It is not very often you hear of a devastating fire taking place at a data centre. There is a reason for that. It's not that such fires happen and data centre operators cover them up; it is that data centre fires are extremely rare. The problem is that when fires do occur, they can be quite devastating. As such, there is a nearly universal requirement for fire suppression equipment in data centres worldwide.
Protecting a data centre against a devastating fire isn't as easy as purchasing and installing a few Seton fire extinguishers in specific locations throughout the building. In the data centre environment, you are dealing with multiple factors. You have to worry about the loss of life first and foremost. Second is damage to the building followed by a loss of sensitive computer equipment.
Fire Suppression Systems and Priorities
In nearly every jurisdiction, different parties have different priorities where fire suppression is concerned. Fire officials and government regulators obviously place a priority on human lives. To them, buildings and computer equipment are replaceable. Interestingly enough, insurance companies tend to see things the same way. If forced to accept a system that saves lives but sacrifices equipment and data, they will gladly pay to replace buildings and equipment as needed.
The data centre perspective is slightly different. Data centre operators certainly want to save lives as well, but they want to do so while still protecting their buildings and equipment as much as possible. As such, inert gas fire suppression systems are favoured among data centre owners.
An inert gas system typically uses nitrogen and argon to reduce the oxygen level in a given space. Reducing the amount of available oxygen essentially starves a fire to death. A properly designed and calibrated system can extinguish a fire in under a minute.
Automatic fire suppression systems dispensing water or foam are also options for data centres, but they are virtually guaranteed to damage sensitive computer equipment. Where no inert gas system is available, a water or foam system is better than nothing. But if data centre owners have to choose, they will go with inert gas more often than not.
Challenges of Inert Gas Systems
What must be understood is that there is no such thing as a perfect fire suppression system. An inert gas system is the best option for data centres in theory. In practice, however, things might be different. The biggest challenge with inert gas is that it is released under pressure.
For an inert gas system to work, it must fill the space with nitrogen and argon fairly quickly. Releasing a gas at too slow a rate will not be effective in stopping the fire before it does extensive damage. As such, rapid deployment is the preferred method.
This is achieved by storing the gas under pressure and then using a small explosion to quickly release it. An inert gas system will send out a shock wave upon activation. It is similar to the shock wave generated by a bomb blast. If you know anything about sensitive computer equipment, you recognise the problem here.
There have been multiple reports in the past of data centres being shut down as a result of problems that arose while testing an inert gas system. One particular case in Romania resulted in the loss of all of the data centre's primary equipment. They had to rely on backup equipment to keep things going until the damaged equipment could be replaced.
Accidental Discharge Issues
According to the Uptime Institute, upwards of one-third of all data centre operators have experienced accidental discharge – sometimes during testing of an inert gas fire suppression system. Moreover, their data shows that operators are three times more likely to experience an accidental discharge than an actual fire.
The unfortunate issue here is that accidental discharge can be just as damaging to sensitive equipment. Accidental discharge would not lead to loss of life or serious damage to the actual data centre building, but it can easily wipe out a lot of computer equipment in mere seconds. That is no way to make friends with your insurance company.
Fortunately, there are solutions. Data centres can work with their vendors to redesign nozzles to reduce the amount of shock produced by activation and release. They can work with vendors to improve sensors that reduce the chances of accidental discharge. Finally, operators can modify the equipment they use.
Sound-insulated cabinets, solid-state servers, and racks with built-in doors can all be utilised to prevent equipment damage. Operators can also locate servers away from discharge nozzles to reduce the risk of direct impact from a shock wave.
Fire suppression is an absolute necessity for data centres. Nevertheless, how an operator goes about addressing the issue is not always black and white. Operators have to account for local regulations, insurance company policies, and their own need to protect equipment without compromising lives. It is challenging to say the least.