Nick Goddard, R&D Manager at Geoﬁre, talks about the importance of ﬁre doors and the technology available to hold them open safely and legally.
Fire doors are designed to prevent the spread of smoke, flames and toxic gases throughout a building in the event of a fire. However, when a fire door is held open, fire can quickly pass through the building, blocking escape routes and endangering lives. Legally, a building’s fire doors must therefore be self-closing to ensure the door closes to act as a barrier that stops the fire from spreading.
Due to the level of protection a fire door provides, the placement and weight of the doors is often restrictive, such as in a care home setting for residents. It’s recognised that, in these cases, it’s necessary to hold fire doors open for practical reasons. In this instance the fire door must have a device installed to release the door, so that it will close upon activation of the fire alarm system.
Holding open fire doors
Making sure fire doors are closed when the fire alarm sounds is extremely important. The British Standard 7273-4:2015 ‘Code of Practice for the operation of fire protection measures – Part 4: actuation of release mechanisms for doors’ gives guidance on the installation, commissioning and maintenance of fire door holding systems. The system/hardware used to hold the doors open must also be approved to EN1155 standard.
Fire door retainers, also known as fire door holders, use a magnet to hold open heavy fire doors that will release in the event of a fire. Stand-alone door retainers are suitable for doors that already have a closing device fitted, however fire door closers with a built-in hold open function are also available. Depending on the installation and level of protection required, there are a variety of fire door retainers readily available which react to different triggers, in the event of a fire.
Hard-wired fire door retainers are ideal for new buildings as they have a direct wire connection to the building’s fire detection system. In a normal condition, power (usually 24V dc) is supplied to the door retainers so that they can hold the doors in an open position. When a ﬁre is detected by the fire panel power is cut, releasing the doors so that they can close. A fault in the wiring or power supply to the door retainers will cause them to fail safe and release the doors.
Radio controlled ﬁre door retainers are triggered wirelessly by radio waves from a controller connected to the existing fire panel or interface unit. As minimal wiring is needed, these are often used for fitting into large, existing buildings but still offer high levels of protection. These systems are installed by an approved, trained professional as a site survey has to be carried out prior to installation.
Sound activated fire door retainers react to the noise of the fire alarm and some devices can learn the sound of the building’s specific fire alarm, so they’ll only release when the alarm sounds. This is a cost-effective solution as there’s no need for wiring to a fire panel. Sound activated fire door retainers are battery powered and can be installed quickly and easily.