Garage doors can cause injury and property damage (including expensive damage to the door itself) in several different ways. The most common causes of injury from garage door systems include falling doors, pinch points, improperly adjusted opener force settings and safety eyes, attempts at do-it-yourself repair without the proper knowledge or tools, and uncontrolled release of spring tension (on torsion spring systems).
A garage door with a broken spring, or the wrong strength spring, can fall. Because the effective mass of the door increases as the garage door sections transfer from the horizontal to vertical door tracks, a falling garage door accelerates rapidly. A free-falling garage door can cause serious injury or death.
The sections and rollers on garage doors represent a major pinch hazard. Children should never be allowed near a moving garage door for this reason. On manually operated garage doors, handles should be installed vertically, to promote "vertical orientation of the hand".
Mechanical garage door openers can pull or push a garage door with enough force to injure or kill people and pets if they become trapped. All modern openers are equipped with “force settings” that make the door reverse if it encounters too much resistance while closing or opening. Any garage door opener sold in the United States after 1992 requires safety eyes—sensors that prevent the door from closing if obstructed. Force settings should cause a door to stop or reverse on encountering more than approximately 20 lbs (9.07 kg) of resistance. Safety eyes should be installed a maximum of six inches above the ground. Many garage door injuries, and nearly all garage door-related property damage, can be avoided by following these precautions.
Certain parts, especially springs, cables, bottom brackets, and spring anchor plates, are under extreme tension. Injuries can occur if parts under tension are removed.
Extension spring systems should always be restrained by a safety cable that runs through the middle of the spring, tying off to a solid point at the rear and front of the horizontal door track. The safety cable prevents hazards to bystanders when a spring, pulley, or cable breaks under tension and makes the system quite safe.
Torsion spring systems can be very dangerous as they are always under tension and release energy when the spring fails. Serious injury or death can be caused by the projectile pieces of a failed torsion spring. Many people have been injured or killed trying to adjust torsion springs, and special training and procedures are required to safely adjust a torsion spring, it is a job for a professional not a homeowner or DIYer. Article source