Purpose of Door Alarm Monitoring

Most businesses and organizations use some form of card access control system to control entry into their buildings and other facilities. These systems allow authorized employees to conveniently enter through secured doors without needing to use a key.

In addition to controlling access, most card access control systems also provide a door alarm monitoring feature. The purpose of door alarm monitoring is to detect improper use of the card access controlled door. Two types of door monitoring are commonly provided:

“Door-Forced-Open” Monitoring

In the event that any card reader door is opened from outside without the use of a valid access card, the system will cause a “Door-Forced-Open” (DFO) condition to occur.  For example, if an intruder were to pry the door open from the outside, this would cause a DFO condition to occur.

“Door-Open-Too-Long” Monitoring

In the event that any card reader door is propped or held open, the system will cause a “Door-Open-Too-Long” (OTL) condition to occur. For example, if an employee were to wedge a door open, this would cause a OTL condition to occur.

In most cases, the access control system is designed so that a security monitoring center is notified whenever a DFO or OTL condition occurs, allowing an appropriate security response to be made. In some cases this may involve dispatching a security officer to the door to investigate; in other cases, an employee working near the door may be called and asked to see what is going on at the door. If the facility has a video surveillance system, the monitoring center may also use a video camera to observe activity at the door.

The door alarm monitoring feature is a necessary part of any automated security system. It makes no sense to install an expensive card access control system if doors can be opened without using an access card, or if people can walk in freely through doors that have been propped open. When working correctly, the door monitoring feature greatly improves security and provides assurance that all doors are being used as intended.  

The Problem

Unfortunately, the door alarm monitoring feature is a major source of of grief at many facilities. The problem: false DFO alarms. In most cases, these false alarms occur even though employees have done nothing wrong; they simply used the access controlled door in normal manner, yet the system triggered a false DFO alarm. In larger facilities, this can occur hundreds or even thousands of times per day. These alarms can flood the security monitoring center, overwhelming the monitoring staff.

Eventually, monitoring staff may become complacent about DFO alarms, or choose to ignore them completely. At some facilities, false DFO alarms can be such a problem that management becomes frustrated, and chooses to permanently disable the door alarm monitoring feature. Neither of these responses is appropriate as they decrease the overall level of security at the facility and turn the access control system into just an electronic locking system.

Is There a Solution?

Many end-users (and even security systems integrators) have come to accept the false DFO problem as
unsolvable. These people have given up on trying to find a solution and consider false DFO alarms to be a fact of life when using a access control system.

Is there a solution?  Yes!  While false DFO alarms can never be entirely eliminated, Silva Consultants believes that they can be reduced by 95% or more through effective system design.

At facilities that already have systems installed, modifications can be made to existing equipment that will eliminate most false DFO alarms. Fixing false DFO problems on existing systems requires work, but can be done with some knowledge of basic design principles and a little patience.

How Door Monitoring Works

Before discussing specific solutions to the false DFO problem, it is helpful to understand how the door monitoring feature works on the typical access control system.

The typical access controlled door has the following devices:

• Card reader on outside (non-secured) side of door. Common types of card readers include proximity readers, smartcard readers, and magnetic stripe readers.
• Request-to-exit (REX) device on inside (secured) side of door. Common types of REX devices include REX motion detectors, REX switches in lock hardware, and manual REX buttons.
• Electric lock hardware. Common types of electric lock hardware include electric strikes, electric locks, and electromagnetic locks.
• Door position switch. The most common type of door position switch is the magnetic contact switch.

All of the devices at the door are connected to the access control system, usually through some type of intelligent control panel which may be located at the door, or in a nearby electrical closet.

Here is how the access control system door monitoring feature works:

Entering through the door from the outside:

When a user presents his or her card at the card reader, the reader sends a signal to the access control system. If the card is valid, the access control systems sends a signal back to the electric lock hardware, causing the door to unlock. As the user opens the door, the door position switch sends a signal to the access control system, but because a valid card has just been used at the reader, the access control system does not cause a DFO alarm to occur.

Exiting through the door from the inside:

When a user approaches the door to exit, he or she activates the REX device. In the case of a REX motion detector, this occurs when the user steps into the detector’s coverage area. In the case of a REX switch inside of hardware, this occurs when the user turns the door handle or presses the exit bar. When using a manual REX button, this occurs when the user presses the button to leave.  As the user opens the door, the door position switch sends a signal to the access control system, but because a REX device was just activated, the access control system does not cause a DFO alarm to occur.

If an access controlled door is opened without either the use of a valid access card or the activation of a REX device, a door-forced-open (DFO) alarm will occur. This occurs because the access control system has received a signal from the door position switch telling it that the door has been opened, and without having received a previous signal from either the card reader or REX device, it assumes that the door is being forced open.

So, in summary, if a door is opened without using either the card reader or activating a REX device, a DFO alarm will occur.

Common Causes of False DFO Alarms

The following are some common causes of false DFO alarms:

Improper REX Motion Detector Coverage

REX motion detectors need to detect people just as they are ready to open the door. Too often, REX motion detectors are placed where they detect people approaching the door rather than at the door itself. This is sometimes done with good intentions (“I will detect them long before they get to the door”) but can create a “blind spot” in front of the door itself. (See Figure #1 below).

Users can pass through the detector’s coverage area and pause before opening the door, often long enough to allow the REX detector to reset. The user then opens the door, causing a DFO alarm to occur.

