Equipment Case Study
Case Analysis: Food processing facility has an automatic roll up door that is routinely used by forklift operators and pedestrian workers traveling between different areas of the building. Forklift drivers open the door by activating a pull cord switch; pedestrians open the door by pressing a pushbutton switch. Activating either switch initiates a controlled cycle where the door opens and remains open for a predetermined period before automatically closing. On the day of the accident, a forklift driver opened the door and drove through the doorway. A worker subsequently approached the doorway and proceeded to walk through. The door unexpectedly closed and struck the worker in the head. She sustained severe injuries from the force of impact.
Expert Analysis: The door manufacturer was aware of at least thirteen other accidents in which workers were struck and injured by roll up doors. Additionally, there was a prior incident where the same door began closing unexpectedly while a worker was in the doorway. Since the roll up door is intended for vehicular traffic and/or pedestrian traffic applications, it can be equipped with optional activation and safety mechanisms designed to meet the specific requirements of each application.
The door manufacturer offered an optional safety system (OSS) equipped with motion detectors and presence sensors to prevent the door from closing whenever pedestrians are approaching or standing in the doorway opening. The OSS provides the level of protection that is required for other types of power operated pedestrian doors. The roll up door was not equipped with an OSS, but it had a presence sensing device next to the doorway opening. The presence sensing device was inadequate for this application because it was unable to sense the worker and prevent the door from striking her.
The door was equipped with a breakaway edge that minimizes damage if struck by a moving forklift but the edge does not protect pedestrians. Engineering analysis determined the door should have been equipped with an optional safety system and a reversing edge to protect pedestrians. The analysis also determined that an optional safety system and a reversing edge would have prevented this accident.
Results: Case successfully resolved before trial.