methodology will allow more reliable prediction of a feedstock supply area for existing or planned biomass-based processing facilities.

Prediction of temperature distributions in peaked, leveled and inverted cone grain mass configurations during aeration of corn

Three-dimensional heat and momentum transfer for the peaked, leveled, and inverted cone grain mass configurations in a corn silo was studied with aeration airflow rate ranged from 0.26 to 0.31 m 3 /min-t (0.24 to 0.28 cfm/bu) using the 3D finite element stored grain ecosystem model. Non-uniform airflow models for peaked, leveled, and inverted cone grain mass configurations were developed using the finite volume method. Airflow resistance due to porous media of grain material was implemented using Erguns equation and a linear porosity variation with low porosity at the center and maximum at the side. The velocity profile and heat transfer during aeration were quantified for the peaked, leveled and inverted cone grain mass configurations. The change in grain temperature in the inverted cone grain mass configuration was the fastest followed by the leveled and peaked configurations. It took 102, 114, and 186 h, respectively, for cored, leveled, and peaked grain mass configurations to cool the grain from 40°C to below 20°C. For the peaked cone volume, the model predicted an 84-h delay in the cooling front movement (or about 55%) compared to the inverted cone configuration. This has significant implications with respect to fan run time hours, electricity consumption, and the potential for grain spoilage.

Determination of Effort Required to Insert a Rescue Tube into Various Grain Types

This study was conducted to quantify the forces required to insert the individual panels of a grain rescue tube into four grains of varying moisture contents. The study was conducted to address issues raised by emergency rescue personnel involved with extrication of victims entrapped in grain using a fabricated or commercially available grain containment system. These rescue aids are used to separate or protect the victim from the grain mass, enabling safe rescue. Conclusions drawn from the study included documentation that as the moisture content of the grain increases, the amount of resistance against tube insertion increases substantially. It was found that although the moisture content may be similar across several types of grain, the amount of work required to insert a rescue tube into the grain can vary. It was also concluded that the cohesiveness, angle of internal friction, and static coefficient of friction of the grain on the tube surface, which vary with moisture content and type of grain, were primary factors affecting the amount of effort needed to insert the tube. This article recommends that a consensus standard be developed covering the design and testing of grain rescue tube containment systems.