Hold-open device
A hold-open device is a mechanism that enables fire doors to be held open safely and is commonly used to help deal with issues of fire door wedging or improving accessibility.
Fire doors are important in terms of providing proper fire separation, and preventing the spread of fire and smoke, but in some situations, it may be inconvenient or undesirable for fire doors to be closed all the time. Closed doors can negatively impact upon the inhabitants, such as in a care home or school, or can present hazards where there is busy traffic circulation.
A hold-open device can be installed to hold the door leaves in the open position until they are released, either manually or in the event of a fire, at which point the door closes via the closing force of a ‘door closer’.
The operation of a hold-open device comprises:
- A trigger mechanism that processes the signals issued by the fire alarm.
- A fire alarm.
- A hold-open mechanism – such as a hardwired electromagnet or suitable acoustic device.
- Power supply - mains supplied or battery.
In the event of a fire, the trigger mechanism releases the hold-open device, allowing the door to close.
The device can either be an attachment to the door or can be incorporated into the door closer. In the case of ‘delayed-action closers’, they are often installed as separate wall-mounted devices.
Devices should have a manual release mechanism so that the doors can be manually closed if necessary.
Hold open devices should comply with BS 7273-4:2015 Code of practice for the operation of fire protection measures – part 4: Actuation of release mechanisms for doors. This standard categorises products into three installation categories; Standard, Indirect & Critical
Standard and Indirect installations should release the device upon;
- Activation of a fire alarm via smoke, heat, or other fire detection equipment.
- Manual activation of a fire alarm.
- Mechanical fault (fail-safe)
- Loss of power to the device (fail-safe)
Critical installations should release upon the above conditions as well as upon any failure of the alarm system.
Current guidance restricts the use of hold-open devices to applications where there is an automatic fire detection and warning system which incorporates smoke detectors, and which is designed to protect the building’s escape routes.
[edit] Related articles on Designing Buildings
- Automatic fire detection and alarm systems, an introductory guide to components and systems BR 510.
- Automatic release mechanism.
- Door closer.
- Doors.
- Fire detection and alarm systems.
- Fire door.
- Fire Door Inspection Scheme.
- Fire safety design.
- Fire stopping.
- Free-swing door closer.
- Installing fire doors and doorsets (GG 86).
- Means of escape.
- Self-closing device.
[edit] External resources
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