Tuesday, October 28, 2008

Lesson 40: Fire

Fire Fighting and Prevention

Fire prevention can be effectively achieved through good housekeeping. Even though it is essential you know how to fight a fire and have the correct equipment on board, never having to fight fire is a far better course of action.
Fire at sea does not discriminate.

Any fire on a boat, especially fires involving flammable fuel, can be a terrifying experience with the potential to cause serious burns or death.

It is a fact that petrol and oil fires aboard vessels spread rapidly generate intense heat and usually overwhelm those on board. In many cases they are either blown or jump overboard.
The answer to the problem lies in preventing fires rather than fighting them.

A great number of fires or explosions occur immediately after boats have been refueled. By using common sense and taking proper precautions, boating fires can be prevented.

Have the correct fire extinguishers in your boat, know how to use them, maintain them and locate them in accessible areas.

Keep the bilge and engine room clean and free of rags, newspapers and other combustible materials.

Regularly check that engine rooms are properly ventilated.

Use only appliances such as stoves and heaters that are approved for marine use.

Never use cigarette lighters or matches while searching in lockers, use a battery powered torch.

Check fuel systems at regular intervals for leaks and spillage.

Any spare fuel should be carried in approved containers.

Check the electrical system for faults regularly and keep all components as clean as possible.

Some common causes of fire aboard small craft

Engine backfiring in air laden with combustible vapor.

Hot exhaust pipe igniting adjacent combustible materials.

Spontaneous combustion of oil rags in badly ventilated compartments.

A spark caused by static electricity during refueling.

Short-circuiting and overloading of the electrical system.

Remember, to avoid potential fire hazards – all fuel systems, electrical systems and LP Gas systems should be correctly designed, installed and maintained by qualified persons.


Turn off all engines, motors, fans, heating devices, electrical equipment and LP Gas appliances before fuelling.

Take care when refueling! Don’t smoke or allow naked flames on or in the vicinity of your vessel while fuelling. Fuel spilled, either accidentally or from overflowing the fuel tanks, produces vapors which can enter the bilge and may be ignited by a spark – often from the boat’s electrical system.

Have a filled fire extinguisher handy.

Wipe up all spills.

Leave room in tanks for fuel expansion.

Check bilges for leakage and fuel odors, ventilate until fuel odor is gone, before starting engines.

Never refill portable fuel tanks in the boat; take them ashore for filling and wipe off any spillage before replacing them aboard.

Fuel related fires could also start when a vessel is underway. These fires generally result when some component of the fuel system starts to leak and vapors trapped in the vessel’s bilge are ignited. Regularly inspect and maintain fuel systems and avoid using temporary or “stop gap” solutions to fix leaks.

Electrical installation

Frequent, fires and explosions aboard small vessels are caused by short circuits or overloading. To ensure protection from these hazards, have all electrical installation and maintenance carried out by a qualified marine electrician.

Never undertake temporary repairs using makeshift materials, except in an emergency.
Never use multiple adaptors for connecting appliances a circuit not initially designed for this purpose.
Never replace an existing fuse with a larger one.
Never overcharge batteries as these release excessive amounts of the explosive gas hydrogen into the air during recharging.
Ensure battery spaces are well ventilated.

LP Gas

Ensure all LP Gas installations are carried out and serviced by a qualified technician.
Regularly check permanent ventilators, flues and vents to ensure that they are clear.
Leakages can lead to suffocation or explosions.

Remember LP Gas is heavier than air. Any leaked gas will always flow downwards, collect in low places and will be slow to dissipate without ample ventilation and movement of air.
Always turn off gas at the bottle.

What is Fire?

In order to have a fire, there must be three elements:
Fuel -- something which will burn.
Heat -- enough to make the fuel burn.
Oxygen – air (between 16 and 21% O2)

Fire Triangle

All three elements must be present at the same time to have a fire. Fire will burn until one or more of the elements is removed, and then will go out.

It is essential that the vessel’s operator and crew be familiar with the proper use of portable extinguishers and know when and when not to use them. In the event of a fire, deck crew should respond in accordance with a pre-arranged fire-emergency plan. Specifically trained and designated crew members will evaluate the fire scene and, if the fire is small and conditions are reasonably safe, use a fire extinguisher to fight the fire. If the fire is large or conditions are unsafe, all crew members and passengers will evacuate.

Classes of Fires

There are four classes of fires. All fire extinguishers are labeled, using standard symbols, for the classes of fires on which they can be used. A red slash through any of the symbols tells you the extinguisher cannot be used on that class of fire. A missing symbol tells you only that the extinguisher has not been tested for a given class of fire, but may be used if an extinguisher labeled for that class of fire is not available.

· Class A – Anything that would leave an ash residue: wood, paper, textiles, rubber, plastic, etc.

· Class B – Any combustible liquid: oils, grease, alcohols, paints, and etc.

· Class C – Anything involving electricity: electrical equipment and motors, circuits, and etc.

· Class D – Any combustible metal: magnesium aluminum, and etc.

Remember that the extinguisher must be appropriate for the type of fire being fought. Multipurpose fire extinguishers, labeled ABC, may be used on all three classes of fire. If you use the wrong type of extinguisher, you can endanger yourself and make the fire worse. It is also very dangerous to use water or an extinguisher labeled only for Class A fires on a cooking-grease or electrical fire.

