Basic Training for Oil and Chemical Tankers Cargo Operation Course Handout

1. Introduction This course syllabus is prepared to meet mandatory minimum competence in basic training for sea going personnel with specific tasks, duties and responsibilities related to cargo and cargo equipment on oil and chemical tankers as per STCW Code A-V/1-1.This tanker familiarization course comprises three main parts. These are the basic understanding of the characteristics of oils; personnel safety and pollution prevention; and general shipboard cargo-handling system.The first part covers the proprieties and associated hazards related to the cargoes. The second part covers the means and measures to control the hazards and to prevent pollution, for the protection of personnel and the environment.The third part provides a general overview of cargo-handling equipment and operations on board tankers.

This basic training is for oil and chemical tanker is approved by Flag Administration for officers and ratings assigned on specific duties and responsibilities related to cargo or cargo equipment on oil and chemical tankers;This course covers the requirements for level 1 training required by STCW Convention, as amended, including 2010 Manila amendments, Regulation V/1-1 Paragraph 2.

2. THE OIL TANKER2.1Design and Development of Oil TankerAnoil tanker, also known as apetroleum tanker, is amerchant shipdesigned for the bulk transport ofoil. There are two basic types of oil tankers: thecrude tankerand theproduct tanker.Crude tankers move large quantities of unrefinedcrude oilfrom its point of extraction to refineries.Product tankers, generally much smaller, are designed to movepetrochemicalsfrom refineries to points near consuming markets.Oil tankers are often classified by their size as well as their occupation. The size classes range from inland or coastal tankers of a few thousand metric tons ofdeadweight(DWT) to the mammothultra large crude carriers(ULCCs) of 550,000DWT.

Tankers move approximately 2,000,000,000 metric tons (2200,000,000short tons) of oil every year. Second only to pipelines in terms of efficiency, the average cost of oil transport by tanker amounts to only two or three United States cents per 1USgallon. Tankers have grown significantly in size since World War II. While a typical T2 tanker of the World War II era was 162m long and had a capacity of 16,500DWT, the ultra-large crude carriers (ULCC) built in the 1970s were over 400m long and had a capacity of 500,000DWT.Several factors encouraged this growth. Hostilities in theMiddle Eastwhich interrupted traffic through the Suez Canal contributed, as did nationalization of Middle Eastoil refineries.Fierce competition among ship owners also played a part.But apart from these considerations is a simple economic advantage: the larger an oil tanker is, the more cheaply it can move crude oil, and the better it can help meet growing demands for oil.

With the exception of the pipeline, the tanker is the most cost-effective way to move oil today.Worldwide, tankers carry some 2 billion barrels annually, and the cost of transportation by tanker amounts approximately to only US$0.02 per gallon at the pump. The cargo tank area is separated from the vessels after section by a Cofferdam cargo pump room oil fuel bunker or permanent ballast tanks Machinery spaces, accommodation ,cargo control room must be in position aft of the cargo tanks slop tanks cargo pump room and cofferdams.Means shall be provided to keep any deck spills away from the accommodation and service housing. This is in the form of a permanent coaming extending the breadth of the vessel.

Exterior boundaries of deckhouses enclosing accommodation are insulated for the portion facing the cargo tank area and for a distance of three meters aft. Entrance air inlets and openings to accommodation spaces shall not face the cargo area.Windows and ports facing the cargo deck area and for three meters aft of the front boundary are of the non- opening type.The accommodation air conditioning must be of the recirculating type so as to prevent gases entering the accommodation from the outside. At this point it should be mentioned that loading ports will stop berthing if the air conditioning plant is out of commission.At a terminal hazardous areas are graded in to hazardous zones depending on the probability of the presence of a flammable gas mixture. The zones are graded accordingly

ZONE 0 An area in which a flammable gas mixture is continuously present or is present for long periods.ZONE 1 An area in which there is likely to be a flammable gas mixture Under normal operating conditionsZONE 2 An area in which the presence of flammable mixture is un Likely but if such a mixture is present it is likely to persist for only a short period.When a tanker is at berth it is possible that an area which is regarded as safe may fall in to one of the hazardous zones of the terminal.

2.2Types of oil tankers in current serviceOil tankers:Crude Oil tankers:Product tankers:Combination carriers:While no standardized system for the classification of oil tankers exists; the fleet is typically divided into four major categories based on carrying capacity. These categories are ULCCs and VLCCs, Suezmax, Aframax, and Panamax and Handysize tankers. To benefit from economies of scale charterers typically charter the largest possible vessel that can be accommodated in a particular voyages arrival and discharge ports.

Single hull and double hull oil tankersSingle hull tankers are more likely than double hull vessels to rupture and break up, spilling oil into the sea.Adouble hullis ashiphulldesign and construction method invented by Leonardo da Vinci where the bottom and sides of the ship have two complete layers of watertight hull surface: one outer layer forming the normal hull of the ship, and a second inner hull which is some distance inboard, typically by a few feet, which forms a redundant barrier to seawater in case the outer hull is damaged and leaks.The space between the two hulls is often used for storage of fuel or ballast water.

Double hulls are a more extensive safety measure thandouble bottoms, which have two hull layers only in the bottom of the ship but not the sides.Double hulls' ability to prevent or reduce oil spills led to their being standardized for other types of ships includingoil tankersby theInternational Convention for the Prevention of Pollution from Shipsor MARPOL Convention.A double hull does not protect against major, high-energy collisions or groundings which cause the majority of oil pollution.

