The main stages of creating a perimeter control system for an object.
The main stages of creating a perimeter control system for an object
As noted in the materials of the Carnahan Conference on Security, a precise description of the composition of threats to the protected facility from both untrained and experienced intruders has a decisive impact on the final effectiveness of the perimeter control system. The system developer must be informed about all possible methods of penetration into the facility and the level of the expected «qualification» of a possible intruder.
It is important to keep in mind that a fence cutting detection system is not suitable for detecting fence climbing. Conversely, fence climbing detection systems are rarely ideal for detecting fence cutting. Most likely, no fence monitoring system will be able to detect digging under the fence. This is why a comprehensive approach must be used when organizing perimeter protection.
The choice of technical solution is greatly influenced by the response time to the alarm signal of the facility's security forces. The security line must create an obstacle, the time to overcome which must correspond to the response time. It should be borne in mind that any perimeter protection system solves four problems starting with the letter «3»: «intimidation» (deterrence), «notification» (detection), «delay» (the time spent by the intruder on overcoming the space from the boundary of the facility to the building itself after the alarm is triggered), «detention» (physical capture of the intruder).
Before designing a monitoring system, it is always a good idea to walk along the future perimeter line and take photographs or video of the area. It is also important to have meteorological data at your disposal, especially if the area is bare and elevated, where gusty winds can seriously hamper the operation of a highly sensitive detection system mounted on a fence. Data on snow depth and ice loads are also necessary.
Perimeter protection systems usually aim to create straight fence sections of approximately 100 m per zone. Shorter zones increase equipment costs, while longer ones make it difficult to determine the location of an intruder's entry. There should be enough space between the facility's boundaries and the fence line to perform maintenance work. It is also necessary to know how to deliver service personnel to the required perimeter location — by car or on foot.
If the fence faces a pedestrian area, you can expect frequent false alarms. To eliminate them, you may need to create an intermediate boundary outside the controlled fence.
Access points to the facility should be considered as independent zones. This will make it possible to turn them off during the passage of people and vehicles, leaving other areas of the perimeter under control.
The «sterile» zone between the outer and inner fences, if provided, should be wide enough to prevent entry to the site by the «bridge» method.
If the site is to use «line of sight» systems (e.g. microwave) as the sole or in combination with fence monitoring systems, then to avoid the formation of «blind spots» it will be necessary to level all folds of the terrain, which can create problems with the drainage of rainwater. When installing protection over grass, it is necessary to know whether regular mowing of the grass can be organized.
It is known that large trees near the fence are ready places for penetration into the territory of the object. Low bushes near the fence serve as camouflage for potential intruders, allowing them to slowly and therefore unnoticed overcome the fence. At the same time, unnecessary vegetation can be a source of false alarms.
There are cases when the installation of above-ground perimeter control systems is not to the liking of the owner of the facility. In this case, it is necessary to resort to the use of buried perimeter control systems, which requires analyzing the composition of the soil in individual zones and assessing the possibility of replacing it. For satisfactory operation of most types of buried systems, it is necessary to know the location of water pipes and other utilities. Concealed buried systems, in the absence of other means of perimeter protection, do not create any physical obstacles to intruders and therefore should be laid away from the protected buildings.
It is known that no perimeter protection system can be free from false alarms. The latter can irritate security personnel, who may eventually start ignoring all alarm signals, including true ones. That is why any control system should usually be supplemented with television surveillance to verify any alarm signal.
The main task of the customer at the stage of concluding a contract is to clearly record all technical requirements for the control system, the procedure for demonstrating by the contractor the full compliance of the already installed system with these requirements, i.e. the procedure for conducting acceptance tests.
In perimeter protection systems, the construction of the fence itself can be the main cost of protecting the facility in general. Separate contracts for the construction of the fence and the installation of the electronic perimeter control fence system can be a source of difficulties. If it turns out that the installed system does not meet the requirements previously presented, the customer may find itself in a situation where it is necessary to conduct an investigation between the two contractors, which is undesirable in any case. Therefore, when concluding independent contracts, it may be useful to provide for a formal transfer of the fence to the supplier of the perimeter control system. This will provide an opportunity to confirm the quality of the fence before the installation of the perimeter control system begins.
The selection procedures for a perimeter control system supplier usually involve organizing a tender for the system's technical specifications. While it is almost always possible to establish a list of requirements for an already installed system, perimeter control systems often face problems confirming that the installed system fully complies with the requirements. For example, if the system was installed in the summer, then naturally such indicators as the probability of detecting an intruder and the level of false alarms can only be determined for warm weather conditions. On the other hand, a serious problem arises when, at the stage of acceptance testing, it turns out that the system was unable to fully meet the requirements. This may delay the transfer of the facility to the customer or affect the order of its operation. At the same time, new costs may be required to hire additional security.
Taking into account the above, the importance of carefully preparing the technical specifications for the system is emphasized, while at the same time limiting the choice of equipment to only systems that have undergone rigorous testing in an independent organization and have demonstrated reliable operation under all possible external conditions.
