Fire on board is undoubtedly the most difficult situation to deal with.
Although it is the most feared, and above all the one with the most devastating effects, it is also the topic that those who surf know the least about, the one to which they dedicate very little time for training, and sometimes not even that.
In these few lines we want to address this topic in a complete way and provide ideas of interest and in-depth analysis for the reader, because “nothing happens”, but if it happens…

The phenomenon of the combustion reaction has been known for several millennia but dates back to the beginning of the 18th century. that the theory of “phlogiston” spread, a substance present in everything that can burn, which was released giving rise to heat. At the end of the 1700s, the chemist A.L. Lavoisier demonstrated experimentally that air is a mixture of oxygen and nitrogen and that combustion is a phenomenon of uncontrolled oxidation in which oxygen acts as an oxidizer while nitrogen does not take part in the reaction.

DEFINITION: combustion is the chemical reaction of two substances (fuel and oxidizer) with the development of heat. Necessary conditions for the above reaction
chemistry are:
• presence of fuel
• presence of oxidizer
• presence of a heat source (ignition)

When one of the three elements of combustion is missing, this does not occur or if already underway, it is extinguished.

This process is usually represented graphically by the so-called Fire Triangle.

If we want to be a bit academic, complete combustion (read fire) is the result of the combination of four essential elements that must be present simultaneously:
• fuel, which is the material capable of chemically combining with oxygen (or other substance) with the emission of thermal energy;
• the oxidizer, which is the substance that fuels combustion through oxidation of the fuel, i.e. oxygen.
• a source, which releases an adequate value of thermal energy and which is capable of starting the combustion process, for example, a wooden match, or the flame of a candle.
• the formation or liberation of chemically active atomic groups (radicals) capable of producing chain reactions (oxidation).

The set of physical and chemical transformations of a material subjected to the action of fire establishes the “reaction to fire of materials” (there are different combustion reactions). But what is a chemical reaction?

If we have a liquid fuel, this does not burn directly, but its vapors will burn when, once the ignition temperature is reached, they start to burn. So it is not so much the liquid that burns as the vapors that it emits.

Even in the case of solid fuels (such as wood) we start with the flammable gases emitted when the body is heated, and then extend at a later stage to the solid residue.
The extinguishing agents, those that make up the extinguishing systems, mobile or fixed, are many and different, because the types of fire are different.

Some examples:

CLASS A: wood, paper, coal, fabrics, rubber.
Usable extinguishing agents: water, foam, chemical powders, potassium salt aerosols
CLASS B:
hydrocarbons, oils, greases, alcohols, ether, solvents, fuels, lubricants.
Usable extinguishing agents: Foam, CO2, chemical powders, potassium salt aerosols
CLASS C:
LPG, methane, hydrogen, propane, butane, ethylene, propylene.
Usable extinguishing agents: CO2, chemical powders, halogenated, potassium salt aerosols
CLASS D:
light alkaline earth metals such as magnesium, manganese, powdered aluminium, alkali metals such as sodium, potassium and lithium, peroxides, chlorates and perchlorates.
Usable extinguishing agents: CO2, chemical powders, potassium salt aerosols

The oxidant that participates in combustion is oxygen, i.e. a “gas”.
For this reason, the other element involved, the fuel, must also be a gas or vapour, and this explains why, in order for the combustion reaction to start, it is necessary for the solid fuel to be heated up to the temperature at which it begins to emit combustible gases.
The more oxygen there is in the air (volumetric percentage ≥ 21%) the easier it is to start the combustion process.
The combustion reaction gives rise to combustion gases (carbon dioxide, carbon monoxide, sulfur dioxide, carbon monoxide, methane combustion), flames, smoke, heat.

But how do you put out a fire on board?

The most widespread method of all to put out a fire on board is the manual fire extinguisher.
But fire extinguishers are not all the same and differ in relation to extinguishing with respect to the classes of fire
The most common types of fire extinguishers are:
• Powder extinguishers
• Carbon dioxide (CO2) fire extinguishers
• Water-based fire extinguishers
Among these, the most used types of extinguishers are certainly the powder ones and the water-based ones.

The powder extinguisher

It is the best-selling fire extinguisher, the most affordable in price and the most common in small businesses. It extinguishes Class A, B and C fires. It consists of a steel casing pressurized with inert gas (nitrogen) or dehumidified air and composed of a chemical powder consisting mainly of saline compounds.

The carbon dioxide fire extinguisher

Also known as a CO2 fire extinguisher, it is ideal for installing near electrical panels. It should be used together with and not in place of the Powder one because at a regulatory level it covers Class B fires but not A and C because by its very nature it would lead to a lowering of the temperature but not the extinction of the embers.

The tank is made of a single block of steel alloy (resistant to the strong pressures developed by the gas) connected to a high pressure pipe and to a PVC cone equipped with a handle, which serves to avoid cold burns to the operator as during use, the evaporation of the gas brings the temperature to -79°C.

The water-based fire extinguisher (hydro)

It is composed of a steel sheet cylinder treated against corrosion with a charge composed of foaming liquid diluted in water. It is suitable for Class A, B and F fires, but unsuitable for Class D fires. It is mainly used in the naval sector. When the fire extinguisher is activated, the foaming or water-based liquid (with other substances that amplify its effect) will come into contact with the air through small holes located at the base of the nozzle. This contact will generate foam.

How do you use a fire extinguisher to put out a fire on board?

