Tom has 17 years experience as a commercial locksmith and over 20 years in door hardware distribution.
High Energy and Low Energy
Power Operators - also known as automatic door openers - are devices that open doors for persons with disabilities. They are available in two main varieties:
- High Energy
- Low Energy
High energy power operators are installed by AAADM (American Association of Automatic Door Manufacturers) certified technicians and are used in high traffic applications like hospital emergency room entrances, supermarkets, and large office buildings. They are used on both swinging and sliding doors. If your application demands a high energy power operator, you should call a door control or automatic door company. You should do this because a high energy power operator improperly installed could injure someone.
Low energy power operators can be installed by non-AAADM certified technicians and are used on swinging doors in lower frequency applications such as a small doctor's office with 2 doctors, a separate entrance dedicated to persons with disabilities or otherwise subject to occasional use, an apartment entrance, or the entrance to an apartment building housing no more than 10 or 12 units.
If a low energy power operator encounters and obstacle, it will stop, and so it is less likely to injure a person. High energy power operators are more powerful and require safety sensors to ensure that no one is in the path of the door as the operator shuts it.
Aside from wiring, a low energy power operator can be as easy to install as a regular door closer.
The drawing above shows basic wiring for a power operator system. Power operators usually run on house current – around 115VAC – however, there are some low-voltage power operators as well. Two-conductor wire runs from each actuator to separate inputs on the internal control board of the power operator. When a user activates the actuator, usually by pushing on it, the power operator starts its door opening cycle. Some power operators have a low voltage output to run an electric strike, and most have dry contacts that allow the installer to use a separate power supply to run their electric locking device as shown in the drawing. The power operator control board will activate the electric strike before opening the door.
A power operator system includes the power operator and activation devices (called "actuators"). A power operator on a swinging door can have an internal activation device, in which case the power operator is said to have "push and go" operation: a user simply starts pushing or pulling the door open and the power operator is activated.
Field conditions such as consecutive swinging doors and/or locking doors may require special equipment. If you are applying a power operator to an existing door that currently shuts and locks and you want the door to continue to shut and lock automatically, the power operator will need to have the capability to unlock the door before it opens it. If you have consecutive doors, for example, in a vestibule situation, the power operator may need to have the capability to open the doors sequentially. Many power operators have an internal logic board that will enable it to perform these operations internally. Aftermarket logic boards are available to achieve advanced functions not achievable with the internal logic board.
Incidental to the installation of the power operator, any locks that need to work with the power operator will need to be electrified. Electrification may be as simple as installing an electric strike, or, particularly when pairs of doors are involved, my require exit devices with electric latch retraction.
Actuators are normally open, momentary contact switches. Any normally open, momentary contact switch can act as an actuator for a power operator. For example, one can use an access control panel to activate a power operator. One can also use a handheld wireless transmitter and receiver.
An actuator starts the door opening cycle. Two are typically required for each power operator. Usually these are mounted on the wall, one on the inside of the door, one on the outside. This allows folks to use the power operator on the way out as well as on the way in.
There are a wide variety of actuator styles available. The most common ones are four-and-a-half inches square and have “PUSH TO OPEN” and the wheelchair logo engraved on them. The largest ones are circular, six inches in diameter. These provide disabled persons with a big target to hit when they need to open the door. There are also touchless actuators (see picture below) that are activated by a wave of the hand – an option that prevents the spread of germs via the actuators. Smaller actuators are made to fit on door frames. Most actuators can be installed flush with the wall or in a surface mounted back box.
Actuators can be wireless. This makes sense if there is no locking device involved and stone or brick walls make running wires very difficult; however, when there is a locking device involved the installer is already running wires, so wireless actuators make less sense. The downside to wireless actuators is that they are battery operated. Periodically the battery will die and so will the actuator. But in some situations they are worth the upkeep because of the difficulty of running wires. In order to use wireless actuators, the power operator must be equipped with a wireless receiver. Most power operator manufacturers offer the wireless option.
Instead of actuators, a motion detector (such as the MS Sedco pedestrian door sensor below) can be used to activate the power operator. Weatherproof versions are available for outdoor use.
Safety sensors are most often used with high energy power operators, but many low energy power operators are designed to accept safety sensor input as well.
Safety sensors are presence detectors that sense when a person is in the path of the closing door and stop the door from closing on the person. When the people who use the door need variable amounts of time to get safely through the opening, safety sensors can be a valuable accessory.
Often, power operators are new installations on existing doors that were not originally intended to be automatic doors. Usually this is no problem, but sometimes it can be a challenge. For example, a building has a vestibule with a pair of doors on the outside and another pair of doors on the inside. Currently the doors have old style Doromatic 1990 concealed vertical rod cross bar exit devices that are dogged open all day during business hours. Building management wants power operators and access control on this entrance. The door leaves are all three feet wide and seven feet tall.
Here are the issues:
- There is only one good way to electrify the Doromatic 1990, if the internal rods and latches are in good condition; that is to replace it with a Doromatic 1690 with factory installed or aftermarket electric latch retraction.
Do we want electrified exit devices on all four leaves, or on just one leaf of each pair? If on just one leaf of each pair, do we want to install non-electric 1690’s on the leaves that do not have power operators? Or if aesthetics are not important, should we just leave the 1990 devices on the non-powered doors?
- Since it is a vestibule we must sequence the operation of the power operators. That is, when a user presses the inside actuator, the inside operator opens the inside door first, then the outside operator opens the outside door. When a user presses the outside actuator, the outside operator opens the outside door first, then the inside door.
Sequencing is accomplished either by on-board logic boards in each power operator wired to each other so that they communicate, or by an external logic board.
In addition, because it is a vestibule, we need to make sure no user gets stuck in the between the doors because they weren't fast enough to make it through before the second door closed. This can be accomplished by using a presence sensor or by installing a vestibule actuator that can activate either door selectively.
- How will the access control interact with the electrified exit devices and power operators? Will the access control act as an actuator? Or will it enable/disable one of the manual actuators?
These are some of the questions that may need answering as you design your power operator system. As always, connect with your local Authority Having Jurisdiction (fire marshal or building inspector) to make sure you are obeying all the rules.
Tom rubenoff (author) from United States on February 04, 2011:
Automatic Doors on February 04, 2011: