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SDC - CHOOSING THE RIGHT ELECTROMAGNETIC LOCK FOR YOUR ACCESS CONTROL SYSTEM
by Richard Geringer

Electromagnetic locks have no parts to bind or wear, making them ideal for fire life safety applications that require the assurance of trouble-free release in an emergency. The benefits of their easy installation and trouble free operation have also made the magnetic lock a popular choice for applications other than fire life safety.

Because of the increasing popularity of the electromagnetic locks for many access control applications, careful concern should be placed in the proper choice of holding force and the possible need for battery back up. Battery backup is recommended to compensate for the inherent failsafe operation in applications with higher security requirements, particularly on inner office doors. Under no circumstance should battery backup override electromagnetic lock release in perimeter safety applications. In U.S. cities, when installed on perimeter doors, connection to the fire command center is mandatory and battery back up is usually not permitted.

MAGNETIC LOCK SECURITY LEVELS
SDC magnetic locks are available in different holding forces and design configurations to accommodate specific application needs.

1580 Series: 600 Lbs / 272 Kg - Surface Mount, Traffic Control
1570 Series: 1200 Lbs / 545 Kg - Surface Mount, Medium Security
1510 Series: 1650 Lbs / 748 Kg - Surface Mount, High Security
1561 Series: 2000 Lbs / 907 Kg - Concealed or Surface Mount High Security
1565 Series: 2700 Lbs / 1224Kg - Concealed, High Security

Traffic Control
Any magnetic lock with a holding force of 1000Lbs or less should only be used for traffic control, as would a light duty electric strike. It is this authors experience that magnetic locks with less than 1200 lbs holding force may be defeated under the right conditions. At the same time, this is a benefit for traffic control applications when compared to light duty electric strikes. As the electric strike may break when forced, a low holding force magnetic lock will release without damage and the door will simply relock when closed.

Medium Security
Magnetic locks mounted on an aluminum glass door are capable of providing medium security, as the door is more likely to flex and shatter before a lock of 1200 lbs holding force or more will release. However, openings with metal frames and wood or hollow metal doors present different conditions that affect the integrity of the opening. For most interior commercial installations, 1200 lbs holding force may be adequate. But, there are several situations where 1200 lbs may not be sufficient on these types of doors. Such as perimeter hollow metal doors and interior doors of psychiatric facilities where patients may be extremely aggressive, 1200 Lbs holding force may prove inadequate.

High Security
It is important to note that the term high security is used only in the context of a failsafe magnetic door lock application, which cannot compare to the true higher security of electromechanical locking devices, such as heavy-duty failsecure electric strikes and failsafe or failsecure electromechanical locks.

For most commercial and industrial openings with hollow metal frames with wood or hollow metal doors deemed high security, an electromagnetic door lock with at least 1500 Lbs. of holding force is recommended. It is also this manufacturers experience that hollow metal doors may not release, but may sustain damage under such a force.

Magnetic Shear Locks - Medium to High Security

Magnetic shear locks are capable of providing anywhere from 1000 to 2700 lbs of holding force. When installed on openings with hollow metal frames and wood or hollow metal doors, a magnetic shear lock with a holding force of 2000 lbs is capable of withstanding a force that will deform or damage most commercial doors and frames beyond repair before they release.

When installed on aluminum and glass doors the door is more likely to flex and shatter before a lock of 1200 lbs holding force or more will release. When installed on full glass or "Herculite" type doors with a top rail, magnetic shear locks are capable of providing significant holding force. As there are usually no header stops for any of these glass doors, the contact point between the armature and magnetic lock may be exposed to tampering on both sides of the opening. The primary benefit of concealed magnetic shear lock installation on glass doors is an architecturally superior appearance. When mounted on hollow metal frames the shear lock benefits from concealment by the frames doorstop for security.

LISTING AND PERFORMANCE SPECIFICATIONS

ANSI / BHMA A156.23 Compliance for Electromagnetic Locks
When choosing a quality electromagnetic door lock, look for the proper listing and performance specifications. To ensure product quality and performance capability, the American National Standards Institute (ANSI) has adopted construction and performance standards established by the Builders Hardware Manufacturers Association (BHMA). All electromagnetic door locks must comply with several mechanical, electrical and holding force requirements according to ANSI A156.23. These rigorous performance standards also place electromagnetic door locks in three categories.

