Mission-critical facilities, such as data and telecommunications centers, must maintain operations without interruption. Mission continuity is assured for facilities through the use of redundant power supplies and mechanical systems, and cutting-edge fire protection systems.
Fire in these facilities can threaten the business and human life. Key to defending against a catastrophe is a sophisticated fire protection system that integrates seamlessly with the entire environment.
Fire protection for mission-critical facilities can be complex and daunting. System designs should be based on a total fire protection approach through which three conditions are met: Identify the presence of a fire, communicate the existence of that fire to the occupants and proper authorities, and contain and extinguish the fire, if possible. Being familiar with all technologies associated with fire detection, alarming, and suppression is important to developing a sound fire protection solution.
Fire Detection Strategies and Choices
There are many ways of detecting and suppressing fires, but only a few should be used for mission-critical applications. For example, the main goal of the fire protection system in a datacenter is to get the fire under control without disrupting the flow of business or threatening occupants. Let’s take a look at the two main categories, spot detection and aspirating smoke detection.
Spot Detection — For the purposes of protecting a mission-critical facility, addressable early warning smoke detectors and heat detectors can be an option. Because the airflows are rapid in an area such as a datacenter, it is important to realize the differences between types of detectors.
Ionization smoke detectors are quicker at detecting flaming fires, such as those commonly found in chemical storage areas, rather than slow, smoldering fires that most typically occur in datacenters and telecom equipment spaces. Ionization sensors almost immediately recognize fires characterized by combustion particles from 0.01 to 0.3 microns. However, ionization sensors offer limited or slower capabilities when installed in areas with high airflow — which is often the case in these mission-critical environments.
Photoelectric smoke detectors, however, quickly respond to smoldering fires characterized by combustion particles from 0.3 to 10.0 microns, making these detectors more appropriate for most mission-critical settings.
One solution to detect a broad range of fires quickly would be a multicriteria detector that uses photoelectric particulate detection in tandem with sensors that detect other products of combustion, such as carbon monoxide (CO) and light (infrared). Together, these signals are cross-referenced by an onboard microprocessor that uses algorithms to “process out” false alarms while enhancing the response time to real fires.
Another solution is to use intelligent high-sensitivity detectors, which are very similar to standard detectors except that they employ a more highly advanced detection method.
High-sensitivity spot detection typically employs a focused laser-based source to achieve sensitivities that are 100 times more sensitive than standard addressable or conventional IR-based photoelectric smoke detectors. They are designed
to respond to incipient fire conditions as low as 0.02% per-foot obscuration to provide valuable time for personnel to investigate the affected area and take appropriate action to mitigate risk.
These detectors are addressable and are able to send information to the central control station, thereby pinpointing the exact location of the smoke. Some can automatically compensate for changes in the environment, such as humidity and dirt buildup. They can also be programmed to be more sensitive during certain times of the day. For instance, when workers leave the area, sensitivity will increase.
High-sensitivity detectors are commonly placed below raised floors, on ceilings, and above drop-down ceilings, as well as in air handling ducts to detect possible fires within the HVAC system.