Electromagnetic locks, like this one from Security Door Controls (SDC), can be mounted either at the top or bottom of a door.
Delayed egress devices, like this one from Detex, require a person to wait 15-30 seconds before the door will unlock.
Electric strikes, like these from Dortronics, are a favorite among architects and security system designers.
The modular design of the Schlage AD-Series security platform from IR enables users to customize door openings by credential reader, networking, finish and levers without replacing the lock or even taking it off the door.
When you consider all of the hardware and software elements that constitute an access control system, perhaps the least technical is the door hardware. Yet the application of that hardware is the least understood and subject to more headaches than any other component. Why should that be? And what are the factors that need to be overcome to allow innovation and advancement?
At the heart of this dichotomy is struggle between two different disciplines and the standards that control them. The security discipline has a need to control access and egress at portals, and life safety requirements dictate that all persons - including those intent on criminal activity - can readily escape an area in an emergency or life-threatening situation. And, because the life safety is the more important, it is subject to more standards and codes than security. In most areas of conflict between the two (except, perhaps, in the military), security is the one that is required to compromise.
The Impact of Codes and Standards
Thus, the application and operation of door locking hardware, which ultimately controls access and egress at portals leading to and from spaces that store assets, are subject to strict codes and standards while other systems components - such as access control software and intrusion alarm sensors - are not so burdened. Indeed, in most major U.S. cities, the authority having jurisdiction (AHJ) over building codes insist that the division between life safety and security systems be complete. For example, most AHJs require that the release of an electrified door lock in an emergency situation must be performed by approved (rigidly and independently tested) fire alarm system components.
It is the rigid and independent testing of devices to meet life safety codes that separates fire alarm and security systems. However, the great benefits of requiring devices and systems to conform to strict codes creates an Achilles' Heel, and this is the underlying reason why most access control components and systems do not submit to such standards. Design changes - be they a better line of software code or a new design for a fixing screw - require costly and time-consuming re-testing and re-certification. Thus, product development is somewhat stifled by the additional costs and delays associated with standards compliance.
For door hardware that is subject to life safety, code simplicity is king: mechanical systems are considered less complex, and therefore more reliable than electrical systems. Indeed, some AHJs will not approve the installation of electromagnetic locks to control doors that are in the required path of life safety egress and delayed egress systems. With all of their fail-safe components, the locks are still treated with suspicion.
In such an environment, it is not surprising that there is much less innovation in locking hardware than in the other, less-rigidly codified elements of security systems. However, necessity being the mother of invention, new door hardware products are always being developed and innovative designs that provide needed functionality, improved reliability and reduced hardware or installation cost reach the market every year.
Some of these innovations are immediate successes, some take a little longer in this very conservative marketplace; and some are bright ideas, but they flicker and fail in the harsh environment in which they must operate. Do not forget that door hardware is abused, mistreated and tested like no other: the shoulder against the door whose handle has not completely disengaged the latch, the mail cart that is rammed into the exit device ("crash" or "panic" bar) to unlatch and open the door that the mail delivery person cannot reach, and let's not forget the piece of two-by-four that is jammed into the hinge side to prop the door open. And those are examples of "legitimate" access! The door and its hardware also has to withstand the attempts at unauthorized intrusion by picking, jimmying, spreading, bumping and plain brute force.
One of the most innovative locks to reach the market was a device patented in 1984, the electromagnetic lock. Now used for many applications, it has the benefits of simple installation without impacting the operation of the regular door latch, handle or hinges. However, since it is bulky and overt, architects drove the industry to design the less-simple and more problematic shear lock with a floating armature plate hidden in the top channel of the door and the electromagnet concealed in the top of the door frame.
Due to a penchant for frameless glass entry lobby doors matched to frameless glass transom and frameless glass side panels, the architect has driven the shear lock design deeper into realms of maintenance headaches with the gravity shear lock. The electromagnet is buried in the floor (a "magnet" for dust, grit, stones, rain, snow, ice and salt in winter climates) and the armature floats in a shoe on the foot of the door.
The evolution of the delayed egress systems incorporating magnetic locks was the first real compromise between life safety and security. Fire/Life Safety code dictates that a door in the "path of egress" must allow free egress at all times of occupancy regardless of whether a fire alarm has been tripped - an emergency evacuation could be required for reasons other than fire.
Although a thief with a laptop or pocketbook under their arm is free to make a quick exit at any time, delayed egress can increase security and response. For example, the exit device ("crash" or "panic" bar) does not immediately unlock the egress door but starts an irrevocable countdown (15 or 30 seconds) after which the door unlocks. While 15 or 30 seconds is a very short delay, it gives ample time to sound a local horn and initiate recording of video on both sides of the door.
If there is a fire alarm, the countdown is eliminated and the door can be opened immediately. However, as noted previously, a few AHJs mistrust the "complexity" of these systems and will not permit their use.
While electric strikes were the most common controlled door locking device, the innovations to electric locksets - both mortise and cylindrical - over the last few years have increased their recent popularity. With a full range of styles and finishes to match their non-electrified siblings, integrated request-to-exit switches, and fail-safe/fail-secure interchangeability in the field, these devices are now the favorite with architects and security system designers.
One of the most important waves in recent years has been the proliferation of standalone electronic locking systems. These units integrate the locking functions and a credential reader into a single, battery-powered unit. Many provide a selection of credential reader types - keypad, proximity card, smart card, magnetic stripe and ibutton (Dallas chip) or combinations - and many models have the intelligence to store transaction data for subsequent audit via wired or wireless data transmission.
A newer innovation to this type of lock is the Schlage modular AD system by Ingersoll Rand Security Technologies (IR), with field-interchangeable credential (and credential combination) readers. These units are also field-upgradeable from standalone to wireless and to wired units as the sophistication of the access control application evolves. Although this type of hardware is expensive, total installation costs can be reduced significantly. For example, an installed wired proximity card-reading electronic lock with built-in request-to-exit and door position switch can be installed for about a third less than installing all of these components separately. Stanley's Wi-Q line of integrated wireless locks also features latch position and key override monitoring.
Cav•, an Italian line of intelligent locks under the Assa Abloy banner, uses a technology that makes use of the credential holder's body as an antenna. If only those antenna properties could be used as a biometric. However, if a lock is to unlock under fire alarm control, it must still be wired - wireless switching is not yet reliable enough for NFPA approval.
As these integrated locking systems proliferate and the pricing is further reduced, they may become the standard in offices and classrooms to eliminate mechanical keys and costly rekeying. Battery replacements must still be scheduled - although some units warn you of a low battery condition well in advance - and credentials must be administered, but this can be performed at a fraction of the cost of periodic rekeying and the products provide the higher level of security with a searchable audit trail.
However, locking product innovation is still slow to be accepted by building and life/safety code developers as well as by specifiers and users. It is a conservative industry - and new ideas, like a good wine, are required to mature slowly.
David G Aggleton, CPP, CSC, is principal consultant at Aggleton & Associates, Inc., a security consulting firm, has been specifying security systems and coordinating lock application with architects for more than 30 years. He can be reached at firstname.lastname@example.org