NBCD Docket Basic Course PDF
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NBCD School
S Sabesan
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This document is a course material on Damage Control, Fire Fighting, and NBC defense. It covers topics such as fire chemistry, fire-fighting appliances, personal protection, fire-fighting organization, major fire-fighting systems, hot work operations, warship design features, watertight and gastight markings, and NBC practices. The document includes a table of contents, an introduction to the use of weapons of mass destruction, and an overview of each chapter's subject matter.
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RESTRICTED TO FLOAT TO MOVE TO FIGHT NBCD DOCKET BASIC COURSE NBCD SCHOOL LONAVLA - 410 402 MAHARASHTRA, INDIA 0 RESTRICTED TABLE OF CONTENTS Chapter Title...
RESTRICTED TO FLOAT TO MOVE TO FIGHT NBCD DOCKET BASIC COURSE NBCD SCHOOL LONAVLA - 410 402 MAHARASHTRA, INDIA 0 RESTRICTED TABLE OF CONTENTS Chapter Title Page No. Foreword 02 FF 1 Chemistry of Fire 04 2 First Aid Fire Fighting Appliances 16 3 Personal Protection and Breathing Apparatus 31 The Fire-main and Associated Fire Fighting 4 46 Equipment 5 Fire Fighting Organisation 54 6 Major Fire Fighting Systems (MFFS) 63 7 Hot Work Operations 88 DC 1 Design Features of a Warship 95 2 Location Markings 106 3 Watertight and Gastight Markings and Conditions 119 4 NBCD States of Readiness and NBC Practices 129 5 Leak Stopping Devices 138 6 Materials and Methods of Shoring 145 7 Basic Ship Stability 158 8 Damage Repair Stores & DC Lockers 175 9 Pumping, Flooding and Drainage Arrangement 181 10 Damage Control Simulator 186 NBC 1 Basic Nuclear Physics 191 2 Phenomenon of Nuclear Explosion and Nuclear Burst 201 3 Radiac Instruments 215 4 Biological Warfare 223 5 Chemical Warfare 231 6 Personal and Collective Protection 243 7 First Aid 255 Self Assessment Question Bank 1 RESTRICTED FOREWORD 1. The use of weapons of mass destruction in war today is an extreme measure, which represents the ultimate escalation of hostilities between the warring states. These weapons hang over our heads like the proverbial 'Sword of Damocles'. Rapid advances in protective and defensive measures are mandatory for the Armed Forces if the nation has to survive the initial strike and operate effectively in a post attack scenario. 2. An intensive effort towards dissemination of information is therefore needed to keep the manpower trained and alert to the dangers posed by such weapons. NBC preparedness directly affects fighting efficiency and survivability of a ship at sea. Even during peacetime operations, a ship’s crew may be called upon to meet a serious NBCD emergency, wherein timely and correct response can result in significant savings in human life and material damage. 3. This training material has been prepared to serve as a Training Aid in the subjects of Damage Control, Fire Fighting and NBC defense for NBCD capsule courses conducted at the training establishments. Efforts have been made to bring out the various aspects of the subject in a comprehensive but simple manner to facilitate easy understanding by the reader. 4. Any useful suggestions to improve upon the contents of the book are most welcome and the same may be forwarded to NBCD School for incorporation. (S Sabesan) Captain Officer-in-Charge NBCD School Lonavla – 410402 2 RESTRICTED 3 RESTRICTED CHAPTER 1 CHEMISTRY OF FIRE ---------------------------------------------------------------------------------------------------------------------------- -------- OBJECTIVES: Trainee should be able to understand and define related terms to fire chemistry like heat of combustion, specific heat, fire triangle and tetrahedron, combustion process, activation energy, chain reaction, flash point, fire point, spontaneous ignition, flash over. Trainee should also be able to understand the various components of fire, the modes of heat transfer and classification of fire. ---------------------------------------------------------------------------------------- -------------------------------------------- 1. Introduction. The atoms of many elements can exist alone, but seek partners with either another atom of the same or a different element. It is this tendency to link up with other atoms as a result of chemical affinity which gives rise to Chemical Reactions with all its practical consequences. The capacity of an element for combining with other elements is known as the Valency of that element. 2. Chemical Reaction. During the chemical reaction the atoms unite or combine together to form a molecule and are held together. If one of the reactants combines with oxygen, such reactions are known as Oxidation. 3. Heat of Formation. Whenever there is chemical reaction, either heat is liberated or heat is absorbed from the reacting substances. In the former case, it is called Exothermic reaction and in the latter case it is called Endothermic reaction. In case of combustion involving a carbonaceous fuel and oxygen, CO 2 gas is generally produced, with the liberation of heat. This may be expressed in terms of the following chemical equation, which means that 12 gm of Carbon react with 32 gm of Oxygen to produce 22.4 litre of CO 2 at NTP or 44 gm of CO2 , with the liberation of 27,44,280 calorie of heat, which is the heat of formation. C + O2 = CO2 + 39, 2920 Joule 4. Heat of Combustion. Heat of combustion is the amount of heat released during a substance's complete oxidation (combustion i.e. conversion to carbon dioxide and water). Heat of combustion, commonly referred to as calorific or fuel value, depends on the kinds and number of atoms in the molecules, as well as their arrangement in the molecule. Calorific values are commonly expressed in Joules per gram, but are sometimes reported in Btu/lb or calories/g. (1 cal/g = 4.18 J/g). The quantity of heat required to raise the temperature of 1 gram of water through 1 deg C is called a Calorie. 5. Mechanism of Combustion. The term mechanism of combustion refers to the reactions by which the fuel is transformed to the combustion products. The chemical reaction will take place only if the following conditions are met:- 4 RESTRICTED (a) Collision of molecules of the reactants. (b) Molecules should possess a certain critical minimum energy (activation energy). (c) The concentration of fuel should be within the inflammable range. 6. Specific Heat. Specific heat denotes the quantity of heat required to raise the temperature of one gram of substance through one degree centigrade. It is interesting to note that the specific heat of all other substances is less than that of water and some are very much lower. Organic substances such as petrol, alcohol, etc. have low specific heat. This means that such substances, when exposed to a given quantity of heat, show a much greater rise of temperature than water - a factor of considerable importance from the point of view of fire propagation. 7. Fire Triangle. The term fire may be defined as a rapid, self-sustaining oxidation process accompanied by the evolution of heat and light of varying intensities. In other words "fire is a chemical reaction between a fuel and oxygen in the presence of heat". The three components essential for a fire to take place are heat, combustible material or fuel, and supporter of combustion or oxygen, represented as three arms of fire triangle (Fig 1.1). Oxygen Fuel Fire Heat Fig. 1.1 Triangle of Combustion Components of a Fire 8. Oxygen. It is a good supporter of combustion, and can undergo chemical reactions with almost all kinds of fuel during combustion, except inert gases. There must be at least 16% oxygen present for a fire to burn. This is usually not a problem since the air we breathe is about 21% oxygen. 9. Fuel. Fuel may be any combustible material in the form of solid, liquid or gas. Typically solids and liquids must be heated to the point where they are converted into a vapor or gas before they will burn. On combustion the fuels may be considered undergoing thermal decomposition; the resulting product may either undergo further decomposition or be burnt to the final product. Inspite of the wide range in composition and properties, generally, all fuels may be regarded as mixtures of four components viz. Carbon, Gaseous Hydrocarbons, Hydrogen and Carbon Monoxide. Fuel can be solid or liquid, which, when heated, gives off 5 RESTRICTED flammable vapors. Fuel can also be a gas which starts to burn when its ignition temperature is reached. Examples are paper, wood, cardboard, paint, oils, acetylene and propane gas. 10. Heat. Heat, being a form of energy has the following effects:- (a) Increases in size and pressure (b) Changes the physical state e.g. solid, liquid and gas. (c) Produce glow or luminosity or colour. (d) Generate small electric current (thermo-electric effect). 11. Tetrahedron of Fire. Combustion is an exothermic, self-sustaining reaction involving a solid, liquid, and/or gas-phase fuel. The combustion of fuel, air and heat does not cause a fire unless a chemical reaction is initiated. Once you have three sides of the fire triangle you promote a fourth element, a chemical reaction between oxygen and fuel, consequently you have a fire tetrahedron (Fig 1.2). Heat Combustible Free Radicals Substance Oxygen Fig. 1.2 Fire Tetrahedron 12. In a fire there are two different phases in which combustion proceeds, viz. the surface combustion mode and the flaming mode. The surface combustion mode incorporates the three essential elements of fire as represented by the triangle of combustion, viz. heat, oxygen and combustible substance. The flaming mode, on the other hand, incorporates four basic requirements, viz. Heat, oxygen, combustible substance and in addition, another factor called the uninhibited chain reaction of combustion process. 