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Maintenance
A typical garage door may weigh hundreds of pounds, and is typically sprung by a torsion or extension spring to counterbalance the weight of the door. The great force on these springs can make them dangerous to replace for the inexperienced or incautious handyman. Many cases have been reported where even experienced garage door technicians have suffered severe lacerations and/or broken bones in the replacement of garage door springs. Garage door torsion springs are rated in cycle life, with 10,000 cycles being the industry standard minimum, and upgrades available to around 100,000 cycles. The average spring breaks about every 7 to 12 years.If a garage door has two or more springs and one breaks, all springs should be replaced to maintain proper balance.
The leading causes of garage door failure and/or replacement include lack of maintenance and being hit by vehicles. A proper maintenance schedule for a garage door includes lubrication of the rollers, bearings, pulleys, and springs once a year; washing painted steel surfaces several times a year; painting or refinishing wood surfaces as necessary; and making proper adjustments to the counter balance system as necessary to maintain door balance. A properly balanced garage door should be able to be stopped mid-travel without drifting down or up when operated manually.
Garage doors operated by an electric opener should be tested twice a year for proper reversing. To test place a cardboard box under the door to see if the door reverses on contact. If not call a qualified, certified door technician. (Door technicians are certified by the The Institute of Door Dealer Education and Accreditation.[1] Another danger area for doors are the bottom brackets. These brackets are under tremendous tension and should only be touched by a qualified door technician.
Safety
Due to the size and weight of garage doors, there are some very large forces being employed to make opening and closing easier. One of the most common components are very large heavy springs up to a meter long used to counterweight the door, which are attached to cables at the base of the door.
It is now common for garage doors to be installed with part of the lifting cable running through the center of these springs and securely tied to the upper track frame. This is necessary because as garages age, these metal springs begin to corrode and eventually break from the weakening and the stresses involved. These broken spring fragments can swing aroung the garage at a high rate of speed, cutting and injuring anyone in the garage when it breaks. The cable running through the center retains the broken fragments so that they can only slide along the cable rather than randomly flying around.
Breakage of the door support cable is also a hazard since it will whip around at high speed and cause impact and slicing damage with the frayed end of the cable.
Garage doors with automatic openers usually employ three safety features:
- One is a downward force measurement, which causes the door to retract if the door strikes an object in its path. This is important if the door is activated with a vehicle halfway through the door, but more importantly if a child or family pet were to become trapped under the door.
- To further prevent the potential for injury, a recent design change is that most doors are now also equipped with a light-beam sensor near the base of the door. If anything blocks the path of the beam near the floor such as a pet or a child, the door will automatically fully retract.
- If the door hits an obstruction while rising, rather than reversing downward, the door will just stop moving. This prevents repeated crushing if the door hits an obstacle descending but then also cannot rise to the fully open position.
See also
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