Types of Fire Door Retainers

What are fire door retainers?

Fire door retainers, also called fire door holders, hold fire doors open safely. Fire doors can be heavy, restricting access through buildings and preventing the free flow of air which is often why people prop them open. However, they have a very important purpose - preventing the spread of fire - so wedging a fire door open is dangerous. A fire door retainer automatically allows the door to close in the event of a fire alarm sounding to prevent the spread of fire, ensuring compliance with fire regulations.

Acoustic fire door retainers

Acoustic fire door retainers are fitted to fire doors and hold fire doors open until the sounder from a smoke alarm or fire alarm system triggers the retainer to release the fire door, allowing the door closer to close the door. The units sold by Safelincs are certified to EN1155 and can be used in most business/public sector applications.

One such acoustic retainer is the Dorgard which is placed at the bottom of fire doors to legally and safely hold them open using a plunger. Once an alarm is activated, the plunger automatically retracts, allowing the door closer to close the door. The Dorgard is a wireless system powered by batteries. Manual release is achieved by either kicking the plunger upwards or by pressing the fire door open wider. The Dorgard can hold a fire door open in any position. Dorgard units can also be used on heavier fire doors. They are, however, not suitable for noisy environments.

An alternative is the Agrippa acoustic door retainer which uses a battery-controlled permanent magnet and steel plate to hold a fire door open. This retainer is fitted behind the fire door, and hence only able to hold the fire door in the fully-open position. The Agrippa has a "training" feature which allows the optional fine-tuning of the retainer to the sound of the alarm system, allowing it to be used in slightly noisier environments as well. The units have a manual override button, which allows you to release the door to close at any time.

Acoustic fire door retainers are ideal for:

Retrofit installations as the wireless technology minimises disruption during installation.

Magnetic fire door retainers

Magnetic fire door retainers have a wall or floor mounted electro-magnet that can hold a metal disc fitted to the back of the fire door to hold it open. Once an alarm activates, the fire doors are automatically released. There is a manual release button to override the system to release the door. Traditional magnetic fire door retainers, such as Doormouse, are powered by cables coming from the fire alarm panel or through mains power supply with a signal cable from the fire alarm panel to interrupt this power supply which releases the door. Magnetic fire door retainers are fail-safe as they will always release a fire door should the power supply fail.

Magnetic fire door retainers are ideal for:

Hardwired magnetic door retainers are more cost-effective to install in new-builds where other construction work is already taking place, and are effective in noisy environments.

Free swing overhead door closers

Free swing door closers integrate both the door closer and the door retainer function in one unit. They are installed in the position of the usual overhead door closer. The main benefit is that they allow the fire door to be operated like a normal door without the resistance from a door closer. They can be left open at any angle (they are allowed to "swing freely"). Acoustic free swing door retainers, such as the Freedor or the Agrippa, are not wired to the fire alarm system and instead, similar to the Dorgard, pick up the sounder from an alarm system or smoke detector. In noisy environments it is important to select a version which is able to recognise your fire alarm's sound.

Free swing overhead door closers are ideal for:

Care homes, hospitals or hotels where people may find heavy fire doors difficult. They are also less likely to get damaged by knocks from wheelchairs, beds or trollies.

If you need assistance or advise to help you select the right type of fire door retainer for your particular application, please contact our knowledgeable team on 0800 433 4289 or email support@safelincs.co.uk

Reviewed: 06/07/2021 (doc:528 V1.2). Our articles are reviewed regularly. However, any changes made to standards or legislation following the review date will not have been considered. Please note that we provide abridged, easy-to-understand guidance. To make detailed decisions about your fire safety provisions, you might require further advice or need to consult the full standards and legislation.