13. These two modes may occur either singly or in combination. Flammable liquids or gases burn in the flaming mode only. Examples in which both the modes exist are solid carbonaceous fuels such as coal, wood, vegetable fibers etc. With these materials, the early stages of combustion start with the flaming mode with a gradual transition towards the surface combustion mode, during which both the modes are simultaneously in action. Ultimately, flaming mode is terminated with the residual surface combustion mode existing alone. Examples in which surface combustion mode exists alone are fires involving pure carbon and other readily oxidized non-metals like magnesium, aluminium, uranium etc. 6 RESTRICTED 18. Combustion of Hydrogen. During the initiation phase of the combustion reaction, active chain carriers are formed by such reactions as:- H2 2H O2 2O H2O OH+H 19. These reactions may result from intermolecular collisions or from thermal dissociation. These active particles diffuse into the unburnt gaseous mixture of a flame. The active chain carriers thus formed take part in the propagation reaction. From the following reactions, it could be seen that the reaction between H and O 2 produces two chain carriers, thus resulting in the branching or reaction. OH + H2 H2O + H H + O2 OH + O O + H2 OH + H 20. Activation Energy. For the majority of substances, combustion cannot occur at room temperature because the reacting molecules repel each other. To react, they must possess sufficient energy to overcome the initial mutual repulsion and come together to form an activated complex for the combustion to occur. The energy required to overcome the mutual repulsion is known as Activation Energy. Modes of Heat Transfer 21. There are three distinct processes by which heat may be transferred from one place to another. These are: (a) Conduction. This is the process in which heat is transmitted from hotter part of the body to the colder one or from a hot body to another colder body in contact with or without any transference of material particles. Conduction can be through any suitable material such as steel or aluminum, decks or bulkheads. (b) Convection. In this process the heated particles go up and move in the air or the liquid, in a cycle, called convection current carrying the heat with them from hotter to colder place. In other words the heat is transferred by actual movement of heated material particles from a region of higher temperature to another of lower temperature. Convection can be via gases, liquids or hot air circulated through ventilation trunking, lifts shafts etc. (c) Radiation. Radiation is the transmission of heat in the form of electromagnetic waves. It does not require a medium and the waves travel at a very high speed. Radiation can be from any heating appliances, flames or explosion. The radiated energy can pass through certain materials without loss of any energy, can be absorbed by certain material slowly 7 RESTRICTED raising the temperature of the absorbing media and can get reflected by the media. 22. Flash Point. Flash point is the lowest temperature at which there is sufficient vaporisation of the substance to produce a vapour which will flash momentarily when flame applied. It is an indicator of the degree of the safety of a material. Flash points of some of the commonly used gases and liquids are given in Table 1.1. Table 1.1 Name of Gas/Liquid Flash Point Gasoline - 40C Kerosene 45C Jet fuel 43 to 65 C Diesel 61 C Furnace fuel oil 90 C Vegetable oil 230-282C Lubricating oil 230 C 23. Fire Point. Fire point may be defined as the lowest temperature at which the heat from the combustion of a burning vapour is capable of producing sufficient vapour to enable combustion to continue. It will be seen that the difference between flash point and fire point is that the flash point temperature is only required to produce vapour to enable a momentary flash to take place, whereas the fire point temperature has to be high enough to produce sufficient vapour to sustain the reaction, so that the substance continues to burn independently of the ignition source. 24. Spontaneous Ignition Temperature. Spontaneous ignition temperature is the lowest temperature at which the substance will ignite spontaneously, that is the substance will burn without the introduction of a flame or other ignition source. This is sometimes referred to as the auto-ignition temperature. This implies that as the temperature increases, the number of molecules that possess sufficient energy to form an activated complex increase rapidly. There is a critical temperature (called the auto-ignition temperature) above which enough molecules possess sufficient energy for the process to become self-propagating, leading to flammable combustion. Ignition temperature of some of the commonly used gases and liquids are given in Table 1.2. Table. 1.2 Name of Gas/Liquid Ignition Point Gasoline 250C Kerosene 295C Lubricating oil 371 C 8 RESTRICTED 25. Certain materials, especially organic materials based on carbon, may react with oxygen at room temperature. Compounds such as linseed oil which contain carbon-carbon double bonds are very prone to this reaction. If fuel is a good thermal insulator, the heat generated in such a reaction cannot get away, the temperature rises which increases the rate of reaction and the situation escalates. Eventually the ignition temperature is reached and true combustion commences. Alternatively the action of bacteria on certain organic materials can cause a rise in temperature eventually leading to active combustion. A fine state of sub-division, as in powdered coal and some metals, could lead to spontaneous combustion. Cross linking of some plastics may also lead to spontaneous combustion. 26. Thermal Run-away. Above the auto-ignition temperature, the energy released by the reacting molecules is sufficient to activate even larger number of molecules and there is an ever-increasing rate of production of heat energy. The temperature rises and the mixture enters a stage of thermal run-away, which rapidly becomes a flaming combustion (a thermal explosion). 27. Flash Over. In a compartment fire, there can be a stage where the total thermal radiation from the fire plume, hot gases and hot compartment boundaries causes the radiative ignition of all exposed combustible surfaces within the compartment. This sudden and sustained transition of a growing fire to a fully developed fire is called flash over. 28. Lean Flash Over and Combustibility of Smoke. When a fire starts in a compartment, the heat given off decomposes the combustible material faster than it can burn. The smoke, full of fuel, rises to the deck-head and as it gets hotter, the three sides of the triangle namely Fuel, Oxygen and Heat come together, reaches its ignition temperature and it ignites. This is known as lean flash over. As the fire runs across the deck-head it radiates heat downwards, decomposing combustible substances in the compartment and starting secondary fires. 29. Back draught. Limited ventilation can lead to a fire in a compartment producing fire gases containing significant proportions of a partial combustion products and un-burnt pyrolysis products. If these accumulate then the admission of air when an opening is made to the compartment can lead to a sudden deflagration. This deflagration moving through the compartment and out of the opening is a backdraught. 30. Delayed Back draught. In the event of a smouldering deep seated fire, if the door to the fire room is opened, air entering the oxygen deficient environment, alters the explosive limit from the rich mixture towards the ideal mixture, but not immediately causing a backdraught. The delayed backdraught happens when the carbonized layer of a smoldering fire is disturbed, either by a length of hose or the moving of smoldering furniture to reveal an ignition source. 9 RESTRICTED Classification of Fire 31. The fires are classified by the nature of the materials involved and are as follows: - (a) Class A. These are most common fires, involving solid materials normally of an organic nature (compounds of carbon), in which combustion generally occurs with a formation of glowing members. The most effective extinguishing agent is generally water in the form of a jet or spray. For example paper, cloth, grass, timber, rubber, plastics etc. (b) Class B. These are fires involving liquids or liquefiable solids. For the purpose of choosing effective extinguishing agents, flammable liquids may be divided into following two groups. Depending on these two groups, the extinguishing agents include water spray, foam, light water, vaporising liquids, carbon dioxide and dry chemical powders. For example lubricants, Oil-based paints, chemicals, Flammable Liquids like Gasoline, Cooking Oil, etc. (i) Those are miscible with water, and (ii) Those are not miscible with water. (c) Class C. These are fires involving gases or liquefied gases in the form of a liquid spillage or a liquid or gas leak, and these include methane, propane, butane, acetylene, chlorine gas, ammonia, etc. Foam or dry chemical powder can be used to control fires involving shallow liquid spills. Water in the form of spray is generally used to cool the containers. (d) Class D. These are fires involving metals. Extinguishing agents containing water are effective, and even dangerous; carbon dioxide and the bicarbonate classes of dry chemical powders may also be hazardous if applied to most metal fires. Powdered graphite, powdered talc, soda ash, limestone and dry sand are normally suitable for Class D fires. Special fusing powders have been developed for fires involving some metals, especially the radioactive ones. For example fires involving Combustible metals such as copper, magnesium, zinc, aluminium, sodium, lithium, hafnium etc. (e) Electrical fires. It is not considered that electrical fires constitute a class, since any fire involving, or started by, electrical equipment must, in fact, be a class of fire of Class A, B or D. The normal procedure in such circumstances is to cut off the electricity and use an extinguishing method appropriate to what is burning. Only when this cannot be done with certainty will special extinguishing agents be required which are non conductors of electricity and non-damaging to equipment. These include vaporizing 10 RESTRICTED liquids, dry powders and carbon dioxide, although the latter's cooling and condensation effects may affect sensitive electronic equipment. (f) Class F/ Class K. Fires involving cooking oils and fats are classified as “Class F” under the Europian and Australian systems and “Class K under the American system. Though these fires are technically a subclass of the flammable liquid class, special characteristics of these types of fires namely the higher flash point, are considered important enough to re recognized separately. 32. Types Of Combustion. Combustion can be classified as: - (a) Type I. Direct oxidation or combustible gases, liquids or solids that need not undergo decomposition or pyrolysis in order to oxidize or burn. The substance must be raised to ignition temperature in order to oxidize e.g. Methane (CH4), Acetylene (C2 H2), Alcohol (C2H5OH), Charcoal etc. (b) Type II. The molecules of the substance must breakdown or pyrolyse, under the influence of heat to produce simple combustible gases and solids that will unite with the oxygen in air. Almost all solids and liquids having Carbon or Hydrogen or both will burn by pyrolysis e.g. wood, paper, paints, plastic, rubber, cooking oils etc. 33. Properties of Solids. For combustion, a common combustible solid must be heated at its surface by some external means until that surface reaches a temperature where combustible vapours or gases are given off and are subsequently ignited. These vapours may arise because of the chemical decomposition of the solid under the flame attack, or because of a vaporisation of the solid combustible substance that will evolve combustible vapour or gases. The ignition and rate of burning will depend upon:- (a) Physical shape of material (b) Heat conductivity of solid (c) Extent combustible surface is surrounded by air. 34. Properties of Liquids. When flash point is reached in liquids, the heat of combustion travels by radiation and conduction. The phenomenon of boil over and slop over occur in liquid fires. 