Features of the design of ASPT for large server rooms.
In the early 80s, several data centers burned down one after another in Moscow. At that time, data centers processed tons of punched cards and punched tapes per day. As it soon turned out, the ventilation ducts were covered with a thick layer of paper dust, which flared up like gunpowder, so that the fire engulfed the entire building in a matter of seconds.
Nowadays, they don’t build such huge buildings designed exclusively for computers. The most important thing is that there is practically no paper in server rooms now; regular office rooms are much more fire hazardous. However, since server rooms are usually unattended and operate around the clock, the probability of a fire breaking out there is quite high. The main source of fires are cables, wires, and poor contacts. An additional danger comes from old power supplies in old computers. First of all, electrolytic capacitors age, after which excessive heat generation and overheating of the elements begins. In addition, over time, insulation is damaged, dust accumulates (even if not paper). In general, everyone gets used to the fact that equipment works for years without human presence, and for some reason they are surprised that everything was fine for six years, and on the seventh, for some reason, it suddenly caught fire. But the cost of information located on servers usually significantly exceeds the cost of the servers themselves, and the cost of enterprise downtime caused by damage to the infrastructure can exceed the cost of all equipment by several orders of magnitude. In general, no one objects to the need to equip a server room with a fire extinguishing system.
However, how can it be made effective?
As for the fire extinguishing material, there are essentially no options: only gas extinguishing. Of course, if you are concerned about protection not from fire, but from the fire inspector, then powder is fine. Although then it would be easier to rename the room from a server room, for example, to a switch room. Or if you are concerned not about the servers themselves, but about the entire building (the server is still being thrown out, but at least the fire will not spread further), then you can also discuss whether powder is enough or sprinklers are better, as in the entire building. If there are 100 computers in one room, the cost of their possible damage is too high. Some experts suggest using finely misted water, but how safe it is for computers is not an obvious question, after all, high humidity is harmful to electronics, although it sometimes extinguishes a fire more effectively than gas (due to the rapid cooling of the smoldering material).
The most difficult thing is to choose the right detectors. Let's briefly consider the existing detector technologies. Most modern smoke detectors are configured to detect white («cotton») smoke. This is true for household use. However, in server rooms, plastic, rubber, possibly wood (furniture) can burn, but not cotton. The conclusions from this observation are the saddest. Since domestic detectors do not spoil with a variety of technologies, you will have to use imported ones. Moreover, you will have to use imported detectors that are not the simplest, they will be addressable and will drag the entire alarm system along with them.
The most effective will most likely be a carbon monoxide detector. However, smoke detectors configured for «black» or «colorless» smoke can also be effective. By the way, in advertising literature, the former are sometimes described as detectors with an acute scattering angle — most often, detectors are produced with two sensors located at different angles: one for «sulfur» smoke, and the second for «white». The second — detectors for «colorless» smoke — are often designated as detectors with a «blue beam». Flame sensors are unlikely to be particularly effective (unless you have solid wood furniture), but you should not neglect any possibilities. Of course, thermal maximum differential detectors can also help, especially if they are placed directly in cabinets with equipment, because a powerful air conditioning system typical for server rooms can very effectively clean the air in the room from smoke at the initial stage of a fire.Hence the conclusion: there should be many different detectors. And most importantly, there can never be too many detectors. Don't be greedy, install them not «according to the fire safety regulations», but in such a way as to minimize the detection time. Often, in addition to the general detectors on the ceiling of the room, a pair of detectors are installed in each cabinet with equipment. It is clear that the total number of detectors in the room will be much more than the required fire safety regulations, but compared to the cost of the entire system, this is still the smallest expense.
The second major problem is the need to turn off all equipment in the room when a fire is detected. Calculate how much it will cost you to interrupt the operation of all servers in the room, and design a division of a large room into small ones with fire partitions. Then you will be able to localize the fire in one section, probably without interrupting the operation of servers in neighboring sections. In addition, if you have many small sections, the fire extinguishing system may have a significantly smaller capacity of gas cylinders. What is important: if the system is falsely triggered in one section, the gas consumption will be significantly less than if the system were to trigger on the entire floor at once.
The extreme case is autonomous equipment cabinets equipped with an autonomous air conditioning system, fire extinguishing, uninterruptible power supply, and possessing sufficient fire resistance to be able to extinguish one cabinet individually. Such cabinets are mass-produced and are usually used for particularly important applications. I recall a commercial — such a cabinet is thrown into a river from a burning building, then fished out, opened, and a computer continues to work inside. This is a slight exaggeration — in a regular computer, only hard drives would not withstand mechanical impacts. By the way, when talking about fire partitions, do not forget that cable channels can be routes for the spread of fire, even if all the cables are non-flammable. Dust, not even paper, especially in the presence of draft like in a chimney, will help the fire spread to the next compartment. It is worth saying that there is still enough paper dust near any computer. Although punch cards are not in fashion now, printers use paper more and more efficiently, no punchers could even dream of such a thing
.