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Safety And Security

Unlocking The Mystery

September 19, 2010
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Electrified hardware is becoming increasingly more sophisticated in both functionality and appearance.

An electrified opening can be linked to a network, allowing user access privileges to be changed instantly.

Important security tasks, such as integration of door locking hardware, changing user profiles, identifying possible security breaches and issuing lockdowns, can all be completed from a centralized computer.

In addition, electrified openings can be linked with the facility alarm controls.

If a fire alarm is activated, the control panel will send a signal to automatically close all fire doors and bypass delayed egress exit devices.

This versatility makes electrified openings ideal for facilities that require tight control over security and life-safety.

Why Choose Electrified Hardware?

Justification for the purpose of choosing electrified hardware in lieu of mechanical hardware includes security, life-safety and convenience.

With electronic hardware you can monitor the state of the opening — whether the door is in the open or closed position — monitor the latchbolt to determine if it is "thrown" properly into the strike, and with the use of electronic keys and software, you can audit the opening to have a record of who unlocked and entered an opening at what time of the day or night.

Life-safety is also enhanced by electrified hardware, which allows fire-rated doors to be held open and tied into the fire alarm system so that when the fire alarm engages, the power to the electromagnetic holder or closer cuts off, allowing the door to close and latch as required by code.

While security and life-safety are the most critical issues that must be addressed, convenience is a luxury every user and building owner desires.

Automated openings make operation of the door very convenient.

New technology allows an opening to be monitored from anywhere in the world via the Internet.

In addition to security, life-safety and convenience, other benefits include better access, egress control and more efficient operation.

With electronic keys, an employee is unable to simply walk into a hardware store and cut extra keys to the office.

These keys are controlled by a computer which is monitored by the person responsible for the maintenance of the system.

The control offered by electronic keys allows the person in charge to be made aware that a key has been lost or misplaced and that key be removed from the system.

There are four components required in an access control system; these components are: The power source, load, control and conductor.

Power Source

The power source, also known as the power supply, ensures proper voltage, which is a term used most often to describe the electrical energy that causes current to flow in a conductor, similar to pressure in the water pipes in a plumbing system.

The power supply also ensures that the proper current — alternating current (AC) or direct current (DC) — is present in order to properly operate the system.

The amp, which is a unit of measurement for the rate of electrical current, is the last piece of information required in order to specify the proper power supply.

The power supply has a transformer, which takes in the high voltage from the power company and reduces it down to the low voltage required by the load, and the rectifier within the power supply changes the current and converts the voltage to DC.

Power supplies should be specified with capacitor filters and regulators that will ensure the correct voltage output required for the device.

If the device requires 24 volts of DC and there is no capacitor filter and regulator, the output could be too high or too low, which will either not allow your device to operate properly if at all or burn it out, requiring replacement.

The last point regarding the power supply is the amps.

The power supply must be specified with the amps equal to or greater than the device.

If the device requires one amp, the power supply must be able to handle at least one amp if not more; if more is available, additional devices can use the same power supply, also depending on other factors such as the conductor gauge and distance.

A battery backup option is available for systems that are not required to be tied into the fire alarm system.

This ensures that the system will remain operational during a power outage for as long as the battery life will allow.

Load

The load, also know as the electronic locking or release device, can be one of many types including mortise locksets, cylindrical or bored locksets, panic or fire exit devices, electric strikes or unlatch devices and electromagnetic locksets — surface mounted or shear-type.

The loads need to be specified as fail-safe or fail-secure, depending on the application, operation required and the codes having jurisdiction, including building, life-safety, fire and local codes.

Fail-safe would be specified if a particular opening needs to open when a fire alarm is engaged, which means that this type of function is locked only when there is power put to the device and unlocked when there is no power present.

Fail-secure would be the opposite, locked when there is no power and unlocked when power is put to the device.

Control

The control, also known as the switch, can be a magnetic strip card reader, proximity reader, smart card reader, a motion sensor, push button or any type of device that turns an electrified locking device and/or off.