Naturally, the owner of the facility and the operators of the perimeter control system are usually extremely interested in thoroughly testing its operation before purchasing the product. It is advisable to carry out tests by the owner's own engineering departments or, in extreme cases, by an independent testing organization. Ideally, tests are carried out at the owner's site, but in practice this is never possible. Therefore, it is desirable that the climatic and other conditions of the test site correspond as closely as possible to the real facility or, in any case, be no less severe.
In areas of the globe where there is a clear change of seasons, the test program must necessarily be no shorter than one year, and may even include two or more winter periods, if it is necessary to evaluate the operation of the system over the entire range of possible climatic influences. This will allow, firstly, to ensure compliance with technical requirements throughout the year and, secondly, to check the durability of the system elements used outdoors.
It is recommended to test several variants of the system design, which makes it possible to compare their operation in different weather conditions. All of the above applies to systems mounted on a fence, buried in the ground, and also operating on the basis of radiation (microwave, IR, etc.).
To assess the effectiveness of zone overlap, at least two full zones of above-ground or underground systems are supplied for testing. It is important that the tests are carried out on a fence of the same type as the one installed on the site itself.
If the system is installed at the test site by the manufacturer, it is necessary to strictly control the timing of its implementation in order to exclude work on subsequent fine-tuning of the system. In general, it is desirable to install it by the test site workers with strict adherence to the manufacturer's installation instructions. Before this, it is necessary to conduct a training course on installation with the manufacturer, which will make it possible to evaluate the quality of the installation documentation and instructions. It is desirable that the manufacturer be informed about the testing and invited to monitor the progress of installation and adjustment of the equipment even before entering the full-scale testing mode.
During testing, weather conditions should be recorded and the test area should be videotaped. This will make it easier to determine the cause of any activation. The test program should include attempts to overcome the system in all possible ways. For fence-mounted systems, the actions must necessarily include cutting fence elements, which will allow us to assess the maintainability of the system and the costs of its restoration. If the system uses adaptive software to compensate for changes in weather conditions, then it is necessary to carry out a full set of attempts to overcome the system in the entire range of climatic conditions.
The manufacturer is usually notified of any significant deficiencies in the system's operation identified during testing, since these deficiencies may be caused by design or technological flaws.
Typically, system testing does not yield a clear pass/fail result. A test decision is usually made by compiling a table with ranking results in a range of, for example, 1 to 10 points for each requirement item. This allows for quantitative comparison of different systems and informed decisions on their selection.
When installing buried perimeter monitoring systems, it is advisable to continuously monitor the site during the cable laying and trench backfilling stages. If the buried system is installed under a lawn, the grass turf must be carefully removed and then replaced. There should be no sharp objects at the bottom of the trench. The soil surface is restored using sifted soil removed from the trench. If the previously removed soil is not enough to fill the trench, it should be taken from places with the same soil composition. Otherwise, the cable line will be clearly visible on the soil surface due to differences in vegetation density.
Special attention should be paid to monitoring the depth of the cable. In places where the cable passes under cultivated soil, it should be placed in a protective pipe, although this will lead to some decrease in the sensitivity of the section. To eliminate possible problems, it is better to protect the cable along the entire length of the control zone, and compensate for the decrease in sensitivity by adjusting the system. Of course, pipes cannot be used for push-action systems. When laying such systems in heavy clay soils, it is useful to replace the soil with soft soil in a strip several meters wide. It is a good idea to lay a perforated nylon mat in the trench over the entire zone.
Immediately after filling the trench with soil, it is necessary to conduct tests, since if it is necessary to change the cable depth in order to obtain a profile of the same sensitivity, this is easier to do while the soil is still soft. As soon as the zone begins to work satisfactorily, it is necessary to take measurements and draw up a drawing of the cable laying. This will be more difficult to do later due to the overgrowth of the laying line with vegetation.
In systems with fence control, it is important to strictly maintain the distance between the supports. It would seem that increasing the spans allows reducing installation costs, but too large spans lead to an increase in the level of false alarms.
The stage of transferring the system to the customer creates the last opportunity to check the system's compliance with technical requirements. At the same time, it is often the first opportunity to demonstrate that the system really solves the tasks set before it. If the owner of the facility does not have its own engineering staff to participate in the acceptance tests of the system, then it is best to hire an independent expert for this. In this case, it is necessary to proceed from the fact that as few external organizations as possible are privy to the intricacies of the protection systems (including their weak points).
Acceptance tests are carried out according to a special program, stipulating the sequence of individual tests, test methods and expected results. The program must be agreed upon by the system developer, the installation organization, the operators and the owner of the facility from the very beginning of the contract, since payments to the contractor are usually made on the basis of its implementation. Upon completion of the tests, the program will serve as a valuable document in the event of disagreements.
In integrated control systems, individual subsystems are usually tested first. If the results of such tests are positive, the subsystems are gradually (sequentially) connected until a single whole is formed. For example, they check that after one of the fence zones is activated, the alarm is triggered, the printer records the triggering, the TV cameras turn to the required position, the control screen turns on, the video recorder switches to normal recording mode, etc.