Anywhere, on a boat, at home or in the office, you should have a fire extinguisher handy. This constitutes one of the best solutions to defend against fires, especially because external intervention is not always immediate. However, not everyone knows the rules for handling a fire extinguisher or which extinguisher to use for a specific type of fire on board.

The correct use of a fire extinguisher could save our lives and the lives of those who live or work with us. The right methodology for handling a fire extinguisher can be summarized in 4 steps:
1. remove the safety pin;
2. hold the discharge tube;
3. press the dispensing valve;
4. Keep the tube in horizontal direction.

It seems easy but to be able to put out a fire on board you need more in-depth knowledge, both of the use of the fire extinguisher and of the nature of the fires and the extinguishing agent.

• First of all, before removing the safety lock on the fire extinguisher, it is advisable to call the fire brigade. It is advisable to do this first, since their intervention may not be immediate: firefighters travel with large and cumbersome vehicles, which could stop in traffic or be far from the scene.

• Once the warranty plastic has broken, you must hold the fire extinguisher with strength and decision, perhaps taking a deep breath first and trying to remain calm, despite the apparently difficult situation. It is advisable to direct the fire extinguisher hose with your main hand, in order to minimize the complexity of the operation.

• Before using the fire extinguisher, you must identify the nearest escape route and turn your back to it, so that you can escape easily once the fire on board has been extinguished. To use the fire extinguisher it is necessary to position yourself a maximum of 4 meters away from the fire, gradually moving closer as the fire goes out. The tube must be kept at a safe distance from your body; it is advisable to swing it left and right and direct the jet towards the base of the fire. Once used, the extinguisher must be replaced or recharged.

Which Fire Extinguisher to Use

A fire extinguisher is a first aid firefighting device: correct use of the extinguisher can only occur in the presence of small outbreaks or the beginning of a fire on board. However, the action of a fire extinguisher is essential to limit damage, to prevent the situation from worsening and above all to protect people’s safety; for this purpose, it is also necessary to know the various types of fire extinguishers and fires, thus understanding which one to use in different situations. For example, in the event of fires in electrical systems, which fire extinguisher should be used? Let’s try to understand it.

• Class A: indicates fires from solid materials; all the various types of extinguishers can be used, CO2 (less recommended), powder and foam.
• Class B: fires from liquids or liquefiable solids are included here; also in this case, we can use all three fire extinguishers.
• Class C: includes gas fires; Co2 and powder extinguishers can be used.
• Class D: metal fires, extinguishable only with powder extinguishers.
• Class E: currently no longer contemplated, it concerns electrical appliances, for which we can use powder and Co2 extinguishers.
• Class F: fires from vegetable or animal oils and fats fall into this last class; in this case, only the foam extinguisher can be used.

How to Put Out a Fire

Before seeing how a fire is put out on board, it is good to understand its evolution. The fire, in fact, consists of four moments:
1. ignition phase;
2. propagation phase;
3. generalized fire;
4. extinction and cooling phase.

The ignition phase corresponds to the initial moment of the fire, during which the quantity of flames and heat produced are still rather limited. At this first moment, it is possible to resort to first aid measures to be able to extinguish it, in a rather simple way.

During the next phase, that of propagation, the combustion affects a larger area, with such heat and a quantity of flames that it is impossible to approach it without the necessary equipment. In the generalized fire phase, materials present in the environment spontaneously ignite; there is a sharp increase in temperature and an exponential growth in the combustion speed.

When the fire on board has stopped affecting all the combustible material, the extinction phase begins, characterized by a drop in temperatures and heat dissipation through fumes and thermal conduction phenomena. To put out a fire, you need to eliminate one of the sides of the fire triangle.

1. Fuel side, through the separating or moving action. This is done by removing combustible substances that have not yet been set on fire, thus proceeding to exhaust the fuel itself. This separation can occur using non-flammable guards and barriers, strong jets of water or mechanical means.
2. Combustion side, via suffocation. In fact, the fire needs oxygen to survive; once this has been eliminated, for example with a blanket, the fire will disappear.
3. Priming side: by removing heat, so as to obtain a temperature lower than that necessary for combustion. It is possible to act by reducing temperatures through, for example, water.

It is not very easy to put out a fire on board and all the operations listed are made even more difficult by the fear, worry and panic that grips any person, even the most experienced, who has to deal with this devastating element.

We also add, without fear of contradiction, that there are very few people who have followed a firefighting course, who have tried to use a fire extinguisher, who have done, or regularly do, fire extinguishing tests with a manual fire extinguisher.

For this reason it is important to put fixed, automatic shutdown systems on board, placed in the most at-risk points of the boat, such as the electrical panels, the kitchen hood, the engine compartment, the lithium batteries.

The most suitable extinguishing agent for these solutions, the cheapest one, which allows you to protect even the smallest compartments, is condensed potassium salt aerosol.
AERPRO®, present this year at the METS edition, pavilion 5, place 568, will present a new Secure4Sea (S4S) initiative, created together with companies that have been operating in the recreational, commercial and military nautical sector in the security sector for many years.
S4S is a single interlocutor, for shipyards, captains and private individuals, to obtain information and advice on everything relating to safety on board, starting from fire extinguishers, passing through life rafts, personal protective equipment, and ending with systems for detecting and extinguishing fire, aerosol, water mist, gas, etc.
Finally, those who sail, those who build, those who refit, have a qualified contact to resolve their safety needs in the best way.