Mag Lock Attractions: When, Where, How?

Electromagnetic locks have been in use since at least the 1980s and are a mainstay among the locking solutions we use in access control security and life safety. Misuse of electromagnetic locks has resulted in their being banned in some jurisdictions, and the development of exhaustive building and safety codes to regulate their use.

My first exposure to maglocks involved Locknetics maglocks in the early 1980s. At that point, this was still a relatively new technology, and mag locks were typically installed by locksmiths and what were at the time called access control installers.

Maglocks were a great solution for securing and permitting electronic control of storefront doors where other electric locking devices were either not practical to deploy or not considered aesthetically pleasing.

Many companies began manufacturing electromagnetic locks, and they were aggressively marketed to a growing number of individuals who were becoming involved with access control. Back then, there were fewer codes and a more limited understanding of what maglocks were or how they worked, and therefore safeguards and enforcement were inadequate. The result was that individuals were deploying maglocks without giving adequate regard to the life safety consequences of an improperly deployed electromagnetic locking system, and accidents resulted.

In reaction, electromagnetic locks were, and continue to be, illegal in many jurisdictions. In all instances, it is the Local Authority Having Jurisdiction (LAHJ) who determines what can be used on a door.

National building codes have spelled out the criteria for electromagnetic lock usage, and locks and accessories are available which are intended to conform to these criteria. Regardless of what Code you refer to, it is still the LAHJ who decides what can be used.

Today’s access control system designers recognize the benefits of electromagnetic locks and the constraints placed on their deployment by the codes. They understand that electromagnetic locks are not the one-size-fits-all solution some people seem to think they are.

Electromagnetic locks can be used on swinging, sliding and overhead doors and gates, within the interior, on the perimeter, or outdoors.

Maglocks with conduit fittings and additional weather proofing are available for these types of installations.

 

Security vs. Pedestrian Control

Electromagnetic locks are useful for security as well as traffic control applications. For security applications, holding force and vandal resistance are concerns which the security professional must address when specifying the lock, and planning the installation.

Electromagnetic locks for traffic control are frequently in the 600 lb. holding force range. Security rated maglocks are typically 1200 lbs holding force. Higher holding force maglocks are also available.

The only real advantage to using a smaller maglock, besides perhaps a smaller lock and a lower current consumption, is cost. The smaller maglock will cost you less. However, please consider that the holding force ratings are based on a few things: the right voltage, an optimal alignment of the electromagnetic lock and the armature, and the mating surfaces are clean and not dirty, or corroded. The maglock may not be providing the rated holding force once it has been in service for a while. Using a larger maglock provides an additional margin of security for your customer.

Critical components of the maglock and the power source and wiring to the lock must be protected and immune to compromise, especially from the unprotected side of the opening. For traffic control, in other words on interior openings within the protected area, maglocks with lower holding force may be appropriate, and ant-vandalism measures may not be required.

 

Door and Frame Types

The type of door and frame, the swing of the door, and the adjacent walls and ceilings all factor into the selection of the maglock and maglock mounting accessories, as well as the execution of the installation.

The swing of the door is one of the first concerns. If the door is a means of egress (is there an EXIT sign above it?) and the door is not outswinging, there may be a problem right there. I recommend you call the LAHJ and confer with your client before you proceed.

Generally speaking, any door in the means of egress must open in the direction of egress. Whenever I encounter an inswinging egress door, it indicates to me that the occupancy of the building may have changed from when it was first built, and the floor plan has been modified, perhaps without filing the plans and obtaining a building permit.

You are not doing anyone any favors trying to conceal a violation, and you are looking for big trouble installing hardware on a non-compliant door. As a matter of fact, your having been on-site could implicate you if ever an accident involving the door were to ever happen.

Aside from the life safety issue, it is possible to install a maglock on either the push or pull side of a door with the correct hardware.

Next, the amount of flat surface on the header for the secure mounting of the electromagnetic lock must be addressed. Each maglock has its own requirement. The bracketry you will need to use will depend on the profile of header.

Also the presence of a blade stop in the frame must be dealt with. The least attractive solution would be to cut the blade stop out of the frame.

There are two parts to an electromagnetic lock - the magnet (fixed portion of the lock which is mounted on the stationary frame) and the armature, which attaches to the door or gate.

For solid wood or metal doors, there is usually no problem with drilling through the door and installing the Sex bolt typically used for mounting an electromagnetic lock armature.

If you are installing on a full Herculite door, you will need a special bracket. Some manufacturers also have special adhesives available for these occasions. If you are installing on a gate, you may need adapters for mounting on the gate.

For aluminum storefront doors, you may be confronted with a top rail which is too narrow for the centerline of the sex bolt, or there may be an obstruction (specifically a threaded rod which extends through the width of the top of the door frame which is holding the door together) in the way. Many manufacturers offer adapters and workaround solutions for all these situations.

 

Features (options)

Conduit fittings: These are used for situations such as outdoor installations on gates, and also on interior frames which are in block walls and or concrete frames.

High/low profile: Maglocks vary in height from manufacturer to manufacturer. The Americans With Disabilities Act (ADA) requires a clear opening of 80” high and 32” wide. Therefore figure all this in when planning your project.

Door Status Monitor: This is usually an optional feature. Since the sensor is built into the maglock, it saves you the labor and expense of providing an additional door position sensor component.

Bond Sensor: This is another optional feature used for higher security applications. The bond sensor sends a signal that indicates that a magnetic bond exists between the armature and the face of the electromagnetic lock. Be aware that if your access control system specifies a door position sensor for timing purposes, a bond sensor is not a suitable substitution. For example if your system controller will relock the door when the door position sensor indicates the access (or REX) event has been completed, a bond sensor might prevent the door from ever relocking. The bond sensor would be used for security and in addition to the Door Position Sensor.

Timer: An integral timer circuit might be useful for your design. When the power is cut to the maglock then re-applied, the timer keeps the maglock unlocked for whatever delay you have it set for. This is not useful or appropriate in all scenarios.

Integral Motion Sensor: Having a motion sensor integrated into the maglock makes for a more streamlined installation and eliminates the labor and expense of another component on the bill of materials. Most Life Safety Codes require that a maglock-equipped door open by the movement of the person towards the opening. This requires a motion sensor. This device is referred to as REX motion sensor, and there are a variety of these products available.

Besides unlocking the maglock, REX sensors usually provide a dry set of contacts for interconnection to external electronic access control equipment. If the door being controlled is being monitored by a door position sensor, and programmed to report FORCED DOOR or PROPPED DOOR events, then a REX sensor is required so that the door may be used for authorized egress without the system reporting a FORCED DOOR or PROPPED DOOR message.

When using a REX motion Sensor, care must be taken to aim the detector so that it only picks up movement in a precise area in front of the door so that the sensor cannot be tricked into unlocking the door by individuals wishing to gain unauthorized entry.

Self Contained Delayed Egress: All the components required for a Delayed Egress Locking system are built into the device. Besides simplifying installation, having everything designed and integrated in the factory ensures the device will operate as expected after it is installed.

To read additional Locksmith Ledger articles on electromagnetic locks, visit http://tinyurl.com/maglock1111

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