35. Boil Over. It is a phenomenon in liquids with wide boiling range, like Furnace fuel oil. Lighter fractions/ density burn at surface and heavier fractions become hot and sink. Heat is transferred to lesser density fractions and they move up, setting up a circulation. If water is present it will steam and force the contents of the tank upwards, with an explosive expulsion. 11 RESTRICTED 36. Slop Over. It is the formation of emulsion of fuel and expanding water (steam) or foam. The froth issues out from the open space in tank, and removes volumes of hot fuel. 37. Classification of Gases. The gases can be classified as shown in Table 1.3. Table 1.3 Classification Common Example Flammable Hydrogen Toxic Sulphur dioxide and methyl- bromide Flammable and Toxic Ammonia, Hydrogen Sulphide Supporter of Combustion Oxygen and Nitrous oxide Poisonous and supporter of Chlorine and Nitrogen combustion Inert gases Carbon dioxide Methods of Fire Extinction 38. Fire safety, at its most basic, is based upon the principle of keeping fuel sources and ignition sources separate. Fire extinction, in principle, consists in the limitation of one or more of the factors essential to combustion. In extinguishing a fire, either the heat may be removed and temperature brought below the ignition point (Cooling), or the supply of oxygen to the fire may be stopped (Smothering), or the fuel may be removed from the scene of fire (Starving), or else interfere with the chemical reaction. One way of interfering with the chemical reaction is to remove the free radicals in the chemical reaction using certain chemicals (Quenching of Free Radicals). 39. Cooling. Cooling is the process of reducing temperature of the combustible substance to a point where combustible vapours are no longer evolved or where activation energy is lowered to the extent that no activated atoms or free radicals are produced, usually by using water (Fig.1.3). The extinguishing medium operates by absorbing heat from the fire, as a consequence of which it may undergo one or more of the following changes:- (a) Its temperature is raised. (b) It is converted to the vapour state. (c) It is decomposed. (d) It reacts chemically with the burning material. Oxygen Fuel 12 RESTRICTED Fig 1.3 Cooling–Removal of Heat 40. In applying the principle of fire extinction, the first step is to accelerate the speed with which heat is removed from the fire, thus reducing the temperature of the burning mass. In due course the rate at which the heat is lost from the fire exceeds the rate of heat production and the fire dies away. The application of a jet or spray of water to a fire is invariably based on this simple but fundamental principle. Another example is the emulsification of the surface of oil by means of the emulsifying type of sprinkler head producing an oil-in-water emulsion. 41. Smothering. Smothering is the process of removal or dilution of oxygen (air) to a point where combustion ceases (Minimum 16% oxygen required for combustion to sustain). This is achieved usually by using Carbon dioxide gas , steam or foam. Small fires, such as those involving a person's clothing, can be smothered with a rug, blanket, etc., while the use of sand or earth on a small metal fire is a further instance of the same principle (Fig 1.4). Fuel Heat Fig 1.4 Smothering – Removal of Oxygen 42. Foam forms a viscous coating over the burning material and limits the supply of air, in so far as it is complete. It also tends to prevent the formation of flammable vapour. Another method is application of a cloud of finely divided particles of dry powder, usually sodium bicarbonate. A further development is powdered compound for use on metal fires, such as uranium and plutonium, thorium and magnesium. The vigorous discharge of an inert gas in the vicinity of the fire may so reduce the oxygen content of the atmosphere for the time being that combustion cannot be maintained. Carbon dioxide and nitrogen are familiar examples of this. 43. Starving. Physically separating/removing the combustible material from the neighborhood of the fire, or sub-dividing the burning material, to a point where there is nothing remaining to oxidize (Fig 1.5). Oxygen Heat Fig 1.5 Starving 13 RESTRICTED 44. The extinction of fire by starvation is applied in three ways: - (a) By removing combustible substance material from the neighborhood of the fire. Examples of this are drainage of fuel from burning oil tanks, the working out of cargo at a ship fire etc. (b) By removing the fire from the neighborhood of combustible material as, for instance, pulling apart a burning haystack or a thatched roof. (c) By sub-dividing the burning material, when the smaller fires produced may be left to burn out or to be extinguished more easily by other means. A typical example is the emulsification of the surface of the burning oil, whilst the beating out of a heath fire owes much of its effectiveness to this. 45. Quenching of Free Radicals. Interruption of flame chemistry of the chain reaction of combustion can be achieved by injection of compounds capable of quenching free radicals production during their residence time. Any specific extinguishment technique may involve one of these methods or, more often, several of them simultaneously. For example, when water is applied to a fire of a solid combustible burning in air, several extinguishing mechanisms are involved simultaneously. The solid is cooled by contact with water, causing its rate of pyrolysis, or gasification, to decrease. The gaseous flame is cooled, causing a reduction in heat feedback to the combustible solid, and a corresponding reduction in the endothermic pyrolysis rate. Steam is generated which under some confined conditions, may prevent oxygen from reaching fire. Water in the form of fog may block radiative heat transfer. 46. Effective Extinguishing Media for Different Class of Fires. The extinguishing media for different class of fires are: - (a) Class A. Pressurized water or Dry Chemical, ammonium phosphate. (b) Class B. Carbon dioxide, expelled as a gas or Dry Chemical, Ammonium phosphate or Dry chemical, sodium bicarbonate and potassium bicarbonate, urea-based potassium preferred for extinguishing cooking oil fires or Halon expelled as a gas or Water spray, foam, light water, vaporising liquids. (c) Class C. Foam or dry chemical powder, Ammonium phosphate. Water in the form of spray is generally used to cool the containers. Halon also can be used. (d) Class D. Powdered graphite, powdered talc, soda ash, limestone and dry sand. (e) Electrical fires. Carbon dioxide, expelled as a gas or Dry Chemical, Ammonium Phosphate or Dry chemical, sodium bicarbonate and potassium bicarbonate, urea-based potassium or Halon expelled as a gas. 14 RESTRICTED (f) Class F/ Class K. Some special extinguishers designed for this use smother the fire by turning the oil into foam. A waster mist can also be used.As with class B fires, a solid stream of water should never be used to extinguish this type because it can cause the fuel to scatter, spreading the flames. 47. Extinguishers for Class D fires are specially-formulated to treat organic and alkali metals that cannot be safely extinguished by other fire extinguisher agents. Never use a Class D-rated extinguisher for Class A, B, or C fires. Class D fires are caused by ignition of organic metals such as lithium (an alkali metal), aluminum, or sodium. Class D fires are particularly troublesome to extinguish because of the intensity with which they burn and their ability to react chemically with normal extinguishing agents. As an example, carbon dioxide will not react with cold sodium but accelerates the burning rate of ignited sodium. Two agents that are used to extinguish Class D fires are sand and sodium chloride. To extinguish Class D fires, use water, foam, carbon dioxide, or halons in cases of fires involving alkali metals. Use graphite, soda ash, or powdered sodium chloride incases of fires involving non alkali metals. Be very sure that the extinguishing agent is dry or else the moisture can react with the metal. Summary 48. Whenever there is chemical reaction, either heat is liberated (Exothermic reaction) or heat is absorbed from the reacting substances (Endothermic reaction). Heat of combustion is the amount of heat released during a substance's complete oxidation. Fire is a chemical reaction between a fuel and oxygen in the presence of heat. A fire cannot take place in the absence of any one of these three factors. The combustion of fuel, air and heat does not cause a fire unless a chemical reaction is initiated. So there is the fourth side of fire triangle i.e. the chemical reaction between fuel and oxygen. In a fire there are two different phases in which combustion proceeds, viz. the surface combustion mode and the flaming mode. The flaming mode incorporates four basic requirements viz. Heat, oxygen, combustible substance and in addition, another factor called the uninhibited chain reaction of combustion process. This is called the tetrahedron of combustion. The intermediate products formed in a chain reaction are known as chain carrier since they help to carry the reaction to completion. Reacting molecules must possess sufficient energy (Activation energy) to overcome the initial mutual repulsion and come together to form an activated complex for the combustion to occur. The three distinct processes by which heat may be transferred from one place to another are conduction, convection and radiation. Flash point is the lowest temperature at which there is sufficient vaporisation of the substance to produce a vapour which will flash momentarily when flame applied. Fire point is the lowest temperature at which the heat from the combustion of a burning vapour is capable of producing sufficient vapour to enable combustion to continue. Spontaneous ignition temperature is the lowest temperature at which the substance will burn without the introduction of a flame or other ignition source. The classification of fires as per the nature of the materials involved is Class A, B, C, D and Electrical fires. Fire extinction is achieved by cooling, starving, smothering & quenching of free radicals. 