HEALTH & SAFETY SECTION TITLE
Warped doors or damaged seals, service transits and enclosure modifications all lead to poor enclosure integrity and thus the effectiveness of total flood. Small cabinets of less than 2m3
can
easily be protected with small cylinders of less than nine litres, depending on the agent, which are easily transported, fitted and low cost to replace. Systems can be designed to operate entirely mechanically such as a frangible tube, that bursts when in contact with a flame. Passing this frangible tube around the equipment within the cabinet releases agent out of the burst hole in the tube. Alternatively, the frangible tube can be used to detect the fire and the agent released through dedicated pipework to nozzles, effectively flooding the inside of the cabinet where the flame has been detected. Relying on a frangible tube as the detection method requires no external power, control logic or battery backup – all of which add an extra layer
of complexity that needs to be managed. If the frangible tube is used as the means of delivering the firefighting agent, the tube will always burst at the hottest place in the cabinet and thus the discharge is conveniently adjacent to the fire. Te best of both worlds can realised
by having both cabinet protection in addition to the existing room total flood, which would mean that the small fire is suppressed with the supplemental system, but in the event of escalation, the enclosure protection is released as a backup. In any event there is an intermediate step to help prevent the large inert gas cylinders from being discharged. Moving forward with decommissioning
of older, obsolete assets becoming more prevalent, the use of containerised temporary control equipment is likely to be more popular. In the decommissioning phase and cessation of production, the asset remains connected to live wells and
process, known as warm suspension prior to entering cold suspension where the asset may either remain manned or transition to being unmanned before finally progressing into removal or dismantling. As the process begins for draining
down liquid hydrocarbons and breaking containment, the type of risk from fire and explosion on the asset change. Tere is potential fire risk due to the opening of hydrocarbon containing equipment, hot working and sparks from cutting and grinding. Care needs to be given to the levels of detection in place as long duration pool fires are replaced with the increased risk of explosion from gas fractions being ignited. Are these gas fractions lighter or heavier than air? Do we detect at high or low level? Have we got means of dispersing and preventing the accumulation of flammable gases? When containment has been broken, it’s too late to start playing catch-up. With
Even in the decommissioning
stage, assets and personnel must be protected from fire
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