One of the marvels of today’s garage door industry is the advent of high-speed or high performance doors. These doors are meant for commercial use only and they have many advantages such as higher speed operation, better performance in cold or hot environments, high cycle use, great durability and break-away features.
The Door & Access Systems Manufacturer’s Association International (DASMA) defines a high performance door as, “A power-operated
rolling, folding or sliding non-residential door, generally characterized by either 100 or more cycles per day or 20 or more inches per second opening speed, and typically made-to-order and/or designed for higher durability, and/or designed to break away due to equipment impact.”
While these are great features, designers, architects, building owners, installers and maintainers of these doors must remember that because of their higher operating speed, additional safety features are strongly recommended and required by standards and hazard analysis. Unfortunately, safety standards such as UL 325 are only minimum standards, and do not address all hazards in all applications. For this reason, hazard analysis must be done to determine what hazards may present themselves to persons, property and vehicles, and additional safety devices should be added to the system to protect against damage or injury.
- Safety sensors. The UL 325 standard and practices in the industry require safety sensors that will sense persons or objects in the path of the door.
- Examples of safety sensors include photo eyes mounted no higher than 6″ above the floor. This is the requirement of UL 325. But additional photo eyes should be added that are mounted higher – some types of traffic such as fire trucks for example, would not trip a photo eye mounted near the floor as soon as the front bumper of the truck which may be two feet or higher above the ground.
- Bottom safety edges are also acceptable. These devices require contact with a person or object
- Advance audio or video warning signals or alarms. We are all familiar with the beeping or buzzing sounds from a forklift that is backing up, or a strobe light that warns of a baggage carrier beginning operation at the airport. Often, high performance doors are actuating in “unattended operation” situations. In other words, the door is activated without a person present to monitor it. This activation could come from a timer that closes the door after a certain time. These alarms and signals will sound several seconds before the door begins to move, warning those in the area of impending closure.
- Other advance sensors. Several types of advance sensors are available that will sense vehicles, but some of these will not sense pedestrians, bicycles or motorcycles. These devices are required to sense persons or traffic that is approaching the door as it is preparing to close, and they will send signals to the control system to hold the door open until the person or traffic has cleared the opening.
- For example, driveway loops are wires buried below the pavement that will sense masses of metal passing over them due to induction. But such loops will not often sense motorcycles, bicycles or pedestrians in the area because they do not have enough metal in them. So their application is limited to larger vehicles.
- Photo eyes can be mounted forward of the door system so that if the infrared beam is interrupted by traffic, a signal will be sent to the control system to hold the door open. Photo eyes have the advantage that they will sense pedestrians, bicycles and motorcycles.
- Slippage or Soft Landing Devices. In the event of an unanticipated hazard or if other devices fail, a slippage system should be incorporated