Door Considerations: Specification with Security in Mind
By Thomas A. Westerkamp - January 2005 - Doors & Hardware
Organizations continue to update their facilities to enhance the security of occupants and visitors, and door hardware products play a central role in these efforts. Savvy specification requires a solid understanding of both existing options and emerging technology.
A Look at Locksets
Maintenance managers have three main types of concealed locksets to consider: mortise, integral and cylinder.
The mortise lock is a large rectangular assembly that fits into the door edge. The mortise lock is the most frequently used in applications such as hotel rooms, storerooms, and institutional and residential outside doors because of the double-bolt design.
The integral lock fits into a cutout or mortise, depending on style. It provides the security of a mortise lock but is smaller and more economical. The integral lock is used for inside applications.
The cylinder lock fits in a rectangular shallow mortise in the door edge and a separate drilled hole in the lock stile, or face, of the door. This type is most often used for indoor offices and closets.
There are a number of electronic, electromagnetic and electromechanical locks available. These locks can be changed from a remote station, and they can be time-limited, only granting access during certain hours. They can be locked or unlocked throughout a facility from a central station in an emergency, and they might have entry-time-stamp logs showing access occurrences over a certain period.
Managers also have several choices of electric locks. Electromechanical locks are actuated electrically but operate mechanically, just like a mechanical mortise or cylinder lock, and fit in the same standard opening. Magnetic card locks replace the mechanism and have a magnetic force of up to 3,000 pounds. Touch-entry key locks require a coded key or an identification badge to enter. Digital keypad combination locks require users to select a set of numbers on a touch pad.
Help with Hinges
The most common hinge types are butt, surface, invisible, floor and pivot.
Butt hinges are mortised into the edge and jamb of wood and hollow metal doors. When the door is closed, only the hinge pin and pin housing, called the knuckle, are visible. For security, managers can specify that the pin be non-removable.
Surface hinges are used where it is not possible to mortise the door and jamb. Invisible hinges are completely concealed in a mortised hole in the door and jamb.
Floor hinges are inserted into a mortise in the door head and bottom for a double -swinging door. Gravity-type pivot hinges are used for cafe doors that swing in both directions, while pivot hinges are used primarily for cabinet doors.
Electric hinges supply electric power continuity between the door and jamb for alarm systems or electric locks. They are mounted in the center, non-load bearing hinge position for three-hinge doors. An armored door cord, consisting of a cable and two end plates, is mounted on the door for two-hinge doors.
Door-panic hardware consists of a door latch assembly that releases when users apply pressure to the push bar, a horizontal bar that attaches to the door stiles. The latches in the head and floor are connected to the push bar by vertical rods.
Hydraulic and pneumatic door closers control doors so they close quickly but quietly. They reduce shock to door members and hardware. Hydraulic closers, used most often in commercial applications, contain an oil reservoir and cylinder with an adjusting nut that controls oil flow into the cylinder to adjust closing speed and impact against the door frame.
Automatic door operators can be installed on swinging, sliding, folding or overhead doors. Available operators include: non-contact motion and presence detection, push button, push plate, keyed switch, rotary switch, radio-controlled switch, and industrial switches, such as a pull-chain type. Easy opening and low-energy versions are ADA-compliant.
State-of-the-art integrated controllers are capable of handling the many functions and locations. They control all the input and output signals generated so electric hardware can respond to any entry or exit sequence.
Besides controlling the power requirement and wire termination, they are the designated gathering point for all devices and services, including line power, monitoring and control systems. Controller boards provide a series of relays that can be selectively linked from input switches to switch output devices, providing either power or isolated dry contact signals to external systems.
Associated timer-controlled operations are selective. They can be linked to each other, as well as to relays.
Maintenance and engineering managers specifying door hardware and security devices might want to consider new enhancements to improve existing door hardware and facility security as follows.
Battery eliminators. These systems are designed to power security devices, such as exit control locks or exit alarms, without batteries. One version supplying 6- or 9-volt power to the security device can drive up to three units. It connects via 16 gauge stranded wire run from the most remote unit up to 75 feet away. Other standard features include line input transient suppression and power status LED.
Flexible armored cable connects the battery eliminator easily to the security device without interfering with door use. For extra security, the connecting cable can be concealed in the door using a continuous electric hinge.
Vertical rod assemblies. These assemblies provide exit control for double out-swinging doors. With three-point latching feature, they also can provide extra security for single doors. Integrated with a pair of exit control locks and outside key control on the active door, they offer outside and inside lock-controlled entry and egress through a double door exit.
Double door holders. These holders work with exit control locks to lock the inactive side of an out-swinging double door. Releasing the active leaf disengages the double door holder, freeing the inactive leaf to open. The holder, with interchangeable pin that enables installation on either leaf, automatically locks the inactive side when the active side is closed. A stainless steel spring feature allows instant emergency egress.
Magnetic surface-installation switches. These switches are versatile sensing devices that perform a number of security functions. They detect the opening of a door or window, they assure that a door or window is under surveillance, they trigger a wall-mounted exit alarm, they signal that a door has been unknowingly left open, or they act as a switch to energize alarms. Using reed-switch technology, these switches can deliver over 1 million performance cycles.
Proximity-based verification. Pointing a proximity pen — a hand-held data acquisition unit — at radio frequency identification (RFID) tags located throughout a building assures that guard tours are made properly, documented and time-stamped. The device simply needs to get close to the tag. It does not need to touch it to record the data. Tags can be behind dirt, paint, plaster, wallpaper, sheetrock or any non-metallic surface where vandalism or aesthetics are issues.
The pen can deliver 50,000 readings from one AA battery. Readings are confirmed by visual and audio signals, and tampering is controlled by an automatically recorded time-stamp when the battery is removed for more than ten minutes.
Whatever the combination of door hardware specified and installed, the priorities for managers need to include reliability as well as cost-effectiveness.