Tag: Case Study

Problems at the Pump

Posted by John R. Yannaccone, PE on December 3, 2018 with 0 Comment

Case Synopsis: A customer at a large, self-service gas station stopped to fuel her vehicle. Upon arrival at the station, she pulled up to a pump and parked so that the gas tank filler was on the side of her vehicle opposite the fuel pump. She was able to extend the hose across her vehicle to fuel it. After removing the fuel nozzle from the vehicle, the customer claimed the hose suddenly retracted with great force, pulling her over and causing her to fall on the concrete resulting in injuries to her head, right shoulder and right hip. Following the incident, the customer was able to drive herself to an urgent care center.

Expert Analysis: The entire event, from the moment the plaintiff arrived at the gas station until after she departed, was captured on surveillance video. The video clearly showed the woman extend the hose to the far side of her vehicle to fuel it. It then showed her start to return the hose to the pump. As she began to walk behind the vehicle, facing the pump, she stumbled and fell to her right, away from the pump. There was no indication on the video of the hose pulling her toward the pump, as her arms remained down, holding the nozzle when she fell to the side. Continue reading “Problems at the Pump” →

Man v. Machine

Posted by John R. Yannaccone, PE on April 11, 2018 with 0 Comment

Case Synopsis: On the morning of the incident, a machine operator reported that the clamps used to hold a workpiece were not gripping as tight as they normally do. The maintenance worker was alerted to this problem, and he and his helper went to repair equipment. The maintenance worker reported he adjusted the clamping mechanism and asked his helper to press the button to actuate the clamps. The helper moved to the control panel and depressed a button. At that time the two portions of the machine moved together, entrapping and crushing the lower portion of the maintenance worker’s body. The maintenance worker alleged the machine malfunctioned during the repair, resulting in him sustaining serious crush injuries to his lower body. It was further alleged that the equipment lacked the safety system to prevent motion of the machine during maintenance. Continue reading “Man v. Machine” →

Safety First on the Fire Truck

Posted by John R. Yannaccone, PE on March 12, 2018 with 0 Comment

In this case study, an Equipment Expert was requested to inspect the folding steps on a fire truck to determine if the folding steps were secured properly.

Case Synopsis: A firefighter needed to stow a piece of equipment in an open storage area on the top of a fire engine. As he was climbing the folding steps on the side of the engine, one of the steps shifted causing the firefighter to fall and strike his head on the concrete floor and sustain a serious head injury. Following the incident, one of the steps was found to be partially separated from the side of the vehicle with the top two mounting screws pulled out of their locations.

Expert Analysis: Inspection of the vehicle revealed the steps were mounted to the side of the engine with four bolts that extend through the sheet metal and into the storage compartments. The bolts were fastened to the sheet metal with large flat washers and nuts on the inside of the compartment. During the inspection, several different combinations of mounting hardware were found to be in use attaching the various steps to the engine. These included flat washers with non-locking and locking nuts. In some cases, in addition to the flat washers, there were lock washers also in place. These were used both with locking and non-locking nuts. The specific hardware used to secure the dislodged step could not be identified, as only the bolts were recovered. The nuts or washers used on the two dislodged screws were not found. It was hypothesized that the hardware for the dislodged screws did not incorporate any adequate locking features, and subsequently allowed the nuts to loosen over time and eventually separate from the bolt. When the step was loaded by the weight of the firefighter, it dislodged causing him to lose his footing and fall. Continue reading “Safety First on the Fire Truck” →

Case Study: The Importance of Lawn Mower Safety

Posted by John R. Yannaccone, PE on July 25, 2017 with 0 Comment

Case Synopsis: A landscaper was operating a commercial riding mower at an industrial plant early one morning. The ground was covered in dew resulting in a slippery terrain. As the worker was cutting the lawn, he proceeded down a hill, was unable to stop, and slid into the side of a building. Due to the wet ground and the incline, he was unable to back the mower up from the building. At that point he dismounted the mower and attempted to pull it away from the wall so he would be able to drive again. While attempting to move the mower, the worker slipped, entangled his foot under the mower deck resulting in a partial amputation.

Expert Analysis: According to the operator’s manual for the mower, there were several interlocks, or safeties, which should have prevented the mower blades from operating after dismounting the mower. The system should turn off the mower’s engine if the blades were still engaged, or the parking brake was not set when the operator removed his weight from the seat. The manufacturer had performance requirements on how quickly the engine was required to stop after weight was removed from the seat. There was also a recommendation that the seat interlock be checked weekly to confirm it operated properly by shutting down the mower if weight was removed from the seat. Continue reading “Case Study: The Importance of Lawn Mower Safety” →