15 RESTRICTED CHAPTER 2 FIRST AID FIRE FIGHTING APPLIANCES ------------------------------------------------------------------------------------------------------------------------------------ OBJECTIVES: Trainee should be able to understand the use of various types of portable extinguishers, their extinguishing features, their operating and charging procedures and the fire fighting appliances available. ----------------------------------------------------------------------------------------------------------------------------- ------- 1. Introduction. Fires are most easily extinguished when they are small. Portable fire extinguishers, which are specifically designed for putting out small fires, are the first line of defence in fighting fires. Successful use of portable fire extinguishers depends on several factors which must be considered before you decide to use a portable fire extinguisher on a fire. (a) What is burning? (b) Do you have the right type of extinguisher to fight the fire? (c) Is the fire small enough for a portable fire extinguisher to be effective? (d) Do you know how to use a portable extinguisher? (e) Is there a route of egress should your attempts to fight the fire be unsuccessful? 2. Portable Fire Extinguishers. First aid fire fighting extinguishers are portable equipment which can be brought into action with the least possible delay for extinguishing fires in their early stages. The fire extinguishers are classified by the type of fire on which they can be used. These extinguishers work by either removing one of the three elements needed to sustain combustion or by interrupting the reaction between the elements. 3. Types of Portable Extinguishers. All portable extinguishers and their accessories, including their refills are stowed in readily accessible positions and distributed throughout the ship to suit the action organisation. The first aid extinguishers used onboard ships and establishments are: - (a) CO2 extinguisher (2 Kg) (b) Twin CO2 trolley extinguisher portable trolley (6.5 kg) (c) AFFF extinguisher (9 Litres) (d) Dry chemical powder extinguisher (5 Kg) (e) Dry chemical powder extinguisher (10 Kg) (h) Dry powder extinguisher trolley mounted (75 Kg) Carbon di-oxide Extinguisher 4. Carbon dioxide (CO2) extinguisher (Fig. 2.1) consists of a cylinder containing liquefied carbon dioxide at a pressure of 850 psi at 16 deg C. Carbon dioxide in gaseous form is released when operated extinguishing fire by 16 RESTRICTED smothering. It is painted black with white or silver top. A plastic or fibre discharge horn is provided as a spare and is replaceable onboard. The extinguisher can be used on: - (a) Electrical fires especially for high voltage, and (b) Solid or liquid fuel fires, but there is danger of re-ignition when CO2 disappears. Fig. 2.1 CO2 Portable Extinguisher 5. Operation of CO2 Extinguisher. The extinguisher is required to be stowed at the coolest possible place preferably near the door. While operating grip the fibre/ plastic horn of the cylinder as it will avoid cold burns. The testing pressure is 3360 psi. The operating procedure is as follows: - (a) Hold the extinguisher by trigger assembly. (b) Remove the safety pin. Safety Disc operating pressure - 2700 psi (c) Approach fire and point diffuser at the base of the fire. Effective Range 4 to 6 ft (d) Squeeze trigger/open the valve fully. (e) Direct CO2 from wind ward side of flame. Endurance 16-18 seconds 6. 6.5 Kg Twin CO2 Trolley Extinguisher (Fig 2.2). It is designed for fighting fires in engine bays of aircraft. It can be used on electrical, solid and liquid fuel fires. It is suitable for B, C and E fires and extinguishes by smothering. The unit consists of two cylinders each containing 6.5 Kg of CO2 mounted on a two wheeled trolley, operating at 750-850 psi with the discharge of each lasting 16 to 18 seconds. The testing pressure is 3360 psi. The procedure for operation is: - (a) Bring the unit to vertical position. (b) Remove the gag from the operating head. (c) Pull off the retaining spring and sharply move the operating lever of one cylinder upwards to release the CO2. 17 RESTRICTED (d) Remove the nozzle from its stowage on the frame of the trolley in readiness for immediate use. (e) Squeeze the nozzle control valve handle to discharge the gas. The handle must be held on for as long as the discharge is required. (f) If the fire is not extinguished, bring the second cylinder into operation. The Safety disc operating pressure is 2700 psi. Note : - The squeeze grip handle should not be kept closed for periods longer than about 16-18 seconds because of the danger of it freezing. Fig. 2.2 6.5 Kg Twin CO2 Trolley Extinguisher AFFF Extinguisher (9 Litre) 7. The Aqueous film forming foam extinguisher (9 ltr. AFFF) (Fig. 2.3) weighs 18 kgs and is used against A, B and E class of fires. It can be charged by any personnel onboard using a mixture of 8.45 litres of fresh water, 0.55 litres of 18 RESTRICTED Aqueous film forming foam compound and 60 gram CO2 cartridge. The working pressure is 250 psi and testing pressure is 350 psi. The extinguisher is painted in Red color and when operated forms a blanket of foam, extinguishing fire by smothering. The output of foam produced is 54 litres. The length of the hose is 400-600 mm. It is used for: - (a) All fires involving solid and liquid fuels. Fig. 2.3 9 litre AFFF Extinguisher. 8. Operation of AFFF Extinguisher. The extinguisher must be used in the upright position and it is to be ensured that the wheel head is screwed down tight. The operating procedure is as follows: (a) Remove the hinged guard and firmly strike the operating knob to pierce the sealing disc of pressurised 60 gram CO2 cartridge. (b) Allow the knob to spring back to its original position to make a tight seal. Pressure is thus created in the extinguisher which forces the foam out through the rubber hose and nozzle. (c) Holding the nozzle, ensuring the holes are not blocked, direct it towards the fire making figure of eight or sweep motion on the fire to achieve complete coverage. (d) In case the extinguisher fail to operate or bursts along the welded seam, safety of men should be ensured by kicking it with leg. 19 RESTRICTED 9. Charging Procedure for AFFF Extinguisher. (a) Unscrew the wheel head and empty the contents of the extinguisher. (b) Remove the used CO2 cartridge. (c) Observe body internally for corrosion marks or holes, especially along the welded seam. (d) Wash the extinguisher internally with fresh water. (e) Fill the container with fresh water to the internal level indicator or 8.6 litres. (f) Add 0.4 litre of AFFF liquid compound from the container. (g) Insert new 60 grams CO2 cartridge after checking that the charge/ weight loss is not more than 10% (spare cartridges are available onboard and are replaceable from stores). (h) Ensure wheel washer in place and replace the wheel head firmly by hand. (j) Put safety clip. 10. Foam Extinguisher Trolley Mounted. The foam type extinguisher, painted in cream color, extinguishes A, B and E class of fires by smothering. It is charged by Aluminium Sulphate and Sodium bi-carbonate and has a working pressure of 250 psi and test pressure of 350 psi. The foam output is 76.5 litres and the throw is upto a distance of 6 to 7 metres. It conforms to IS 8100/5507 specifications. Dry Chemical Powder (DCP) Extinguisher 11. The DCP extinguisher (Fig. 2.4) contains sodium bicarbonate, potassium chloride, urea-potassium bicarbonate and mono-ammonium phosphate. Various additives are mixed with these base materials to improve their storage, flow, and water-repellency characteristics. The most commonly used additives are metallic stearates, tri-calcium phosphate, or silicones. The body is painted in blue, and generally used on flight deck and helicopter handling platforms. It extinguishes fire by smothering and free radical quenching. The portable extinguishers come in 2 kgs, 5 kgs and 10 kgs. 12. DCP 5 Kg and 10 Kg Extinguisher. The DCP 5 kg has an internal CO2 cartridge of 180 grams under pressure, with 5 kgs of dry chemical powder and DCP 10 kg (Fig 2.4) has an internal cartridge of 240 grams under pressure, with 10 kgs of dry chemical powder. When activated CO2 drives the powder from the nozzle in a dense cloud which may extend as far as 3 to 4 metres, with a discharge time of 18 - 30 seconds. 20 RESTRICTED Fig. 2.4 Cross-section of 10 kg DCP Extinguisher 13. Operation of DCP Extinguisher. (a) Remove safety clip (b) Aim the nozzle, horn or hose at the base of the fire (c) Strike the knob. (d) Squeeze or compress the handle to release the extinguishing agent (e) Sweep the nozzle, horn or hose from side to side at the base of the fire until it is extinguished. 14. Charging Procedure for DCP Extinguisher. (a) Open cap, remove used cartridge, clean all the parts such as threads, hose and grip, by pressurised air (b) Replace cartridge (c) Strain dry powder by fine mesh and fill in outer body and screw in the cap 15. Dry Chemical Powder Extinguisher (PD 12). The PD-12 extinguisher is provided for use on flight deck and helicopter handling platforms. It consists of a container holding 12.6 kg of dry chemical powder with a cartridge of 240 gms CO 2 under pressure attached to it. When operated the gas ejects the powder through a hose in the form of a jet or a diffused cloud. The CO 2 is controlled by a wheel valve at the bottle and a squeeze grip valve at the nozzle. The discharge time is 45 seconds. Its use is to be immediately backed up by major foam appliances. The 21 RESTRICTED powder is non toxic, compatible with foam and non conductor of electricity. It is provided for flight decks and helicopter landing platforms. 16. As a general rule, a few of the PD 12 extinguishers supplied to ships are filled with pyromet black powder for magnesium fires (such extinguishers bear a label, in block letters on a yellow background "Magnesium and Aircraft wheel fires"). The operating procedure is as follows: - (a) Remove discharge nozzle from its container (b) Open the CO2 valve by turning the wheel anti clock wise (c) Press the squeeze grip nozzle 17. Dry Chemical Powder Extinguisher (PD-150). PD-150 (Fig 2.5) is used to fight major fires on flight decks, helicopter/ aircraft landing platforms and for rescue operation from crashed aircrafts. The unit is designed to deal with fires involving large quantities of oils, spirits, alcohols and solvents. The unit comprises of a chassis with two wheels, tank with valves and filler cap, 15.25 metres of 2.54 mm. bore deliver hose and a CO2 cylinder containing 2 Kg of CO2 to discharge 75 or 68 kgs of dry chemical powder. The extinguisher has following specifications: - (a) Discharge time : 45 sec. (b) Weight (fully charged) : 202.5 Kg (d) Height : 1.2 mtrs (e) Overall width (across wheel) : 0.65 mtrs. 18. To operate, remove unit from stowage, make it vertical, uncoil delivery hose, remove safety pin from CO2 bottle and open the valve on CO2 bottle, now the container is pressurized. Squeeze the nozzle and fight the fire from windward direction to form a cloud on burning oil. The powder type extinguisher is to be backed up by foam appliances. In addition, the following guidelines should be observed after use: - (a) After being pressurized, the hose line should be removed and cleared off powder, using CO2 or HP air (on no account LP air to be used as this is likely to be wet and create caking of the hose). (b) Before fitting new CO2 bottle safety pin should be fitted with a copper wire seal to give a visual indication of the bottle having been operated. (c) Before fitting new CO2 bottle, CO2 delivery line be checked for blockages. (d) Close CO2 valve and de-pressurise unit. (e) Remove filler cap carefully. There are CO2 vent holes on the side of the filler cap and when these holes are exposed, gas can be heard escaping. The filler cap should not be removed until this ceases. (f) After de-pressurisation, slacken back the filler cap before disconnecting the CO2 bottle to release remaining pressure in the container and avoid any powder being forced into the CO2 deliver hose. 22 RESTRICTED Fig 2.5 Dry Chemical Powder Extinguisher (PD-150). 