The datacenter is a system that must never fail and must never be compromised. Even a possible fire must not cause a disaster. It is not so much the lost hardware that can be replaced, the more important problem is the loss of data, which is worth orders of magnitude more than the hardware on which it is stored.
The server room area must therefore be very well protected against fire. The first step is, of course, to put in place preventive measures to minimize the risk of any short circuit, fire, etc.
Preventive measures
It is never possible to completely rule out a short circuit, fire or other similar event. The server room must be built with the understanding that this kind of thing can happen, but the risks need to be minimized as much as possible. The reason is simple – a server room is made up of many different devices, through which a lot of electricity flows, they have different mechanical components, all the devices get hot – and from time to time a fault just happens. Sometimes this is manifested by the device stopping working. Worse comes to worse. Therefore, it is necessary to be prepared in case the preventive measures fail and an emergency situation occurs.
Example of preventive measures:
- Prevent static electricity – maintain proper humidity.
- Have all technology sufficiently grounded.
- Have all power supplies adequately secured. In the extreme case, each device may have its own fuse. A short circuit in one device should result in the disconnection of as few other technologies as possible.
- Minimize the movement of people in the server room area – a person can always cause something intentionally or unintentionally.
- Take care of work safety – do not use fire, do not enter with flammable substances, etc.
When there is a fire
A fire in the server room, that’s a real mess. What to do at such a moment? Do nothing and wait for the fire department to arrive? Certainly not – by the time they arrived, it would be over.
So we need to start firefighting. Definitely do not extinguish with water as all equipment is energized. Also, you should not use powder extinguishers – although this will safely extinguish the fire and you will not risk electrocution, it will destroy all the equipment (not only those that are on fire, but also those around the fire, which will also get the extinguishing powder).
In the server room, only gas extinguishing using gas that does not damage electrical equipment is an option. Of course, this won’t save the equipment that is on fire (nothing can save it, the fire has simply destroyed it), but it won’t destroy other equipment in the vicinity that is not harmed by the gas and can continue to work. It is necessary to have a sufficient number of hand-held fire extinguishers around the server room so that the operator can intervene as quickly as possible to extinguish a local fire.
Stable extinguishing equipment
When the worst comes to the worst, the so-called. SHZ, i.e. stable extinguishing equipment. It is an automatic system, extinguishing the whole area.
SHZ consists of:
- SHZ control panel – control system
- fire extinguishing gas cylinders (“bombs”) with trigger valves
- alarm sirens
- emergency buttons for immediate start of extinguishing (START)
- emergency buttons for immediate cancellation of extinguishing (STOP)
- fire detectors
- extinguishing nozzles
- piping for distribution of extinguishing agent from cylinders to nozzles
It is therefore a complex system. Pipes are distributed throughout the server room for evenly spaced fire extinguishing nozzles. It is something similar to the water extinguishing from the ceiling that you can see e.g. in shopping malls. Fire extinguishing nozzles are located on the ceiling and also on the floor (inside the double floor). The fire extinguisher is fed to them from cylinders. The bottles are pressurised and filled with extinguishing agent. At the same time, detectors are placed throughout the room to detect fire and smoke.
When there is a fire
- The alarm starts when at least 2 detectors detect a fire
- An alarm is triggered to alert workers to the situation – light and sound warnings
- The worker must immediately attend the site and assess the situation. If he decides that he is able to extinguish the fire with a hand-held device, he presses the STOP button to deactivate the SHZ and goes to extinguish the fire. That’s the end of the event.
- If the worker decides that the fire is beyond his/her strength, he/she leaves the room and presses the START button from the outside. This results in immediate extinguishing – the valves on the cylinders open and the extinguishing gas starts to “blast” under high pressure into the entire room. Within seconds or minutes (depending on the technology and extinguishing agent used), the entire space fills with this gas, smothering the fire.
Of course, the system must not rely on the human factor. A certain time interval is set after which it starts extinguishing itself. This interval is used to allow someone to come and stop the firefighting if the problem can be solved by other means.
No alarm occurs if only one detector reports a problem – this is in case this one detector is faulty and reports an alarm by mistake.
Why stop the firefighting and not always let SHZ do the job? It’s a question of money, of course. Fire extinguisher doesn’t have to be a cheap affair. The release of gas can cost tens of thousands to millions of crowns. For this reason, in the event of a small fire, the SHZ is shut down and extinguished with hand-held apparatus. However, when the fire is larger or when human attendants do not arrive, there is no other way than to start the extinguishing, otherwise a much bigger disaster could occur. The fire extinguisher may cost a few million, but the technology and data it saves could be worth hundreds of millions.
Other automatic actions must also occur during extinguishing. The space must be completely sealed to prevent the extinguishing agent from escaping – this would make it all go to waste. This means that various vents, air dampers, ventilation shut off, etc. must be closed automatically. But all this really has to happen all by itself without the need for human intervention, because it’s all about minutes and seconds.
Hasivo
All extinguishing agents for process areas must meet several conditions.
- It must not cause any damage to any equipment, including equipment that is energized.
- It must be at least partially breathable. If a person is left in the area, this must not suffocate him/her (e.g. if an injured person is lying in the area or another person does not manage to escape before the start of the extinguishing).
- It should not adversely affect the environment.
The goal is not to push all the air out of the space, that would make the space unbreathable. The fire will stop if the oxygen ratio in the air falls below a certain level, but this level is still sufficient for human breathing. Even so, it is of course better if people leave the area – for this reason the START button is not located inside the extinguished area, but outside the entrance door.