The Crucial Role of Fire Systems in Data Centre Design

In 2019, Germany, the United Kingdom, the Netherlands, France and Italy rounded out the top five countries in Europe in terms of their numbers of data centres. The challenge for facilities managers is to keep critical infrastructure running, as problems can have very serious consequences.

On 31st October 2016, a Ford Motor Company data centre in Detroit was shut down by an electrical fire. Thankfully, nobody was hurt but the whole Dearborn complex, which houses 30,000 workers, was forced to close for two days and October sales performance figures for the whole of the Ford Motor Company were delayed for a week, which caused fluctuations in the company’s share price. Backup power avoided further disruption, but the incident underscores the potential negative implications of a data centre fire.

Causes of data centre fires are diverse, ranging from squirrels biting through wires (Yahoo, Santa Clara, 2012) to lightning strikes (Microsoft, Dublin, 2011). In 2008, an HSBC data centre in Welwyn Garden City was severely damaged by exploding gas canisters belonging to a building contractor, but the main causes are the much more mundane problems of overheating and electrical faults. Specialised fire systems and procedures are needed to protect this vital infrastructure.

Building design

Building a data centre can cost millions, so adequate fire protection and extinguishant systems are vital to safeguard the servers, the data and the people who manage them. These systems, both active and passive, are designed into the buildings, based on stringent risk assessments. For active fire alarm systems, the bible in the UK is BS5839, but each country will have their own version.

Data centre design offers certain advantages to the specification of an effective fire system. With no need for public access, there is more scope for fire system design than other sites, for example exposed cables or cable trays are less likely to be an issue. However, this is best designed in at an early stage, along with all the necessary extinguishant pipework and suppressant storage, and passive fire containment systems.

Cambridge Datacentre Web Main

A network of ExGo gas extinguishant panels from Advanced protect the Data and High Performance Computing Centre at the University of Cambridge

The fire panel

The fire panel lies at the heart of the active protection system. It can be single or multi-loop, standalone or networked. In a complex data centre, the installation costs are likely to dwarf equipment prices, but if an unreliable or unsuitable system is installed, the downstream costs will be significant. Advanced’s expertise with data centres is based on a history of complex projects, including the £20m West Cambridge Data Centre, specifying systems optimised for performance, quality and ease-of-use.

Speed and resilience are key. In datacentre fire-fighting seconds can make a huge difference to the scale of data loss or downtime, so networking and loop communications protocols that work efficiently are vital and should be key specification requirements, especially on bigger sites where the network will be doing more with more devices, inputs or outputs.

While the server rooms are the primary focus, the building is also likely to contain offices, service areas, staff rooms and other spaces. For example, in many buildings a smaller server room or larger datacentre may very well be part of a much larger office or manufacturing environment. At the other end of the scale, dedicated datacentres can be vast, with a much smaller office attached, and can sometimes be in remote locations.

There are two common approaches to general fire alarm protection and specialist extinguishant release. The first is the use of integrated extinguishing modules on addressable fire alarm panels. The second is an entirely separate (and perhaps monitored) extinguishant release or suppression control system.

Modern addressable panels are highly reliable and resilient, and are used to protect many environments equally as sensitive as datacentres. Suppression control modules can be added to the fire system and can then control extinguishing operations as part of the wider cause and effect programming. 

On smaller sites, where a system is being expanded or where a mindset of ‘separate systems is best’ prevails, many manufacturers will provide a standalone extinguishing system.

Whatever route is taken, the performance of the installed fire systems should be considered at specification stage. Panels and systems that are EN54-13 compliant, such as the Advanced MxPro 5 addressable fire system and ExGo suppression control panel, will continually check the condition of their networks, components and wiring, ensuring that they will work when required in an emergency. Many systems also offer redundancy, switching to an alternative processor, or complete panel if a problem is detected.

Reliability and resilience are key requirements in datacentres. The last thing any site needs are false alarms due to spurious signals, EM noise and power spikes. A system that offers immunity to such problems, with highly professional installation and cable management, should also be major considerations.

Fire detection

Data centres will use a range of detector types with a focus on early and accurate smoke detection. This may combine point detectors, using optical and heat detection, with very early warning aspirating smoke detection systems.

Aspirating systems are one of the fastest growing detector solutions and are ideal for datacentre environments. They continuously sample the air in a space by drawing it in through an array of pipes with small holes at specified points, and pass this air over a highly sensitive detector at a remote location. Some systems can identify precisely where the smoke entered the pipe network. They also offer accessibility and maintenance benefits as the pipes can be installed in hard to access spaces, and there is only one detector to test and maintain. There are several solutions available and all will offer distinct advantages.

