fire detection

Smoke & Fire Detection in a Server Room

In 2015, there was a fire every 23 seconds totaling 1,345,500 fires in the US alone, causing in excess of $14.3 billion in property damage. The goal of a fire protection system is to detect and alert of fire in the early stages and then bring the fire under control. The advantages of early detection are to allow as much time as possible for evacuation and to protect assets from extensive damage.

Server rooms are small spaces designed to accommodate valuable electronic systems which generate a large amount of heat, therefore requiring heavy cooling and ventilation. The combination of heat producing devices and the sensitivity of the electronic equipment put specific requirements on the fire safety system.

A highly sensitive Aspirated Smoke Detector created specifically for smaller areas is the preferred choice for smoke detection in server rooms. Air-aspirating, or air-sampling detectors, are able to detect a fire in its incipient stages and therefore provide earlier warning and faster response time for the suppression system. Air-aspirating detection has the ability to detect smoke at differing levels and provide corresponding alarms; for example, if the detector finds a very low level of smoke, indicating that a fire is about to begin (such as an overheated wire that is smoking), a pre-alarm signal can be activated to alert staff to investigate and take action. If high levels of smoke are detected the suppression system can be discharged to control the fire.

Another option is cross-zoned, spot-type smoke detectors, using multiple technologies. These detectors often have multiple analog sensors so that they respond to smoke, heat and carbon dioxide sensing elements. You can use photoelectric smoke detectors, as they are cheaper than the ones using multiple technologies, but they do not react as quickly to every fire scenario. The multi-criteria detectors are often able to respond faster than traditional type detectors and reduce false alarms. Cross-zoned smoke detection is the preferred strategy to use in server rooms with spot-type smoke detectors as it relies on the activation of two alarms before the suppression system is activated. While this limits the potential for false alarms setting off the suppression system, it can result in a delay of activation when the suppression system is needed. However, with the increased ventilation and airflow in the server room, the cross-zoned system is necessary with spot-type smoke detectors to ensure the space is sufficiently protected.

Some server rooms utilize a pressurized raised floor to provide cold air to IT equipment and an above-ceiling area as a hot air return. Due to the potential for fire within these areas, because of HVAC piping, electrical feeders, or IT cables, detectors should be placed within these spaces.

IT rooms are laid out with the basic premise to isolate hot aisles and cold aisles from each other and prevent hot and cold air from mixing. This system helps to keep IT equipment cool while also being an energy and cost-saving measure for server rooms. If this system is in place in your server room, the layout of the room and any barriers constructed need to be taken into consideration when designing the fire detection and suppression system – if it prevents the flow of air it will prevent the flow of smoke and suppression gas.

What does in-rack detection and suppression mean?

Smoke detection and suppression systems have been designed to fit in an enclosed IT rack. While this type of system is optional in a server room fire suppression system, it has advantages of early detection within the server rack. Being placed within the IT equipment, the system can detect smoke in the earliest stages shut down the connected equipment while activating fans to prevent a fire from overheating devices. Should the fire continue the system will release a suppression agent within the rack enclosure. Read more about these systems here.

Learn more about server room fire protection, and why clean agent systems are the best choice to protect electronics.

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Jack Menke
Jack Menke