As a door expert witness, I am called upon many times a year to evaluate garage door injuries. Garage doors come in many shapes and sizes. Their functions range from basic security of an area to cosmetic concealment. Most doors can be broken down into a few basic styles or categories. Typical modern garage doors for residential applications tend to be predominantly of the overhead sectional variety. That style of door comes in many configurations, materials, levels of insulation, and a wide range of appearance possibilities. They are available as a prefabricated kit, or built as a custom design to complement the decor of any building.
Commercial warehouse type installations often dictate higher security requirements. A good choice for this security type of door is the "roll-up" style that resembles a roll top desk type of door. This door can be manufactured with a variety of materials that can be as strong as the adjacent walls, making forced entry through this opening very difficult. Other common commercial installations include light weight aluminum single or sectional panel doors. These doors function more for closing off an already secured area than for assuring point security.
In the past, the biggest concern with operating an overhead garage door was the potential risks associated with the springs used for balancing the door weight. Pre mid 1960's garage door installations typically relied upon a pair of stretched (tensioned) springs to assist the operation of the garage door pivoting hinges. These springs became loaded (tensioned) as the door was moved into the closed position. Unloading (releasing) of the stored spring energy occurred as the door was opened to the horizontal overhead position. One of the most dangerous aspects of these spring systems was that after a period of time, often without any maintenance or inspection, the points of attachment of these springs would rust or become weak.
This weakening of the springs or points of attachment would often lead to an inadvertent explosive failure flinging the broken spring components across the garage, embedding the spring or steel components into the garage walls, cars or other items in the path of travel. Unfortunately, sometimes people were in the path of travel of these explosive occurrences.
As these springs failed, as an attempted safeguard, some manufacturers devised a "caging" system for the springs. These cages were retrofitted onto the stretched springs in an attempt to capture the parts that would release if a failure occurred. While these caging devices were helpful, they were not completely effective. Some of these spring devices are still in use today. Whenever this condition exists or the quality of garage components are questionable, a qualified professional service technician should be consulted.
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