09 Aug Data centre fire protection
Causes of data centre fires are diverse, although by far the most common are overheating and electrical faults, and specialised fire systems combining both detection and alarm and suppression control are needed to protect this vital infrastructure.
Smoke spread in the building must be managed, fires contained, doors opened and closed, suppressants released, the fire service called and CCTV trained on the area in fire whilst a link to graphical control stations and building management systems can be monitored and controlled over the internet.
Modern fire panels, like Advanced’s, lie at the heart of the active protection system, working with intelligent detectors to monitor for a whole range of fire types. They can tell how fast a fire is spreading, and alert people by voice, light or sound, using multiple tones and frequencies.
The system 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 may be significant. Advanced’s expertise with data centres is based on a history of complex installations, optimised for performance, quality and ease-of-use, including the £20m West Cambridge Data Centre, part of Cambridge University.
Fire happens fast, so seconds matter. The greater the rate of spread of the fire, the more serious the data loss or downtime can be, so even the best fire system is no good if things can’t happen quickly. Therefore, 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.
There are two common approaches to general fire alarm protection and specialist extinguishant release in data centres. 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.
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 Axis EN 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 a complete panel if a problem is detected.
Data centres will use a range of detector types with a focus on early and accurate smoke detection. The choices made may combine point detectors, using optical and heat detection, with very early warning aspirating smoke detection systems – currently one of the fastest growing detector solutions and are ideal for data centre environments.
Once a fire is detected, the priority must be 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’s also important to minimise false alarm incidents. And staff training is also an essential aspect of the efficient operation of any fire safety system.
Many data centres 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.
Extinguishing systems are often designed around flooding and detection zones. 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. People are always the priority, and the affected area must be free of personnel before extinguishant is released.
Air conditioning systems play an important part in data centre operations. On activation of a suppression system the HVAC must be deactivated and all doors and dampers closed otherwise the suppressant can be expelled into the outside air, drastically reducing its effectiveness.
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 flame ignition, making a fire impossible.