Door closer introduction

A door closer is a mechanical device that closes a door, in general after someone opens it, or after it was automatically opened. There are two general styles of door closers: manual and automatic.

Manual door closers come in two main forms, overhead and jamb mounted. Overhead door closers, such as those from Briton, Dorma and Geze, can be concealed or surface mounted, whereas jamb mounted closers, such as Perko-Powermatic, fit between the door and the door frame and are totally concealed when the door is closed.

A manual door closer stores the energy used in the opening of the door and releases it to close the door. To limit the speed at which the door closes, common door closers use hydraulic (oil-filled) dampers, although spring mechanisms may also be used. The speed at which the door closer closes the door may be adjustable by up to two set screws. These screws often adjust the sweep speed and the latch speed of the door. The latch speed is the speed that the door travels in the last third to 10 degrees as it closes and is often set fast so that the door can properly latch closed. The sweep speed is the speed which the door travels at along the first two thirds of its travel and is often set slower than the latch speed. Door closers which provide this two-stage action and close doors at a determined rate are called 'controlled' door closers.

Door closers are most commonly used on fire doors, which need to be closed in the case of fire to help prevent spread of the fire and smoke. 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 (for use by disabled or infirm) as well as health, safety, durability, risk of vandalism/ligature and aesthetics.

An automatic door closer (more often called door opener) opens the door itself, typically under the control of a push button, motion detector or other device, and then closes it as well, typically employing a motion or proximity detector to determine when it is safe to close the door.