Locks and Security News: your weekly locks and security industry newsletter
15th March 2023 Issue no. 647
Your industry news - first
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What is an electro-magnetic lock?
Electro-magnetic locks hold a door shut using the power of magnetic attraction. An electro-magnet only becomes magnetic once electrical power is applied to it. When there is no power applied, it does not generate a magnetic field. This means the door can be freely opened
Is a maglock fail safe or fail secure? Fail safe and fail secure is a key distinction in electronic locking. Each type is better suited to certain environments and particular projects. Fail safe locks are unlocked when power is removed. Power is applied to lock the door and prevent access. Conversely, fail secure locks are locked when power is removed. Power is applied in order to unlock the door and allow access.
By their nature, electro-magnetic locks are fail safe. Power must be applied to the magnet in order to generate the magnetic field and hold the door locked. When power drops, the magnetic field also drops, and the lock is released.
Because of their fail safe nature, electro-magnetic locks are well-suited for use with fire doors and emergency exits. This is because in the case that the power supply cuts out due to an emergency, the door will automatically unlock. Without power, the magnetic field generated by the maglock drops, allowing people inside to safely exit.
Maglocks are also a handy solution for glass doors. Where a wooden or plastic door could have a different type of lock such as an electric strike or solenoid bolt fitted into the body of the door leaf itself, glass doors are more tricky. Electro-magnetic locks can be fitted onto the surface of the glass door and/or a glass frame using brackets.
How do electro-magnetic locks work?
The lock (often known as a maglock) consists of two parts: the electro-magnet itself and an armature plate. The magnet is fitted to the door frame, while the armature plate is fitted to the door leaf. When power is applied to the magnet, it generates a magnetic field. The armature plate is strongly attracted to the magnet. The force of attraction between the two components holds the door firmly closed.
What kinds of electro-magnetic locks are there?
There are many variations of maglocks, each slightly different and each better suited to slightly different installation scenarios. It’s important to understand these distinctions to make informed choices.
Internal or external
Some electro-magnetic locks are only suitable for installation in indoor environments. Others are more hardy and can be installed outdoors on external doors and gates. External maglocks are tested under the IP ratings system to establish their resilience to the elements.
IP ratings consist of two digits. The first digit refers to the lock’s ability to withstand ingress of solids such as dust and other particles. It is ranked from 1 to 6, with 6 meaning the locks is completely protected against dust ingress. The second digit is all about resilience to liquids. It is measured from 1 to 8. Up to level 6, the ratings describe the ability to withstand different strengths of water sprays and jets. Levels 7 and 8 describe degrees of protection when the product is immersed fully in water.
Almost all CDVI external maglocks are rated IP68 – the highest possible protection rating.
Surface or mortice
There are two ways an electro-magnetic lock can be mounted onto a door. Each of the two types requires slightly different brackets to fix the magnet and armature plate to the door in the correct way.
Surface maglocks: pull or push door?
Surface maglocks are fitted on top of the existing door and frame structure. There are two different configurations depending on whether the door is a push or pull door.
For a pull door, you need a Z&L bracket to mount the components. The magnet is fitted to the L bracket and mounted onto the front of the door frame. The armature plate is fitted to the Z bracket and mounted onto the door leaf. The Z bracket ensures that there is space for the magnet and the armature plate to meet without having to cut into the door frame or the door leaf.
For a push door, the armature plate is fitted directly to the closing side of the door leaf. The magnet is fitted to the door frame, hanging down from the top edge.
Mortice maglocks are fitted into the existing structure of the door and frame. A hole the same size and shape of the magnet must be cut out of the door frame. The magnet is then recessed into the hold, leaving a flat surface with the magnet flush with the frame edge.
The armature plate is likewise fitted into the door leaf, leaving it flush with the surface of the door’s edge. When the door is closed and locked, neither part is visible.
A mortice maglock is usually fitted into the top of the door and door frame, but it is also possible to install them in the floor and the bottom of the door.
Monitored or unmonitored
Monitoring is a feature that allows you to track the status of an electronic lock, usually in real time. The magnet includes a sensor that indicates whether it is active (and locked) or inactive (and unlocked). If the maglock is being used in conjunction with a networked access control system, monitoring means that the lock status can be viewed and tracked in the system.
Holding force is the strength of the maglock. It’s measured in weight – usually kilograms in the UK and pounds in the USA. CDVI electro-magnetic locks are generally available in 180kg, 300kg, 400kg, or 500kg holding force. The number tells you how much weight would have to be applied to the door in order to break open the maglock by force. As such, the higher the holding force, the stronger the magnetic field generated, and the more secure the lock.
Can maglocks be used on fire doors?
Provided they have a suitable fire rating, electro-magnetic locks are well-suited for emergency fire doors. Firstly, there are no moving parts that could become distorted or warped in the heat of a fire. Secondly, as they are fail safe in their locking mechanism, if the building’s power was cut due to a fire, the emergency exit would be immediately unlocked to allow people to safely exit.
Electro-magnetic locks are versatile, efficient, and robust locking solutions. Whether you have traditional manual doors, automatic doors, external doors, or emergency doors, magnetic locking could be the right choice for you.
30th November 2022