2.3 Types of cargo shipped in oil tankersOil means petroleum in any form, including crude oil, fuel oil, sludge, oil refuse and refined products (Other than petrochemicals).List of oils:

List of oils:Asphalt solutionsGasolineblending stocksBlending stocksAlkylates fuelRoofers fluxReformatesStraight run residue Polymer fuel

Oils GasolinesClarified Casinghead (natural)Crude oil AutomotiveMixtures containing crude oil AviationDiesel oil Straight runFuel oil no. 4 Fuel oil no. 1(kerosene)Fuel oil no. 5 Fuel oil no. 1-DFuel oil no. 6 Fuel oil no. 2Residual fuel oil Fuel oil no. 2-DRoad oil

Transformer oilJet fuelsAromatic oil (excluding vegetable oil) JP-1 (kerosene)Lubricating oils and blending stocks JP-3Mineral oil JP-4Motor oil JP-5 (kerosene, heavy)Penetrating oilTurbo fuelSpindle oilKeroseneTurbine oilMineral spiritDistillatesNaphthaStraight runSolventFlashed feed stocksPetroleumHeartcut distillate oil

Gas oilCrackedCrude petroleum as discharged at the well head is a mixture of a large number of different hydrocarbon molecules.Hydrocarbons is the common name for substances composed of only the elements hydrogen and carbonThe composition of petroleum depends on its sourceThe petroleum remaining after the removal of products such as methane is termed crude oil

3. BASIC SCIENCE CONCEPTS3.1 GENERAL INTRODUCTIONAll matter, solid, liquid or gas is made up of particles. Physics is concerned with the mass of these particles and how they behave when the pressure and temperature are changed. This is the subject of the first section in these notes. In contrast, these particles known as atoms and molecules can react with each other to form new compounds. These are chemical reactions and involve chemical bonding which will be discussed in the second section.

3.2 SOLIDS, LIQUIDS, GASES and CHANGES OF STATEAll matter exists in one of three forms solid, liquid or gas. In this section the essential properties of these states will be discussed together with the energy changes which occur when a solid melts or liquid evaporates (A CHANGE OF STATE). 3.2.1SolidsAt about 273C, all substances are solid and the particles are rigidly held in place by a balance between attractive forces and repulsive forces. This temperature is known as ABSOLUTE ZERO and the particles are considered to have no energy.

For this reason, heat is a form of energy that can transfer matter from one state to another. When heat is applied on the solid state of a matter, it changes it to liquid state. 3.2.2LiquidsIn a liquid, the particles are not free to move anywhere. There are still attractive and repulsive forces between them and the movement of the particles is restricted. Thus a liquid: will take shape of the vessel that contains it. will flow under the influence of a force (liquids can be poured and pumped).LIQUIDS HAVE A DEFINITE VOLUME BUT NO FIXED SHAPE

As further heat is applied, the particles gain more energy and move faster. The temperature will increase and the liquid will expand. If a particle on the surface has enough energy, it will be able to overcome the attraction of the other particles and escape in to the vapour phase. This is known as EVAPORATION.3.2.3Gases In a gas, the particles are too far apart to have any substantial attraction or repulsion between the particles. Therefore they are free to move and to fill the whole of the space available to them. GASES HAVE NO FIXED SHAPE OR VOLUME

3.3 SOURCES OF HYDROCARBONS Crude OilCrud Oil is a mixture of hydrocarbons formed from the remains of marine plants and other living organisms that lived millions of years ago. Refining Crude OilRefining of crude oil is done in a refinery by the process of distillation which produces gases, petrol, Kerosene, Diesel oil, gas oil, lubricating oil, Fuel oil, Paraffin waxes and Bitumen. These are produced by the distillation of crude oil at different level.

Eg. FRACTION APRROX%IN CRUDE OIL%DEMAND

3.4Chemical Reactions There are different types of chemical reactions, but we will only deal with combustion.3.4.1 COMBUSTION ( OXIDATION)Combustion is a chemical reaction that sustains a flame a flame is gaseous matter raised to incandescence.The requirements for combustion to take place are FUEL, OXYGEN AND SOURCE OF IGNITION (HEAT).fireOxygen Flame Heat

For ignition to occur the proportion of fuel vapour to oxygen or to air must be within the flammable limits.

Flammable range (Explosive Limits) The range of composition by volume % of flammable gas/vapor in a mixture with air which will explode when ignited. If the % volume of flammable gas is below the lower flammable (Explosive) Limit (LFL or LEL), the composition is too lean for sustained combustion; above the UFL (UEL) mixtures are too rich with respect to the fuel, i.e. there is insufficient oxygen to sustain combustion. Depending on the circumstances, a lean mixture may become enriched with flammable gas, or an over-rich mixture become diluted with air, until in either case the composition comes within the flammable range. Sources of oxygen must be excluded from potentially hazardous areas.Spillages of flammable liquefied gases on land or water create vapour clouds which present a fire hazard for some distance around, and particularly downwind. Close to the spill there will be an over-rich cloud (above the UFL) but further away there is a region within which is a mixture in the flammable range.

Flash Point Is the lowest temperature at which a liquid evolves enough vapour to form a flammable mixture with air.Auto-ignition Temperature - is the minimum T at which a flammable vapour-air mixture can ignite spontaneously; risk may arise if vapour escape near a hot surface.Flammability Suppression by Inert Gas is essential when a tank which has flammable liquid cargo, or previously contained a flammable liquid.EXPLOSIONSThere are two basic reasons for the occurrence of an explosion

(i) Thermal explosion During the process of combustion heat energy is liberatedIf the rate at which the heat is liberated is greater than the rate at which the heat is dissipated to the surroundings the temperature rises. The temperature rise increases the rate of reactionThe increased rate of reaction liberates more heat. Eventually the entire mixture reacts in a very short time As the solid or liquid changes suddenly into a gas there is a huge expansion and the volume change can cause structural damage. As the particles are accelerate past the sound barrier, a sonic boom may occur (a bang!).