The solution: Carefully test each REX motion detector to determine its coverage area. Ideally, motion detectors should be pointed at the door knob or handle and provide detection before a person can open the door (See Figure #2 below). Relocate and/or readjust detector to provide positive coverage at the door and to avoid unwanted coverage elsewhere.

Improper REX Motion Detector Settings

Different brands of access control systems process door position switch and REX device inputs differently. Some systems require that the REX input signal be reset after each opening and closing of the door. Often, the time delay settings on REX motion detectors are set for too long a period. This allows the door to be closed and then reopened again before the detector has had a chance to reset. This causes a DFO alarm to occur when the door is opened the second time.

The solution: Learn specifically how your access control system processes door position switch and REX input signals. Adjust the settings on your REX detectors so that they provide a signal of an appropriate duration. On many systems, the REX detector should be adjusted to reset as quickly as possible after each activation, so that the system receives a series of pulses rather than a continuous activation.

Improper Lock Hardware Function

When a door is controlled by an access control system, the lock hardware on that door should not allow it to be left in the unlocked position manually. Lock hardware that allows this can be be a source of DFO alarms when users open the door manually from the outside without using their access card.

The solution: Examine all doors and replace any lock hardware that allows a door to be left in a manually unlocked state. If a door must be left open during certain times of the day, this should be done through programming of the access control system – not by manual operation of the lock. 

Door Doesn’t Latch Properly

Doors that don’t close and latch properly are a major source of DFO alarms. These occur when a user is able to pull a door open from the outside without using a card, or when a gust of wind blows the door open. Failure of a door to properly close and latch can be caused by many things, including defective doors and frames, defective door lock hardware, defective door closer, improper HVAC system air balancing, and obstructions at the doorway.

The solution: Carefully inspect all doors to make sure that they close and lock perfectly. Doors that must be “given a shove” to close won’t work well with a card access control system. Identify sources of problems and take corrective action. Check doors at various times throughout the day and year as certain problems (such as air balancing issues) may only happen at certain times.

Users are Using Brass Key Instead of Access Card

Most access controlled doors are equipped with lock cylinders that allow the door to be opened using a key in the event that the access control system fails. This works fine if keys are used strictly during emergencies, but causes chronic DFO alarms if users routinely use their key rather than a card to open the door. This not only creates false alarms, but also defeats the accountability provided by the access control systems audit trail feature.

The solution: Brass keys should be used on card reader controlled doors only in the event of an emergency. All lock cylinders on card reader controlled doors should be keyed to a special “emergency key” that is not routinely carried by employees, but instead handed out only during emergencies. If necessary, a break-glass box containing emergency keys can be providing in an area where it is accessible by authorized employees during a true emergency. The emergency key should not be part of the facilities master key system.

Users Forget to Use Manual REX Button

At facilities which use manual REX buttons, users sometimes forget to press the button on their way out, causing a DFO alarm.

The solution: Manual REX buttons are counterintuitive and not very user-friendly. In our opinion, they should only be used as a last resort or as a backup to another REX device. Consider replacing existing manual REX buttons with REX motion detectors or REX switches in the door lock hardware.

Users are Taping or Jamming the Latch Open

Users of the door sometimes tape or otherwise jam open the door latch so they can re-enter the door without using an access card. In some cases, this is because the person needs to go in and out of the door frequently and doesn’t want to have to use their access card each time. In other cases, the person has gained access to the inside of the door but doesn’t have a card (or access privileges) that would allow them to re-enter. Each time the door is opened from the outside without the use of a card, it causes a DFO alarm to occur.

 The solution: Provide ongoing security awareness training to all users of the system. Make sure that users have been assigned appropriate access privileges so that they can do their jobs. If doors must be left unlocked during certain times of the day, educate users on the right way of doing this (through programming of the access control system) versus the wrong way of doing this (taping the latch open). If necessary, provide signage at each door that reminds users of the proper procedures. Take disciplinary action against users who continue to violate policies despite repeated warnings. 

Door Not Interfaced with Automatic Door Opener

When a card reader door is also equipped with an automatic door opener, there is a potential for DFO alarms to occur when the opener opens the door before a REX device is activated. There are two ways in which this can occur:

• The inside door opener actuator button is located beyond the range of the REX motion detector at the door. When the user presses the actuator button, it opens the door, but since the user has not yet activated the REX detector, it causes a DFO alarm. (See Figure #3 below)

• The door opener’s motion detector has a greater range than the REX motion detector. When a user approaches the door, he activates the door opener’s detector prior to activating the REX detector, causing a DFO alarm. (See Figure #4 below)

The solution: Provide an interface between automatic door opener devices and the access control system. Outputs from door opener actuator buttons and door opener motion detectors should be connected as REX inputs to the access control system. This can be done by using devices that have double-pole switch contacts (one pole for the opener and one pole for the access control system), or by providing an external relay that provides double-pole contacts.

Tips for Solving False DFO Alarm Problems

1. Troubleshooting of DFO alarms should be done carefully and methodically. At most facilities, you will find that 20% of your doors will be responsible for 80% of your DFO alarms. Run a report that shows all DFO alarms for a 24 hour period to identify those doors with the most problems. Begin attacking the problem by fixing the doors with the most false alarms first, then move on to the other doors.
2. The most reliable type of REX device is a REX switch built into the lock hardware. This switch provides a positive indication when someone is exiting and is the least prone to problems. When installing hardware on a new door, this should be your first choice when the option is available. Also consider retrofitting existing hardware with REX switches, especially at doors that have been particularly troublesome in terms of false alarms.
3. Sometimes, more than one REX device will be required at a door. For example, obstructions may prevent a single REX detector from detecting people approaching the door from different directions. Adding a second REX detector may be able to solve this.
4. If you are pulling your hair out trying to solve false alarm problems at a particular door, consider temporarily installing a camera and video recorder specifically for the purposes of troubleshooting. This camera should be pointed at the inside of the door and allow you to observe activity coming and going. For improved diagnostics, provide indicator lights visible by the camera connected to the door position switch and REX device. These lights should illuminate when each device is activated, allowing you to observe the sequence of events as people pass through the door.

