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Guest DruGi

Please help. We have a maglock entrance door to our building. I have recently had an external company come in and carry out their maintenance. Their remedial works are to fit an interface to the door so in the event of a fire this becomes fail safe. This i understand, but is this a legal requirement to make the door fail safe. The door has a green push button to activate it, but this would not deem it fail safe. Please advise

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Hi, by its nature a maglock is failsafe.

A maglock can only hold a door secure for as long as it is powered. I would guess that the 3rd party company are going to connect the maglock to a fire alarm interface. When the fire alarm activates the interface will remove the supply to the maglock, which means the door will release.

Although you have a green button (probably marked "Press to exit" ) if there is a fire, people often panic and may forget to push the button to release the door, so by having the maglock interfaced with the fire alarm, it removes this possibility.

There should also be one of these GreenBreakGlassUnitD2.jpg by the front door. Unlike the green button you have that is a "request to exit" this will break the supply to the maglock (same as the fire alarm interface does) so releasing the door. If the worst happens, and the supply to the maglock is burnt through, because it is failsafe the maglock will release the door.

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Like many inquiries the lack of necessary information make it’s very difficult to give a reasonable response. Quite often there is no direct link to a regulation but certain actions are required to ensure the principle regulation is completed to a satisfactory standard.

In this case the principle regulation is, all premise subject to the Regulatory Reform (Fire Safety) Order 2005 is required to conduct a fire risk assessment (FRA). Part of the FRA is Means of Escape (MoE) and the door in question is part of that MoE so it has to meet all the requirements of a final exit door which needs to available at all relevant times and be openable without the need of a key.

The fire risk assessment should consider whether

a. A green emergency release unit is required and

b. Whether the magnetic lock is required to release automatically on operation of the fire alarm.

We would need to consider who would use the door- public or staff only, and how many people may need to use the door. We would also need to consider what other exit hardware was fitted and how it all works together, e.g. is it necessary to manipulate more than one device to open the door. If so is this a risk?

For say 10 employees in an office an interface to the alarm is most likely not needed, a green break glass box may be advisable (usually is- depending on the installation) but if members of the public are involved, or large numbers of people it would be advisable to have the door unlocked by the fire alarm before they get to the door in an emergency.

As soon as a maglock is connected to the fire alarm BS7273-4 will apply. Let’s not forget that BS7273-4 only relates to the interface of the magnetic lock with the fire alarm system. If there is no such interconnection then BS7273-4 does not apply.

In this case I am not sure if a FRA was conducted and an inter connection with the fire alarm was necessary and if a mechanical means is available to open the door (Turn screw knob) then BS7273-4 does not apply. Although in this case a mechanical/electrical means is used to open the door which will be tested constantly during the day by person leaving the premise, however should the electric supply fail would it failsafe to open or closed, if it is closed, which is more likely you would need some means of overriding the maglock to escape. I would suggest you find out more about the means of operation of the maglock and find out what is the purpose of the interface fitted.

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  • 4 years later...

Hi I am looking for some advice but realise this post is some 4 years old and regulations may have changed with regards BS 7273-4.

When you have proximity access control system fitted to a final exit door that is secured by a magnetic lock or similar fail safe locking device it is generally battery back up so if the system fails the battery will still hold the door locked until the battery elapses. However without a low battery drop out circuit install a magnetic lock will still hold on battery power to below 3 volts, which will just make the door locked but not very well.

Secured by Design asks for the battery backup facility  and also they have outlawed the use of a green BGU.


The BGU will always be a failsafe device dropping the lock supply positive supply via the normally closed circuit (Providing the door is a failsafe/unlocked locking device).

SBD wish the BGU on residential blocks to be replaced using a self-resetting push to Exit switch. This has its challenges as there are not any such devices on the market


A lot of clients are using a PTE which is double pole double throw, so the normally open connect to the timed circuit of the access control system and when pressed produces a timed controlled release. The normally closed set of contacts switch the positive side of the lock, when the button is held depressed. This is a failsafe exit, but it does rely on you being able to hold down the button while opening the door.


