The importance of IDS inspection.
In many instances, the system is accepted and operated based solely on the installer's assurances that it has been installed and is being operated properly. The system's users are quickly trained, and the system is essentially forgotten until it either fails to operate during a break-in; the designated user is unable to activate it; or a costly nuisance or false alarm rate develops. These problems can be minimized or avoided if an effective program of periodic inspection and testing is in place.
The inspection and test processes are often misunderstood. Everyone involved with intrusion detection systems (IDS) has a different concept of what constitutes an adequate inspection or test. To clear up some of the misunderstanding, it is important to define the inspection and test processes.
An adequate inspection of an IDS can be divided into two components. The first and obvious portion of the process is the inspection of the IDS equipment itself. This portion of the inspection process includes examining the following:
* The physical condition of the individual sensors, including the housings, mounting brackets, and any other peripheral components
* The system wiring and protective conduit, if any, between the individual sensors and their control unit and between the individual control units and the monitor/annunciator
* The internal appearance of the sensor, control unit, junction points, and related equipment housings for evidence of loose or damaged wiring, moisture accumulation, insect infestation, or other adverse conditions
* The system's back-up batteries or other emergency power sources for evidence of overheating, damage, and excessive age. The system's batteries should be tested to ensure their capacity.
The second component of an adequate inspection involves examining the environment in which the system operates. When the system was designed and installed, it was configured to operate within the particular set of circumstances present in each protected premise. When those circumstances change, the effectiveness of the system may be diminished or completely negated. While equipment problems are often obvious, environmental problems may be more subtle. The following environmental factors should be compared with the results of previous inspections:
* Temperature and humidity. Has heated or air-conditioned space been converted to environmentally uncontrolled storage or vice versa? Changes of this type can affect the operating range of some devices.
* Draperies, carpeting, or furnishings. Changes of this type can completely block or adversely affect the range of some motion detection sensors.
* Use. A change in the way the system is used can introduce nuisance alarm sources into the facility.
All IDS equipment manufacturers, recognized testing organizations, and major end users agree that the most effective IDS test is an exercise in each sensor's and other components' detection capabilities. Thus, for a balanced magnetic switch, the door must be moved a sufficient distance to allow the resulting change in the sensors magnetic field to operate the switch.
For a motion detection sensor, a human walk test by a properly sized target is required. Unfortunately, such an operational test is not always possible. Sensors may be located in hazardous or difficult-to-reach areas, such as air ducts or false ceilings, or may be too numerous to test effectively on an individual basis. Also, normal operations may be disrupted when rooms have to be vacated for walk testing or other test-related activities.
One solution to the problems inherent in operational testing is the self-test. Since no standardized definition of a self-test exists within the industry, some difference of opinion exists concerning what constitutes the effective self-test of an IDS sensor.
In some instances, manufacturers claim to have a self-test feature. In reality, all the feature does is monitor continuity through the sensor. The fact that continuity is maintained through the sensor does not guarantee that the sensor will operate as designed in an actual intrusion. It simply verifies the integrity of the alarm circuit.
True self-test systems use a test stimulus, which is located within the sensor or within the protected area. It simulates the actions of an intruder. In the case of a balanced magnetic switch, a test coil, or solenoid, located in the switch housing is electrically activated, disturbing the magnetic field and causing the switch to open. Some motion detection systems are tested with the help of a stimulus located in the protected area. The stimulus either generates a frequency consistent with a Doppler shift or infrared energy consistent with the detection parameters of a passive infrared sensor.
A self-test that is internal to individual sensors is found in few devices. A self-test using external stimuli, however, is easy to accomplish. It increases system installation costs since a second device and related wiring and conduit must be installed for each sensor. Also, self-test using external stimuli may require additional communications wiring and multiplex transponders.
A true self-test of an active sensor must incorporate a test of the sensors transmitter or signal generator. For example, an ultrasonic motion detection sensor transmits a signal into a protected area and then monitors that signal for changes due to intruder motion. A true self-test must verify both the transmitter's operation and the ability of the sensor to recognize and respond to a Doppler shift.
WITH THE RECENT PROLIFERATION OF systems, security managers have begun to consider group testing. The idea behind group testing is that the entire sensor complement of a structure or a particular protective circuit can be tested as a group. Unfortunately, no method is yet available that permits testing individual sensors as a group unless the purpose of the test is simply to ensure continuity of the sensor circuit and that the control unit or transponder is capable of transmitting an alarm.
Two concepts of group testing have recently been promoted, however, particularly within large military systems. The first is group testing from the control unit. This test is conducted from the control unit by measuring the continuity of the protective loop. This test duplicates an internal function performed on a continuous basis by virtually every IDS control unit. A successful test is not a guarantee that any sensor in either the group or the overall system will operate as designed in the event of an intrusion, however.