(ii) Chain reaction explosion Chain reactions involve initiation formation of free radicals- propagation-reactions that regenerate free radicals termination-reacts that cause free radicals to disappear. These are called BRANCHING reactions, and because these increase the number of free radicals the reaction proceeds faster. So that in a very short period of time all the gas can react at the same time. The gases produces by combustion are heated by the reaction. In open spaces the expansion of the gas is unrestricted and combustion may proceed with undue pressure increase developing. If the expansion of hot gas is restricted pressures will rise and flame speeds increase. High pressures stop the chain carrier reaching the walls of the container where they can combine and give up their excess energy. Therefore increased pressure can cause a chain reaction explosion. Also in confined areas, eg. A ships tank, where expanding gases cannot escape, the internal pressure increase may be sufficient to burst the containment

Controlled Tank AtmosphereThe Fire TriangleIn order to understand how fire extinguishers work, it is important to know a little bit about fire.Four things must be present at the same time in order to produce fire:Enoughoxygento sustain combustion,Enoughheatto raise the material to its ignition temperature,Some sort of fuel or combustible material, andThe chemical, exothermicreactionthat is fire.

Take a look at the following diagram, called the "Fire Triangle"

Oxygen, heat, and fuel are frequently referred to as the "fire triangle." Add in the fourth element, the chemical reaction, and you actually have a fire "tetrahedron." The important thing to remember is: take any of these four things away, and you will not have a fire or the fire will be extinguished.Essentially, fire extinguishers put out fire by taking away one or more elements of the fire triangle/tetrahedron.Fire safety, at its most basic, is based upon the principle of keeping fuel sources and ignition sources separate

3.4.2 Variables in tank: Volatility, Ambient temperature, amount of residual cargo, distribution of gases & inert gasAll cargoes can be handled safely by showing the greatest care throughout operation and by following standing instructions at all times:All tankers and gas carriers are designed so that, in normal operation, personnel should never be exposed to the hazards posed by the products being carried. This assumes, of course, that the ship and its equipment are maintained properly and that operating instructions are followed.In the event of accidental leakage, emergency inspections or maintenance tasks, personnel may be exposed to liquid or gaseous product.Many of the fatalities in enclosed spaces on oil tankers have resulted from entering the space without proper supervision or adherence to agreed procedures. In almost every case the fatality would have been avoided if the simple guidance had been followed. The rapid rescue of personnel who have collapsed in enclosed space presents particular risk. It is human reaction to go to the aid of a colleague in difficulties, but far too many additional and unnecessary deaths have occurred from impulsive and ill-prepared rescue attempts.

Precautions taken to avoid health hazards, such as:Strict control of entry into pump-room, cargo spaces and other enclosed spacesProper procedures to be followed before entry into enclosed spaces, including thorough ventilation of the spacesuse of adequate protective clothingThorough cleansing of personal clothing after contact with cargoContinuous monitoring of the atmosphere in working spaces for petroleum vapor and toxic gases

Because of the danger of hazardous atmospheres, an enclosed space should only be entered when it is to do so. At such times a permit to work should be issued and this should be specific as to date, time and space concerned and list the precautions to be taken. Alternatively, for ship tank entry purpose the Maritime Safety Card should be completed. (See IMOs International Maritime Dangerous Goods Code). The Maritime Safety Card consists of General Precautions, Warning and Safety Check List.Operational requirements concerning cargo information are available in the Ch. 16.2 of the IBC Code and in the Ch. 18.1 of the IGC Code.There are strict procedures for ventilation and gas-freeing to ensure that fire and health hazards are minimized. The mechanical ventilation arrangements in the pump-rooms have a capacity to ensure sufficient air movement through the space (IBC Code Ch. 12.2):

Mechanical ventilation inlets and outlets should be arranged to ensure sufficient movement through the space to avoid the accumulation of toxic or flammable vapors or both and to ensure sufficient oxygen to provide a safe working environment, but in no case should the ventilation system have a capacity of less than 20 changes of air per hour, based upon the total volume of the space.The construction of the cargo-tank ventilation system reduces the risk of cargo vapor in gas-safe areas, for example vapor from cargo tank is led by ventilation line to the cargo ventilation tower Ventilation exhaust ducts from gas-dangerous spaces should discharge upwards in locations at least 10 meters in horizontal direction from ventilation intakes and opening to accommodation spaces and other gas-free spaces. gas-freeing as the replacement of cargo vapors, inert gas or any other gases with air.

This is the removal of toxic, flammable and inert gas from a tank or enclosed space followed by the introduction of fresh air. Ventilating to a too-lean atmosphere as gas-freeing.The level to which the hydrocarbon vapor must be reduced varies according to the product. In general it is necessary to reduce the hydrocarbon content in the inert atmosphere to about 2 per cent (vol.) before air blowing can begin. Before personnel enter any tank, the atmosphere must be checked for oxygen content, hydrocarbon content and, after carrying some cargoes, toxic gas content.A cargo tank is gas-free only when oxygen content is 21% by volume and no vapors from cargo or toxic constituents of inert gas can be measured in values above the threshold limit value (TLV) which explains that to avoid fire, reactivity and corrosion hazards, certain precautions are taken.

