Typical mistakes in choosing and designing security and fire alarms.
“Mistakes should not be admitted. They should be washed away. With blood!” – this is what the heroine of an old Soviet comedy said to her self-proclaimed groom and real kidnapper. After these words, the escape of the would-be newlywed was interrupted by a charge of salt from two barrels.
Such radical measures are unlikely to be applicable to unscrupulous designers and installers, although let's be honest: there are many examples where our colleagues, taking advantage of the technical illiteracy of the customer (and he is not required to have the same training as you and me), deliberately choose options that require less labor, but practically guarantee the customer a permanent headache.
Mistakes made unconsciously occur due to a lack of knowledge and limited tools that the designer or installer has. But, as you understand, this does not make things any easier for the customer.
I propose to systematize typical mistakes in the selection and design of security and fire alarm systems according to the following indicators:
- detectors;
- communication lines;
- receiving and control equipment;
- top level (if there is one at the facility);
- integration.
System capacity
The main and most common mistake is that the designer, often at the insistence of the customer, does not provide for the development of the system. Although it is generally accepted that at least 20 percent of the system capacity is a reserve for its potential development. At the same time, if the designed system is modular, there are fewer problems. If the system has radial alarm loops, the problems of its further expansion can be quite serious. Because to increase the capacity of the system, it is necessary to increase the number of devices, which creates inconvenience in management. In addition, it is necessary to lay new loops, to bring their own pair to each consumer. And if the premises have already been renovated? Additional cabling is the most unpleasant work for both the customer and the installer.
By the way, one of the serious competitive advantages of addressable systems is that they are easy to expand.
If the customer chooses a radial system, the designer must work with the customer in detail to correctly calculate the reserve required for the potential development of the system.
Selection of detectors
With fire alarms, everything is quite simple. Because there are clearly defined standards, the NPB specifies in what quantity and what volume certain types of fire alarms cover. But there is a nuance: which alarms to choose — threshold or addressable? If you focus on the cost of implementation, then threshold alarms are cheaper. In terms of operating costs, addressable alarms are much more profitable. Again, where the standards require one addressable alarm, two threshold alarms must be installed.
With the rapid reduction in the cost of addressable components of the fire alarm system, the issue of saving is not so acute. It is clear that the future, of course, belongs to addressable systems. By the way, the reduction in cost is not only the result of technological improvements. Last year, several manufacturers entered the market, who announced very low prices. This is the easiest way — to initially indicate dumping offers, although it is clear that the cost of production of high-quality equipment is approximately the same.
As for security alarms, the choice here is largely determined by the experience and preferences of designers and installers. Design standards exist, but they are generally strictly observed for certain sensitive facilities or premises. For example, a bank has several specially protected areas: a server room, cash vaults, and a weapons storage room. Corporate security standards are prescribed in many large companies.
The main errors are associated not with traditional wire detectors, but with radio channel detectors. There are more and more offers for radio channel solutions on the market. Customers are attracted by the simplicity of installation, but this simplicity is visible. Because to competently design and put into operation a radio channel system is a large amount of work and considerable preliminary research of all the features of the facility. It is necessary to take into account many factors that can affect the operation of the designed system. One of the most important is the electromagnetic environment at the facility and its compatibility with the designed system. It is necessary to take into account that there may be some other equipment in the building, other sources of radio emission. It is known that even a change in the weather affects radio permeability.
That is why radio channel systems are usually used in relatively small facilities. Or in that part of a large facility where it is impossible to lay wired system cables. Sometimes two parts of a facility are connected by radio bridges. For example, wired systems in two separate buildings are connected using radio modems. In essence, this creates a radio gateway to a conventional wired system.
That is, the main problem of radio channel systems is the reliability of their operation. True, today there are interesting offers from Russian manufacturers on the market. These are, for example, duplex radio channel systems. A two-way channel allows flexible configuration of system components, automatic adjustment to the current radio environment. There are few statistics on the use of such systems yet, but the first reviews are very good.
What else can be said about detectors? An important point: when designing systems for industrial enterprises, it is necessary to take into account the features of technological processes at them. Ideally, before starting design work, measure the field strength, make control measurements in those parts of the facility where security systems operate. That is, it is necessary to solve the problem of not just closing off areas, but to take into account what will happen at this enterprise, what technological processes can affect the operation of security systems. And at the design stage, provide for the necessary insulation and grounding systems for cables, other measures to protect systems from external influences.
Communication lines
The most common mistakes: incorrect selection of cable type, as well as violations of the manufacturer's declared characteristics of communication lines and topology when designing cable routes.
The first of the above mistakes is usually made in cases where the facility is already in operation and the customer, in order not to spend additional funds, asks that existing cable systems be used. This is another case where savings can turn into problems. And they may not arise immediately. Over time, the technical characteristics of the cable deteriorate, the operating mode of the equipment that operates in the same cable system can change and very often does change.
A few words about the characteristics of communication lines. Take, for example, RS-485, one of the most popular interfaces today. According to the specification, the maximum length of a communication line in it is 1200 m. Often, designers include a greater length. In principle, this is possible, but it is necessary, firstly, to use additional equipment for signal retransmission, and secondly, to take into account the specifics of the object. If this is not done, failures in the system become almost inevitable.
The requirements for the topology, i.e. the rules for laying cable systems, are quite strict for address communication lines. Some lines have a linear topology, where branching is unacceptable. In others, branching is allowed, but they must be of a strictly defined depth and length. If the communication line has a ring structure, it must be reduced to a ring for guaranteed operation.
Most often, the topology of cable routes is violated when the designed security system is adjusted to the existing cable systems.
Existing transport systems, such as a local enterprise network, are often used to transmit signals. The most important thing here is to know what other information will circulate in this network, what the traffic will be. If a shared resource is used as a transport system, which is accessed by several consumers, the network load must be strictly balanced so that the bandwidth is sufficient for all systems. If this cannot be foreseen in advance, it is better to create a dedicated network for the security system.
Control and reception equipment
The main problems arise if the selected equipment does not correspond to the scale of the facility. After all, it is no secret that many designers and installers often sit on some specific systems. And they install control and reception equipment designed for 50 loops on a large facility that requires 500 loops.
Unfortunately, there are many design and installation organizations on the market that work with a limited range of equipment. The specialists of such companies know it very well, they know all the nuances and features, all the pitfalls. They can design, install, and launch a system in the shortest possible time. But in doing so, they will have to use equipment that does not correspond to the scale of the facility. And then the customer and his security service are left alone with their operating fire alarm system. And even if it works properly for some time, such a system is initially inconvenient to use. And you must agree that the efficiency of the system largely depends on convenience.
Software
We are talking about special software for configuring the system, organizing the workplaces of duty shifts.
My personal opinion: it is often simply not necessary to use a computer in low-information systems, such as fire alarm systems. A computer is the weakest link in any system. But if you can’t do without it in an ACS or CCTV, in most cases it is not needed in a fire alarm system. The simpler, the more reliable.
Integration
If we are talking about heterogeneous equipment, all systems should be reduced to the upper level. For example, if the security alarm is made on one equipment, the fire alarm — on another, of course, it is more convenient if all systems are reduced to one workstation, where the operator has the opportunity to receive information in a single view from all these systems, have access to control them. The efficiency and reliability of the systems increases, as well as the speed of response of the security service. Here the choice should be made in favor of integrating complexes that initially have the ability to work with a large number of heterogeneous equipment. Or, what is even better, the ability to refine and adapt to some new equipment, which, perhaps, has not even been announced today. This applies primarily to large systems. But if the systems are designed separately, if equipment from different manufacturers is used, it is necessary to determine at the earliest stage how it will all work together. If possible, use the equipment of integrated systems, which allows you to implement all the subsystems of the facility on a homogeneous hardware base.
If the system is integrated, it is necessary to select the appropriate upper level, allowing full operation with all subsystems included in the security system. Moreover, as a rule, interaction of subsystems is necessary. If there are no hardware capabilities for its organization, it is implemented through software.
These are, in my opinion, typical mistakes in the selection and design of security and fire alarms. Colleagues, of course, can add something to what has been said. And argue with something. Any controversy is a useful thing by definition, but the main thing is that it has practical significance.