FIRE FIGHTING

FIRE FIGHTING

To support combustion, three elements must be present;

1. Enough fuel to be burned;

= Explain the different kinds of fuel (Class "A"B"C"D"E")

2. A source of Heat/Ignition;

= Direct heat (Cigarettes, soots, hot works, etc.)

= Mechanical Sparks

= Electrical Sparks

= Static Electricity

= Auto-ignition

3. Oxygen in sufficient quantity to support combustion after ignition has taken place.

These three elements are reffered to as:

THE FIRE TRIANGLE

1. On board tankers, these elements are always present either in, on and around the vessel.

Crude Oil = give off hydrocarbon vapour which is always present in the ullage spaces of the cargo tanks. The percentage of these vapours depend on the type of crude oil and the amount of agitation imparted during loading;

While they may stopped giving off vapors after loading, when discharged; the scales, sludge and sediments will given off furhter vapours when splashed by the water or oil from tank washing machine. These vapours are excellent source of fuel and is capable of being burned/ignited.

2. Source of Ignition

They are abound on board, e.g. Burners, Electric stove, generators, cables, lighting and powered equipment, falling objects capable of causing sparks, hot works; like welding, grinding, boring. Static electricity can also be generated under certain climatic conditions. All thes things can represent the Heat as one of the triangle of fire.

Oxygen is also always present in the air and around the ship. To prevent these 3 triangle to co-exist, safety measures for the transport of oil have been adopted by dividing the ship into Two Zones.

a. Safe ZOne - where the machinery spaces, living compartments and operating spaces like the bridge are located.

b. Dangerous/Hazardous Zone - an area on board where cargoes are stowed or contained including its immediate areas.

=Every effort is to be made to prevent the movement of any kind between these zones and if there is a need to do so as operations demands; like an electric cable with current from the safe zone to the hazardous zone precautions must be made to make this cable intrinsically safe. Movement of personnel to the hazardous zone must also be rendered safe by restricting their movement or activities like prohibiting them from smoking, or carrying unsafe sources of ignition like unauthorized torch, lighters, radies and even calculators & also preventing the entry of hydrocarbon gases to the safe zone.

=Oxygeb being one of the elements of fire is now considered as the most practical means of preventing fore on board tankers. Thus the mandatory installation of Inert Gas System form 20,000 tons and above as required by SOlas Protocol 1978 which has entered into force, May 1, 1981.

FIGHTING FIRES

=Early detection accompanied with prompt, intelligent confidence and collective efforts will spill the difference between a minor or major disaster on board.

WHEN FIRE IS DETECTED

1. Sound the alarm continuosly to warn shipboard and shoreside personnel of the danger & equally important, it will summon help. Activate the Emergency Shutdown System

2. Evalute the fire and above all, don't panic:

a. How will it be contained or kept from spreading?

b. How can the source of heat, fuel or O2 be eliminated?

c. What is the greatest danger of this fire? and

d. How can this be blocked?

3. Get the fire under control:

a. Isolate the fire by cooling adjacent areas;

b. Remove vombustible materials from adjacent areas;

c. If possible fill nearby cargo tanks with inert gas, CO2 or steam

d. Cut off air by shutting down ventillation, closing doors, portholes, hatches & other openings.

4. Extiguish the fire = cooling, smoothing or breaking up the chain reaction or a combination of these methods.

5. Guard against re-ignition - cool the areas completely

6. Check missing personnel if any; and

7. Tend mooring lines, rig accommodation ladder/gangplank.

FIRE FIGHTING

On board tankers at any given time, it could be turned into a floating incinerator and worse a coffin for everybody on board. A small spark or a mislaid cigarette could cause the inferno.

It is therefore your duty and responsibility to know the loactions, functions and operations of your fire fighting equipment you are assigned. Your knowledge is crucial to any ships especially on tankers.

In case of fire, your decisive actions, calmness, and collective efforts coupled with your determination, this terrible catastrophy can easily be defeated.

HEAT TRANSFER

Conduction - passes thru a medium like steel bulkheads-causing ignition without any open flame.