These switches are operated by a variety of means, including electronic keys with similar technologies to their respective readers, again including magnetic strip card, proximity card or a smart card — an electronic key with a microchip capable of storing a large amount of information.

Conductor

The conductor, also known as the wire, is the final required piece of the puzzle.

There are two factors that will affect the system in regards to the conductor: The amps and the distance of the wire.

The more the amps and the greater the distance, the larger the gauge of the conductor required so that the voltage does not dissipate over the distance.

If the incorrect gauge wire is used for a high-amp, long-distance conductor, the 24 volts that you started with could be reduced greatly by the time it reaches the load, not allowing the load to operate properly and compromising your system.

In addition to the required components of the system, several additional options can also be incorporated.

Some of the options available include motion sensors, request-to-exit switches and door contacts, some of which might already be required depending on the application and the local building, fire and life-safety codes, not to mention the local authority having jurisdiction.

A Closer Look At Loads

Electromechanical versions of mortiselocks, cylindrical locks and exit devices enhance access control, life-safety and convenience.

Mortise locks fit into a mortise in the door edge and typically feature levers to operate a latchbolt.

They provide greater torque resistance, security and a greater variety of functions than typical cylindrical locksets and are recognizable by the separate key cylinder above the lever.

Mortise locks can be applied to any door in a facility that requires latching or locking and doesn''t require panic hardware.

The brute strength of a mortise lock makes it a popular choice for securing sensitive areas.

Cylindrical locks are a step down from the strength and durability of a mortise lock and are more appropriate for securing interior openings.

A cylindrical lock requires less door preparation than a mortise lock and is also less expensive and easier to install.

Exit Devices

Exit devices, also known as panic or fire exit hardware, allow safe egress while restricting access from outside a building.

Exit devices consist of a push pad or bar which extends across the push side of the door.

When depressed, the device retracts a latchbolt that allows the door to open.

Think of these as a one-way valve through which people can exit but not enter unless authorized.

Life-safety codes establish occupancy or space requirements that dictate which doorways must be equipped with an exit device.

Rooms within education, health care and assembly occupancies with an occupant load greater than 50 persons will require panic hardware.

Strikes And Electromagnetic Locks

Electric strikes or electromagnetic locks can be used to further regulate who passes through access points, providing an even greater level of protection.

Electric strikes are door release devices, usually solenoid-operated, that will unlock the door when electrical power is applied.

An opening that requires a person to be "buzzed in" is equipped with an electric strike.

The buzzing sound is created when a button is pushed, sending an AC electric charge through the device.

This action disengages the device and allows the door to open.

The operation just mentioned is a fail-secure mode of operation, the most common function of an electric strike.

A fail-safe configuration will operate in the reverse condition; normally locked when power is applied and unlocked when power is interrupted.

If desired, the buzzing sound can be eliminated by using a DC power source.

Electromagnetic locks mount on the fixed frame and a strike plate mounts on the moving door or gate.

When the door closes, the strike plate automatically aligns with the magnet.

The magnetic force then takes over, strongly securing the door.

Release is achieved by switching off the power to the magnet.

Electromagnetic locks are available in a range of holding forces.

Facilities that demand greater security, such as a detention facility, will need magnetic locks with holding forces that approach 2,000 pounds.

Since electricity is required to power the magnet, all electromagnetic locks are fail-safe unless they are equipped with a backup power supply.

Electromagnetic locks operate on DC power and, unlike electric strikes, are silent when locked or unlocked.

Both electric strikes and electromagnetic locks are commonly operated with a push-button switch, making them ideal for personnel-monitored openings, such as office suites and hospital ward entrances.


Scott Tobias, AHC, CSI, CDT, LEED AP, is a regional architectural manager for ASSA ABLOY Door Security Solutions managing a team of 16 architectural and specification consultants. Scott has spent 20 years in the architectural door and hardware industry and is a past president of the executive board of the New York Chapter of the Door and Hardware Institute (DHI). He continually presents educational workshops at various conventions, conferences, trade shows and architectural offices. Scott can be contacted by telephone at 845-742-4827 or via e-mail at stobias@assaabloydss.com.

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