HEAL SECTION TITLE TH & SAFETY
A typical Inert gas skid
detector needs to go into alarm before the system is initiated and in the event of a fire it must be of a minimum intensity to be detected. Te larger the fire, the harder it is to control and ultimately, extinguish. Tere is a balance between detecting it early enough to be still small and thus able to extinguish, but not at the expense of an unwanted release.
EARLY DETECTION Detecting the fire early is relatively easy by using sensitive detectors and more of them, however the challenge is whether to act on the information or investigate further. Very early smoke detection apparatus (VESDA) has become more sophisticated in recent years to now pinpoint the products of combustion to the specific sampling tube, which aids tracing the source but still requires intervention to suppress. Fires require an ignition source. Tis is often an electrical short circuit caused by dust, liquid ingress or component failure. Due to the nature of safe area switchgear and control equipment, it is housed in small boxes to protect it from mechanical damage, but the boxes have louvres to maintain an airflow, keeping them cool in normal operation. In the event of a fire, the airflow feeds the flame, creating
a chimney effect and quickly becoming larger than a single flame. A total flood inert gas suppression system in the room will reduce the oxygen concentration below 15% but takes longer to suppress the fire in the box as it must penetrate through the louvres first, by which time the fire damage is more extensive than it could have been.
PROTECTING THE ENCLOSURE Protecting the box rather than the room and tackling the fire when it is small, is the best approach for minimising fire damage and has a higher likelihood of being successful. Enclosures rely on being relatively gas tight, having a hold time following release of a gas suppression system of greater than 10 minutes.
Rapid Deployment Kit portable fire detection
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