Data centres: Intelligent fire protection redefined
Tue 3 Jul 2018 | Carl Bryan
Optimum protection with the power always on
Permanent availability of data, 24/7, for 365 days a year: For data centre operators and their customers, this statement is highly significant. Restrictions or interruptions in data availability can result in business losses and enormous damage to the company’s image. The design specification, as per VdS guideline 2380, stipulates that, in the event of fire, all energy sources and operating equipment such as air conditioning systems must be switched off unless suitable measures are taken to minimise the risk of reignition. Data availability is therefore interrupted and processes are stopped abruptly. Data centres seek to prevent this, even if the data is kept redundantly. This means that if data centre operators do not want to or cannot afford to allow interruptions under any circumstances, they will need a suitable solution for reliable fire protection – without having to switch off the power and without the risk of reignition. The WAGNER Group offers a fire protection solution with the highest-possible safety level: with the earliest possible detection of fires, regular checking of room leak-tightness including notifications, e.g. to the smartphone of the person responsible, an extinguishing concentration that can be maintained for as long as required, and with on-site refilling of the gas extinguishing cylinders with nitrogen.
Classic data centre solutions
Current fire protection solutions in data centres are generally based on gas extinguishing systems. These are mostly designed and installed with safety reserves greatly in excess of the actual number of nitrogen cylinders needed to extinguish a fire. An additional extinguishing capacity of around 40 % of the calculated requirement is generally provided. This ensures that a sufficient concentration for extinguishing can be achieved for a limited time – even if the protected area has leaks, resulting from conversion work, for example. The drawback with this solution, however, is that reignition cannot be effectively and reliably prevented unless the power is disconnected, particularly after the end of the ten-minute hold time for the extinguishing concentration stipulated by VdS. In the worst case, the fire could reach its previous level again and may even spread further. It will not be possible to extinguish the fire again with gas, since by then the gas extinguishing cylinders have already been emptied and no further reserves are available.
Risks for the sustainability of the fire protection system
The conditions in data centres are constantly changing due to the rapid technical development of the infrastructure. The installation of new racks, more powerful servers and network connections requires holes to be drilled through walls or ceilings, for example. These openings must be properly sealed if a suitable concentration for extinguishing is to be maintained, even taking into account the additional safety capacity, and if reignitions are to be prevented after the extinguishing process, in line with the regulations.
“Every data centre operator must be aware of the risk of inadequate gas extinguishing that results from leaks in the room, if he wishes to avoid switching off the power supply”, explains Michael Rupprecht, Head of Business Development at the WAGNER Group.
Strong connection: classic gas extinguishing system with oxygen reduction
What would provide a modern, effective solution that meets the requirements and needs of data centre operators, offers an alternative to switching off power in the event of a fire and guarantees maximum protection at all times?
The answer lies in the intelligent combination of several systems to create an innovative and forward-thinking fire protection solution. The basis of this must be the earliest possible detection of fires. WAGNER air sampling smoke detectors from the TITANUS® family are used in this case. By taking air samples, they detect even the smallest quantities of smoke particles. A smouldering cable, for example, can be detected before a real fire can develop. This head start makes it possible to introduce countermeasures.
Once the highly sensitive air sampling detectors have detected a fire at its earliest stage, the oxygen level in the room will be reduced immediately, in the same way as with a FirExting® gas extinguishing system, from the standard atmospheric level of 20.9 vol % to 17 vol %, by the gentle introduction of nitrogen from dedicated pressurised storage cylinders. The reduction in oxygen concentration results in significantly diminished fire behaviour, so that the fire is unable to spread further, and, in the ideal case, the fire goes out. A nitrogen generator in the OxyReduct® system, then maintains the lowered oxygen level of 17 vol % for as long as necessary by generating nitrogen on-site. This still allows the operator full access to the protected area, giving him the opportunity to locate and put out the fire.
“If during this phase the TITANUS® air sampling smoke detector detects that the fire is spreading, the oxygen concentration is then reduced to a level significantly below the ignition threshold of the predominant materials in the data centre”, says Rupprecht. “This second safety level can also be maintained indefinitely thanks to the nitrogen generator and should completely prevent the spread of fire. In this way, the persons responsible on site gain the time needed to take the correct action in an emergency”, explains the fire protection expert.
Patented: regular verifiability of the room leak-tightness
As with conventional gas extinguishing systems, the two-stage concept also requires that the protected area maintains a certain degree of leak-tightness. This must be checked at regular intervals and the results must be made available to the customer. The conventional method of testing whether a room is sufficiently airtight is the so-called blower-door test, which is carried out once or, at best, at extended intervals. These tests may fail to detect an inadequate level of protection, however, since they are so infrequent.
In place of time-consuming and expensive blower-door tests performed at short intervals, the OxyReduct® system, which forms part of the two-stage concept, can also be used to check the airtightness of a room. Customers are then regularly informed that their protected area is sufficiently leak-tight and that the installed protection system is running smoothly. This system is patented by WAGNER.
“In this way, data centre operators can check the leak-tightness of rooms without any great logistical effort or expense and without any additional personnel,” says Rupprecht.
Complete solution: safe and economical
With WAGNER’s two-stage fire protection concept, data centre operators have at their disposal an all-encompassing solution that is tailored to their risks. While TITANUS® ensures highly-sensitive detection and immunity to false alarms, regular monitoring of the leak-tightness of the room ensures the efficacy of the protection system. Since the system works reactively in the event of a fire, the energy costs are also very low and the number of gas extinguishing cylinders can be significantly reduced. “The level of protection provided, on the other hand, is extremely high,” says Rupprecht in summary. After all, our two-stage fire protection concept makes it unnecessary to switch off the power supply immediately in the event of a fire, prevents reignitions for as long as required and ensures that there are no interruptions in the protection resulting from empty cylinders.”
With its two-stage concept, WAGNER also provides a cost-effective and reliable solution for data centres in which conventional gas extinguishing systems have previously failed to meet the highest safety requirements. With regard to fire protection in data centres, the system leaves nothing to be desired.
Advantages of the two-stage fire protection for your data centre
- No appreciable energy costs in normal operation
- No power shutdown necessary
- Top reliability thanks to regular checking of the leak-tightness of the overall system
- Highly effective fire suppression at all times
Refilling on site: minimum expenditure, maximum safety
Another innovation from the WAGNER Group is the refilling of the gas extinguishing cylinders with nitrogen on site. This concept is suitable for fire protection solutions with the two-stage system as well as for solutions that use only nitrogen gas extinguishing systems.
Gas extinguishing systems with nitrogen extinguish fires without leaving residues and protect persons, buildings and equipment. However, after the system has been triggered, the cylinders need to be filled before they can be used again. This often involves a large amount of logistical effort and expense – for removing the extinguishing cylinders and transporting them to the nearest filling station, for example. In difficult weather conditions or on public holidays, this can be a real challenge.
In larger data centres, it is not uncommon for there to be several hundred gas cylinders installed. Removing and reinstalling all of these requires not only time but manpower. Not so with the solution provided by WAGNER. The OxyReduct® system obtains nitrogen of the highest purity directly from the ambient air on site for refilling the extinguishing cylinders. Data centre operators profit from this intelligent solution, which ensures a permanently high level of operational readiness.