Which Data Center Fire Suppression Solution Works Best for You?
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The Differences Between Water and Clean Agent Fire Mitigation Systems, and How They Provide Specific Data Center Needs
There are two categories of data center fire suppression agents that a you may consider using: water (aqueous) fire suppression systems, and clean agent (gaseous) fire suppression systems. There are benefits and disadvantages to both types of fire suppression agents. Both of these broader categories of fire suppression agents have specific systems, with which these two agents suppress a fire.
Clean Agent Fire Suppression Systems
Clean Agent systems are gaseous systems that either deprive a fire of heat or oxygen in order to suppress it. These types of systems do not leave chemical residue on equipment, and by their configuration, they prevent water exposure to IT equipment. There are three different types of Clean Agents that are most commonly used: Inergen Systems, Sapphire (Novec 1320) Systems, and FM-200 Systems.
Inergen is a breathable gas comprised of 52% Nitrogen, 40%Argon and 8% Carbon Dioxide. It suppresses a fire by lowering the oxygen level in a room below the level needed to support combustion, but still leaves the oxygen level high enough to sustain life, while suppressing the fire. The release time for Inergen is 60 seconds, which is the longest release time of these three options. Inergen systems require more intricate pipe systems that also require more pressure to be maintained within the system.
Novec 1320 Systems
Sapphire or Novec 1320 systems suppress fires by removing heat from the room. Novec 1320 is a synthetic fire suppression agent that is stored as a liquid, but is used to suppress a fire by converting to a gas form. It does not require as much pressure to store as Inergen does, and also has a much simpler piping system.
FM-200 systems also suppress fires by removing heat from the room. They can be used with people in the room with few adverse effects. FM-200 systems are also much quicker than Inergen systems to reach full fire suppression levels. FM-200 has a much better potential for having a global warming effect than the other two systems.
All three of these different clean agent systems can be used while employees remain inside of the room, but Inergen seems to have more of a risk factor for some people because it lowers the oxygen level, which may not be ideal for all people. All three of these systems require floor space and are costlier to install and maintain than water systems. In addition to these disadvantages, clean agent systems can be linked to the EPO (Emergency Power Off) System. This was a requirement of the NFPA until 2011.
Water Systems Used to Mitigate Fires
There are also a few different fire mitigation systems that rely on water as opposed to gases. The most common of these water systems is a sprinkler system, which can vary depending upon the type of head and how the water is stored within the pipes.
Of the sprinkler systems, there are two types of pipes: wet pipes, which store water in the pipe to dump overhead when a fire is detected; and dry pipes, in which water is held back by a secondary or pre-action sprinkler valve until a heat and/or smoke signal causes it to release. Pre-action pipes are the IT industry standard because they stay dry, and therefore cannot collect condensation to drip on IT equipment. The two most common pre-action pipe systems are single interlocked systems and double interlocked systems.
Single Interlocked System
Double Interlocked System
A double interlocked system relies on a detector alarm and the sprinkler head melting, which greatly reduces the risk of an accidental discharge, when compared to the risk of the single interlocked system. The downside is that the added complexity of the system can reduce reliability is one of the two fire indicating mechanisms doesn’t trigger the sprinkler system.
The Best Decision?
Both clean agent systems and water systems have their benefits and disadvantages. Clean agent systems prevent water from entering the server room. However, they cost much more than sprinkler systems and take up much more floor space, as sprinkler systems are installed overhead. On the other hand, clean agent systems leave water out of the server room. They leave no chemical residue on equipment and pose no electrical hazard. The better fire mitigation solution comes down to the individual data center needs.
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