19. Charging Procedure for PD 150 Extinguisher. De-pressurising (a) Leave squeeze grip valve on CO2 bottle open (b) Put out safety pin on de-pressurising valve (c) Open valve and operate local control nozzle valve to release pressure and blow out hose. Refilling (d) Close CO2 bottle, insert safety pin and remove empty CO2 bottle. (e) Remove filler cap carefully (f) Remove main CO2 delivery hose, blow through with CO2 dry air and replace, ensuring threads are clear of powder (g) Remove delivery hose. Lay hose on deck, depress trigger and blow through with CO2 or dry air. Ensure hose is clear or powder. Check nut attachment for wear and cracks on nut flange. Check guns for freedom of movement and ensure that rubber sealing washer on the valve spindle is seated properly. (h) Invert unit and dispose of all remaining powder in the unit. (j) Replace de-pressurising valve pin. (k) Replace delivery hose ensuring threads are clear of powder. Ensure that the sealing washer is in the nut before the delivery hose is attached. (l) Attach new CO2 bottle, check locking wire is intact, weight the bottle, and washer in connection. (m) Recharge with 68 Kg of powder (n) Clean threads, check washer and safety vent holes in filler cap, and replace. (p) Check bleed holes are clean (two are situated on the face plate of diverting valve and one on the rim of the face plate of the reducing valve). 23 RESTRICTED The bleed holes should never be allowed to become clogged by powder, paint dirt etc. (q) Each unit should be stowed in horizontal position with the handles resting on the deck, stoppers should be arranged in suitable position against the wheels. 20. Air Transportable Dry Chemical Powder Extinguisher. This extinguisher is designed to be lifted by helicopter (using the aircraft winch) and rapidly conveyed to the scene of a crashed aircraft. It is similar in operation to the PD 150 but consists of a spherical powder container mounted between two circular rims. The container has a capacity of 135 Kgs of dry chemical powder which is activated by a self contained and rechargeable air vessel. It will discharge in about 45 seconds, driving powder through a hose and discharge horn. The operating procedure is: - (a) Open the main valve on the filler cap assembly. (b) Run out the hose (c) Open the delivery valve at the base of the powder container (d) Operate the squeeze grip control on the discharge horn as required and direct the powder with a sweeping movement at the base of the flames. Fire Fighting Appliances 21. Jet/ Spray Nozzle (Fig 2.6). These are provided for weather deck hydrants and also two in each fire party lockers. By turning rotating sleeve clockwise, looking from coupling end, discharge can be controlled from a nearly radial screen of spray to hollow cone, to a hollow jet and finally shut off. It has 36 tons/ hour (130 gallon/ min.) discharge rate at 80 lb/ sq. inch firemain pressure, heavier than spray/jet nozzle. Fig 2.6 Jet/Spray Nozzle 22. Spray/ Jet Nozzle (Fig 2.7). This is provided on all hydrants in ships except on weather decks. By turning the rotating sleeve clockwise looking from the coupling end, the spray can be adjusted to a wide cone of hollow jet. This nozzle has a low water discharge rate of 14.6 tons/ hour (53 gallons/ min.) at 80 lb/sq. 24 RESTRICTED inch firemain pressure and does not give enough spray protection. It is to be used for fire fighting in a strong wind only. Fig 2.7 Spray/ Jet Nozzle 23. Diffuser Nozzle (Fig 2.8). This is available in each fire locker and used for both, spray and jet mode. It has a capacity of 32 tons/ hour discharge at 80 lb/ sq. inch firemain pressure. Fig 2.8 Diffuser Nozzle Adaptors 24. Adaptors (Fig 2.9) are provided to permit hoses and appliances of different sizes and types of coupling to be connected. These are supplied as male and female instantaneous adaptors or as double male and double female adaptors. The adaptors are to be stowed at section bases in large ships and in fire lockers at fire and repair party posts in smaller ships. 25 RESTRICTED Fig 2.9 Double Male And Double Female Adapter Breeching Piece 25. Breeching pieces (Fig 2.10) are 'Y' shaped metal fittings intended primarily to enable two hoses to be run off from a single hose or hydrant. They should not be used to provide a water wall and a fire fighting hose for the same team of fire fighters. The water wall and fire fighting hose must come from different hydrants. Fig 2.10 Breeching Piece Foam Appliances 26. The main foam appliances operate from firemain and produce large quantities of mechanical foam by mixing water with foam compound in the correct proportion and aerating the water compound mixture. This foam is used to extinguish major fires involving flammable and combustible liquids for which first 26 RESTRICTED aid appliances are inadequate and other extinguishing agent’s sources unsuitable. The composition of the Mechanical foam is:- (a) Water 12.5% which is supplied from firemain, with a minimum pressure 35 Psi. (b) AFFF compound 0.5%, which is supplied in 20 litres plastic drums. (c) Air 87%, drawn in the branch pipe to aerate the water compound mixture to produce foam. 27. The foam extinguishes fire by the following methods: (a) A thick foam blanket which shields the fuel from the heat and flame. (b) Smothering effect by cutting off air to the vapour. (c) Cools the surface of the liquid fuel, by water content of foam, thereby lowering the rate of vaporization. 28. Inline Inductor. Inline inductor (Fig 2.11) is fitted in the firemain system at helo-deck for high level foam sprinkling system. The foam is sucked from the tank by means of venturi effect created due to the firemain pressure. Also, in use at various places is the portable inline inductor which is similar to the foam making branch pipe 5(X). Fig 2.11 Inline Inductor 29. Centre Feed Hose Reel (CFHR). CFHR (Fig 2.12) is used for fighting medium fires. It is used in fixed installations for various premises and on submarines for firefighting where due to lack of space, there is difficulty in handling pressure hoses. It is equipment consisting of the rubber hose of 25 mm dia. on a reel, water inlet pipe, shut-off nozzle and stop valve with hose reel tubing. The hose reel unit has an option for by-pass of foam liquid and can be used for 27 RESTRICTED projecting water on the fire. It is used instead of foam making branch pipes and SO IV system. Fig 2.12 Centre Feed Hose Reel (CFHR) 30. Foam Making Branch Pipes. There are three types of foam making branch pipes used onboard ships namely, FB 5(X), FB 10 and FB 10 (X). Each branch pipe consists essentially of a head connected directly to the water supply, and a discharge tube. Water passes through the central passage in the head which is connected to an inductor which, by the venturi effect of the water flowing through it, draws AFFF compound from the drum through the pickup assembly. The water compound mixture draws air from the rear of the branch pipe due to its momentum to aerate the mixture. 31. Foam Making Branch Pipe 5(X). FB 5(X) (Fig 2.13) is a light weight branch pipe for general use against liquid fuel fires in ships, except in the hangers and flight decks. It produce about 2250 litres of foam per minute when water pressure is 80 psi while consuming 10-12 litres of AFFF compound, thus needing a back up supply of compound in spare container. This foam making branch pipe is also designed to introduce foam in machinery spaces through foam inlet tubes. Fig 2.13 Foam Making Branch Pipe 5(X) 28 RESTRICTED 32. Foam Making Branch Pipe 10. FB 10 (Fig. 2.14) is a large capacity light weight branch pipe which is similar in action to FB 5(X) except that the pickup assembly is screwed to the branch pipe. FB 10 produces about 4000 litres of foam consuming about 25 litres of AFFF compound. The equipment can be used in hangers and on flight decks. Fig 2.14 Foam Making Branch Pipe 10 33. Foam Making Branch Pipe 10 (X). FB 10(X) (Fig 2.15) is a high output branch pipe used only at helicopter landing position or on flight decks with separate sea water mains. Each of the hydrants in these positions incorporates an inline inductor. The pick assembly is attached to the inductor and has a shut-off cock. The inductor passes a mixture of compound and water through an ordinary hose to the FB 10(X) branch pipe which aerates the mixture. It produces about 4500 litres of foam while consuming 25 litres of AFFF compound per minute. Fig 2.15 Foam Making Branch Pipe 10 (X). 34. Contents of Fire and Repair Party Locker. A fixed number of firefighting equipment/gear is stored in fire and repair party lockers for immediate use. The fire and repair party lockers are situated in each section/fire and repair party post. The contents include Bristol Suits, Anti-Flash Hood, refills for foam/water type 29 RESTRICTED extinguishers, CO2 cartridges, Jet/Spray nozzles, adaptor male/ female, Mallet, wheel spanners, torches, flood light, head lamps and hoses of different sizes. Summary 35. CO2 extinguisher consists of a cylinder containing liquefied carbon dioxide at 850 psi at 16 deg C. In gaseous form is released when operated extinguishing fire by smothering. 36. Twin CO2 Trolley Ext. (6.5 Kg) is used for fighting fires in engine bays of aircraft. 37. The 9 ltr AFFF ext is used against A, B and E class of fires. 38. Foam extinguisher trolley mounted extinguishes A, B &E class of fires by smothering. 39. The DCP extinguisher contains sodium bicarbonate, potassium chloride, urea- potassium bicarbonate and mono-ammonium phosphate. 