Shipboard Firefighting, Damage Control and Emergency Response

What the rule requires

The fuel names the class, and the class names the agent

Fires are classified by the nature of the combustible involved, and that classification governs the manner in which the fire must be extinguished NAVEDTRA 14057 Ch. 4 — Fire Classifications.

Class ALPHA — ordinary combustibles: wood, cloth, paper, upholstery. Usually extinguished with water, using high or low velocity fog or solid streams. Class A fires leave embers or ashes and must always be overhauled.
Class BRAVO — the vapor-air mixture over the surface of flammable liquids: gasoline, diesel oil, fuel oil, lubricating oils, greases, paints, thinners, solvents. AFFF, Halon 1211, Halon 1301 or dry chemical PKP, depending on the circumstances of the fire.
Class CHARLIE — electrical equipment. Nonconducting agents only: PKP, carbon dioxide, Halon 1211. CO2 and Halon 1211 are preferred because they leave no residue.
Class DELTA — combustible metals: magnesium, titanium, sodium. Jettison the burning material overboard if possible. Most class D fires are fought by applying large amounts of water to cool the metal below its ignition temperature, though a magnesium fire can be smothered with a large volume of dry sand.
Class K — cooking oils, the galley fire USCG Boatswain Manual Ch. 6 §6.1. Class D is rare on small vessels. Use the extinguisher class that matches the fuel.

Read the class B definition closely, because exam distractors live in it. What burns is the vapor-air mixture above the surface of the oil, not the liquid itself. That is why a solid stream into a bilge full of fuel oil is the wrong answer and a film that stops vapor release is the right one.

Removing a leg of the triangle

Three components are required for a fire: a combustible material, a sufficiently high temperature, and a supply of oxygen — heat, fuel, oxygen NAVEDTRA 14057 Ch. 4 — Fire Components. Fires are extinguished by removing one side of that triangle or by slowing the rate of combustion NAVEDTRA 14057 Ch. 4 — Fire Extinguishment.

Cooling is the leg an oiler works most. The fire goes out if you remove enough heat to cool the fuel below the temperature at which it supports combustion, and water is the most commonly used cooling agent, applied as a solid stream, as a fog, or together with AFFF NAVEDTRA 14057 Ch. 4 — Removing Heat. Heat reaches the next compartment by radiation, conduction and convection: a thick steel bulkhead with fire on one side conducts heat into the adjoining space, and a ventilation system carries heated gases several compartments away, where a combustible of low flash point may ignite.

Smothering is CO2's mechanism NAVEDTRA 14057 Ch. 13 — Aqueous Film-Forming Foam Fire ¶2. Interrupting the reaction is the mechanism of the dry chemicals — the powder suspends fine particles that screen heat, oxygen and fuel from one another just long enough for the fire to be extinguished NAVEDTRA 14057 Ch. 4 — Review Answers. Both Halon 1211 and 1301 chemically inhibit the flame front NAVEDTRA 14057 Ch. 6 — Halon Systems.

Fire in an energised main switchboard. PKP is at hand and a CO2 bottle is one frame away. Which do you take, and why?

The CO2. Both are nonconducting and both are approved for class C, but CO2 leaves no residue, while PKP is the agent known to foul electrical and electronic components as well as the internal parts of turbines and engines NAVEDTRA 14057 Ch. 5 — Review Answers. Ground the cylinder to the deck before using a portable CO2 extinguisher.

Fixed systems in the machinery space

Halon 1301 is the type installed in fixed flooding systems for extinguishing flammable liquid fires, and full discharge into the protected space is completed in 10 seconds NAVEDTRA 14057 Ch. 6 — Review Answers. Halon systems are used for fires beyond the capacity of fire extinguishing equipment, where abandonment of the space is necessary, and an AFFF sprinkling system normally supplements Halon 1301 in machinery spaces and pump rooms.

The short discharge time keeps thermal decomposition products well below lethal concentrations, but Halon decomposes on contact with flames or surfaces above 900°F (482°C) into hydrogen fluoride and hydrogen bromide, which have a sharp irritating odor even at low concentrations . The greater hazard to personnel is the products of combustion from the fire itself, such as carbon monoxide, combined with oxygen depletion, heat and smoke.