What Is An “Access Control System”?

Simply defined, the term “access control” describes any technique used to control passage into or out of any area. The standard lock that uses a brass key may be thought of as a simple form of an “access control system”.

Over the years, access control systems have become more and more sophisticated. Today, the term “access control system” most often refers to a computer-based, electronic card access control system. The electronic card access control system uses a special “access card”, rather than a brass key, to permit access into the secured area.

When used within this document, the term “access control system” refers to an electronic card access control system.

Access control systems are most commonly used to control entry into exterior doors of buildings. Access control systems may also be used to control access into certain areas located within the interior of buildings.

The purpose of an access control system is to provide quick, convenient access to those persons who are authorized, while at the same time, restricting access to unauthorized people.

Basic Components of an Access Control System

Access control systems vary widely in type and complexity. However, most card access control systems consist of at least the following basic components:

Access Cards

The access card may be thought of as an electronic “key”. The access card is used by persons to gain access through the doors secured by the access control system.  Each access card is uniquely encoded. Most access cards are approximately the same size as a standard credit card, and can easily be carried in a wallet or purse.

Card Readers

Card readers are the devices used to electronically “read” the access card. Card readers may be of the “insertion” type (which require insertion of the card into the reader), or may be of the “proximity” type (which only require that the card be held in a 3″ to 6″ proximity of the reader. Card readers are usually mounted on the exterior (non-secured) side of the door that they control.

Access Control Keypads

Access control keypads are devices which may be used in addition to or in place of card readers. The access control keypad has numeric keys which look similar to the keys on a touch-tone telephone.

The access control keypad requires that a person desiring to gain access enter a correct numeric code. When access control keypads are used in addition to card readers, both a valid card and the correct code must presented before entry is allowed.

Where access control keypads are used in place of card readers, only a correct code is required to gain entry.

Electric Lock Hardware

Electric lock hardware is the equipment that is used to electrically lock and unlock each door that is controlled by the access control system.

There are a wide variety of different types of electric lock hardware. These types include electric locks, electric strikes, electromagnetic locks, electric exit devices, and many others. The specific type and arrangement of hardware to be used on each door is determined based on the construction conditions at the door.

In almost all cases, the electric lock hardware is designed to control entrance into a building or secured space. To comply with building and fire codes, the electric lock hardware never restricts the ability to freely exit the building at any time.

Access Control Field Panels

Access control field panels (also known as “Intelligent Controllers”) are installed in each building where access control is to be provided. Card readers, electric lock hardware, and other access control devices are all connected to the access control field panels.

The access control field panels are used to process access control activity at the building level. The number of access control field panels to be provided in each building depends on the number of doors to be controlled. Access control field panels are usually installed in telephone, electrical, or communications closets.

Access Control Server Computer

The access control server computer is the “brain” of the access control system. The access control server computer serves as the central database and file manager for the access control system; and is responsible for recording system activity, and distributing information to and from the access control field panels.

Normally, a single access control server computer can be used to control a large number of card-reader controlled doors.

The access control server computer is usually a standard computer which runs special access control system application software. In most all cases, the computer is dedicated for full-time use with the access control system.

A Simple Access Control System

To explain the concept of a simple access control system, we will use a fictitious building, called the “Administration Building”, as an example.

The management of the Administration Building has decided to install an access control system to improve security conditions at the building. Mary Simpson, the “security coordinator” for the building, has been assigned responsibility for implementing and managing the access control system.

There are two primary entrance doors to the Administration Building; one at each end of the building. Mary wants to control access through each of these doors.

There is a computer room located on the First Floor of the Administration Building. A single door leads from the main hallway into the computer room. Because of the sensitive nature of the equipment in the computer room, Mary wants to control access through this door.

Mary contacts the access control vendor to arrange for the installation of her system. The vendor, working with Mary, determines that three card readers will be required: one at the front building entrance door, one at the back building entrance door, and one at the door to the computer room. Mary decides to use insertion type card readers without keypads.

In addition to the card readers, each of the controlled doors will require the installation of electric lock hardware. A survey of the doors indicates that standard electric door strikes can be used.

To operate the three card readers at the Administration Building, one access control field panel is required. Mary decides to have this panel installed in a telephone closet that is centrally located within the building. Wiring will be installed between each of the card reader controlled doors and the access control field panel.

The vendor recommends that the Administration Building install a stand-alone access control server computer to operate the control system. Because Mary will be responsible for managing the access control system, she decides to locate the access control server computer in her office.

Mary makes arrangements with the vendor for the purchase of the system, and schedules to have the installation begin.

Access Control System Set-up and Operation

The vendor has completed the installation of the access control system at the Administration Building.

Mary, as security coordinator, will have day-to-day responsibility for managing the system. Before the system can be put into use, Mary must set-up or “define” the access control system software.

Set-up of the access control software is accomplished at the host computer. Set-up of the software involves setting various access control system parameters to meet the specific requirements of the building in which the system is installed.

