One such fire safety measure is the installation of fire doors. This includes door closers, which are mainly used in commercial and public buildings but may also be used around the home where circumstances make their use desirable. They have a variety of uses and applications one of the main ones being to keep a door closed to limit the spread of fire and draught throughout a building. There are many different types of door closer available ranging from the simplest gate spring up to the more industrial floor springs.
An automatic door closer requires power to operate while a manual door closer uses physical force. There are also three basic designs available - overhead, jamb-mounted and surface mounted. Those that can be installed on the surface or concealed are known as the overhead door closers. Similarly, installing them between the door and the doorframe can conceal the jamb-mounted closers.
Choosing a door closer can involve the consideration of a variety of criteria. In addition to the closer's performance in fire situations, other criteria may include resistance to opening forces as well as health, safety, durability, risk of vandalism and aesthetics. The electromagnetic hold open door closer uses an electromagnetic force to keep it open. This type of closer is usually connected to the building's fire alarm system. The huge advantage to installing this type of device is that it overcomes the dangerous practice of using wedges or various objects to keep a fire door open. Once the fire alarm is raised, the door closes. The same principle is applied to electromagnetic free swing but instead of keeping it open; it allows the door to move without resistance.
In hospitals, schools and care homes, delayed action closers are commonly used. This allows the door to remain open for a preset period of time before closing at an adjustable speed. Such a system will allow people in wheelchairs or the elderly to get through the door before it starts to close. This is also useful in areas where trolleys are used.
Concealed fitting closers are widely used for the entrance doors of commercial buildings serving both a functional role as well as maintaining the aesthetic appearance of the door. There are also those available that can be concealed into the top of the door. Although this is a great way of 'hiding' the closer, a large part of the door must be cut away to house the body and this will reduce the fire integrity of the door. It is always a good idea to check with a fire-safety consultant that this type of door control is suitable. There is also a type of closer that will fit in the side of the door with the mechanism contained inside the door.
A back check action provides resistance within the door closer to prevent the door leaf from being thrown open. This prevents damage to the door, doorframe and door handles caused by people kicking or throwing the door open and also by the door being violently blown open by the wind. The angle and resistance of the back check can be varied according to your requirements. These are closers are used in busy hallways of schools, hospitals and public superstructures.
For disabled, weak or elderly people, calm action door closer is required to enable them to move the door with lower force. These are used in schools and other public buildings where DDA or the Disability Discrimination Act is considered.
Automatic door closers allow the doors to open or close whenever the person in within the proximity area. It closes when the device knows that it is safe to do so. These are commonly used in commercial areas as well as in local authority buildings and hospitals.
Overhead door closers are manufactured with different or adjustable strengths to cater for the size and weight variation of doors. The bigger and heavier the door, the greater the force required to close it. The recognised standard for classifying door closers is by assigning the closer with a number value between 1 and 7 where the higher number indicates a larger capacity and force of close. The minimum recommended size door closer fitted to a fire door is 3. Air pressure on the door from wind is also a consideration, which could lead to a higher size number than the actual door weight being needed.