So as a backup if there is a FA or AOV system most installer will connect the access control system to the FA or AOV system, which makes sense. However a lot of installers are just connecting the FA/AOV to a timed release of the access control using CAT5. In my mid this is wrong as if that trigger fails the doors will not open. Is there any rules in BS7273-4 or any other regulations that state there should be a local I/O relay connected to the FA/AOV that has the power of the lock going through the Normally open, held closed contact, so when the FA/AOV system are triggered the power to all I/O relays coils are dropped so the relay fails open thus failing the lock supply opening/unlocking the door as this appears to be a grey matter. Also should all lock supply cables be a minimum of 1.0mm as many are using CAT5 cables to power these locks.


How do the rules differ between a FA system and AOV system when it comes down to unlocking a final exit door with access control?


SBD are also trying to replace the fire man drop key switch with a global latching switch which when operated unlocks all doors. What’s the rules here about a global trigger? To achieve this  surely it need to be a fail safe operation as if it’s just a trigger to the access control, if the trigger or trigger cable fail the doors will not release.

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Hi, I did get a little lost with my lack of understanding on these units.  I hope you don't mind if I raise a query on the topic of magnetic locks.  They are frequently used in residential home on final exits and to segregate areas  IE residents with different mental capacity, limit access to stairways etc.

If the magnetic locks fail to the open:

  1. on operation of the fire alarm,
  2. on failure/fault of the fire alarm,
  3. on electrical power failure,
  4. and on operation of a key pad

Then why are manual green overrides necessary?

Staff assist all residents and visitors to safety, key code pads are a balance between safety and escape.  Operation of normal fire alarm call points will release the maglocks - staff are aware.

It still is common practice for some Enforcing Authorities to require the Green Override Call Points - can anyone explain what added value they provide??

Thanks Ron

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  • 5 months later...
Guest Maglock Query



Can you please help? 


I have a client who I have fitted an exit door for. This door is fail open in the event of a fire, and fail secure in the event of a power failure. However exit buttons still work in a power failure, the entry system (a finger print reader) does not. So in the event of a power failure, entry to the building is not possible. 

Is this following British standards??




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Can't fail secure on a power failure if required as an emergency exit. That's why access control systems have back up power supply units next to each door in order to keep it secure if the mains fails. The installation should meet BS7273-4 and would usually fail safe on power failure, fire alarm activation & via a green breakglass unit next to the door that operates a double pole isolator on the doors power supply causing fail safe release.

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  • 7 months later...

Thanks Richard I will add it to my collection and in answer to Ron all the points he raised can fail except the electrical power failure, which may happen if there is no fire emergency, so BS 7273-4 requires a green BGU or a manual release because it is the most reliable system to ensure the door can be opened from the inside. Incidentally my interpretation of SBD New Homes 2016 - Clause 27.8, in not compromised.

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  • 4 years later...
Guest richard

hi all

does anyone know the legal required location for green mag lock over ride boxes  as in which side of the door it has to be on? our mag locks are all linked in to the fire alarm system which is tested weekly 

the mag locks are used to restrict access to certain areas but the green over ride is on the side which is constantly being pressed by the people we are trying to restrict ass to can i move the green over ride to the other side of the doors which is staff monitored and if so is there a bs number that would confirm this 




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  • 1 month later...

Can I have some advise, we had a double door that is fobbed to stop students getting through.  The door releases when the fire alarm goes off but we also have a green door release box.  Students keep pressing this and getting through the door, can it be removed?

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Not generally - not all evacuations are for fire. It's poor design of the premises, you shouldn't have an escape that also requires securing from exit (as oppose to entry) .
Risk Assessment can, in certain situations, remove it, such as in places of detention, but it's the default expectation in guidance and Building Regs that you have the override.

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