CO2 flooding is for spaces that are normally not occupied by personnel. Before operating an installed CO2 system, ensure all openings in the compartment are closed and the ventilation for the space is secured; on the hose-and-reel system, direct the discharge toward the base of the fire .

AFFF, PKP and the firemain

AFFF is primarily used aboard ship against class BRAVO fires, often in conjunction with PKP NAVEDTRA 14057 Ch. 6 — System. It serves three functions against a liquid fuel fire: the foam floats on top of the flammable liquid and prevents vapors reaching the atmosphere, it prevents oxygen reaching the liquid, and being a mixture of concentrate and water it cools NAVEDTRA 14057 Ch. 7 — Attacking a Fire. Covering hot spots with AFFF is therefore how reflash is prevented. AFFF is also the agent used to vapor seal a small fuel spill, and the portable AFFF in-line eductor is the equipment that mixes seawater and concentrate into solution .

The firemain supplies seawater to the fireplug and sprinkling systems . At the station, the plugman connects the hose to the fireplug and opens the plug valve with the nozzle closed, then watches for loss of pressure or a rupture; on a ruptured hose he secures the plug, replaces the ruptured section and reactivates as quickly as possible NAVEDTRA 14057 Ch. 2 — Function ¶2. The hoseman keeps the weight and tension of the hose off the nozzleman and keeps the hose from fouling.

Fire and smoke boundaries

Primary fire and smoke boundaries are set at all bulkheads immediately adjacent to the fire, manned by boundarymen with a fire hose who may have to cool the bulkhead to prevent the fire spreading NAVEDTRA 14057 Ch. 7 — Type of Attack ¶1. A secondary set goes at the next immediate watertight bulkhead. If the first boundary fails, the boundaryman secures the space and evacuates, and what were the secondary boundaries become the primary.

Boundaries are commonly taught as a box, and the definition supports it: the boundary of a space is its outermost limit above, below, and on all sides . Six faces, not four — the deck below and the overhead above are boundaries too. Fire will take any penetration: ventilation, electrical cableways, piping conduits, or defective welds under extreme heat. The first sign of the fire spreading is smoke NAVEDTRA 14057 Ch. 7 — Fire-Fighting Strategies.

Boundarymen also secure all doors, hatches and openings in the boundary of the fire area and remove or relocate combustibles . Where no hose is available, a bucket of water and a swab keep the bulkhead cool.

What flame, heat and smoke do to a crew

Dressed out properly and keeping adequate distance, you can minimise the chance of being burned; the smoke is what makes it hard to see and breathe, and the OBA with a headlamp is the answer to both NAVEDTRA 14057 Ch. 4 — Flame, Heat, and Smoke. The OBA produces its own oxygen and permits entry into otherwise uninhabitable areas; the chlorate candle of the quick-starting canister runs about 5 minutes .

The EEBD is for getting out, not for fighting fire. It provides a limited amount of breathable oxygen to evacuating personnel, the current unit gives 10 minutes of oxygen for escape, and it is a one-time-use device disposed of after use . Watchstanders in engineering spaces carry SEEDs, whose air supply is much more limited and is intended only to last long enough to reach an EEBD.

The fire-fighter's ensemble is designed against the heat of a growing, pre-flashover fire. In a flashover or fully-developed fire it provides only a few seconds of protection for escape NAVEDTRA 14057 Ch. 7 — Preparing to Enter the Space ¶1. Gloves are sized for a loose fit so that heat does not transfer through continuous contact.

Built-in protection the vessel already has

Structural fire protection questions turn on separation and vapor-tightness. Accommodation spaces must be separated from machinery and fuel tank spaces by a fire resistant boundary that prevents the passage of vapors, and every pipe and cable penetration between them must be sealed 46 CFR §28.380.

Engine exhausts, galley uptakes and similar ignition sources must be kept clear of and suitably insulated from combustible material.
Paint and flammable liquid stowage requires a steel or steel-lined locker.
Insulation must be noncombustible, except pipe and machinery lagging in machinery spaces, and cargo spaces and refrigerated compartments of service spaces.
Where insulation is used where flammable liquids or vapors are present, such as machinery spaces and paint lockers, a vapor barrier over the insulation is required — the same requirement appears for small passenger vessels at 46 CFR §177.405.
Surfaces within 0.9144 metres (3 feet) of cooking appliances must be noncombustible or covered with noncombustible material, and no curtains, draperies or free hanging fabrics are permitted within that 3 feet.

