Fire protection for data centres has evolved considerably in the last three decades. Technologies have matured to fulfil market demands for solutions that meet the delicate balance of properties required to maintain continuity of operation over the life of a data centre.
his is good news for purchasers but the decision making process is now more complex than when the only gaseous suppression choice was halon. Some of the technologies are even governed by different standards, making direct comparisons more difficult. Nonetheless, data centres increasingly are at the heart of many businesses and it is vital to keep them running. With the variety of choices available and recent changes in environmental regulations impacting the fire suppression market, it’s important to think more broadly about how choices today could have an impact on the ability to preserve continuity of operations well into the future.
Capitalonline Ltd, the independent online data consultancy, has recently published its rolling 5 year review of catastrophic data centre failures around the world. Their findings are interesting…. Average data centre outage following an incident was 12.5 hours, which equates to over US$151 million dollars globally*. Serious fire events account for 21% of catastrophic failures, yet are responsible for 41% of all outage time once IT issues are removed. According to Emerson Network Power, average data centre downtime costs are $7,900 for every minute of downtime. Preventing system failure in the event of a fire, or at least getting systems back up and running quickly is vital. Because fire suppression systems will differ in the degree to which they minimise downtime in the event of an emergency, this is an important total cost of ownership consideration in the purchasing decision.
So what options are available for protection of computer rooms? And what should purchasers look for when specifying fire suppression systems in data centres? To answer these questions it helps to analyse what is being protected. Where water mist or sprinkler systems may be appropriate for the data centre structure, for example, protection of valued electronics requires a solution that will extinguish fires cleanly with no risk of damage to assets, and minimal disruption to operations. Let’s look at the main system alternatives and their suitability for data centre protection:
Aqueous systems:
When it comes to sustainability, water based systems are certainly exempt from impending regulatory changes that seek to phase down use of HFCs in the fire suppression industry. There are two main technologies in aqueous protection – sprinkler systems and water-mist systems.
Water sprinkler systems have provided effective fire protection for over 150 years, but they are designed to control a fire, not necessarily extinguish it. Sprinkler systems allow occupants to evacuate while enabling fire fighters to enter the building. However, one must consider that release of water onto valuable electronic assets is likely to cause significant damage, additional to the fire itself. Also, consider that the heat generated and smoke accumulation in advance of water sprinkler discharge will have already caused substantial damage to the valued electronics.
Water-mist systems
Water-mist systems are distinguishable from traditional water sprinkler systems in that they use less water than conventional sprinklers to develop very fine sprays and subsequent small water droplets. Nevertheless, water mist systems release a substantial quantity of water into a protected space. Originally developed in the 1940s for marine applications, these systems suppress fire through water’s high-heat capacity, reducing the heat of the flame and surrounding area, and displacement of oxygen by evaporation. Water mist systems are well suited for control of large energy fires but a large fire is the last thing one would want in a data centre. Small (<5kw), hidden or obstructed fires, typical for data centres, have proven to be difficult for water mist systems to extinguish.
Prior to a water mist system being specified for data center protection, purchasers should satisfy themselves by asking the following questions:
- Will the system extinguish the fire or simply control the fire? Will the system be effective on hidden fires?
- Will recommended humidity thresholds within the data centre be exceeded?
- What is the impact of water vapour and residual moisture on sensitive electronics and high value assets?
- How much damage will occur over the duration of the longer system discharge, from heat and the generation of smoke?
- What is the potential down time associated with clean up after the fire incident?
Inert Gas
Inert gas systems – usually mixtures of nitrogen, argon and CO² – were introduced as halon replacements in the 1990s. These systems have comparatively minimal impact on the environment and they are truly clean in that they are non-conductive and extinguish fires without leaving a residue. Inert gases differ, however, in that they rely on a significant agent concentration in the protect space to effectively suffocate the fire by reducing the ratio of oxygen to levels inadequate to support combustion.
Due to the significant volume of gas necessary for extinguishment, venting of the room is required to relieve room pressure that could otherwise lead to structural damage. To accommodate the large volume of gas, inert gas systems are stored under very high pressures and require more real estate to store a larger number of cylinders relative to halon and other in-kind replacements. In addition to more rigorous maintenance schedules, the high pressure of inert gas systems have other consequences. For instance, higher pressures may result in more noise in the data centre over longer discharge times so operators need to assess whether or not the duration, magnitude and frequency of the noise will impact disc drives present in the data centre.
The evolving regulatory landscape
The increase in usage of inert gas and aqueous based systems, in many cases, is due to the diminished use of HFCs, which were ubiquitously used in fire suppression sector after the halon phase-out. Now, the potent global warming potentials (GWPs) of HFCs have them too on a phase-down schedule in the European Union and on a road map for a global phase-down to be negotiated in 2016 under the Montreal Protocol, the same international treaty that dictated the phase out of halons. For instance, the GWP of HFC-227ea (FM-200™) is 3,220. This means it is 3,220 times more potent than CO² in its climate impact. HFCs sold into fire suppression have some of the highest GWPs compared to HFCs sold into other sectors, such as refrigeration and air conditioning.
In July 2015, the U.S. Environmental Protection Agency (EPA) changed the status of HFCs to ‘unacceptable’ for specific uses under the Significant New Alternatives Policy (SNAP) programme. This is based on data showing that other substitutes are available that pose lower risk overall to human health and/or the environment. Although the HFCs sold into the fire suppression sector have not yet been targeted by SNAP regulation due to their climate impact, the availability of substitutes for HFCs in the fire suppression sector, suggests the industry needs to consider that inevitability.
These regulatory changes are putting a substantial amount of uncertainty on the future supply and cost of HFCs sold into fire suppression. Purchasers of fire suppression systems also need to consider that the selection of a non-sustainable solution today may impact continuity of operation in the future. Fortunately there are cost effective, sustainable alternatives available.
The sustainable breakthrough
A breakthrough in sustainable fire suppression came in 2003 with the introduction of a fluoroketone, commercialised by 3M as Novec™ 1230 Fire Protection Fluid. This clean agent achieves the demanding performance and safety necessary for clean agent fire protection without being subject to existing or anticipated HFC phase down regulatory activity. It offers the same space-saving advantages of HFC/halon systems but with a much stronger environmental profile. Novec 1230 fluid has zero ozone-depletion potential and a global warming potential of less than one, resulting in more than a 99% reduction in climate impact relative to HFCs.
Clean agents are particularly suitable for data centres as they are non-conductive and evaporate quickly and cleanly, leaving no residue after discharge. Novec 1230 fluid causes no damage to electronics or other high value assets, and can be used safely on energised equipment, helping to ensure continuity of operations. In fact, Novec 1230 fluid has the highest dielectric strength of any clean agent. Use of clean agent systems can significantly reduce business downtime if a fire does occur.
Again, the selection of a clean agent system is complex. The differences between available technologies have consequences that can impact total cost of ownership and continuity of operations over the life of the system. Considerations include real estate costs, maintenance costs, clean-up costs, refill options, venting requirements, and the uncertain costs associated with ownership of legacy technologies such as halons or HFCs. Also, recall that the cost of downtime is $7800 per minute and, in the event of a fire, some technologies such as water may result in longer downtimes than can be tolerated.
The choice of fire suppression systems for data centres has never been greater. Clearly there are multiple sustainable solutions available to substitute for halons and HFCs in fire suppression, but purchasers should keep in mind that when it’s your most critical business assets, the ‘heart’ of your business that you’re seeking to protect, it’s well worth taking the time to invest in the right solution.
For more information, go to www.3m.com/novec1230
About the Author
Kurt Werner is the Environmental Affairs Manager at 3M