Mary has already issued access cards to each of the tenants who will have access to the Administration Building. The first step in setting up the access control system is to “validate” each of the access cards. To validate the access cards, Mary must tell the access control system at what doors each of the cards can be used, and at what times.

• The access control system allows a great deal of flexibility in “tailoring” the access privileges assigned to each card:
• Doors: The system can allow the card to work at all card reader controlled doors; or only at specific doors.
• Time Of Day: The system can allow the card to work 24 hours per day; or only during certain time periods (7:00 P.M.- 12:00 P.M. only, for example)
• Day of Week: The system can allow the card to work seven days per week, or only on certain days (Monday, Wednesday, and Friday only, for example.)
• Holidays: The system can allow the card to work differently on days defined as holidays.
• Start and Stop Dates: The system can allow the card to only work during certain defined ranges of time (June 1 through June 15, for example.)

Mary sits down in front of the access control server computer and begins to validate each of the access cards. Here are several examples of the different access card privileges that Mary will assign:

 Sally Strong:

Sally is a regular office worker at the Administration Building. Sally normally works Monday through Friday, 8:00 A.M. to 5:00 P.M.

Mary assigns privileges to Sally’s card to allow access Monday through Friday, 7:00 A.M. to 6:00 P.M. at the building entrance doors. Sally does not require access to the computer room, so her card does not allow access through that door.

Susan Bright:

Susan is also a regular office worker at the Administration Building. Sally normally works Monday through Friday, 8:00 A.M. to 5:00 P.M.. Every Wednesday afternoon, Susan substitutes for a computer operator who works in the computer room.

Mary assigns privileges to Susan’s card to allow access Monday through Friday, 7:00 A.M. to 6:00 P.M. at the building entrance doors. In addition, Susan’s card is also defined to allow access into the computer room door from 11:00 A.M. to 5:00 P.M. on Wednesdays only.

John Smith:

John is the manager of computer operations, and requires seven day a week, 24 hour per day access to all doors of the Administration Building, including the computer room.

Mary assigns privileges to John’s card to allow 24 hours per day, 365 day per year access through all doors.

Bill Nelson:

Bill is a part-time worker that comes in to work only on Monday and Tuesday nights.

Mary assigns privileges to Bill’s card that allows access Monday and Tuesday, 5:00 P.M. to 11:00 P.M., at the building entrance doors to the Administration Building. Bill does not work in the computer room, so his card will never allow access through that door.

Mike Able:

Mike is a technician for a computer company. Mike is working on a computer installation in the Administration Building computer room. The computer installation is expected to begin on June 1st, and is expected to be completed by June 15th. Mary assigns Mike’s card access privileges for the computer room door, Monday through Friday, 8:00 A.M. to 5:00 P.M. Mike’s access privileges will begin on June 1, and will automatically expire on June 15.

As Mary begins to validate each of the access cards, she soon realizes that many of the cards in her system will receive identical access privileges. For example, all of the regular office workers will be given the same access privileges as Sally Strong.

To save time, the access control software allows the creation of “clearance codes”. Clearance codes are pre-defined sets of access privileges.  Once a clearance code has been created, it can be assigned to any number of access cards. Clearance codes can be given a name. Usually this name is a short description that corresponds with the intended use of the clearance code.

For example, Mary might create a clearance code and name it “Regular Office”. She would set this clearance code to allow access Monday through Friday, 7:00 A.M. to 6:00 P.M. at the building entrance doors.

When validating Sally Strong’s card, Mary would simply assign it the clearance code “Regular Office”. This would give Sally exactly the access privileges that she needs. All of the other office workers who required access privileges identical to Sally’s would also be assigned the “Regular Office” clearance code.

Mary will create several clearance codes corresponding to the various categories of tenants that have access to the Administration Building.

Validating each of the access cards requires at least three entries: the access card number, the cardholder’s name, and at least one clearance code. The use of standard clearance codes will allow Mary to validate a large number of access cards in a short period of time.

Mary finishes entering the information for all of the access cards, and the access control system at the Administration Building is now ready for use.

Mary makes arrangements to conduct orientation sessions for all tenants of the building, and establishes a date when the access control system will be placed into service.

Using the Access Control System

On the day the access control system is placed into service, all persons desiring to enter the Administration Building must use their access card.

Using the access card is simple. To enter the building, the user simply inserts his card into the slot, allowing the card to be “read” by the card reader.

The card reader instantly sends the card’s identity number to the access control field panel, which verifies that the card is valid at that door at that time. If the card is valid, the field panel immediately sends a signal to unlock the electric strike at the door, allowing the user to enter. The time between card insertion and door unlock is usually one second or less. In addition to unlocking the door, the access control field panel also sends a “valid access” transaction record to the server computer for storage. The valid access transaction record indicates the name assigned to the card, the name of the door that was entered, and the time that entry occurred.

Sometimes, a user may attempt to use his card at the wrong door; or at the wrong time. For example, if Bill Nelson (the part-time worker who is only supposed to work Monday and Tuesday) attempts to use his card to enter on Friday, he will not be granted entry.

When a user attempts to use his card incorrectly, the access control field panel will declare an “invalid access attempt”. A transaction record of all invalid access attempts will be sent to the access control server computer for storage. The transaction record indicates the name of the cardholder, the name of the door at which entry was attempted, the reason for rejection (wrong time, wrong door, etc.), and the time that the entry attempt occurred.

Door Status Monitoring Feature

For the access control system at the Administration Building to work successfully, it is important that the card reader controlled doors be used as intended.