3.4.3Flash point & auto ignition temperatureTheflash pointof avolatilematerial is the lowesttemperatureat which it can vaporize to form an ignitable mixture inair. Measuring a flash point requires an ignition source. At the flash point, the vapor may cease to burn when the source of ignition is removed.The flash point is not to be confused with theauto-ignition temperature, which does not require an ignition source, or thefire point, the temperature at which the vapor continues to burn after being ignited. Neither the flash point nor the fire point is dependent on the temperature of the ignition source, which is much higher.

The flash point is often used as a descriptive characteristic of liquidfuel, and it is also used to help characterize the fire hazards of liquids. Flash point refers to bothflammableliquids andcombustible liquids. There are various standards for defining each term. Liquids with a flash point less than60.5 C(140.9F)or37.8 C(100.0F)depending upon the standard being appliedare considered flammable, while liquids with a flash point above those temperatures are considered combustible.Gasoline(petrol) is a fuel for use in aspark-ignition engine. The fuel is mixed with air within its flammable limits and heated above its flash point, then ignited by thespark plug. In order to avoidpre-ignitionby dint of the hot combustion chamber, the fuel must have a low flash point and a highauto-ignition temperature.

Diesel fuelflash points vary between 52 and 96 C (126and 205F). Diesel is suitable for use in acompression-ignition engine. Air iscompresseduntil it has been heated above theauto-ignition temperatureof fuel, which is then injected as a high-pressure spray, keeping the fuel-air mix within flammable limits. There is no ignition source. The fuel is, therefore, required to have a high flash point and a low auto-ignition temperature.Jet fuelflash points also vary greatly. Both Jet A and Jet A-1 have flash points between 38 and 66 C (100and 151F), close to that of off-the-shelf kerosene. Yet both Jet B and JP-4 have flash points between -23 and -1 C (-9and 30F).

3.4.4Tank atmosphere during gas freeing, purging, dilution with air and dilution with inert gasCargo Tank entry shall not be permitted unless the Oxygen Content is 21% and the hydrocarbon vapor content is less than 1% of the Lower Flammable Level (LFL). Follow companys Procedure for Entry into Enclosed Spaces with related permits.If the previous cargo contains Hydrogen Sulfide (H2S) or other toxic contaminants which could evolve toxic gases (eg benzene, toluene, Mercaptans, etc), the tank should be checked for such gases. Refer to Guidelines for Toxic Gases HazardsCarrying out Hot Work inside Tanks within the Dangerous Area need special caution as per Procedures for Hot Work and carry out preparation accordingly.

For the operations to be followed, (Tank cleaning, HC Gas Purging, Gas Freeing and Re-Inerting), the Chief Officer shall carry out by completing the necessary sections of Tank Cleaning, Purging and Gas Freeing Checklist to confirm safety strictly at the appropriate time.Atmosphere Control during Tank Cleaning OperationsTank atmospheres can be any of the following, However, ships fitted with an inert gas system, shall carry out the operations under the Inerted Condition, unless otherwise as instructed: It should be met with atmosphere containing less than 8% oxygen, and tank pressure of minimum 200 mmAqInerted TanksAn atmosphere made incapable of burning by the introduction of inert gas and the resultant reduction of the overall oxygen content. For the purposes of this procedure, the oxygen content of the tank atmosphere should not exceed 8% by volume.

This is a condition where the tank atmosphere is known to be at its lowest risk of explosion by virtue of its atmosphere being maintained at all times Non-Flammable through the introduction of inert gas and the resultant reduction of the overall oxygen content in any part of any cargo tank to a level not exceeding 8% by Volume, while being under positive pressure at all times.Purging with Inert Gas (IG)For reduction in hydrocarbon (HC) content in tank atmosphere for Cargo / Vapor contamination reasons:After tank cleaning operations the cargo tanks may be purged with inert gas to reduce the concentration of the hydrocarbon gas inside the tank atmosphere.

Oxygen content in Inert Gas for purging Since the main purpose of HC gas purging is displacement HC gas with IG, the procedure first priority shall be supply IG with full capacity of IG Blowers. Under the procedure, Oxygen content in Inert Gas for purging may be permitted by 8% by Volume or less.For carrying out Gas Freeing of the tank After cargo discharge / tank cleaning, whenever it is necessary to gas free an empty tank containing hydrocarbon gas mixtures or a mixture of IG + HC gases, it shall first be purged, using inert gas, until the HC (hydrocarbon) content reaches to below the critical dilution line or HC concentration in the tank atmosphere is less than 2% by volume.This is done so that during the subsequent gas freeing no portion of the tank atmosphere is brought within the flammable range.1) Dilution: It takes place when the incoming inert gas mixes with the original tank atmosphere to form a homogeneous mixture through the tank so that, as the process continues, the concentration of the original gas decreases progressively.2) Displacement: It depends on the fact that inert gas is slightly lighter than hydrocarbon gas so that, while the inert gas enters at the top of the tank, the heavier hydrocarbon gas escapes from the bottom through suitable piping

3.4.5Venting arrangementsVenting systems are required to meet the requirements of SOLAS. They are necessary for achieving safety on board a tanker and it is essential that they are operated to meet their design intent and that they are properly maintained.To facilitate dilution of the hydrocarbon vapours into the atmosphere clear of the tankers deck, venting systems allow vapours to be released. Forced Air VentilationBefore starting to Gas free, the tank should be isolated from other tanks.Do not commence forced air ventilation (Gas free) until it has been confirmed that the oxygen level is less than 8% and the hydrocarbon vapor content is less than 2% by Volume.