ANSI Grade 1 - 1,000,000 Cycles
ANSI Grade 2 - 500,000 Cycles
ANSI Grade 3 - 250,000 Cycles

BHMA Certified
This is the only certification in the industry that verifies the manufacturers magnetic lock holding force and ANSI compliance. This indicates that the magnetic door lock has passed an independent pull test and a dynamic impact test for holding force and complies with all ANSI and BHMA construction and performance criteria. While many manufacturers holding force claims may be based on slower pull tests, the electromagnetic door lock may not necessarily pass the dynamic impact test. The dynamic impact test measures integrity against a sudden impact generated by a significant moving force.

UL Listings
UL listings confirm the magnetic lock is safe and that it has been tested for the purpose the product was intended. Minimum UL Listings for magnetic locks should include:

UL Listed - Auxiliary Lock: The label located on the lock must contain the words "Auxiliary Lock" adjacent to the UL mark on the label, to verify the electromagnetic lock has been tested for the purpose it was intended. As an electromagnetic lock cannot provide primary latching that may be required on most doors, it is listed as an auxiliary. Beware of electromagnetic locks that do not bare this "auxiliary lock" description. This listing description should be in the product datasheet and provided on all electromagnetic locks.
UL Listed- Burglary Resistant Electrically Operated Door Lock. In addition to the Auxiliary Lock Listing, the listing "Burglary Resistant Electrically Operated Door Lock" indicates that UL has performed a physical attack test and the lock has passed. This description should be located in the product datasheet and on the UL label. Look for this listing on all magnetic locks rated 1200 Lbs or more. While the manufacturer may rate a locks holding force, magnetic locks are known to perform differently under similar conditions, making this an important test.
UL 10C "Positive Pressure Compliant" and "Classified in accordance with Uniform Building Code UBC "Fire Test for Door Assemblies". The UL 10C rating verifies that the lock does not have negative impact on the integrity of fire rated openings, and complies with UBC code requirements. The UBC code applies to many U.S. cities west of the Mississippi River. This listing should be in the product datasheet and on the UL label adhered to the lock.

US City and State Listings

California State Fire Marshal Listed: In addition to above listings, this listing is required for California installations. The State of California is known as consistently setting fire life safety trends and having the most stringent code requirements in the world.
MEA Listed: Required for the City of New York by the building department Materials & Equipment Acceptance Division.

FEATURES THAT ENSURE EASY INSTALLATION AND MINIMUM SERVICE NEEDS

Installation Features
Look for electromagnetic locks that have easy mount features and do not require special tools, special nuts and mounting hardware that may increase installation time and service costs. Magnetic locks with interconnecting or interlocking quick mount assemblies, captive mounting screws and internal wire connection enable very quick and easy installation and troubleshooting. Wires may be pulled before or after magnetic lock mounting. Some manufacturers even provide self-drilling and self-tapping mounting screws. Considerable hours and installation costs can be saved on such features when installing several locks.

Lifetime Warranty
SDC magnetic locks carry a Lifetime Warranty.

Serviceability of All Components Without Removing the Lock From the Frame
While service requirements are rare for electromagnetic locks, it is an inconvenience should a single internal part or optional status contact fail. If you have a replacement warranty, you still must contend with the inconvenience of ordering, delivery lead-time and install the replacement lock. While the lock is no charge, someone usually ends up absorbing the cost of labor to remove the old lock and install the replacement.

Unlike epoxy filled magnetic locks, SDC surface mount magnetic locks are completely serviceable without removing from the frame and provide a quick and economical solution compared to unserviceable locks. Any part of an SDC surface mount lock is completely serviceable and may be replaced in 5 - 10 minutes. Using interchangeable modules from back-up stock or other locks eliminates all issues associated with lock delivery, labor and replacement costs.

KNOW YOUR COMPONENT PERFOMANCE SPECIFICATIONS

The Benefits For Installing Dealers And Systems Integrators
For a competitive edge, specify and promote the testing and performance attributes of the components you are providing with your installations. Include information on code compliance, city and state compliance, quality (ISO 9001), performance listings (ANSI/BHMA), laboratory listings (UL), service ease and warranty.

The Benefits For End User Professionals
Both mechanical and electrical door hardware components have a direct impact on your facilities safety in an emergency. Don't assume the companies biding your projects are providing quality or properly tested components. It is not uncommon to have untested economy priced products included for low bidding. Know the door hardware products being installed or call SDC's experts for information. Request that component information such as code compliance, city and state compliance, quality (ISO 9001), performance listings (ANSI/BHMA), laboratory listings (UL), service ease and warranty information are supplied with the installation bid. This information may be a deterrent to having an inspector suspend an installation due to non-compliance, causing cost increase. Also, non-compliance of components could potentially lead to liability should a fire or life safety emergency occur in your facility.