The entire course of testing and the results of the checks must be recorded and signed by the head of the testing group and the expert witness. All deficiencies are included in the list of comments, which then determines who is responsible for their elimination and sets deadlines for their implementation.
Upon completion of the tests, the documentation on them is included in the documentation for the system. The system parameters measured during the tests will serve as the basis for measurements already during its operation.
If the owner of a facility wants to get the most out of the money invested in a perimeter control system, he must ensure that the system operators are well trained. It is important to make sure that the training manuals and documentation are written in understandable language and are specific to the facility. In this regard, simply filing the manufacturers' description sheets will do little.
Good maintenance of the system is a prerequisite for its successful operation over many years. The owner of the facility here has to choose between using its own personnel for this and engaging external specialists, or both. The main thing here is to ensure a quick response to malfunctions.
A distinction is made between scheduled preventive maintenance and current maintenance. Scheduled preventive maintenance is usually carried out in the mode of checks, measurements and adjustments according to a certain program. It allows you to identify any deterioration in the system parameters and may include restoration work that brings the system to an acceptable state.
Routine maintenance involves work that cannot be planned in advance: repair of failures, damage (accidental and intentional), replacement of burnt-out lamps in IR floodlights, etc. Despite the random nature of these events, it is reasonable to prepare for them in terms of creating sets of spare parts and elements, etc. The volume of the set is determined by the cost of the elements, their delivery time from the supplier, and the permissible shelf life.
The procedures for scheduled preventive maintenance are developed by the equipment supplier and include a list of checks, a test methodology, the composition of the devices used to conduct the checks, criteria for failures and malfunctions, and measures to eliminate them.
The intervals for scheduled preventive maintenance are established based on the experience gained from operating similar systems and the specific requirements for the facility. On the one hand, this interval cannot be small, since this increases the costs of performing frequent scheduled preventive maintenance. On the other hand, if the interval is too long, the deterioration of the parameters may reach an unacceptable level. The usual procedure is as follows. During the first year or so of operation of the system, scheduled preventive maintenance is performed fairly frequently, then the inspection period is adjusted based on the accumulated information. At the same time, this approach allows technical personnel to become better acquainted with the maintenance procedures.
When selecting a perimeter monitoring system, the total operating costs should be considered, not just the initial capital investment. This consideration becomes critical when choosing among several similarly priced options. Vendors who claim low prices for their systems are usually more well received if they are prepared to provide a specific cost for maintenance work over, say, the first three years of the system's operation.
The choice of the system is also affected by the qualifications of the technical personnel required for its maintenance. It is noted that the cost of the actual repair and restoration work may not be a decisive factor. Rather, it is more important to take into account the costs of organizing patrols of the failed perimeter zone. In this regard, it may be more profitable for the manufacturer to choose a faster restoration method, even if it turns out to be more expensive.
Particular attention should be paid to the qualifications of the technical personnel who will be repairing the equipment. Parts that can only be repaired by highly qualified technicians using complex diagnostic equipment are best repaired by replacing them with serviceable ones and sending the failed ones to a specialized service center. To replace printed circuit boards, it is better to use a design with removable blocks, which eliminates the need to use a soldering iron at the site. Of course, using connectors on blocks leads to an increase in the cost of electronics, but this increase in cost will pay off after the first replacement of the removable block. Especially if the replacement has to be done outdoors in bad weather. The block design makes it easier to modify electronic circuits during operation.
Maintenance programs should include periodic inspection of the fence to detect damage caused by trespassers, animals, and gardeners mowing close to the fence. Tall, wet grass that is not cut can trigger microwave fences, and grass thrown up by lawn mowers can become lodged in the fence mesh and cause false alarms for fence-mounted alarm systems. Loosening the fence wire reduces the likelihood of detecting trespassers and increases the rate of false alarms. It is usually advantageous to inspect all perimeter protection elements during a single inspection.
Periodic testing of the perimeter monitoring system should be non-destructive, simple, and repeatable. It should be possible to test the equipment for operability in all weather conditions. Retests should be performed on system elements after repairs have been made.
The results of all checks and information on restoration work must be recorded in the system log. These records make it possible to identify weak points and establish trends in the system's condition. Based on them, changes can be made to the equipment maintenance mode. Naturally, the log must be kept in a safe place.
So, the main stages of creating a perimeter control system can be as follows:
— an exhaustive listing of all possible threats and ways to overcome the protection;
— an assessment of the time of delivery of response forces;
— a complete inspection of the facility;
— a clear assignment of technical requirements;
— an independent assessment of possible system options;
— limiting the choice to only systems that have demonstrated their effectiveness;
— strict control of installation work;
— preparation of detailed drawings of the location of the mounted system;
— carrying out a full cycle of acceptance tests;
— thorough training of personnel;
— complete documentation of scheduled preventive maintenance modes.