To ensure the dilution of the toxic components of inert gas to below their Threshold Limit Values (TLV), Gas freeing should continue until tests with an oxygen analyzer show a steady oxygen reading of 21% by volume and tests with a flammable gas indicator show not more than 1% LFL. If the presence of a toxic gas such as benzene or hydrogen sulfide is suspected, Gas freeing should be continued until tests indicate that its concentration is below its TLV.Completion of work & Inerting Cargo tanksAfter completion of man entry or repair work (in dry docks / lay-up berth) Cargo tanks shall be prepared for Loading as follows:

An Officer shall confirm each tank free of waste & material used in maintenance & inspection. Related pipelines and supports, including hydraulically operated valves, H.P. pipes and flanges are all in place and tightly secured.All personnel out of tank & close tank dome or access, only keep designated vent ports open. Inert tanks to 8% of Oxygen level.Replace the tanks atmosphere by an inerted atmosphere, using IG with the oxygen content of less than 5% by Volume. This gas replacement should continue, until the average measured oxygen content in the tanks drops to below 8% by Volume.

3.5 Principles of ElectrostaticsStatic electricity presents fire and explosion hazards during the handling of petroleum and during other tanker operations such as tank cleaning, dipping, ullaging and sampling. Certain operations can give rise to accumulations of electric charge that may be released suddenly in electrostatic discharges with sufficient energy to ignite flammable hydrocarbon gas/air mixtures.General Precautions against Electrostatic HazardsWhenever a flammable atmosphere could potentially be present, the following measures must be taken to prevent electrostatic hazards:

The bonding of metal objects to the metal structure of the ship. The removal from tanks or other hazardous areas of any loose conductive objects that cannot be bonded.Restricting the linear velocity of the cargo to a maximum of 1 metre per second at the individual tank inlets during the initial stages of loading, i.e. until: The filling pipe and any other structure on the base of the tank has been submerged to twice the filling pipe diameter in order that all splashing and surface turbulence has ceased and Any water collected in the pipeline has been cleared. Continuing to restrict the product flow to a maximum of 1 m/s at the tank inlet for the whole operation Avoiding splash filling by employing bottom entry using a fill pipe terminating close to the bottom of the tank.

The following additional precautions should be taken against static electricity during ullaging, dipping, gauging or sampling of static accumulator oils:Banning the use of all metallic equipment for dipping, ullaging and sampling during loading and for 30 minutes after completion of loading. Banning the use of all non-metallic containers of more than 1 litre capacity for dipping, ullaging and sampling during loading and for 30 minutes after completion of loading.Non-metallic containers of less than 1 litre capacity may be used for sampling in tanks at any time, provided that they have no conducting components and that they are not rubbed prior to sampling. Operations carried out through a correctly designed and installed sounding pipe are permissible.

Some examples of objects which might be electrically insulated in hazardous situations and which must therefore be bonded are:Ship/shore hose couplings and flanges, except for the insulating flange or single length of non-conducting hose required to provide electrical isolation between the ship and shore. Portable tank washing machines.Manual ullaging and sampling equipment with conducting components.The float of a permanently fitted ullaging device if its design does not provide an earthing path through the metal tape.

Certain objects may be insulated during tanker operations, for example:A metal object, such as a can, floating in a static accumulating liquid.A loose metal object while it is falling in a tank during washing operations.A metallic tool, lying on a piece of old lagging, left behind after maintenance.Every effort should be made to ensure that such objects are removed from the tank since there is evidently no possibility of deliberately bonding them. This necessitates careful inspection of tanks, particularly after shipyard repairs.

Other sources of electrostatic hazardsFiltersFixed Equipment in Cargo TanksFree Fall in TanksWater MistsInert GasDischarge of Carbon DioxideClothing and FootwearSynthetic Materials

4. OIL TANKER HANDLING SYSTEMSGeneral Pipeline SystemsRing mainThe basic principle of this system is that there is a line running forward on one side of the ship, across to the other side and then back aft again, so making a ring around the bottom of the ship. Tank suction valves do not lead off this line but from crossovers which connect both sides of the ring in the way of each set of tanks. Crossovers can be isolated from each main and further isolation is available by locating line masters between each of the crossovers.To increase the number of pumps each can be directed to each part of the system, a pair of additional mains lead from the pump room to connect with the ring main about half way down the deck. Loading drop lines may be provided in to each of the four bottom lines to allow loading directly from the deck lines without the need to load through the pump room.To provide even more versatility and cargo segregation, a double ring main may be provided in specialized product carriers.

Direct line systemThe direct line system came in to its own with the advent of centrifugal pumps and their requirement for minimum restriction on the suction side.The principle is that each main line from a particular cargo pump serves a group of tanks. Flexibility is provided by connecting the mains to each of their neighbors, crossovers and isolating valves are usually fitted.Direct loading drop lines are usually provided from the deck lines to each of the main bottom line, bulkhead master valves separate the main lines from the pump room so avoiding the need for oil to flow through the pump room when loading.

Free flow system (Obsolete?)This concept is very different from the previous two in that bottom lines are reduced to an obsolete minimum and in extreme case dispensed with altogether. To discharge, tanks are connected to each other by bulkhead sluice valves so that cargo can drain from one tank to another towards the stern of the ship. In the aftermost center and wing tanks is a bank of suctions and multi-grade flexibility is limited. Loading is carried out via drop valves from the deck lines and rudimentary ring main system is used to distribute the oil together with the bulkhead sluice valves. It is sometimes necessary for ships loading more than one grade with this system to trim by the head.

