Non Contact vs. Contact Safety Devices for Rolling Applications
When deciding on the correct rolling closure for a facility there is a lot to consider. Not only is it important to select the proper rolling product (either commercial roll up doors or grilles), but it is also equally crucial to select the most effective safety device in order to maximize security and efficiency. Safety devices for rolling overhead door products, such as – sensing edges, photo eyes, and light curtains, fall into one of two categories: contact or non-contact. Here’s how to figure out what overhead door safety you need.
Light curtains and photo eyes are classified as rolling door non-contact safety devices – this means that no contact is needed for it to perform its safety function of halting downward travel and returning to the open position. Instead, these non-contact door devices use beams of light that, when interrupted by an obstruction, signals the roll up door to stop and reverse. When thinking about high traffic facilities, light curtain safety devices for commercial roll up doors offer more functionality since they cover a greater area than photo eyes reaching up to a 6 foot height. If an object is present within this door’s 6 foot window, a descending closure equipped with a light curtain device will sense the entity, stop, and reverse the overhead door.
Having this large sensing plane makes this commercial door safety device option perfect for buildings that endure high door traffic, or where the coiling door opens and closes more quickly. Parking garages, for example, are often outfitted with a door light curtain device when high performance doors or grilles are used that travel up to 24 ips on open and 12 ips on close.
Photo eye door safety devices also don’t require contact with an object to activate their safety features. To detect an obstruction in a rolling door or closures path, the photo eye sensor uses a reflective or through beam to detect interferences with a 6 inch height from the floor. Once the photo eye door device senses an object, again, the commercial roll up doors stop closing and returns back to the open position. These features make it a suitable device for complexes with medium to low vehicle and/or pedestrian overhead door traffic.
There are also contact safety industrial door devices available. A popular type of contact safety device is a door sensing edge, which is activated when the bottom bar of a rolling door makes contact with an object obstructing its path. After the object makes contact with the edge, the roll up door stops closing and returns to its open position. Sensing edges can be installed on overhead closures in lieu of or in combination with photo eyes, making them a great option for low traffic locations, where a rolling closure is travelling a standard rate of 8 ips on open/close or slower.
Retail locations, and other areas with a lot of pedestrian foot traffic, often decide that installing a door safety device is unnecessary. Instead, they opt for the control station to be equipped with a close button that makes the user push it the entire time the commercial roll up doors close – known as “constant pressure to close.” In this situation the close button must be installed in direct sight of the rolling door product according to UL 325 Compliance. Having this direct line of vision is crucial for the simple reason that if an object or person gets in the way of a rolling overhead door, the individual manning the control station can lift their finger from the button and immediately stop the coiling grille or door from closing.
Before deciding what overhead door safety device is right for you, there are key points to consider:
- The amount of traffic your facility experiences
- The type of traffic your facility encounters
- The average amount of cycles your rolling application completes per day
Having the right rolling door and safety device combination ensures efficiency and safety while saving time and money.
Cookson continues to lead in innovations in roll up door, security gate and closure products. To inquire how Cookson’s experts and customer service can help you with your next roll up door project, call 1-800-294-4358.
