Safety systems at petrochemical plants.
A special feature of petrochemical plants is their huge territory with fairly evenly distributed security facilities. They do not have a small final finishing shop with a highly concentrated expensive product, as at a diamond processing plant. They do not have a compact, very dangerous reactor, as at nuclear power plants. Large plants, as a rule, do not even have a loading rack for trucks, which is accessible to outsiders and where thefts can be committed due to misclassification or unaccounted for products — at large plants, shipment takes place through a thick pipe or, in extreme cases, in railway tanks. Theft at such loading points is only possible in trains, and video surveillance and access control systems are not able to help against such theft. If the enterprise has a rack for small-scale wholesale distribution of products, then the main means of protection should be the means of accounting and control of products, including scales at the vehicle checkpoint. Of course, customer access control and video recording of key points will also help detect and prevent theft, but only if closely linked to the product inventory system.
In some cases, weight sensors can be very useful, they can be part of both the product accounting system and the security system. Load cells that monitor unauthorized changes in the weight of a tank or stack can be the most direct theft detector.
As for the security itself, as a rule, it is the perimeter that is primarily protected, but it must be very thorough and effective. There are known cases when thieves at an oil refinery drove straight through a remote section of the fence, drove up to an internal pipeline, opened it and drained a considerable amount of oil products. The worst thing is that the thieves then do not bother to close the hole, and before the damage is discovered, a considerable amount of product has time to leak. To detect such an attack, it is necessary to have an effective perimeter alarm system. However, it is the passage of heavy vehicles that is really dangerous, and such penetration is confidently and reliably recognized by any perimeter detection systems. This signal from one person climbing over may not be very confident and can be lost against the background of false alarms. A signal from a cable break on a large section of the perimeter cannot go unnoticed and ignored.
Perimeter is also a flexible concept. Large petrochemical plants actually consist of several independent plants specializing in different products or different technologies. The general perimeter of the entire territory is subject to the most careful protection, although for accounting and control purposes, ACS is usually installed at internal checkpoints between individual workshops. It happens that some workshops or plants on a common territory are subject to special protection if they contain large quantities of hazardous (explosive or toxic) substances.
Often, there is also a residential area on the territory of the enterprise — dormitories for shift workers. The residential area is fenced off from the production area, but in the event of an accident, everyone in the residential area is also subject to evacuation, in connection with which the accounting of people on the territory (in foreign companies, the maritime term — people on board) is important not only directly in dangerous areas, but also in the residential area. Please note: people can be on the territory of the enterprise for weeks and months, moving only to work in the production area and returning to rest in the residential area. Therefore, the trouble-free operation time of the ACS should be years in order to accurately and confidently account for all personnel «on board» of the enterprise.
For the same reason, for the precise accounting of personnel «on board», strict means are used, such as turnstiles or gateways, to avoid mistakes caused by forgetfulness. One entered with a comrade, forgetting to check in, another, on the contrary, checked in on the reader, but forgot to leave. Even in the pre-electronic era, mechanical turnstiles with passage counters were installed in dangerous areas and mines. At enterprises that are potentially dangerous for personnel, it must always be known exactly how many people entered and how many left. Modern systems allow us to answer the question more precisely: who exactly entered and did not leave, where exactly on the territory he was last and where he is most likely to be looked for.
Despite popular belief, explosion-proof security equipment is practically not required at petrochemical plants. As already mentioned, the main work of security systems occurs on the perimeter, at a sufficient distance from explosive zones. And according to regulations, ordinary products can be used a few meters outside the dangerous room. However, special attention should be paid to the common case of a bunded storage facility or processing plant. In this case, the entire volume of the bunded pit is considered an explosion hazard zone. Ordinary (non-explosion-proof) products can only be used if they are installed at least a few meters above the surrounding earthen embankment. Therefore, for example, video cameras have to be installed on poles on the embankment with appropriate long-focus lenses or near the plant itself, but on high masts, above the embankment level.There are, of course, exceptions. Fire protection systems must be present in all premises, and first of all in explosion- or fire-hazardous ones, therefore fire alarms and fire extinguishing systems are often required to be explosion-proof, but we will not go into the specifics of fire protection, we are talking about security systems, as it has become fashionable to say now, about anti-crime and anti-terrorist protection systems.
