Addressable fire alarm systems.
An addressable system is a system in which each sensor has a specific address and is regularly polled by the control panel.
Signals are classified as «normal», «malfunction», «absence», «alarm», etc.
An analog system is a system in which the sensor does not have an exact address and when an alarm signal is given, only the loop beam to which it is connected along with several other sensors is known.
Which system is better?
I would answer this question like this: it depends on who it is installed for and for what purpose.
For the owner of a facility who installs a fire alarm system primarily to protect his property and people from fire, an addressable fire alarm system is better.
The addressable system enables precise determination of the location of the fire, as well as the direction and speed of fire spread.
The system remains operational if the loop is damaged.
Addressable systems are more reliable than analog ones, they have fewer false alarms, and also perform self-diagnostics.
If you go further and install detectors with built-in video cameras, the operator will be able to see the location of the fire and assess its scale.
As for the security alarm, self-diagnosis is also important for it, and especially minimization of false alarms, since frequent false alarms can lead to the guard trying to turn off the system altogether.
The systems are programmed in such a way as to not allow a person with limited authority (i.e. a guard) to turn off the system whenever he wants.
But an inquisitive mind combined with clever hands will do the job.
Knowing the exact address of the alarm sensor, of course, will not hurt, although this issue can be resolved in the case of using an analog system.
For example, each room can be connected to a separate loop. This will result in a higher cable consumption, but ultimately the analog system will be cheaper.
For the owner of the facility who needs a fire alarm system to a greater extent in order to obtain a visa from the fire inspection, an analog system is more suitable.
The advantage of an analog system is its relative cheapness, and the disadvantage is its low information content, the need to install two detectors per room (although with addressable systems it is often necessary to install the same two detectors per room), a high probability of false alarms, multiple loops instead of one, higher cable consumption and, as a result, the use of cross-connect equipment.
An analog fire alarm system will certainly do its job – warn of a fire, but an addressable one is still more effective.
I worked in a company where I often had to make three versions of specifications for one object to draw up a commercial proposal: expensive, average and cheap.
An addressable system always turned out to be about 30% more expensive than an analog one.
Therefore, for small objects, an analog system is more appropriate — there you won't have to look for the source of the fire for a long time due to the limited area, and, perhaps, there is nothing to burn.
As for the security alarm system, first of all, it is worth paying attention to its compatibility with other systems.
Addressable systems often have a closed protocol, which complicates their integration with other systems if their protocols do not match.
This often happens when using equipment from different manufacturers.
If the fire alarm at the facility can exist separately (and it is often purposefully built separately from other systems), then the security alarm must interact with the video surveillance system and the access control and management system.
For a commercial manager representing a design and installation organization, the system that is more expensive is preferable, because in the end the profit will be greater.
The more expensive the equipment, the greater the profit — this trend is usually always traced, with the exception of some nuances such as profitable deliveries and other things.
But that's another story.
For a designer, a system is preferable… no, not one that is simpler in itself.
I'll tell you how a designer chooses equipment for an object in general.
Usually, the designer does not gain materially from the choice of equipment, his salary does not depend on the contract amount.
Therefore, the designer has no commercial interest.
Then what drives him?
In the case where there are no instructions on the choice of equipment, only an abstract wish like: «so that everything works», the designer will take the equipment that he used in his previous project, similar to the new project.
And not because he is too lazy to deal with unfamiliar equipment or it is difficult.
Even if the designer is slow-witted, has little knowledge and less than a week of experience, he will cope.
He will turn to colleagues, to the chief engineer, ask his dad-electrician, will pester the developer to give him the necessary schemes and consult. In short, he will do it if he wants.
The reason lies elsewhere.
If you use equipment that has been tested in the previous project, then there will be fewer problems with the purchasing department, fewer questions will be asked by estimators, fitters, commissioning engineers — it is more convenient for everyone to work with familiar equipment than with new equipment.
And this equipment is often analog, since for previous projects it was selected according to the same principle: the project was carried out on the basis of a template inherited, which was developed back in the days of Tsar Gorokh.
If the designer has dealt with both an address and an analog system during his work, he will choose the one that was in his last project, since it is fresher in his memory.
When asked which system is more difficult to design if you do not use templates and design from scratch, the answer will be ambiguous.
There are some peculiarities in the design of both systems. For example, when using an addressable system, you can do without cross-connection equipment — boxes, cabinets, since in this case the loop is directly connected to the device. This means that you will not need to draw a cross-connection diagram.
But if it becomes necessary to add or remove a detector from the loop, you will have to change the numbering of the detectors in the entire long loop.
In an analog system, the loops are shorter, so it will be easier to correct the numbers.
An addressable system requires an address table, an analog system requires a loop table.
The address table is longer than the loop table, but its compilation is not so labor-intensive that this criterion should be put at the forefront when choosing a system.
Other services influence the designer's choice.
For example, the procurement service. For example, it may prohibit the inclusion of some equipment in the project due to inconvenient delivery times or unfavorable prices. But if the designer proves that the system requires a blank painted the color of ripe papaya, and no other will do, they will buy it.
The decision is approved by the Chief Project Engineer.
The Chief Project Engineer does not need complications with the procurement service, estimators, and installers. In addition, it is easier to check a project completed on familiar equipment.
Or the Chief Project Engineer is often also the designer.
In any case, the Chief Project Engineer agrees with the designer on this issue: it is more convenient to use the equipment that was used in the previous project, was successfully purchased and implemented.
It works on site — and that is the main thing.
And the new one (for the organization in which the Chief Project Engineer works) is still unknown, how it will behave, how much time will be needed for its delivery, where to get specialists for setup, easily trained installers. The Chief Project Engineer is also a person who is not very interested in profit.
He, like the designer, gets nothing from the purchase of this or that equipment, as well as from the profit on the project as a whole, with the exception of cases of mega-profits from mega-projects.
But these are already different scales, in which the equipment is selected not by the chief engineer or the designer.
No one is attracted to experiments with new, even flawless equipment.
A thirst for research, enthusiasm, a desire for perfection — these are not words from the dictionary of a design organization.
If there are no strict instructions on what equipment to take, projects will be built on a well-worn track, where specifications are repeated from project to project.
Within reasonable limits, of course.
If the solution is not suitable for a given object, then no one will implement it.
This is not so bad.
As they say, an old horse doesn't spoil the furrow.
A well-trodden path is more reliable than a new one, the execution mechanism is debugged, the deadlines are verified.