There are many reasons why Electromagnetic door closers are highly useful devices.Electromagnetic door holders, actually do not close the doors, rather they keep them open in certain situations, but unlike a door stopper or a rope tie they close them when they should not be kept open.
An electromagnetic door holder works by using electrical current to create a magnet, thereby holding a door open. When the current is disconnected, the door releases. The auto close function included per the building code on doors in commercial or high occupancy residential buildings then activates and closes the door.
Fire Suppression or Suspected Fire
Commercial door hardware is designed to act as a key component of the fire safety systems of a commercial building. This includes doors, which are usually of high-grade steel, either solid or with fire resistant glass. This is designed both to allow people in other areas of the building to successfully evacuate, and to stop the spread of fire from one area of a building to another.
In the case of electromagnetic door closers, they release upon the activation of the fire system. The fire system cuts the circuits to the electro magnets allowing the doors to close. This is why upon entering a school, commercial building, or high density residential complex after a false fire alarm all of the main doors on the premises which are usually held open, will be closed. You do, of course, have to do your checks of all your fire safety equipment.
These types of door hardware also form an important security feature. Many doors are kept open in various complexes during the day; especially in offices and institutions of higher learning where a large volume of people and the public interact in the facility. However, many of the areas of these institutions, and offices carry out sensitive research and contain information, which is not available for public consumption. During the day door locking is not as important as the information and projects are supervised, meaning the biggest threat is via the Internet.
Electromagnetic doors can be programed to cut their circuits and shut all of the doors at a certain time. This ensures as the number of people in the building dwindles, so too does the ability for people who are not supposed to be there to gain entry. It also serves as a good guard against people forgetting to shut all of the relevant doors and ensure everything has been secured after the day has ended.
Additionally these days many businesses and institutions are opting to install extra commercial door hardware. This can include electromagnetic locks, which work similar to the door holders; they can be locked and unlocked by disengaging the current. Similarly this can either be set to a timer, or linked with a key card access to allow staff to come and go from the building in a monitored way after hours. Similar systems can also be used to ensure fire doors are not opened unless the alarm system is already engaged.