4.2Basic Pumping concept and EquipmentsA fluid or hydraulic pump is a machine that transfers energy from its moving parts to the fluid passing through the pump. The energy transferred from the pump to the fluid appears as the pressure and velocity of the fluid.4.2.1 Pumping System Choices:Hydraulic :- Pumps driven by hydraulic, motor oil of high pressure supplied from hydraulic pumps.Electric:-Relatively new technology is now available to allow ships to use variable speed AC drives for the cargo pumps.Steam:-The steam pumping system consists of a pair of boilers producing saturated steam feeding turbines that drive the pumps and exhaust the steam to a seawater condenser from which it is returned to the boiler.

4.2.2Types of PumpsCentrifugal pump:- Rotary pumps which are designed to handle large flow rate. Reciprocating stripping pump (Positive displacement)The original standard main cargo pump until after the war, simple, have good suction characteristics, use low pressure steam and very adequate at low capacitiesSubmerged (Deep well) pumpsSubmerged cargo pumps are gaining popularity, they have definite advantages:Eliminating the pump room and so suction lines, suction valves, bulkhead penetration.

Increased cargo space the space formerly set aside for the pump room can now be added to the cargo carrying capacity.Eliminating a dangerous area the pump room is an acknowledged dangerous space for both fire/explosion and personnel.Segregation total segregation between various grades of cargo is achieved.

4.2.3 Valves and their useValves isolate, switch and control fluid flow in a piping system.Gate Valves:Gate valves are an ideal isolation valve for high pressure drop and high temperature applications where operation is infrequent.Globe Valves Globe valves are ideal for shutoff as well as throttling service in high pressure drop and high temperature applications.Ball Valves They provide tight shutoff and high capacity with just a quarter-turn to operate.Butterfly valves Are commonly used as control valves in applications where the pressure drops required of the valves are relatively low. Butterfly valves can be used in applications as either shutoff valves (on/off service) or as throttling valves (for flow or pressure control). As shutoff valves, butterfly valves offer excellent performance within the range of their pressure rating.

4.2.4 Eductor and its useEductors are commonly used for draining tanks as part of a cargo or ballast pumping system.Eductors are self priming and because they have no moving parts, require little maintenance.The efficient operation of an educator depends on:High drive pressure.Minimum discharge pressureSuction lift

4.2.5 Pressure surge and its risks and dangersA pressure surge is generated in a pipeline system when there is an abrupt change in the rate of flow of liquid in the line. In tanker loading operations, it is most likely to occur as a result of one of the following:Closure of an automatic shutdown valve.Slamming shut of a shore non-return valve.Slamming shut of a butterfly type valve.Rapid closure of a power operated valve.If the pressure surge in the pipeline results in pressure stresses or displacement stresses in excess of the strength of the piping or its components, there may be a rupture, leading to an extensive spill of oil.

4.3Cargo and Ballast measuring devices4.3.1 OPEN AND CLOSED GAUGING/TYPES OF GAUGESGauging cargo tanks may be for four reasons these are.To establish the contents of the tankto establish in the temperature of the cargo in the tankto establish the position of an oil/water interfaceToo establish if any water is present in the cargo.All gauging should be carried out under close conditions, i.e. without opening the tank to atmosphere, this has the following advantages.

If the tank is pressurised by inert gas venting of the tank to check contents is not required.Prevents the risk of cargo vapours affectin g ships personnelreduces the number of personnel required on deck during loading and discharge which is inherently safer.4.3.1.1 MEASUREMENT BY SOUNDING TAPE The sounding is the actual depth of fluid in tankThe ullage of a tank is the distance from the top of the tank to the surface of the oil cargo. A graduated steel tape is used (earthed).This method is too slow not suitable for loading/discharging.

Advantages Quick and easy assembly. Weather-resistant. No electricity needed. Allows continuous measurements at various water fluctuations.

4.3.1.2 FLOAT INDICATORSIndicates the ullage directly by steel tape attached to float, guide wires act as earth wire reasonable accuracy, and various resistors can be employed to enable remote readouts Accuracy +/- 2mm

4.3.1.3 PNEUMATIC GAUGEThe head of fluid in the tank determines the pressure in the small diameter pipe which is led to a manometer via a charge over valve. The accuracy of this type of gauge is poor and reading can be affected by change of tank pressure and changes in control air pressure.The use of these gauges is usually for ballast tanks.

4.3.1.4 HYDRAULIC GUAGEThe fluid head in the tank is used to indicate the ullage through a fluid filled capillary tube a gauge .

4.4 Venting arrangementsVenting systems are required to meet the requirements of SOLAS. They are necessary for achieving safety on board a tanker and it is essential that they are operated to meet their design intent and that they are properly maintained.To facilitate dilution of the hydrocarbon vapours into the atmosphere clear of the tankers deck, venting systems allow vapours to be released.

4.4.1 Tank Over-pressurization and Under-PressurisationOver- pressurization of cargo and ballast tanks is due to compression of the ullage space by the inadequate release of vapour or by the overfilling of the tank. Under-pressurization can be caused by not allowing inert gas vapour or air into the tank when liquid is being discharged. The resulting over or under-pressure in the tank may result in serious deformation or catastrophic failure of the tank structure and its peripheral bulkheads, which can seriously affect the structural integrity of the ship and could lead to fire, explosion and pollution. Cargo tanks on oil tankers and carriers can be ventilated using the inert gas fans employing a gas freeing connection. Once the tank has been declared gas free to keep it in that condition portable water driven fans are used.

