Fire Door Retainers
Fire doors are an important part of any building's fire safety strategy as they enable movement throughout a building while stopping the spread of fire to allow occupants enough time to evacuate safely. However, fire doors can only function if they are closed or close automatically if a fire occurs. This is the reason why it is dangerous and illegal to hold fire doors open with a wedge or extinguisher.
Fire door retainers (also called fire door holders) allow occupants to hold fire doors open in a legal and safe manner, removing the temptation of wedging the doors open. These devices hold the doors open in the day-to-day running of the building but will release the fire doors if there is a fire, allowing the fire door closers to do their job.
Some fire door retainers are wired into the building's fire alarm system, others 'hear' the fire alarm by listening for the sound of the fire alarm with an acoustic sensor. The former type may be battery or mains powered while the latter are typically battery powered and are usually quicker and easier to install. The best known of the acoustic fire door retainers is the Dorgard.
The Dorgard is a completely wire-free solution to holding open fire doors, requiring neither a power nor a fire alarm connection to work. Being a battery-powered device which listens for the building's fire alarm sounders, the Dorgard is quick and easy to install and requires very little maintenance. These fire door holders are fully certified to BS EN 1155, the standard which defines manufacturing and testing requirements for "Electrically Powered Hold Open Devices For Swing Doors" including fire doors.
When equipped with a Dorgard, fire doors can be held open at any angle by simply pressing the plunger down with your foot, and nudging the top of the plunger is all that’s required to release the door manually. In the event of a fire the Dorgard will release automatically when the fire alarm system activates by retracting the plunger which passes through the main body – the standard model listens for a sound level of over 65dB while the SmartSound model listens for an actual alarm tone.
Safelincs offer an exclusive FREE 5 year extended warranty on both Dorgard models, excluding consumables such as batteries or feet, and any order containing a Dorgard qualifies for FREE shipping.
Traditional fire door retainers typically consist of a floor- or wall-mounted electromagnet which is responsible for determining if the fire alarm has activated along with a door-mounted metal plate. The electromagnet units will have override buttons which deactivate the magnet and release the door, though the unit's small size means the position of this button may be inconvenient – especially for disable occupants when mounted on the floor or at the top of the door.
These door holders can be powered by batteries, from the mains, or from nearby power supply units (PSU) rated at 12V or 24V DC. It is generally recommended to install them at the top of the door to prevent warping caused by the door closer pulling against the electromagnet. Battery-powered versions typically use an acoustic sensor to listen for an alarm sounder while wired models will often be connected directly to the fire alarm panel.
Hold Open & Free Swing
Instead of installing additional components to fire doors, there are door closers available which have retainer features built-in for convenience. They may have the ability to hold a door open at certain angles (Hold Open models) or to temporarily disengage their mechanical components so that fire doors feel as light as normal doors (Free Swing models). Both models require power to work, either wired into a power supply or fitted with batteries, and will "fail safe" during a power failure – meaning that electricity is used to disengage the closing force and by default they will try to keep the door closed when no power is supplied.
Hold Open is a relatively simple feature as it only requires the closer to hold the door in place once it has been opened to a certain angle. Free Swing also requires the door to be opened a certain amount before it activates, but from then on the door can be used freely without occupants feeling any weight. These types of closer require either a wired connection to the fire panel or to be in proximity of a fire alarm sounder in order to engage their mechanical force and close the door in the event of a fire.