40. The DCP 5 kg has an internal CO2 cartridge of 180 grams under pressure, with 5 kgs of dry chemical powder and DCP 10 kg has an internal cartridge of 200 grams under pressure, with 10 kgs of dry chemical powder. 41. PD-150 is used to fight major fires on flight decks, helicopter/ aircraft landing platforms and for rescue operation from crashed aircrafts. 42. Halogenated extinguishing agents are chlorofluorocarbons, and contribute to the depletion of atmospheric ozone. 43. Jet/Spray nozzle is provided for weather deck hydrants. 44. Spray/ Jet nozzle is provided on all hydrants in ships except on weather decks. 45. Inline inductor is fitted in the firemain system at helo-deck for high level foam sprinkling system. 46. FB 5(X) is a light weight branch pipe for general use against liquid fuel fires in ships, except in the hangers and flight decks. 47. FB 10 produces about 4000 litres of foam at a hydrant pressure of 100 psi, and can be used in hangers and on flight decks. 48. FB 10(X) is a high output branch pipe used only at helicopter landing position or on flight decks with separate sea water mains 30 RESTRICTED CHAPTER 3 PERSONAL PROTECTION AND BREATHING APPARATUS ----------------------------------------------------------------------------------------------------------------------------- ------- OBJECTIVES: Trainee should be able to understand the fire fighting rig, personal protective clothing, thermal imaging camera and breathing apparatus for fire fighting and escape. ----------------------------------------------------------------------------------------------------------------------------- ------- 1. Introduction. Fire Fighting personnel need to be protected as far as possible, against the effect of heat, toxic gases (or lack of oxygen), loss of vision, loss of communication and physical damage. 2. Fire Protective Clothing. The fire-fighting party or team onboard ships and those involved in fire risk operations are to be dressed in full clothing, i.e. FR overalls. This is also known as the basic fire fighting rig and is mandatory for extinguishing or engaging fires till the fire fighters in full fire fighting rig do not arrive and take over the fire fighting operation. When wearing this rig woolen socks are to be worn, the sleeves rolled down and buttoned up and trouser bottom tucked in the socks. The Attack BA dons BASCCA set with the basic rig (Fig 3.1). Fig. 3.1 Basic Firefighting Rig with BASCCA set 3. Advantages of Wool over Cotton. Fabrics and materials of animal origin are less susceptible to ignition and flame propagation than are the cellulose compounds or most of synthetic fabric. With wool an igniting flame will scorch and char the area of wool it contacts and burning will not continue if the flame is removed. However with materials of cotton composition, a deepening, glowing area of burning will continue after the source of ignition has been removed. 31 RESTRICTED 4. Full Firefighting Rig. The protective clothing used by fire fighters for fighting fires is called Full Fire Fighting Rig and is to be worn over the basic fire fighting rig with anti- flash hood and gloves. Breathing apparatus is to be used along with it. The various fire protective suits used in service are: (a) Aluminised fire proximity suit. (b) Bristol suit 5. Aluminised Fire Proximity Suit (AFPS). AFPS (Fig 3.2) is an effective protective suit available to enter into close proximity of fire. The suit along with anti flash hood, boots and gloves (gauntlets) weighs only 6.5 Kg. The complete suit with breathing apparatus can be donned in 135 seconds with the assistance of a helper. The fabric used is made up of three layers. The outer Aluminised shining layer reflects main heat, the middle fibre glass layer is fire proof and gives strength to the fabric, the inner woolen layer may be black or blue in colour and absorbs any minor penetration of heat from middle layer. The air particles trapped in woolen layer further insulate any minor heat transfer to human body. 6. The suit is quite comfortable to wear and allows free movement. It is resistant to many chemicals, oils, petrol and acids. It can sustain occasional flame lick and gives protection in close proximity to radiant and ambient heat up to 1400 C. The wearer can go within 0.6 meter of fire and can stay there comfortably for 45 seconds to one minute. While fighting the fire, do not allow the suit to get wet with water, to avoid any vapor or steam formation inside Fig. 3.2 Aluminised Fire Proximity Suit 7. The one piece suit has a front brass zip and chromium plated steel stud covered with aluminised fabric overlap to avoid hot spots. Fire retardant (Kevlar) 32 RESTRICTED thread is used for stitching the whole garment. The one piece suit has got a built in back pouch to accommodate breathing apparatus inside and protect it from heat. The anti flash hood has a plastic fibre helmet inside and visor glass assembly. The gloves (gauntlets) are made of aluminized fabric into five fingers design and a securing strap is provided with chromium plated steel studs. The boots are made up of aluminised fabric, toe is fitted with Aluminium or any light metal toe piece to protect from any external injury. Bottom sole is made of reinforced neoprene rubber and is nonskid type to facilitate working in oil contained compartments. Boots are provided with side brass zip and securing strip with chromium plated steel studs. 8. New Fire Proximity Suit (FPS). The suit shall consist of a composite of an outer shell, moisture barrier and a thermal barrier. The composite shall be permitted to be configured as a single layer or multiple layers. The outer shell shall be of aluminized para-aramid blend rip stop knit fabric. Garment shall have a means of securing the moisture barrier and thermal barrier to the outer shell. Garments and their closure systems, including the coat front and trouser fly, shall be constructed in a manner that provides continuous moisture and thermal protection. The closure systems shall be secured with positive locking fasteners including, but not limited to, hooks, dees or zippers. The sewing thread utilised in the construction of garments and accessories shall be made of an inherently flame- resistant para-aramid fiber. 9. Design Requirements. The fire proximity suit shall include coat, trouser, boots, gloves, hood and helmet with shroud. The trousers shall have suspenders. Each coat sleeve shall have a protective wristlet or other interface component permanently attached to the coat sleeve thermal barrier/moisture barrier. The coats shall have a composite collar at least 75 mm in height at any point when measured from the top of the collar down. The three sizing requirements of the coat/trouser are as follows:- Ser Description Size – Large (in Size – Medium Size – Small Inches) (in Inches) (in Inches) (a) Chest 50 48 46 (b) Sleeve 36 35 34 (c) Waist 40 36 32 (d) Inseam 30 28 26 10. The protective helmet retention system shall include a chin strap (minimum width - 19 mm) and a nape device. The helmet face shield shall provide at least the field of vision. The helmet face shields shall be attached to the helmet. The helmet elements shall consist of at least the following assembled components: - (a) Shell (b) Energy Absorbing System (c) Retention System (d) Face shield (e) Shroud 33 RESTRICTED (f) Cover for radiant reflective protection (integrated with shroud) 11. The shroud shall be attached to the helmet and shall be designed to cover and provide continuous radiant reflective protection for the head, face and neck areas that do not receive primary protection from the helmet or face shield. 12. The glove shall extend from the tip of fingers to at least 150 mm from the wrist crease. Gloves are not permitted to have any hardware. The outer shell of the back and portions of the sides of the glove body including the back of the digits shall be of radiant reflective material. 13. The gloves are to be of the following dimensions:- Ser Description Size - Large Size - Medium Size - Small (a) Glove 82W 76W 70W 14. The footwear shall consist of the following assembled components: a sole with a heel, an upper with a lining, a puncture resistant device, an insole, a ladder shank or whole sole equivalent, and an impact and compression resistant toe cap. The footwear height shall be a minimum of 250 mm. 15. The footwear is to be of the following dimensions: - Ser Description Size - Large Size - Medium Size - Small (a) Footwear US Men’s 9.5 US Men’s 8.5 US Men’s 7.5 Width-E Width-E Width-E 16. The hood shall not be integrated with the protective coat. The hood shall be designed with a face opening to interface with a SCBA face piece. 17. Wristlets shall be designed to cover and provide limited protection to the wrist areas and shall be permanently attached to the protective coat sleeve thermal barrier/moisture barrier in a manner that will not permit a gap in the thermal protection. 18. Bristol Suit. The Bristol (Fig 3.3) fire resistant Coverall is made of a synthetic flame resistant fabric, the outer shell is of Nomex Delta T. It provides minimum resistance of movement, and can be very easily washed in an ordinary domestic washing machine. It can be washed over 150 times without affecting the inherent fire resistant and thermal resistant properties. The washing requirements are: - (a) Cold or warm, fresh or recovered water (b) Dip with reduced mechanical action. (c) Raise the temperature to 40 degree C. (d) Use non-ionic detergent. 34 RESTRICTED (e) Do not use any bleach. (f) Give 7-10 minutes, after mixing and temperature achieved. (g) For 1 minute drain. (h) For 1 minute give interspin. Fig. 3.3 Bristol Suit/ Suit for Fire Fighter 19. The leather gloves of Bristol suit are five fingered, manufactured from a microporous PTFE giving water protection and breathability. The wristlet design incorporates a thumb loop to ensure wrist protection of wearer when his arm is extended. The leather boots are 14 inches high and are of chrome leather, highly resistant to water and chemicals. 20. Thermal Imaging Camera (TIC). The TIC (Fig 3.4) is primarily used to locate the seat of fire through dense smoke in smoke filled compartments and for locating the trapped personnel in smoke filled compartment. It is also used as an effective preventive maintenance tool to locate hot-spots in electrical circuits, pipelines, routing shafts, windings etc. By just connecting the camera to a PC, the thermal pictures can be recorded on tape for viewing and engineering crew in a convenient location. It is used by the Team Leader of a firefighting team and may also be used by the members of the Attack Party. 21. The TIC is of two piece construction with a pistol grip for holding/ handling. It is provided with nylon straps for supporting the camera over the shoulders. It is fitted with a (germanium) lens objective in the front and rectangular viewfinder at the rear for viewing the monochrome CRT (Cathode Ray Tube) Unit. They should be stowed at each Fire and Repair Party Post (FRPP) and in NBCDQ. Ni-Cad rechargeable batteries (duration 45 minutes) are to be used for training purposes, and Duracell MN1500 batteries duration 90 minutes) are to be fitted before use in an emergency. 