The second is group testing by exercising the detection phenomenon of a single (typically the last) sensor in each group. A test of this type is valid only for the sensor tested. Again, there is no guarantee that any other sensor in the group or system will operate as designed in the event of an intrusion.
Walk test lights are incorporated into most motion detection sensors. The lights, which activate when the sensor has detected sufficient motion to initiate an alarm, are used as an aid to the initial positioning of the sensor and help with the periodic inspection and testing process. While walk test lights appear to be an answer to the process of rapidly testing motion detection sensors, this may not be the case. Two problems associated with walk test lights must be considered.
First, operational walk test lights introduce a vulnerability to the system. When a sensor's walk test light is left operational, a potential intruder can covertly map the areas of motion detection coverage while legitimately present during normal working hours. Most manufacturers provide a means of disabling the walk test light after installation to prevent this activity.
Second, system installers and maintenance technicians occasionally bypass a sensor's detection circuit while leaving the walk test light operational. This practice has been used by both installers and maintenance technicians to resolve application and maintenance problems. When a test, using only the walk test light, is conducted, the sensor detects the motion and activates the walk test light. Unfortunately, the alarm circuit has been bypassed within the sensor, and the alarm signal is never transmitted. For this reason, a valid test requires that alarms from each sensor be transmitted to and recognized by the system annunciator.
A NUMBER OF CIRCUMSTANCES DICTATE the time for an operational test, inspection, or both. Some of the circumstances include:
Acceptance of a new system. An acceptance test verifies that the system meets the requirements of the specification and drawings used to procure it. Additionally, it demonstrates that the final system is operational and capable of all required functions. System procurement documents should specify that the successful completion of an acceptance test is necessary before the final payment on the system will be made. Acceptance testing is normally accomplished by the installation contractor and observed by the security manager. In essence, the contractor demonstrates the capabilities of the system for the customer.
A major renovation. Acceptance testing after a major renovation or addition to a system is identical to the acceptance testing of a new system described above.
Maintenance or repairs. Testing after completion of a system maintenance or repair operation is an important step in maintaining system integrity. Occasionally, a maintenance technician, either in anticipation of returning to commit an after-hours break-in or to compensate for an inability to locate or repair a problem, will simply disable one or more sensors or other system components. Since most maintenance technicians know how to do this, an operational test is essential after any maintenance operation.
A perceived system deficiency. An inspection and operational test should be done any time an actual or a perceived deficiency in the system exists.
A random, periodic plan. The random, periodic inspection and operational test forms the basis of an effective inspection and testing program. Scheduling should allow a complete operational test and inspection of each zone annually. While some high-security systems may require more frequent attention, the one-year interval is adequate in most cases.
Once the test frequency and procedure is determined, the next step is to determine who will conduct the tests.
The end user. The end user or occupant of the protected premises is often responsible for conducting both inspections and operational tests. While the end user has substantial knowledge of the premises and its operational characteristics, he or she typically has limited knowledge of the system.
Proprietary officers. Proprietary officers are a good choice for inspecting and testing the company's detection system since they typically combine a working knowledge of the security system with reasonable knowledge of the protected premises. Unfortunately, proprietary officer forces are typically understaffed, leaving little time for additional duties.
Maintenance. While system maintenance personnel have substantial knowledge of the security system, they typically have no operational knowledge of the protected premises. Since many tests are conducted after a maintenance procedure is completed, maintenance personnel are not suitable for conducting routine inspections. However, in conjunction with the security manager, maintenance personnel can conduct annual or biannual full-scale maintenance inspections.
Security manager. The security manager is probably best suited to inspect and test the system. He or she combines a knowledge of the security system with a knowledge of the protected premises and is often able to do an inspection with other duties.
Contractor testing. Contractor testing is a relatively recent phenomenon. Several security consulting organizations that have a great deal of knowledge about IDS have begun to offer either one-time or periodic testing and inspection services. These organizations have the advantage of substantial knowledge coupled with specialized test equipment. Contractors can often structure their test procedures to include tests of the effectiveness of a proprietary guard force.
The importance of inspecting and testing cannot be overstated, but it is not enough just to perform these activities. The procedures must be effective. Ineffective testing may lead to financial loss due to criminal activity not detected by the IDS; loss of competitive advantage due to the compromise of proprietary documents, devices, processes, or formulas; civil action for assaults, rapes, or other criminal acts occurring in places where a fully functional security system would have detected them; or failure of an insurance company to honor or pay a claim.
The need for an effective inspection and testing program exists in virtually every facility with an IDS. Careful consideration of the factors discussed in this article will provide the security manager with a basis for planning an effective program.
Martin L. Vitch, CPP, is senior security consultant at C.H. Guernsey and Company in Norcross, Georgia. He is a member of ASIS.
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|Title Annotation:||Physical Security; intrusion detection systems|
|Author:||Vitch, Martin L.|
|Date:||Mar 1, 1993|
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