Hse offshore fire and explosion strategy – fire and gas detection b games play online


There are two principal types of detector which are commonly in use in off-shore installations: heat, flame smoke, and flammable gas instruments. The most significant for risk reduction are gas detection s gashi systems, since they give the earliest warning of hazardous situations. Infra Red (IR), line-of-sight or point type detectors which identify an accumulation of gas and acoustic leak detectors, are also used. The OSD strategy is to promote the use of a combination of sensors, thereby giving early leak detection with the acoustic detectors and identifying a gas cloud accumulation with the IR type sensors. Strategy objectives

Oil mists are generated by the release of flammable liquids under pressure. Oil 1 unit electricity cost in andhra pradesh mists are very flammable and can ignite at a lower temperature electricity invented than most hydrocarbon gases. Most oil mist detectors are optical beam devices. The current evidence is that gas detectors do not seem able to detect oil mist releases. Wormald Shell have developed a mist detector for installation in ships engine rooms. Fire and smoke detection

Various rules of thumb are used to determine the location and coverage of the different types of fire detector. Point heat detectors in open, naturally ventilated areas are sited at approximately a density of 1 per 25m2 and at spacing of 7m with a maximum distance from bulkheads of 3.5m. In enclosed mechanically ventilated modules, they are sited at approximately 1 per 37 m2 and electricity projects ks2 9m apart with a maximum distance from bulkheads of 4.5m.; They are not applied in areas with high ceilings above 8m (point heat detectors have poor sensitivity with height).

Flame detectors are sited such that their vision cone covers areas where fire may occur. For IR flame detectors around 15m is considered a reasonable range because of obscuration by smoke and lack of sensitivity at the periphery of their field of view. They are electricity and magnetism generally sited at the corners of an area or module. CAD tools are used to optimise their coverage at the design stage. Triple band IR systems are less prone to false alarms.

Point smoke detectors rely on the transport of combustion products (particulates and gases) to the detector by convection. The numbers of detectors can be reduced with increased table d gaskets ceiling height because of more uniform distribution, although the concentration will be less and the sensitivity of the detectors must be adequate. Current smoke detectors are located electricity khan academy at not more that around 7.5m apart and are not appropriate for high ceilings (10.5m). Gas detection

Detector head spacing is governed by the size and geometry of the area (confinement and congestion), ventilation and the nature of the release. Typically the minimum spacing in congested areas is around 5m based. Problems can occur in large volumes or trapped volumes where there is local confinement that restricts the venting path. Gas/vapour tends to slump, particularly in low air movement areas, after a liquefied gas release because the electricity facts local gas cloud is relatively dense and cold. Detector heads should be located in a 3D pattern with some heads at low level in modules that are liable to have gas vapour slumping.

Acoustic detectors. Location is based on identifying the potential sources of leaks, e.g. all gas laws worksheet joining parts in high pressure gas installations. An ultrasound map of the background noise can be determined to decide the alarm level and assist with selection of the optimal location. Care must be taken to avoid acoustic reflections that may produce false alarms.