Fire Extinguisher Sizes

Portable extinguishers are also rated for the size of fire they can handle. This rating is expressed as a number from 1 to 40 for Class A fires and from 1 to 640 for Class B fires. This rating will appear on the label --- 2A:10B:C, for example. The larger the numbers, the larger the fire of a specific class on which the extinguisher can be used (but higher-rated models are often heavier - make sure you can hold and operate an extinguisher before you buy it). No number accompanies an extinguisher's Class C rating. The C on the label indicates only that the extinguisher is safe to use on electrical fires.

Extinguishers for Class D fires must match the type of metal that is burning. These extinguishers do not use numerical ratings. Extinguishers for Class D fires are labeled with a list detailing the metals that match the unit's extinguishing agent.

Types of Fire Extinguishers

Depending on their intended use, portable extinguishers store specific "extinguishing agents," which are expelled onto the fire.

Pressurized water models are appropriate for use on Class A fires only. These must never be used on electrical or flammable-liquid fires.

Carbon dioxide extinguishers contain pressurized liquid carbon dioxide, which turns to a gas when expelled. These models are rated for use on Class B and C fires, but can be used on a Class
A fire. Carbon dioxide does not leave a residue.

Dry-chemical extinguishers are either stored-pressure models or cartridge-operated models. The stored-pressure models have a lever above the handle for operation. The cartridge-operated models require two steps: Depress the cartridge lever, and then squeeze the nozzle at the end of the hose. The dry chemicals leave a residue that must be cleaned up after use.
Ammonium phosphate dry chemical can be used on Class A, B, and C fires, but should never be used on a fire in a commercial grease fryer because of the possibility of reflash and because it will render the fryer's automatic fire-protection system less effective.
Sodium bicarbonate dry chemical, suitable for fighting Class B and C fires, is preferred over other dry-chemical extinguishers for fighting grease fires. Where provided, always use the extinguishing system first. This also shuts off the heat to the appliance.
Potassium bicarbonate, urea-base potassium bicarbonate, and potassium chloride dry chemical are more effective and use less agent than sodium bicarbonate on the same fire.
Foam (or AFFF and FFFP) extinguishers coat the surface of a burning flammable liquid with a chemical foam. When using a foam extinguisher, blanket the entire surface of the liquid to exclude the air.

Remember the PASS Word

Keep your back to an unobstructed exit and stand six to eight feet away from the fire.
Follow the four-step procedure:Pull, Aim, Squeeze, and Sweep
» PULL the pin: This unlocks the operating lever and allows you to discharge the extinguisher. Some extinguishers may have other lever-release mechanisms.
» AIM low: Point the extinguisher nozzle (or hose) at the base of the fire.
» SQUEEZE the lever above the handle: This discharges the extinguishing agent. Releasing the lever will stop the discharge. (Some extinguishers have a button instead of a lever.)
» SWEEP from side to side: Moving carefully toward the fire, keep the extinguisher aimed at the base of the fire and sweep back and forth until the flames appear to be out. Watch the fire area. If the fire re-ignites, repeat the process.

Fire Extinguishing Equipment [46 CFR 25.30].

Hand-portable fire extinguishers and semi-portable fire extinguishingsystems must be of the "B" type (i.e.; suitable for extinguishing firesinvolving flammable liquids, greases, etc.).b. Hand-portable fire extinguishers and semi-portable fire extinguishingsystems must have a plate listing the name of the item, rated capacity(gallons, quarts or pounds), name and address of person/firm for whomapproved, and manufacturer's identifying mark.c. Portable fire extinguishers must be inspected and weighed every 6 months.d. Minimum number of B-II hand portable fire extinguishers required to be on board motor vessels: one if less than 50 tons and two if 50-100 tons..e. Fixed fire extinguishing systems must be an approved carbon dioxide type and must meet the U.S. Coast Guard requirements.

All fire extinguishers must CG approved or UL listed for marine use. All hand portable extinguishers must be Type “B”. Vessels less than 26’ must carry one fire extinguisher. Vessels 26-40’ must carry two while vessels greater than 40’ must carry three.
èProcedures for Fighting Onboard Fires
a. SIGNAL: Continuous sounding of ship's whistle for at least 10 seconds.
b. FIND the fire, the location, and its size
c. INFORM the Captain immediately to:
Sound the general alarm to muster the crew and notify all hands.
Make a distress call to Coast Guard and nearby vessels.
Activate emergency firefighting equipment.
d. RESTRICT the fire
Shut off air supply to the fire - close hatches, ports, etc.
De-energize electrical systems in affected space
Set fire boundaries to confine the fire
Shut off fuel supply and ventilation
Maneuver vessel to minimize the effect of wind on the fire
Prior to activating fixed extinguishing system, ensure that all personnel have been evacuated from the space
e. EXTINGUISH the fire
Determine class of fire, appropriate equipment, extinguishing agent and method of attack
Overhaul and set re-flash watch
Muster crew to account for all personnel.
If unable to control fire, prepare to abandon vessel.
If water is used for extinguishing, dewatering procedures should start immediately to avoid vessel stability issues.
èNEVER fight a fire if even one of the following is true:
· The fire is spreading beyond the immediate area in which it started or is already a large fire.
· The fire could block your escape route.
· You are unsure of the proper operation of the extinguisher.
· You doubt that the extinguisher you are holding is designed for the type of fire at hand or is large enough to fight the fire.

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