As mentioned previously the accommodation ventilation systems must be in the re- circulation mode when in port or tank cleaning Pump rooms on oil tankers and chemical tankers (if fitted) must have a ventilation fan which draws any gas from the bottom of the pump room.4.4.2 VAPOUR CONTROL ARANGEMENTS AND VENTING SYSTEMSPetroleum cargoes produce which can increase the internal pressure of a cargo tank, also it is possible to subject a cargo tank to sub atmospheric conditions. It is impherical to fit pipes to cargo tanks due to the amount of vapour produced by the cargo, thus each cargo tank must be protected by a pressure relief valve and vacuum relief valve.

NO-ONE SHOULD ENTER A PUMP ROOM WITH OUT OBTAINING PERMISSION FROM A RESPONSIBLE OFFICER.

4.5Cargo heating systemThe following oil are usually heated during carriage.Thick crude oils , heavy fuel oils, Bitumen, some lubricating oils,High pour point gas oilsThe reasons for heating the cargo areTo prevent SettlingTo prevent solidificationTo achieve a quicker dischargeThe heating media employed are:SteamThermal oil Glycol water mixtureThe mode of heating is to pass these medium through sets of coils and to circulation in the tank achieved by natural convection

5. Tanker Operation5.1 Cargo Loading and discharging operationBefore starting to load cargo, the Responsible Officer and the Terminal Representative should formally agree that both the tanker and the terminal are ready to do so safely.Emergency Shutdown Plan An emergency shutdown procedure, and alarm, should be agreed between the ship and the terminal and recorded on an appropriate form.The agreement should designate those circumstances in which operations must be stopped immediately.Due regard should be given to the possible dangers of a pressure surge associated with any emergency shutdown procedure.

SupervisionThe following safeguards should be maintained throughout loading:A Responsible Officer should be on watch and sufficient crew should be on board to deal with the operation and security of the tanker. A continuous watch of the tank deck should be maintained.The agreed ship-to-shore communications system should be maintained in good working order.At the commencement of loading, and at each change of watch or shift, the Responsible Officer and the Terminal Representative should each confirm that the communications system for the control of loading is understood by them and by personnel on watch and on duty.The standby requirements for the normal stopping of shore pumps on completion of loading, and the emergency stop system for both the tanker and terminal, should be fully understood by all personnel concerned.

Commencement of Loading Alongside a TerminalWhen all necessary terminal and tanker valves in the loading system are open, and the ship has signified its readiness, loading can commence. The initial flow should be at a slow rate. Whenever possible, this should be by gravity and to a single tank, with the shore pumps not being started until the system has been checked and the ship advises that cargo is being received in the correct tank(s). When the pumps have been started, the ship/shore connections should be checked for tightness until the agreed flow rate or pressure has been reached.

Periodic Checks During LoadingThroughout loading, the ship should monitor and regularly check all full and empty tanks to confirm that cargo is only entering the designated cargo tanks and that there is no escape of cargo into pump rooms or cofferdams, or through sea and over board discharge valves.The ship should check tank ullages at least hourly and calculate a loading rate. Cargo figures and rates should be compared with shore figures to identify any discrepancy.The ship should carry out frequent inspections of the cargo deck and pumproom to check for any leaks. Over side areas should likewise be checked regularly. During darkness, where safe and practical, the water around the vessel should be illuminated.The ship should advise the terminal when tanks are to be topped-off and request the terminal, in adequate time, to reduce the loading rate sufficiently to permit effective control of the flow on board the ship.

Discharging ProceduresBefore starting to discharge cargo, the Responsible Officer and the Terminal Representative must formally agree that both the tanker and the terminal are ready to do so safely. Throughout pumping operations, no abrupt changes in the rate of flow should be made.Periodic Checks During DischargeThroughout discharging, the ship should monitor and regularly check all full and empty tanks to confirm that cargo is only leaving the designated cargo tanks and that there is no escape of cargo into pumprooms or cofferdams, or through sea and overboard discharge valves.The ship should check tank ullages at least hourly and calculate a discharge rate.Any drop in pressures or any marked discrepancy between tanker and terminal estimates of quantities could indicate pipeline or hose leaks, particularly in submarine pipelines, and require that cargo operations be stopped until investigations have been made

5.2 Tank washing proceduresThis Section deals with procedures and safety precautions for cleaning cargo tanks after the discharge of volatile or non-volatile petroleum carried in non-gas free, non-inert or inert tanks. Guidance is also given on the cleaning of contaminated ballast spaces.All tank washing operations should be carefully planned and documented. Potential hazards relating to planned tank washing operations should be systematically identified, risk assessed and appropriate preventive measures put in place to reduce the risk as low as reasonably practicable (ALARP).In planning tank washing operations, the prime risk is fire or explosion arising from simultaneous presence of a flammable atmosphere and a source of ignition. The focus therefore should be to eliminate one or more of the hazards that contribute to that risk, namely the sides of the fire triangle of air/oxygen, ignition source and fuel (i.e. flammable vapours).

5.2.1 Inert Tanks:The method that provides the lowest risk is washing the tank in an inert atmosphere. The inert condition provides for no ambiguity; by definition, to be deemed inert, the tank MUST meet the SOLAS requirement for inerting of the cargo tanks and reducing the oxygen content of the atmosphere in each tank to a level at which combustion cannot be supported.Failure to prove through direct measurement that the tank is inert means, by default, that the tank MUST be considered to be in the non-inert condition. During tank washing operations, measures must be taken to verify that the atmosphere in the tank remains non-flammable (oxygen content not to exceed 8% by volume) and at a positive pressure.

