BHMA PUBLISHES REVISED STANDARD FOR CABINET LOCKS

ANSI/BHMA A156.23 Covers Products Used in Access Control;
Important for Safety and Security

NEW YORK, NY — The Builders Hardware Manufacturers Association (BHMA) announces the publication of ANSI/BHMA A156.23–2004 American National Standard for Electromagnetic Locks.

This updated standard covers requirements for electromagnetic locks, including cyclical, dynamic, operational, strength and finish tests. A variety of electrical tests are included in this standard as well.

Electromagnetic Functions
Electromagnetism can be used to lock or unlock a door by activating or deactivating an electromagnet that is coupled to an armature. Also called a strike, the armature is a plate that is attracted by the energized electromagnet component of the lock. When the armature is in contact with the magnet, it is resistant to being separated from the magnet. Used in access control, they are critical to security. Where means of egress is important, this standard also affects safety.

Identifying Numbers
The standard provides an explanation of a standard numbering system for identifying electromagnetic locks. An example identifying number is E18501-1000. In this numbering system, the first letter denotes BHMA Product Section (E). The first numeral indicates indoor or outdoor type, where “0” refers to all except indoor-only and “1” refers to indoor only. The second numeral identifies the type of product, where “8” refers to electromagnetic locks. The third and fourth numerals further identify product types based mainly on the mounting location and whether they are direct pull or shear designs (see explanation below). The fifth numeral designates the grade of the item. The highest grade is 1. Finally, the appropriate level of holding force for the application is specified by a suffix, known as the “holding force rating,” in 500 pound increments.

Thus, the identifying number E18501-1000 describes an indoor only, electromagnetic, Type 50, Grade 1 lock with a holding force rating of 1000 pounds. Type 50 refers to a lock that is mounted on the header of the door with the armature mounted on push side of door. Product type designations 50 through 99 are reserved for electromagnetic locks in various types. The standard provides example illustrations of Types 50 through 60.

A Grade 1 lock must meet a cycle test requirement of 1,000,000 cycles.

Direct-Pull and Shear Types
Electromagnetic locks can be classified as direct pull or shear locks. For the direct pull type, an opening force applied to the face of the door is directly opposed by the attraction between the magnet and armature, along an axis perpendicular to the face of the door; the contact plane between magnet and armature is parallel to the door face. For the shear type, the attraction between the electromagnet and armature moves one or the other (usually the smaller armature) not only into contact with each other but also into a position of mechanical restraint by a third member. The latter prevents sliding separation (shear) of the magnet and armature along their contact plane. To unlock, the moving member is then retracted into its original resting position by mechanical, magnetic, gravitational, or other force.

To purchase copies of the ANSI/BHMA A156.23-2004 standard, and see a list of manufacturers who certify their products to the Standard through a third-party test program, please visit BHMA’s web site at www.buildershardware.com Purchased standards are available as printed documents or as electronic files (PDF) for immediate download. You can also order standards by phone by calling 800-699-9277.

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