Fire alerts

Once a fire has been detected it’s important to safely evacuate the building and manage the spread or suppression of the fire.

Although the number of people working in the data centre itself is likely to be less than a conventional office, care still needs to be taken to alert and evacuate people as rapidly as possible. In the server rooms, where noise levels are likely to be high, EN54-23 compliant visual alarm devices (VADs) should be used, usually in the form of a strobe unit.

Any shutdown and evacuation can be very costly, so it is also important to minimise false alarm incidents. There are several verification and investigation delay solutions available that will significantly reduce false alarms, both before and after a fire signal has been latched on by the panel. Getting information to responsible staff when a signal occurs, or in some cases before a detector has reached threshold, can save valuable time and money. This can currently be achieved using integrated fire paging systems that will pass detailed fire systems status to relevant staff.

Direct confirmation of the fire incident is preferable, if not essential, because there are so many factors at work within a data centre, from the heat generated by the equipment to the high airflow within the server rooms. A false alarm can have far-reaching consequences and the primary goal, once an incident is validated and personnel have been safely evacuated, is to keep the servers online. Where a shutdown does occur, it should ideally be only for a short time, covering the lowest possible number of units.

Staff training is vital to the successful operation of fire systems and should be factored in from the beginning, with in-depth courses for new personnel and regular updates for their colleagues, plus fire drills covering multiple emergency scenarios. With systems this complex there are many safeguards built in, but these are not foolproof and would be totally ineffective against an incorrect input, so effective training and procedures are essential.

Exgo Web Main

ExGo is Advanced’s ultra-dependable extinguishant release system

Extinguishant systems

Many datacentres will use an addressable fire system for general detection and alarm, with a dedicated or integrated extinguishant release system alongside, such as Advanced’s ExGo.

Suppression systems also come in a wide range of configuration options from networked and interlinked systems to completely standalone. The selection of a solution will depend on budget and performance required. Extinguishing systems are often designed around flooding and detection zones. Detection zones are used to ensure signals are valid and double-knock signal confirmation is very common, essentially using two detection circuits or zones to confirm a signal on multiple detectors at once before signalling a fire or a release.

A flooding zone is the area in which suppressant will be released and, given the costs of suppressants and the effect a release can have on wider operations, it is often desirable to only release as much gas as required in a specific area, either from separate gas arrays or a managed central resource.

Extinguishant panels can use pre-programmed parameters (e.g. a countdown) to flood a zone automatically once a fire has been confirmed and the timer has elapsed. The timer can offer valuable time to evacuate staff from the flooding zone or cancel release if the issue has been dealt with or found to be false.

Most extinguishant panels will be in manual operating mode when people are on-site, but can be switched to auto to cover all eventualities. Most systems will also have a range of repeaters so that the system status can be seen inside and outside a protected area, and hold and abort buttons that allow the gas release to be paused or cancelled on visual confirmation of the area. This can be important in protecting staff as much as avoiding unwanted suppressant release. People are always the priority and the affected area must be free of personnel before extinguishant is released.

Air Flow

Air conditioning systems play a very important part in datacentre operations. Keeping vast server racks well ventilated is a core requirement, but on activation of a suppression system the HVAC must also be deactivated and all doors and dampers closed. If this is not done, the suppressant can be expelled into the outside air as fast as it is pumped into the affected space, drastically reducing its effectiveness. This process can be integrated into some fire alarm systems or can be managed by a third-party system.

A new solution that is available for some sites is to reduce the level of oxygen in the protected area to a level that is safe for humans but inhibits flames ignition, effectively making a fire impossible. While this is an elegant solution, however, the investment in controls and infrastructure can be significant.

Smoke kills, but can also present other problems in datacentre environments. Figures released by the US Federal Commission on Communications (FCC) suggest that 95 percent of the damage in a typical data centre fire is not caused by the fire itself, but by smoke from PVC and digital circuit boards, which has a highly corrosive effect on electronic systems in the vicinity. This makes the containment of smoke and smoke extraction vitally important, and the HVAC system can also be used to accomplish this in some cases as an automatic or manual control from the fire system.

Smoke must also be effectively removed from an area prior to inspection following an incident, and the time to get a datacentre back in operation following an incident is often a critical requirement.

In summary, there is no ‘standard’ fire solution for a data centre. As these facilities become larger and even more complex, the risk of fires will increase and fire systems need to be designed into them from the earliest stages. Specifiers and users need to understand the pros and cons of the solutions available and, importantly, how the fire systems themselves can help deal with the unique challenges presented by data centre installations.


Advanced Fire Systems

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