Fire hazards and precautions on board

liquefied gas carriers

BY MT&C SASA FRKOVIC

IS LNG SAFE?

LNG consist of hydrocarbons which will burn when exposed to air and ignited by a suitable source of ignition.

LNG is a cryogen which means it must be distributed and stored in specialized equipment and tanks in order to keep in a

liquid state

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LNG vapors are flammable within a certain concentration range. This is called the “flammable range”; the limits are commonly called the “Lower Flammable Limit” (LFL) and the “Upper Flammable Limit” (UFL). For natural gas (methane) the range is 5-15%. This means that LNG will likely only ignite when the vapor concentration is between 5-15% in air . Vapor concentrations outside this range contain either insufficient fuel or oxygen to ignite.

CAN LNG IGNITE ?

Sources of ignition

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There are many possible sources of ignition in the engine room and gas carriers are designed to reduce the chances of gas entering these spaces.

• DOORS- located away from the cargo area•VENTILATION FAN INTAKES-positioned at high level•ENTRANCES IN THE ENGINE ROOM –must be kept shut all times

•All external doors and ports should be kept shut, especially during loading and discharging operations.

present in spaces such as the accommodation, galleys and engine rooms, and it is essential to prevent cargo vapour entering these spaces.

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Procedure to follow in the event of a fire•AT SEA FIRE•VESSEL IN PORT

Scenario at sea ( Fire on the manifold port side )

•the initial alarm will be activated either automatically by the fire detection system, or manually by the person discovering the fire.( most common continious alarm bell )

MANUAL RELEASE

ACTIVATION POINT

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•Action on deck : Fire parties muster and

report to Bridge, it is essential that the

Master is advised if any persons are

missing or unaccounted for.

•Master advises Ch Off/Ch Eng of result of

Muster & Fire Location if known

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Manoeuvre as required, traffic and navigational situation permitting Advise traffic in the vicinity on VHF Ch 16 and DSC VHF Ch 70 Consider use of following:

1. Fire/Water Spray Pumps2. Vent Fan Stops3. Engine to Standby

ACTION

ON THE

BRIDGE

Ch Off/Ch Eng takes control of Fire Fighting and Rescue operations

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Ch Off/Ch Eng takes control of Fire Fighting and Rescue operations

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• Ship’s staff to commence fighting the fire using normal drilled procedure

•Emergency party team proceeding fight with fire

•Start water spray pump.

•Engine Room Party to supply services in the normal manner. (Fire Pump would already be running and Fire Main pressurised.)

•TARGET –Closing the manifold valve which will cutt off the source of fire

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METHOD OF TECHNIQUE TO BE USED:PROGRESSIVE COOLING

•In its early stages, a fire may be effectively dealt with by cooling the surface with advancing sweeps of fog or spray across its whole width.

•It is highly effective because in the early stages the fire is only fed from the vapours of a thin hot layer of LNG.

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END OF PRESENTATION

SOURCE ELIMINATED BY CLOSING THE MANIFOLD VALVE – FIRE EXTINGUISHED

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