35 RESTRICTED Fig. 3.4 TIC 22. Technical Data of TIC. (a) Operating range : Up to 50 mtrs. 100% obscuration. (b) Weight : Approx. 3.5 kgs. (c) Body : Fire resist & light weight. (d) Visor : Neoprene (e) Detector : Pyro-electric Vidicon Battery: (f) Voltage : 6 Volts (g) Type : Sealed lead acid (h) Charging voltage : 14.4 to 15 V (for two batteries in series). (j) Charging time : 12 to 15 hrs. (k) Operation time : 2 hrs (when batteries are charged fully). 23. Operation of TIC. To power camera from the battery bring the 2 position toggle switch to “Bat Power” position. To charge battery, operate the switch to “Bat Charge” position after connecting the cable to the 4 pin connector fitted to the control panel. The operating instructions of the camera are: (a) To energize the camera, connect the cable of the camera to the 4-pin connector provided in the battery belt. (b) Put the power On/Off switch in the battery belt to “On Main” position depending on the power source selected. A green L.E.D will glow indicating camera power is on. (c) At ‘ON’, camera enters the poling mode automatically which is indicated by a circular pattern appearing on CRT screen and a yellow light adjacent to CRT glows. (d) After 35 seconds, yellow light stops glowing indicating end of poling sequence. (e) On completion of poling, screen gradually clears and camera is ready for use. (f) The camera is only sensitive to changes of temperature. Hence, the camera must be ‘Panned manually or the image must be chopped by 36 RESTRICTED switching to the chop when viewing stationary objects. The chop’s mode is convenient. The ‘pan’ mode gives better resolution. 24. Some of the ‘Don’ts’ to be kept in mind while handling the camera are: - (a) Do not point the camera towards hot objects/flame for long duration’s. (b) Do not keep the camera on hot surface. (c) Do not dip the camera into water. (d) Do not touch the lens (objective/view finder) with bare hand. (e) Do not use fuses of higher ratings. (f) Do not allow oil splashing etc, on to the camera. (g) Do not mix cells of different makes as their current & voltage ratings are not identical. (h) Do not over tighten the knobs for detachable pistol grip. (j) Do not overcharge the rechargeable batteries/cells. 15. The following points must be remembered for good care of the camera: - (a) Clean the camera and lenses using Muslin cloth after each operation/use. (b) Recharge the rechargeable lead acid batteries after each use. (c) Store the camera in the storage case & keep in safe place. (d) Replace the defective/leaking batteries/cells immediately. (e) Check the condition of batteries daily. (f) Operate the camera at least once a week. (g) Put the batteries into the container in tight way. Breathing Apparatus 16. Respirators are used to allow personnel to safely breathe without inhaling toxic gases or particles. Two basic types are, air-purifying which filter dangerous substances form the air; and air-supplying which deliver a supply of safe breathing air from a tank or an uncontaminated area nearby. 17. The various breathing apparatus used in the service are: - (a) Breathing Apparatus Self Contained Compressed Air (BASCCA) (b) Emergency Life Support Apparatus (ELSA) 18. Breathing Apparatus Self Contained Compressed Air (BASCCA) Set. The BASCCA set (Fig 3.5) is used for fire-fighting operations. It has a face mask assembly (Fig 3.6) fitted with an ori-nasal mask, exhalation valve and demand valve assemblies. The demand valve is designed to permit use of the apparatus as a positive pressure set for normal operations, ensuring that any leak in the face seal would be outwards. The frame comprises of back plate with harness (Fig 3.7) attachments and cylinder cradle with a free air cylinder. The warning whistle provided is set to sound when the duration of the remaining air supply reaches 7 37 RESTRICTED Min or 43 bar or 10 minutes 50 bar. This is indicated on the pressure gauge by the red coloured segment covering the reserve period of 43 bar/50 bar to zero i.e. 7/10 minutes duration respectively. Fig. 3.5 BASCCA Set 19. When being worn, the wearer must try to control his breathing so that it is rhythmic and steady. Fast breathing or leakage will greatly reduce the endurance, since actual duration of the set will depend on the individual and the nature of the activity under taken. The face mask harness straps should be hand tightened only to avoid damage to the delicate ‘O’ rings. Extension hose used is of 2 metres length. Fig. 3.6 Face Mask Assembly 38 RESTRICTED Fig. 3.7 Back Plate And Harness 20. Technical data of 200 Bar BASCCA Set. (a) Weight fully charged : 14.6 Kg (32 pounds) (b) Dimensions of complete set- length : 660 mm (26”) (c) Breadth : 325 mm (12.75”) (d) Depth : 165 mm (6.5”) (e) Max. Working pressure : 2900 psi or 200 Bar (f) Cylinder water capacity : 06 Litres (g) Nominal free air capacity : 1200 Litres (h) Maximum endurance at hard work : 25 to 30 minutes 21. Technical Data of 300 Bar BASCCA with Carbon Composite Cylinders. (a) Water volume : 6.807 Ltrs (b) Cylinder capacity : 1800 Ltr free air or above (c) Endurance of the set : 45 mins at a demand of 40 Ltrs/Min (d) Cylinder test Pressure : 450 bar minimum (e) Cylinder weight : less than 05 Kgs (f) Cylinder filling pressure : 300 bar & above (g) Dimensions overall Height : below 675 mm (h) Dimensions overall Dia : below 175 mm (j) Weight of full set : Less than 12 Kg. 22. The main components of BASCCA are: - (a) High Pressure Cylinder with cylinder Valve. (b) Reducer. 39 RESTRICTED (c) Lung Governed Demand Valve. (d) Gauge with Whistle Warning. (e) High pressure and low pressure hoses. (f) Back frame assembly with waist belt & shoulder strap. (g) Connecting hose. (h) Connecting Tubes. (j) Full Vision Face Mask. 23. Donning Procedure of BASCCA Set. (a) Remove the face mask from its stowage clip and face the neck strap over the head so as to allow the face mask to hang on the chest. The neck strap must always be outside the operator’s clothing and not in contact with the skin. (b) Release the apparatus securing bands and pass the right arm through the right shoulder strap. Lift the apparatus clear of the locker and pass the left arm through the left shoulder strap. (c) Adjust the shoulder strap by pulling backwards towards the cylinder, and then fasten the waist belt and chest strap. Don’t over tighten the shoulder strap. (d) The BA controller must check that the operator can reach the air cylinder valve. (e) Select negative pressure mode using change-over knob on the demand valve. (f) Open the cylinder valve carefully. The warning whistle should sound briefly. If the whistle is not heard shut the valve. (g) Select positive pressure mode and reduce the pressure in the HP air hose to 43 bar if the whistle still does not operate it is defective and this fact must be reported to the BA controller. Until the warning whistle is made operational the set should not be used except in emergency and only in conditions where the operator can observe and read the pressure gauge. (h) Gain select negative pressure mode and then open the cylinder valve. Should the air leak from the demand valve the apparatus is faulty and must not be used. The BA controller is to be informed. (j) The BA controller retains the control board and records the set number and the operator’s name on the control board. 24. Face Seal checks. The face mask sealing check is to be carried out whenever an operator dons the facemask for operation. When wearing the facemask the operator can select the negative pressure by pulling out the change over knob and rotating it clockwise till it engages. Positive pressure mode is 40 RESTRICTED engaged by turning the change over knob in the opposite direction and let it engage in position. The following checks are to be carried out: - (a) Don facemask, select positive pressure mode and then commence to breathe from apparatus. Ensure that head harness is centered at the top/ back of head by first adjusting the 2 lower straps simultaneously and then upper two straps (b) Breathe deeply to ensure, the demand and exhalation valves are working. (c) Observe pressure gauge. Take a breath and hold breath, shut cylinder valve. Check pressure gauge reading does not fall by more than 5 bar in 10 seconds. Open the cylinder valve. (d) Check bulb horn works. It is to be used only for signaling the emergency. 25. The following safety equipment should be used with Breathing Apparatus: - (a) Record tally or control board, with the following information: - (i) Identification particulars of BA (ii) Name of wearer. (iii) Pressure in set. (iv) Time commenced breathing from set. (v) Time operator should commence returning. (vi) Entry instructions, exit instruction, endurance table and time remaining after warning whistle. (b) Distress signal horn or device. (c) Life line of 37 metres. (d) Personnel line of 0.9 metres, nylon rope with snap hook. (e) Arm band. 26. After use, the following routines must be carried out: - (a) Thoroughly wash apparatus in fresh water to remove dirt, smoke deposits etc, and dry completely. Care be taken to prevent water entering into breathing tubes. (b) Disinfect the face mask and mouth piece with hospital Savlon solution applied with a moist rag for removal of dirt and blood stains, if any. (c) Rinse with clean water; thoroughly dry the mask mouthpiece, duct rubber parts and non-return valves making sure that they are not defective. (d) Lubricate the shoulder hook pivot with approved grease. Check that the locking pin is free from grease. (e) Lubricate the control valve spindle and parts of the equalizing lever with approved pattern grease. (f) If the apparatus has been underwater, strip the demand valve and lightly lubricate the metal parts. (g) Check the security of the cylinder bands and examine the cylinder for scores and abrasions. The critical depths of scratches are 0.8 mm. (h) Charge cylinders to full pressure. (j) Apply anti-dim solution to the visor. 41 RESTRICTED 27. BA Controller. When BASCCA are used operationally, a BA Controller must be detailed. The BA Controller must be well trained in the use of the apparatus, and must understand the vital part he plays in the safety arrangements for firefighters. He must always be equipped with a reliable watch/ clock and a Chinagraph pencil. The BA Controller must remain outside the smoke boundary, adjacent to the I/C Main Group, at the point of entry. The BA Controller may act as Controller for up to ten BA wearers, but must never be detailed for any other duties. Permission of Oi/C Main Group is required is BASCCA set charged upto less than 180 bar is to be used for firefighting purposes. BA Control Boards (Table 3.1) are stored in selected BASCCA lockers. 