In fact, petrochemical facilities are not of great interest to terrorists. An accident there that would pose a serious danger to the surrounding population is unlikely. Other chemical plants are truly dangerous, such as those in the nitrogen cycle, which are often small in size but sometimes occupy thousands of square kilometers. Some plants associated with petrochemical plants that produce products other than fuel can also be classified as dangerous. As a rule, on the territory of such plants, there are separate installations that contain hazardous substances in significant quantities. There are not many of them, because a truly hazardous substance must not only be hazardous, but also sufficiently stable and volatile so that in the event of an accident it could reach the nearest city in significant concentration. And the installation itself must contain a sufficient amount of this substance in one place so that a single accident could release a significant amount of this substance into the air. Fortunately, in our country, hazardous plants are traditionally located quite far from large cities, in sparsely populated areas.In the described case, the task of increased protection of these individual installations (or storage facilities) arises. As a rule, this is an additional level of access control and additional protection against unauthorized entry from the main territory of the enterprise. In general, this is the same task of protecting the perimeter of a separate section, which was on the general perimeter of the entire enterprise. Fortunately, the perimeter of an individual installation (storage facility) is much smaller, it is quite cost-effective to use not only sensor systems on it, but also to back them up with video surveillance. Let me remind you that video surveillance on the perimeter is not an independent means of detection at all, but is used for remote verification of alarms, and therefore allows you to significantly increase the sensitivity of sensors and increase their number, without fear that the system will become inoperative due to increased false alarms.
By the way, do you know why video surveillance systems on large perimeters are very expensive and only very dangerous enterprises can afford them? Do you think video cameras are expensive? Nothing of the sort. The main expense items are cable products, installation equipment and cable laying work. On long perimeters, on average, at each point there are 3-5 coaxial cables (to the nearest section cabinet), multi-core fiber optic cable, video camera power cable, main power cable, lighting power cable, main high-voltage power cable, and some other little things. High-voltage cable is no joke. Even with the most modern video cameras and the most efficient LED illuminators, the video surveillance and lighting system consumes at least 1 watt per linear meter of the perimeter. If the perimeter is 20 km, that is 20 kilowatts. It is impossible to transmit such power over 20 km at a voltage of 220 V (who remembers Ohm's law, you can check — all the voltage will drop on the wires, even if you take a wire with a cross-section of 300 sq. mm). It is inevitable to build transformer substations distributed around the perimeter, reducing from 6 kV to the usual 220 V.
However, all of the above was intended only to detect criminal activity. But it is not enough to detect it, it is necessary to stop it. Of course, no technology can call to order or arrest criminals on its own. The main work is still done by people — mobile security groups. How can technology help these groups?
Firstly, communication. Starting with the usual voice communication, with the help of which the central operator will be able to coordinate the actions of mobile groups, give them target designations based on sensor data. In addition to voice communication, such solutions as mobile terminals of the security system, including the video surveillance system, have ceased to be a fantasy. The mobile group's car can contain a portable computer connected via a wireless network to the general security system, so that the group commander does not need to receive advice from the central service operator via radio, he himself directly sees the current state of the entire system.
Secondly, it does not matter whether it is done through an operator or using a mobile terminal, but in order to provide the fighters with information about the enemy's actions, this information must be available. And for this, control and surveillance means are needed not only on the perimeter, but also on the main routes of movement or at least on the main nodes of such routes. Otherwise, even having received a signal about penetration, it is possible to search for the criminal for several days, because on an area of 10,000 hectares, quite densely built up with complex technological installations and intertwined with pipelines, the criminal can hide so that 10,000 guards will be needed to find and extract him. As such means, sensors and controlled video cameras on high masts are installed at the main intersections of intra-facility roads. The signal from the sensor attracts attention, and the rotating camera itself turns in the direction of where the transport is moving, and if this is the wanted transport or intruders, it allows you to manually follow them on the ground for quite a long time.