To prevent misuse, the access control system provides a “door status monitoring” feature at each of the card reader controlled doors. The door status monitoring feature provides two important functions:

1.  ”Door-Forced-Open” Monitoring: In the event that any card reader door is opened from outside without the use of a valid access card, the system will cause a “Door-Forced-Open” (DFO) condition to occur.
2.  ”Door-Open-Too-Long” Monitoring: In the event that any card reader door is propped open, the system will cause a “Door-Open-Too-Long” (OTL) condition to occur.

The access control system at the Administration Building has been designed to sound an audible alarm inside the building when either a DFO or OTL condition occurs at any card reader controlled door. In addition, a transaction record of all DFO and OTL conditions is sent to the access control server computer for storage. The transaction record indicates the name of the door at which the condition occurred, the type of event that occurred (DFO or OTL), and the time that the condition occurred.

The actual actions that occur upon a DFO or OTL condition at the Administration Building can be set at the access control server computer by the security coordinator, Mary Simpson, on a door by door basis. The access control software allows Mary to define the time periods during which the DFO and OTL monitoring functions will be in effect

For example, Mary may decide that it would be O.K. for the back door of the Administration Building to be propped open during regular working hours (8:00 A.M. to 5:00 P.M., Monday through Friday) to permit the loading and unloading of furniture. Mary does not want the back door to be propped open at any time other than regular working hours.

To accomplish this, Mary sits at the access control server computer and enters the time periods during which she does want DFO and OTL monitoring functions to be in effect; in this case, 5:00 P.M. to 8:00 A.M. Monday through Friday, and 24 hours per day on Saturday, Sunday and Holidays.

If the back door to the Administration Building is propped open during normal working hours, nothing will happen. However, if the door is propped open during the evening or on weekends, the audible alarm will sound.

Automatic Unlock Feature

The access control system allows each card reader controlled door to be “automatically unlocked” during certain time periods if desired. An automatically unlocked door can be opened without requiring the use of an access card.

The automatic unlocking feature can be set at the access control server computer on a door by door basis .

For example, the management of the Administration Building has decided that the front door of the building should remain open to the public during regular working hours (8:00 A.M. to 5:00 P.M., Monday through Friday).

Mary Simpson, the security coordinator, configures the access control system software to automatically unlock the front door at 8:00 A.M., and to automatically re-lock the front door at 5:00 P.M., Monday through Friday, excluding holidays.

Each weekday, the front door of the Administration Building will automatically unlock at 8:00 A.M., allowing free entrance into the building. At 5:00 P.M. the front door automatically re-locks. Persons desiring entry into the building after 5:00 P.M. must use their access card.

Door status monitoring (DFO and OTL) features are automatically disabled at a card reader controlled door that has been automatically unlocked by the system.

Reporting Features

The access control system automatically records various types of system “transactions” on the access control server computer’s hard disk. The collection of these stored transactions is called the “system journal”. The system journal is simply a computer database in which records of access control transactions are stored.

There are many different types of access control system transactions. Some of the more common types of transactions include:

• Valid Access: A entry through a door using a valid access card.
• Invalid Access Attempt: An attempt to use an access card at the wrong door or at the wrong time.
• Door-Forced-Open (DFO) Condition: A door opened from the outside without the use of a valid access card.
• Door-Open-Too-Long (OTL) Condition: A door propped open.
• Equipment Failure Condition: Failure of a portion of the access control system or it’s related wiring.
• Power Failure Condition: Loss of primary power to the access control system.

The system journal can normally store several months’ worth of transactions, depending on the volume of activity generated at the building, and the size of the computer’s hard disk.

The access control system allows the creation of reports of various types of system transactions. These reports are created at the access control server computer; and may be displayed on screen, or printed on a computer printer.

Reports can be created based on a set of parameters defined by the person managing the access control system. Some of these parameters can include:

•  Specific types of transactions
•  Specific ranges of time
• Specific ranges of dates
•  Specific doors
•  Specific access cards

The flexible nature of the reporting feature allows the person managing the access control to custom-tailor a report to meet their specific needs.

Day-To-Day Operations

The following are some day-to-day operations that Mary Simpson, as manager of the access control system at the Administration Building, is likely to encounter:

Card Doesn’t Work

Situation: Susan Bright attempts to use her card to get into the computer room this Wednesday. Her card does not allow access into the computer room as it should. Her card works fine at the building entrance doors. This is the first time that Susan has tried to use her card at the computer room door since the access control system was installed. Susan tells Mary that her card doesn’t work.

Action: Mary checks the clearance code assigned to the card, and finds that she inadvertently assigned the wrong code. Mary reassigns the correct clearance code, and the card now works fine.

Lost Access Card

Situation: Sally Strong has lost her wallet which contains her access card. Sally tells Mary that her access card is lost.

Action: Mary immediately invalidates (cancels) Sally’s lost access card. Mary gives Sally a new access card, and validates it using the appropriate clearance code.

Change Of Access Privilege

Situation: Bill Nelson, who previously only worked part-time, will become a full-time regular employee next week. Bill’s supervisor asks Mary to upgrade Bill’s card to permit access during regular work hours.

Action: Mary changes the clearance code assigned to Bill’s card to a clearance code that corresponds to his new job responsibilities.

New Employee

Situation: A new employee, Brian Wilson, is hired to work in the computer room. Brian will not be given building access privileges during his first 90 days, but will require daytime access to the computer room. Brian’s supervisor asks Mary to issue Brian an access card.