28. Duties of BA Controller. (a) Assist wearer to don and adjust BA and carry out functional and face seal checks. (b) Mark up the BA control board. (c) When used for search and rescue, ensure that the tail of the guide line is secured to an anchorage point at the incident entry point. (d) Keep a sharp listening watch for any signals from distress alarms. (e) Ensure that the I/C Main Group is kept informed of the time that a relief team should be committed to relieve the previous team. The warning whistle of the set blows at 43 bar with 7 minutes of breathing time remaining. (f) Inform the Officer-in-Charge of firefighting if a BA wearer has not emerged by the TIME DUE OUT. (g) Replace the ‘set number’ tally back on the set when the wearer has completed the task. Table 3.1 BA Control Board A B C D E F G Set Operator's Task Cylinder Time to Time Time Time Return Time No. Name Pressure Whistle Started to Relief Commences Due (Bar) (Min) Breath due in (Min.) Out (Min) (Min) (Min) 29. Emergency Life Supporting Apparatus (ELSA/ BASCCA (EE)). ELSA (Fig 3.8) is a short duration compressed air set, used for escape from or through smoke-logged compartments or for entering a gas free location/ compartment in which isolated pockets of toxic gases may possibly be encountered. The set should not be used to enter areas already containing an irreparable atmosphere (except of course during the process of escape), nor for uses generally associated with long duration apparatus, such as fire fighting or rescue work. The carrying case contains a small compressed air bottle with a pressure gauge and a control valve, a supply hose, and a plastic hood with an elasticated neck. A harness is fitted, for 42 RESTRICTED securing the equipment to the wearer. Each ship should carry an allowance of 150 per cent. The cylinder is pressure tested to 301 bar once in 5 years. 30. Technical Data of ELSA. (a) Max. Working pressure : 200 bar (2900 pi) (b) Cylinder capacity by water : 01 litre (c) Max free air capacity : 200 litres (d) Reducer pressure : 5.5 Bar (80 psi) (e) Maximum endurance : 08 minutes (f) Weight : 3 Kgs Fig. 3.8 ELSA 31. Operation of ELSA. The set is compressed air breathing apparatus with semi-closed circuit consisting of an alloy steel cylinder containing 200 litres of air when charged to 200 bar (2900 psi) carried in carrying bag. A pressure gauge is calibrated in bar is fitted to the reducing valve and gives a constant indication of the cylinder contents. The equipment is operated by means of an ON/OFF hand wheel allowing HP air to pass from the cylinder to pressure reducing valve, where it is reduced in pressure to approx. 5.5 bar (80 psi). The air then passes through a flow control orifice and then via a flexible supply hose to the air hood. 32. Procedure for using ELSA. (a) Remove the ELSA from the stowage. (b) Place the carrying strap around the neck, with the carrying case on the chest. (c) Secure the carrying case to the body, using the harness. (d) Open the control valve until the valve wheel spins free. (e) Place the hood over the head, so that the elasticated neck is secured around the wearer’s neck. (f) Ensure that the supply hose is to the front and clean air is being delivered to the wearer (the hood will inflate). (g) Vacate the compartment. 43 RESTRICTED 33. The hood does not have an exhaust port, so the level of carbon dioxide inside it will build up as the wearer breathes out. This may cause the wearer to feel breathless or dizzy. If this happens, the wearer should: - (a) Place fingers under the elasticated neck and pull it away from his neck. (b) Collapse the hood around his head to force out the carbon dioxide. (c) Release the elasticated neck, allowing the hood to re-inflate with clean air. 34. Before entering work area, carry out the following checks: - (a) check cylinder contents gauge should read full pressure i.e. 200 bar. (b) Check that the air hood is properly attached to the supply hose. (c) Check that supply hose is properly attached to cylinder. (d) Lift flap and remove air hood. (e) Open ON/OFF valve by one turn only. (f) Pull the hood over the head and proceed to safer zone. 35. Maintenance Routines on ELSA. (a) The pressure gauge should be checked at least once a week to ensure that the cylinder is full and ready for use. (b) The apparatus should be operated every six months to ensure that it functions properly. (c) Cylinder should be proof tested after every 05 years interval. (d) Defective or demand parts like hood, neoprene tube and pressure gauge sound be changed immediately on detection. 36. Lifeline. The lifeline is 37 metres (120 feet) long and is coiled inside a canvas pouch attached to the breathing apparatus harness waist belt. The standing end of the line is knotted inside the pouch and the running end terminated in a soft eye. When a lifeline is ordered to be used the soft eye is secured over the control numbers wrist so that the line pays out as the operator proceeds to his task. 37. Personnel Line. The personal line is 910 mm (3 feet) long fitted with a spliced eye for securing to the waist belt one end and a snap hook at the other. One side of the snap hook is marked with grooves and whenever the personal line is clipped to a guide line the grooved side of the hook must always be towards the way out of the compartment. 38. Guide line. The guide line is rigged from the gangway to the scene of fire to assist the external fire fighters to reach the scene of fire. The maximum length of guide line should be 1.5 times the length of the ship and it is laid by sideboy or quarter master. 39. When two or more operators are using the same point of entry, the leading hand only should lay his lifeline and operators following him should make their way 44 RESTRICTED by clipping their personal line to it. When returning, the operator should use his lifeline to find his way out of the compartment if re-entry is required. The lifeline should be coiled in the operators hand as he returns if re-entry is not required. The operator should detach the pouch from waist belt and secure it to some suitable structure in the vicinity of the task. He should then find his way out by clipping his personal line to the guide line. Summary 1. The fire fighting party or team onboard ships and those involved in fire risk operations are to be dressed in full cotton clothing (basic FF rig), i.e. FR overalls. 2. Basic Firefighting rig is also known as the basic fire fighting rig and is mandatory for extinguishing or engaging fires till the fire fighters in full fire fighting rig do not arrive and take over the fire fighting operation. 3. AFPS is an effective protective suit available to enter into close proximity of fire. It can sustain occasional flame lick and gives protection in close proximity to radiant and ambient heat upto 1400 C for duration of 45 sec to 60 sec at a distance of.6 mtr. 4. The Bristol fire resistant Coverall is made of a synthetic flame resistant fabric, the outer shell is of Nomex Delta T. 5. The TIC is primarily used to locate the seat of fire through dense smoke in smoke filled compartments and for locating the trapped personnel in smoke filled compartment. 6. Smoke mask is used to enter smoke filled compartments and unventilated confined spaces. 7. The TIC is primarily used to locate the seat of fire through dense smoke in smoke filled compartments and for locating the trapped personnel in smoke filled compartment. 8. The face mask sealing check for BASCCA set is to be carried out whenever an operator dons the facemask for operation. 9. When BASCCA are used operationally, a BA Controller must be detailed. The BA Controller must be well trained in the use of the apparatus, and must understand the vital part he plays in the safety arrangements for firefighters. 10. ELSA is a short duration compressed air set, used for escape from or through smoke-logged compartments or for entering a gas free location/ compartment in which isolated pockets of toxic gases may possibly be encountered. 11. The guideline is 37 metres (120 feet) long and is coiled inside a canvas pouch attached to the breathing apparatus harness waist belt. 12. The personal line is 910 mm (3 feet) long fitted with a spliced eye for securing to the waist belt one end and a snap hook at the other. 45 RESTRICTED CHAPTER 4 THE FIREMAIN AND ASSOCIATED FIRE FIGHTING EQUIPMENT ------------------------------------------------------------------------------------------------------------------------------------ OBJECTIVES: Trainee should be able to understand the components, operation and use of firemain system onboard ship. He should be able to understand the utility of associated equipment used with firemain system. ----------------------------------------------------------------------------------------------------------------------------- ------- 1. Introduction. The firemain system in addition to fire fighting, and spraying of magazines /inflammable stores, also supplies sea water to many essential services such as: - (a) Domestic and sanitary services. (b) Ballasting and de-ballasting of water compensated fuel tanks and other compartments for stability purpose. (c) Eductors for salvage and general drainage. (d) Pre-wetting to minimize contamination by NBC agents. (e) For hangar spraying systems in aircraft carriers. (f) Fire fighting on flight deck in aircraft carriers (g) For emergency cooling of certain machinery/electrical equipment. 2. Firemain System. The Firemain System is a single line or cross connected double lines of piping, running fore and aft with extension and branches as necessary to carry sea water under pressure to all parts of the ship. It is identified either by bands of red tape on the pipeline or by bright red paint of the pipeline. The firemain is fed by electrically driven fire pumps of 75 to 150 tons/hr capacity, with number varying with size of the ship. They are designed to maintain 6 to 8 bars (80-100 psi) pressure in the system. However, damage (or other causes) may cause the system pressure to drop below this and hence most appliances are designed to operate up to a pressure of 2.4 bar. These pumps are known as 'Fire and Bilge pumps' or 'Hull and Fire pumps'. They normally take suction from sea through a strainer and discharge the sea water to the various services, although one or more of these pumps can also take suction from machinery compartment bilges or sea water discharge side of condensers of various machineries. 3. General Arrangement of Firemain System. The fire pumps discharge through vertical pipes called rising mains, leading to firemain. Pressure gauges are fitted in the firemain system at each connectio