Safety & Sensors
Automated driveway gates require safety precautions that protect against entrapment and hazardous pinch points. Photo eyes, safety edges, induction loops, and other sensing mechanisms are designed to detect a potentially dangerous situation, such as a vehicle or pedestrian blocking the gate travel path, and either stopping or reversing the cycle of the gate depending on the direction of travel. Industry standards are created by the Underwriters Laboratory under the UL325 code which is occasionally updated. All operators have a built in obstruction sensor that will reverse the gate if it makes contact, in addition to that all swing operators must have at least one UL325 approved monitored non-contact sensor, and all slide operators are required to have one in each direction of travel. These requirements are fulfilled by photo eyes or safety edges but not by induction loops or motion detectors. If you fail to install the minimum requirement for safety devices your operator will not run and just because the minimum requirement is met does not mean that your installation is UL compliant. Safety considerations and needs vary widely and should be designed based around the needs of your particular job to protect yourself from liability. If you have questions or concerns it is recommended you speak to a licensed gate or door contractor.
Loop Detectors are use in conjunction with vehicle detection loops to detect vehicular traffic traveling or stopping overhead in a roadway. These are commonly used to trigger traffic lights and you have undoubtedly traveled over thousands of them without even realizing it. In the automated gate industry we use these devices to trigger gates to open for access and egress and also to serve as safety devices that protect vehicles in the path of the gate. Loop detectors can be used for a variety of other purposes including counting vehicular traffic, arrival notifications, and turning on driveway lighting. Although it is common to install loops for safety they do not meet UL325 compliance because they only detect vehicular traffic and not pedestrians or animals.
Exit Wands work in a similar fashion to an induction loop but they detect vehicles in a 360 degree sphere. Because of this they are more likely to pick up the moving gate or other unintended trigger so they are not used as a safety device. It is recommended that you install an exit wand at least 30' back from the gate to avoid unintended openings. These devices are typically used when a homeowner does not wish to sawcut into an existing roadway.
Photo Eyes or Beams are “non-contact” devices that operate by shooting a beam of light across the gate opening. When wired up as an entrapment device interrupting the beam will stop the gate in its path and reverse the gate 1' towards the closed position. If used as a reversing device it will stop and reverse the gate all the way to the open position. Photo Eyes are approved for use as safety devices in compliance with UL325-2018 requirements.
Safety Edges are “contact” devices that operate when touched using pressure sensitive sensors. If an obstacle is encountered, the device signals the gate opener to stop and/or reverse operations. These devices are sold by the foot with 4', 5', and 6' versions typically carried in stock. Safety edges can be placed on fixed surfaces such as posts, or the can be installed on the edge of a gate depending on your needs. The safety edge is combined with a wireless edge transmitter and receiver set to send the signal to the gate operator. Monitored safety edges are approved for use as safety devices in compliance with UL325-2018 requirements.
Warning Devices such as Signs, Signals, Lights and Bells are useful accessories to any automated vehicular gate system. They provide visible and / or auditory indicators of potentially hazardous situations.