Telling it apart

Four agents, separated by mechanism and by what they leave

Water — cools by absorbing heat, and the sea is an inexhaustible supply NAVEDTRA 14057 Ch. 4 — Review Answers. Conducts, so it is not the agent for energised electrical equipment.
AFFF — a film that seals vapor, excludes oxygen and cools; the class B agent, and the one that prevents reflash over hot spots.
PKP — interrupts the chemical reaction. Nonconducting, so class C is permitted, but it fouls electronics and the internals of turbines and engines.
CO2 — smothers, leaves no residue, and is restricted to spaces not normally occupied when used as a flooding system.
Halon 1301 — a dense, colorless, odorless gas that does not conduct electricity or leave a residue, discharged in 10 seconds into a total flooding system. Halon 1211, by contrast, is not used in total flooding systems.

Flash point, fire point, auto-ignition

The criterion is whether a spark or flame is applied, and whether burning continues NAVEDTRA 14057 Ch. 4 — Fire Components.

Flash point — the lowest temperature at which a substance gives off vapors that will burn when a flame or spark is applied.
Fire point — the temperature at which the fuel will continue to burn after ignition. Usually a few degrees above the flash point.
Auto-ignition (self-ignition) point — the lowest temperature at which the substance gives off vapors that burn without any spark or flame.

Working a question

Fuel oil spraying onto a hot surface in the main machinery space. Halon and AFFF bilge sprinkling are installed. Work it as a sequence of decisions.

Report and classify. Report the fire to the officer of the deck, then extinguish it rapidly NAVEDTRA 14057 Ch. 4 — Fire-Fighting Fundamentals. Burning oil vapor over a liquid surface is class BRAVO, which rules out a solid water stream as the primary agent.
Secure the source and evacuate. Whether the leaking or spraying fuel was secured, whether bilge sprinkling was used and whether Halon was activated are all reported by the evacuating watchstanders NAVEDTRA 14057 Ch. 7 — Type of Attack ¶1. Evacuees muster outside the designated smoke and fire boundaries, and missing personnel are reported to DCC.
Set boundaries before anything else is attempted at the access. Proper fire boundaries must be set prior to accessing the compartment, to give the hose team a safe area to attack from NAVEDTRA 14057 Ch. 7 — Review Answers.
Isolate electrically. Electrical isolation must be complete prior to re-entry, the only exception being lighting, and the on-scene leader decides whether to secure it. Complete isolation reduces the number of ignition sources in the space. Mechanical isolation need not be complete, but it makes the space safer NAVEDTRA 14057 Ch. 7 — Preparing to Enter the Space ¶1.
Establish whether Halon worked. Investigators judge effectiveness from the color of the smoke through the battle ports at the escape trunk, or from topside if the space is not airtight NAVEDTRA 14057 Ch. 7 — Type of Attack ¶2.
Time the entry off that answer. Halon effective: allow at least 15 minutes before entry. Halon not effective: attempt re-entry as soon as evacuation and mechanical isolation are complete, using secondary Halon if available. Either way, activate AFFF bilge sprinkling for 2 minutes prior to entry NAVEDTRA 14057 Ch. 7 — Preparing to Enter the Space ¶2.
Attack. A direct attack is short bursts with a narrow fog or direct stream as the team leader directs, advancing into the fire area and applying AFFF onto the fire NAVEDTRA 14057 Ch. 7 — Attacking a Fire. If conditions do not permit entry, the attack is indirect: fog introduced from a cracked doorway or any available penetration, then entry and a direct attack.
Set the reflash watch, then overhaul. The reflash watch stays near the seat of the fire with a charged hose to ensure no new fire breaks out; a second hose team then searches cableways, areas beneath deckplates and overheads for hangfires with the NFTI.
Test before the space is called safe. Reports from the scene include fire contained, fire out, reflash watch set, fire overhauled, compartment ventilated, then tested for oxygen, flammable gases and toxic gases . Post-fire oxygen must read between 19.5 and 22 percent, and a space flooded with Halon 1301 also requires a test for hydrogen fluoride .