Action: Mary issues Brian a new access card. Mary discovers that she does not have a clearance code that corresponds to Brian’s access privileges, so she creates one, and then assigns it to Brian’s card.

Employee Terminated

Situation: A janitorial employee, Steve Woods, has been terminated. The contract janitorial company notifies Mary that Steve has been terminated, but that he has not yet returned his Administration Building access card.

Action: Mary immediately invalidates the access card assigned to Steve Woods.

Change of Auto-Unlock Time

Situation: The management of the Administration Building decides that the front door of the building should open to the public at 7:00 A.M., rather than at 8:00 A.M. as it presently does.

Action: Mary redefines the automatic unlock time setting for the front door to 7:00 A.M..

Lock-Out Of Doors

Situation: The floors at the Administration Building are being refinished this weekend. It will take 24 hours for the new floor finish to dry. The building management has notified all employees not to enter the building this weekend, but is afraid that some employees may forget and come in anyway.

Action: Mary sets the access control system to temporarily disable the access privileges of all employees (except custodial workers) until Monday morning.

Creation Of Report

Situation: Last weekend, someone accidentally turned off the power to a critical piece of equipment in the computer room. John Smith, the department manager, thinks that the accident occurred on Saturday morning. John wants to know all of the employees who entered the computer room on Saturday. John asks Mary to create an access report.

Action: Mary uses the access control report feature to print out a report of all persons who entered the computer room last Saturday.

Optional System Enhancements

In addition to the standard access control system features described above, there are many optional features available. Some of these optional features include:

Automatically-Locked Doors

In some cases, it may be desirable to lock and unlock doors automatically. This is often done on buildings which are open to the public during the day, but are closed at night. In these cases, automatic locking and unlocking eliminates the need for a person to perform this function manually.

As indicated above, all doors which have a card reader already have the capability to be programmed to lock and unlock automatically.

In some cases however, the building management may wish to automatically lock and unlock doors that are not equipped with a card reader.

Doors which lock and unlock automatically but which do not have a card reader are called “Automatically Locked” doors. Automatically locked doors can be programmed to lock and unlock at specific times just like card reader controlled doors can. The cost of an automatically-locked door is less than the cost of a card reader controlled door.

Normally, automatically locked doors are used in conjunction with card reader doors. For example, in many buildings, there are four doors at each building entrance. To permit night entrance, one of these four doors is equipped with a card reader. The other three doors are equipped with electric lock hardware to allow them to be automatically locked. All four doors are then programmed to automatically lock and unlock at the same time.

Automatically locked doors usually also provide the “Door-Open-Too-Long” (OTL) monitoring feature to prevent them from being propped open.

Monitored Doors

In some cases, it is desirable to have door status monitoring on doors which are not card reader controlled and not automatically locked. A door that is connected to the access control system for monitoring purposes only is called a “monitored door”.

To create a monitored door, a door position switch is installed on the door and wired into the access control field panel.

When a monitored door is opened, it reports to the access control system server computer. The actions to be taken when the door is opened can vary depending on how the system has been configured.

For example, at the Administration Building, there is a door that leads to the roof. Mary Simpson, the security coordinator, wants to know anytime that this door is opened. Mary arranges to have this door monitored by the access control system.

When the door to the roof is opened, it sounds an alert at the access control system server computer, notifying Mary. In addition, the event is recorded on the system journal at the server computer allowing future recall through the reporting feature.

Monitored doors can be configured to cause other system events to occur, such as sound audible alarms, turn on lights, etc. The actual sequence of events (what device is activated, when, for how long) can be defined on a door-by-door basis through the access control system software.

Elevator Control

In many buildings, it may be desirable to secure only certain floors of the building. In these cases, it is often necessary to provide security control of the elevators to prevent unauthorized access to the secured floors of the building.

The access control system can be designed to provide security control of elevators. This feature is known as “elevator control”.

Elevator control can be provided in one of two ways.

Simple elevator control is accomplished by providing a card reader at the elevator lobby. To call the elevator to the lobby, an access card is presented to the card reader, activating the elevator call button. Once the elevator has responded to the lobby, the person may enter and travel to any floor served by the elevator.

Simple elevator control works well when all access card holders are entitled to have access to all floors.

In some cases however, it is necessary to restrict access on a floor by floor basis. To accomplish this, a more sophisticated form of elevator control is required. This method requires that a card reader be installed in the cab of each elevator; and that a special electronic interface be made to the elevator controllers.

Using this more sophisticated method, it is possible to assign a clearance code to each access card that allows access only to a certain floor or group of floors.

Remote Workstations

In the examples used for the Administration Building, it has been assumed that all management of the access control system (set-up, card validation, creation of reports, etc.) would be accomplished from the server computer located in Mary Simpson’s office.

In some cases, it is desirable to manage the access control system from more than one location. This is particularly true of larger systems, which may require that more than one person be involved in managing the access control system. When needed, it is possible to provide remote workstations connected to the access control server computer. These remote workstations are typically standard personal computers on which special access control system “client” software has been installed.

Purpose

The anti-passback feature is designed to prevent misuse of the access control system. The anti-passback feature establishes a specific sequence in which access cards must be used in order for the system to grant access.
The anti-passback feature is most commonly used at parking gates, where there is both an “in” reader at the entry gate and an “out” reader at the exit gate. The anti-passback feature requires that for every use of a card at the “in” reader,
there be a corresponding use at the “out” reader before the card can be used at the “in” reader again. For the typical user of the parking lot, this works fine, because the user would normally swipe their card at the “in” reader to get into the lot in the morning, and swipe it at the “out” reader to get out of the lot in the evening. So long as the sequence is “in – out – in – out – in – out”, everything works fine. However, if a user swipes his card at the “in” reader to get in, and then passes his card back to a friend, the card would not work the second time when it was swiped by the friend. The attempt to use the card a second time would create an “in – in” sequence that is a violation of the anti-passback rules, and this is why access would be denied.