Convection - passes thru openings like portholes, doors, vent ducts caused by the expansion of hot air.

Radiation - pass thru a vacuum equally in all directions like the heat of the sun.

Note: FIre that never start or happens can destroy no cargo or equipment, harm no crew, in fact do no damage at all. It is very easy to start but extremely difficult to extiguish.

Fire prevention is much better than cure.

FIRE FIGHTING EQUIPMENT / MEDIA

1. Water - it has the highest cooling effect, not expensive and are all arond the ship. One or more pumps draw water form the sea and deliver it to the fire main; a system of pipes which carries the water to the fire stations located stragetically throughout the ship. Stop valves are fitted between stations so that sections damaged can be isolated to prevent loss of pressure. Each fire stations has a hydrant and a fire hose with 2-1/2 inches on weather decks and 1-1/2 inches in confined spaces allowing water to be delivered in solid stream or high velocity fog via the all purpose nozzle. Low velocity fog can also be used with special applicator breaking the water into fine mist with a maxumum surface area to the fire and also very ideal in protecting fire fighters when approaching the fire.

Foam - very effective for Class "B" fires and very valuable for tankers because ot its ability to blanket the burning liquid.

Types = Chemical and Mechanical with the latter now very commonly in used. The mechanical foam has three constituents; namely, air, water and concentrated foam liquid.

These three constituents must be mixed turbulently with especailly designed nozzle which when charged with water from the fire main siphon concentrate into the line and mix it with the air in correct proportion.

=Some new tankers are fitted with fixed foam system which protects the engine room and pumproom. In addition, fixed foam monitors are often provided at amni deck fire stations.

=Older ships are equipped with portable foam nozzle fitted with pick up tube to be inserted into a 5 gallon container of concentrate foam. It has a little cooling effects & therefore, it must be maintained on airtight blanketed over the entire area to eliminate air.

3. CARBON DIOXIDE (CO2) = An inert gas, odourless & colourless 50% heavier than air. Very effective in Class "B" & "C" when used in confined areas. They are applied in three methods:

a) Fixed System - mostly used in engine room. Stored in a cylinder of tanks in a special area / remote control pull box provided for each space protected. They are fitted with auto alarm with a time delay mechanism for the crew to clear the area.

b) Semi-Portable CO2- also provided in some engine room in addition to the fixed system CO2. Bolted permanently in bulkhead attached to a portable hoses stored in reels which can be run quickly to the affected areas.

c) Portable CO2- located in bulkhead holders throughout the ship particularly in spaces where Class "B" & "C" fires are likely to occur like machine shop, Radio Room, & Galleys.

4. DRY CHEMICALS - impede combustion by breaking up the molecules chain reaction. Delivered in hand held extiguisher located strategically throughout the ship. SOme tankers are provided with large dry chemical units for use against spill fire on deck. They are effective in Class "ABC" fires. If the fire is outside, it must be applied winward. Never apply in petroleum fire. It will only agitate the fire and cause it to spread.

5. HALON 1301 & 1211 = THEY DO NOT PRODUCE TOXIC GASES. They prevent chain reaction required for combustions. In a lesser extent, they tend to smoother the fire by their vapours.

=Halon 1301-In some ways they are move effective than CO2 for used in fixed system. It is not dangerous for personnel when breath for a short period of time.

=Halon 1211- Used in portable extiguisher. Like CO2, both halos displaces oxygen upon vaporizing.

6. INERT GAS = Although designed to prevent fire, they can also be used to extiguish fires in cargo tanks. If the tanks has not been raptured as in collision or explosion the addition of inert gas in sufficient quantities will lower the oxygen content below where combustion can no longer exist.

7. CARBON TETRACHLORIDE = A very popular extiguishing agent in the past but now banned because it produces a lot of toxic vapours upon contacting the fire.

8. STEAM SMOOTHERING SYSTEM = the oldest of fire fighting equipmentr on board tankers. It consist of steam piping which lead to a master valve to a series of headers with a separate valves fitted to each tank. These valves are left open to avoid delay in case of emergency. Valves to unaffected tanks are then closed.