The Halon dumped and the smoke report indicates it was effective. A shipmate wants to open the hatch at once to check for damage. What do you tell him?

That the space cools first — at least 15 minutes before entry when Halon was effective, with AFFF bilge sprinkling run for 2 minutes beforehand. Opening the access introduces fresh oxygen, and if space temperatures are above the auto-ignition point of any combustible in there, it will start burning again once air reaches it.

Where candidates lose the point

Choosing CO2 flooding for a manned space. The distractor reads as decisive action. A CO2 flooding system is only for spaces that are normally not occupied by personnel, and openings must be closed and ventilation secured before it is operated.
Opening up and dousing with water to prevent reflash. Water and reflash appear together often enough that the pairing looks sound. The reflash control is AFFF over the hot spots plus a cooldown period before entry, because fresh oxygen into a space above the auto-ignition point restarts the fire.
Testing for carbon monoxide after a Halon 1301 discharge and stopping there. CO is a genuine product of combustion, which is what makes the answer attractive. The test the discharge itself requires is for hydrogen fluoride, Halon's decomposition product above 900°F.
Calling a class ALPHA fire out because there is no flame. Class A fuels leave embers or ashes and must always be overhauled; "fire out" and "fire overhauled" are separate reports from the scene.
Ruling out water on class DELTA absolutely. Most class D fires are fought by applying large amounts of water to cool the metal below its ignition temperature. Dry sand in volume is the smothering option for magnesium, and jettisoning the burning material is preferred where it can be done.
Treating the secondary boundary as a fallback position rather than a station. When the primary boundary fails and the boundaryman secures and evacuates, the secondary boundary becomes the primary and must be fought as the new threat.
Charging a hose with the nozzle open. The plugman opens the fireplug valve while the nozzle is closed, on order.

Check yourself

Lube oil has ignited in the bilge under a running generator. What class of fire is this, and what is burning?

Class BRAVO. What burns is the vapor-air mixture over the surface of the flammable liquid, not the liquid itself NAVEDTRA 14057 Ch. 4 — Fire Classifications. AFFF is the primary agent, often with PKP.

You are told to test the space after a fire before securing from the emergency. What oxygen reading permits entry?

Between 19.5 and 22 percent NAVEDTRA 14057 Ch. 7 — Review Answers. Under normal conditions oxygen accounts for 20.8 percent of air.

A fire in a paint locker two compartments forward. Where do the primary boundaries go?

At all bulkheads immediately adjacent to the fire, manned with a fire hose and cooled as required, with the secondary set at the next immediate watertight bulkhead NAVEDTRA 14057 Ch. 7 — Type of Attack ¶1. Include the deck below and the overhead above — a boundary surrounds the space above, below and on all sides.

Smoke fills the passageway on your escape route from the engine room. You are wearing a SEED. What do you do with it?

Use it to reach an EEBD. The SEED's air supply is much more limited, and the EEBD is the preferred device for evacuation, giving 10 minutes of oxygen for escape . Neither is used to fight the fire.

A shipmate proposes shutting a ventilation damper that serves a compartment three frames from the fire, arguing the fire cannot reach that far. Is he right?

No. Heated air and gases transfer by convection, and a ventilation system can carry them several compartments away; where a combustible of low flash point is served by the same system, a new fire may start NAVEDTRA 14057 Ch. 4 — Removing Heat.

You are about to use a portable CO2 extinguisher on a small class C fire. What step precedes discharge?

Ground the cylinder to the deck before use NAVEDTRA 14057 Ch. 5 — Review Answers.

Insulation is being renewed on a fuel oil service pipe in the machinery space. What does the structural fire protection requirement add to the job?

A vapor barrier covering the insulation, because the space contains flammable and combustible liquids or vapors 46 CFR §28.380. Combustible insulation is permitted for pipe and machinery lagging in machinery spaces; elsewhere insulation must be noncombustible.

Halon flooded the space and the fire is out. A hose team member asks why he still needs an OBA if the Halon discharge was short enough to keep decomposition products below lethal levels.

Because the hazard is not only the Halon. Products of combustion such as carbon monoxide, combined with oxygen depletion, heat and smoke, pose a great hazard to personnel NAVEDTRA 14057 Ch. 6 — Halon Systems.