Anti-passback can also be used at employee entrance doors. This requires that a card reader be installed on both the inside and the outside of the door. Employees are required to both “card-in” when they enter the building and “card-out” when they leave the building. The anti-passback feature is also commonly used with turnstiles.

There is an expanded version of the anti-passback feature called “regional anti-passback”. This establishes an additional set of rules for card readers inside of the building itself. Basically, this rule says that unless a card is first used at an “in”
reader at the building exterior, it cannot be used at any reader within the interior of the building. The theory is that, if a person did not enter through an approved building entrance, he or she should not be permitted to use any of the readers within the building.

Depending on the access control system manufacturer, there may be additional anti-passback features in the system.  Some of these features could include “timed anti-passback”, which requires that a designated amount time pass before an access card can be used at the same reader again,  and “nested anti-passback” which requires that readers be used in only designated sequence to enter or leave a highly-secured area.

Denying access when a user attempts to use a card out of sequence is sometimes called “hard” anti-passback. Hard anti-passback means that when a violation of the anti-passback rules occurs, the user will be denied access. Some access control systems also offer a feature known as “soft” anti-passback. When a system is using this option, users who violate anti-passback rules are permitted access, but the incident is reported to the person managing the access control system so that corrective action can be taken – most often notifying the offending employee that the access card should be used in the proper sequence in the future.

The anti-passback feature can also be integrated with the corporate computer system, preventing users from logging on to the network at their desktop computer unless they have properly entered the building using their access card. This feature can also temporarily disable the users remote log-on privileges while the user is in the building – the theory being that if the user is at work, there is no reason for someone from off-site to be logging on to the network using his or her user name and password. When the user leaves the building at the end of the day, his or her remote log-on privileges are turned back on.

(See related Security Tip: The Problem of Tailgating )

One of the biggest weaknesses of automated access control systems is the fact that most systems cannot actually control how many people enter the building when an access card is presented. Most systems allow you to control which card works at which door, but once an employee opens the door, any number of people can follow behind the employee and enter into the building. Similarly, when an employee exits the building, it is very easy for a person to grab the door and enter the building as the employee is leaving.

This practice is known as “tailgating” or “piggybacking”. Tailgating can be done overtly, where the intruder makes his presence known to the employee. In many cases, the overt “tailgater” may even call out to the employee to hold the door open for him or her. In these cases, good etiquette usually wins out over good security practices, and the intruder is willingly let into the building by the employee.

Tailgating can also be done covertly, where the intruder waits near the outside of the door and quickly enters once the employee leaves the area. This technique is used most commonly during weekends and at nights, where the actions of the more overt tailgater would be suspicious.

Solutions To The “Tailgating” Problem

First, recognize that the tailgating problem is probably the biggest weakness in your security system. This is particularly true at doors that handle a high volume of employee and visitor traffic. Many security managers spent a lot of time worrying about unauthorized duplication of access cards and computer “hackers” getting into their security system over the network. It is far more likely that someone who wants access to your facility will simply “tailgate” into the building rather than using one of these more exotic methods to breech your security.

The practice of overt tailgating can be reduced somewhat through employee security awareness training. If employees are frequently reminded of the tailgating problem, they are less likely to let a person that they do not know into the building deliberately.

It is difficult to overcome the problem of covert tailgating through employee security awareness alone. While it would be possible to ask employees to wait at the door until it locks after they pass, it is probably not likely that this procedure would be followed except under the most extreme circumstances.

The problem of covert tailgating can usually only be reliably solved through the use of special “anti-tailgating” devices.

“Anti-Tailgating” Devices

To minimize the problem of tailgating, the security industry has created a number of “anti-tailgating” devices. These devices include mechanical and optical turnstiles, security revolving doors, security portals, and doorway anti-tailgating devices.

The essential function of each of these devices is that they permit only one person to enter or leave the building at a time. They either do this by providing a physical barrier that only allows one person to pass, or electronically by providing sensors that detect when a person attempts to tailgate in, or when more than one person tries to enter using the same card.

The following is a brief summary of each of the common types of anti-tailgating devices:

HALF-HEIGHT MECHANICAL TURNSTILE

Description: Rotating mechanical barrier arms installed at waist height prevent passage through opening. Electrically-controlled, using valid access card causes arms to unlock allowing passage of one person. Turnstile can be controlled in both directions, or allow free-passage in one direction.

Approximate cost: $3,000 to $5,000 per opening.

PROS: Lowest cost anti-tailgating device, readily accepted by most users, relatively unobtrusive, well-proven and reliable.

CONS: Can easily be climbed over or under, requires separate door or gate for emergency exit and for handicapped users, easily defeated by knowledgeable intruder, can be somewhat noisy when operated.

Comments: Good choice for use at visitor lobbies or employee entrances where cost is a consideration. Works best when turnstile can be observed by security officer or receptionist to allow detection of people climbing over or under the device.

FULL-HEIGHT MECHANICAL TURNSTILE

Description: Rotating mechanical barrier arms installed to prevent passage through opening. Extends from floor to height of approximately eight feet. Electrically-controlled, using valid access card causes arms to unlock allowing passage of one person. Turnstile can be controlled in both directions, or allow free-passage in one direction.

