When you leave your office, the gym, a school or a hotel, chances are you don’t give any thought to walking through those doors and stepping outside. But an entire range of builders hardware exists to control those exit doors by holding them open, keeping them closed, and automatically closing them behind you to conserve energy or keep a property secure.
Even more importantly, exit devices play a key role in emergencies by allowing large groups of people to leave a building quickly and by automatically and safely shutting fire doors behind them to contain fires.
The Builders Hardware Manufacturers Association (BHMA, www.buildershardware.com) has been certifying builders hardware since 1969 and a great deal of its standards cover exit devices and means of egress, due to its enormous importance in maintaining safe, secure, and convenient spaces.
With natural disasters, fires, and school safety dominating headlines lately, people are paying closer attention to how we get out when we absolutely have to – and how we keep buildings secure when we don’t.
Builders Hardware for Exits and What It Does
While thousands of specific builders hardware products control means of egress, general categories defined and specified by BHMA include exit devices, door control-closers, stops and holders, and release devices.
Exit devices. Exit devices are required by code in buildings with at least 50 occupants. They are also referred to as “panic” exit devices and some can be found on fire exits. All include an “actuating bar” which extends at least half the width of the door. Examples include crossbars on school doors, automatic and self-latching flush bolts, and removable mullions.
Exit devices are always for egress, not for entering, so additional hardware may be required to allow access from outside. Most of these exit doors contain or have the option to include entry trim with available functions such as keyed locking and latch retraction by lever.
Door control-closers. Door control-closers are usually mechanical, worked by hydraulics and springs. They keep the door from flying open, control its swing, and hold a door open when necessary. A large spring down the middle with hydraulic oil inside is used to slow down the closing process and prevent doors from quickly slamming shut. These products work by utilizing the energy used to open in order to close it again.
While bigger doors may need stronger closers, that’s not the only factor when choosing the type of control-closer. The location of a door must be considered. For example, high rise buildings contain excess air, which will naturally seek to move downward and out. This is referred to as “stack pressure”. When this is a factor, even a regularly sized door may need a stronger closer.
Stops and holders. The general term for overhead stops and holders is “door controls.” These are all of the products that control the opening and closing of a door. Surface-mounted and concealed at the top of the door, door controls are found on larger doors in schools, churches, and some office buildings. Unlike release devices, these are not electrical or tied into an alarm system.
Surface-mounted and concealed, door controls usually involve putting something large, such as an arm, above the door in order to prop it open. They are also used to close doors in emergency situations, after use to conserve energy, or for security, to make sure potential entrances to a property are inaccessible.
Release devices. Release devices hold doors in an open position. They include closer holders, electromagnetic, and electromechanical releases. Usually housed on a wall, release devices are commonly found on fire doors.
While fire doors remain closed and securely latched during a fire for containment, these doors are commonly kept in an open position during non-emergencies. Release devices operate in conjunction with a door closer. The devices are electronic and tied into a building’s alarm system so that in an emergency, fire doors can be automatically closed once the fire alarm is triggered.
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