Approximate cost: $5,000 to $8,000 per opening.

PROS: Provides good security at a moderate cost. Well-proven and reliable.

CONS: Obtrusive in appearance, requires separate door or gate for emergency exit and for handicapped users, lacks sophisticated anti-piggybacking detection features, can be somewhat noisy when operated.

Comments: Good choice for commercial and industrial facilities where security and cost considerations are more important than appearance.

OPTICAL TURNSTILE

Description: Consists of two freestanding pillars mounted on each side of opening. Equipped with electronic sensor beams that transmit between pillars. Passing though opening interrupts sensor beam and causes alarm unless valid access card has first been used. Sensor beams are connected to computer processor that detects when more than one person attempts to pass though opening on a single card. Turnstile can be controlled in both directions, or allow free-passage in one direction. Available with or without mechanical barrier arms and in a wide variety of styles and finishes.

Approximate cost: $15,000 to $20,000 per opening.

PROS: Aesthetically-pleasing appearance, accommodates handicapped users, does not require separate emergency exit, has sophisticated anti-piggybacking detection systems, provides good visual and audible cues to users.

CONS: Expensive, units without barrier arms provide no physical deterrent, must be used at an entrance manned by security guard, relatively high “false alarm” rate, some user training required to work effectively.

Comments: Good choice for use in manned building lobbies where aesthetics prevent the use of a half-height manual turnstile.

SECURITY REVOLVING DOOR

Description: Standard revolving door that has been specially modified for security use. Extends from floor to a height of approximately eight feet. Typically has multiple quadrants equipped with electronic sensors that detect number of people in each quadrant. Use of valid access card allows one person to pass through door, if more than one person attempts to enter, door sounds alarm and reverses to prevent entry. Door can be controlled in one or both directions.

Approximate cost: $35,000 to $50,000 per opening.

PROS: Provides best protection against tailgating and piggybacking, fast, handles high volumes of traffic, unobtrusive in appearance, provides energy savings when used at exterior entrances.

CONS: Very expensive, requires separate door or gate for emergency exit and for handicapped users, door cannot be used for loading/unloading of large objects, relatively high maintenance costs.

Comments: Good choice for use at unattended building entrances where appearance is important.

SECURITY PORTAL (also called “Security Vestibule” or “Mantrap”)

Description: Consists of passageway with door at each end. Regular swinging doors or automatic sliding doors can be used. Passageway is equipped with sensors that detect total number of people present. Sensors can include electronic beams, floor mat switches, and weight detectors. Video cameras with analytic software can also be used (see video analytics below). To use, user enters passageway and closes door behind him. He then proceeds to second door, and uses access card to enter. If more than one person is present in passageway, portal sounds an alarm and prevents entry. Portal can be controlled in one or both directions.

Approximate cost: $15,000 to $50,000 per opening.

PROS: Provides good protection against tailgating and piggybacking, unobtrusive in appearance, accommodates handicapped users, does not require separate emergency exit, allows load/unloading of large objects.

CONS: Expensive, relatively slow, cannot support large volumes of traffic, some versions can have high maintenance costs.

Comments: Good choice for use at unattended building entrances with relatively low traffic volumes and for entrances into high security internal areas, such as computer rooms.

DOORWAY ANTI-TAILGATING DEVICE

Description: Consists of devices installed on each side of regular doorway. Equipped with electronic sensor beams that transmit between devices. Passing though opening interrupts sensor beam and causes alarm unless valid access card has first been used. Sensor beams are connected to computer processor that detects when more than one person attempts to pass though opening on a single card. Doorway can be controlled in both directions, or allow free-passage in one direction.

Approximate cost: $5,000 to $7,000 per opening.

PROS: Easy add-on to existing doors; provides good protection against tailgating and piggybacking, unobtrusive in appearance, accommodates handicapped users, does not require separate emergency exit, allows loading/unloading of large objects, relatively inexpensive.

CONS: Must be used at an entrance manned by security guard, does not provide good visual and audible cues to users, some false alarms.

Comments: Good choice for use at doorways with relatively low traffic volumes and where conditions do not permit the use of another type of device.

VIDEO ANALYTICS ANTI-TAILGATING SYSTEMS

Description: Consists of video cameras installed at doorway opening. Cameras are connected to a computer with special video analytics software that detects and analyzes people and objects at the door. System may use multiple cameras that allow precise determination of object size, height, and direction of travel. When used at single door, video analytics anti-tailgating systems work similarly to doorway anti-tailgating devices and sound alarm when more than one person attempts to enter through door after a valid access card has been used. Video analytics anti-tailgating systems can also be used with security portals to both sound alarm and deny access when more than one person attempts to enter.

Approximate cost: $10,000 per opening for single door system, $15,000 to $20,000 for security portal system.

PROS: Easy add-on to existing doors; provides good protection against tailgating and piggybacking, unobtrusive in appearance, accommodates handicapped users, does not require separate emergency exit, allows loading/unloading of large objects.

CONS: Single door systems do not provide a physical barrier so must be used at an entrance manned by security guard, requires frequent user training to prevent false alarms, relatively expensive.

Comments: Popular choice for use at computer rooms and other high-security facilities.

Selecting the Right Anti-Tailgating System

Choosing the right anti-tailgating system is an important decision. You need to consider your overall level of security risk, your ability to provide security staff to monitor your entrances and respond to alarms, and your budget for initial purchase and ongoing maintenance of the anti-tailgating systems.