5.2.2 Non-Inert Tanks:In ships that do not have access to inert gas, either through on board facilities (e.g. IGS plant) or shore supply, it is only possible to address the fuel and the sources of ignition sides of the fire triangle. In a non-inert condition, there are no physical barriers that will ensure elimination of these two hazards individually. Therefore, the safety of tank washing in the non-inert condition depends on the integrity of equipment, and implementation of strict procedures to ensure these two hazards are effectively controlled.Non-inert cargo tank washing should only be undertaken when two sides of the fire triangle are addressed by a combination of measures to control both the flammability of the tank atmosphere AND sources of ignition.It is recommended that all tankers that operate in the non-inert mode incorporate within their design and equipment the ability to mechanically ventilate cargo tanks concurrently with tank washing, in order to control tank atmosphere.

A Responsible Officer must supervise all tank washing operations. All crew involved in the operation should be fully briefed by the Responsible Officer on the tank washing plans, and their roles and responsibilities prior to commencement.All other personnel on board should also be notified that tank washing is about to begin and this notification MUST in particular be extended to those on board not involved directly in the tank washing operation but who, by virtue of their own concurrent tasks, may impact upon the safety of the tank washing operation.Both before and during tank washing operations, the Responsible Officer should be satisfied that all the appropriate precautions set out are being observed. If craft are alongside the tanker, their personnel should also be notified and their compliance with all appropriate safety measures should be confirmed.

Before starting to tank wash alongside a terminal, the following additional measures should be taken:Relevant precautions should be observed.The appropriate personnel ashore should be consulted to ascertain that conditions on the jetty do not present a hazard and to obtain agreement that operations can start.The method of tank washing utilised on board a tanker is dependent on how the atmospheres in the cargo tanks are managed and will be determined by the equipment fitted to the vessel. Non-inert cargo tank washing should only be undertaken when both the source of ignition and the flammability of the tank atmosphere are controlled. To achieve this, the following precautions to control sources of ignition and fuel MUST be taken for tank washing operations in a non-inert atmosphere condition.

5.2.2.1 Before Washing:The tank bottom should be flushed with water, so that all parts are covered, and then stripped. This flush should be undertaken using the main cargo pumps and lines. Alternatively, permanent pipework extending the full depth of the tank should be used. This flush should not be undertaken using the tank washing machines.The piping system, including cargo pumps, crossovers and discharge lines, should also be flushed with water. The flushing water should be drained to the tank designed or designated to receive slops.The tank should be ventilated to reduce the gas concentration of the atmosphere to 10% or less of the Lower Flammable Limit (LFL). Gas tests must be made at various levels and due consideration should be given to the possible existence of pockets of flammable gas, in particular in the vicinity of potential sources of ignition such as mechanical equipment that might generate hot spots, e.g. moving parts such as found in in-tank (submerged) cargo pump impellors.Tank washing may only commence once the tank atmosphere reaches 10% or less of the LFL.

5.2.2.2 During Washing:Atmosphere testing should be frequent and taken at various levels inside the tank during washing to monitor the change in LFL percentage.Consideration should be given to the possible effect of water on the efficiency of the gas measuring equipment and therefore to suspension of washing to take readings.Mechanical ventilation should, whenever possible, be continued during washing and to provide a free flow of air from one end of the tank to the other.The tank atmosphere should be maintained at a level not exceeding 35% LFL. Should the gas level reach 35% LFL at any measured location within a tank, tank washing operations in that individual tank MUST immediately cease.

Washing may be resumed when continued ventilation has reduced and is able to maintain the gas concentration at 10% or less of the LFL.If the tank has a venting system that is common to other tanks, the tank must be isolated to prevent ingress of gas from other tanks.The ability to mechanically ventilate concurrent with tank washing is recommended but, where mechanical ventilation is not possible, the monitoring of the tank atmosphere should be more frequent as the likelihood of rapid gas build-up is increased

5.2.3 Precautions for Tank Washing:Portable Tank Washing Machines and Hoses:The outer casing of portable machines should be of a material that will not give rise to an incendive spark on contact with the internal structure of a cargo tank.The coupling arrangement for the hose should be such that effective bonding can be established between the tank washing machine, the hoses and the fixed tank cleaning water supply line.Washing machines should be electrically bonded to the water hose by means of a suitable connection or external bonding wire.When suspended within a cargo tank, machines should be supported by means of a natural fibre rope and not by means of the water supply hose.

Portable Hoses for Use with Both Fixed and Portable Tank Washing Machines:Bonding wires should be incorporated within all portable tank washing hoses to ensure electrical continuity. Couplings should be connected to the hose in such a way that effective bonding is ensured between them.Hoses should be indelibly marked to allow identification. A record should be kept showing the date and the result of electrical continuity testing.

Testing of Tank Cleaning HosesAll hoses supplied for tank washing machines should be tested for electrical continuity in a dry condition prior to use, and in no case should the resistance exceed 6 ohms per metre length.Tank Cleaning Concurrently with Cargo:As a general rule, tank cleaning and gas freeing should not take place concurrently with cargo handling. If for any reason this is necessary, there should be close consultation with, and agreement from, both the Terminal Representative and the port authority.

Free Fall: It is essential to avoid the free fall of water or slops into a tank. The liquid level should always be such that the discharge inlets in the slop tank are covered to a depth of at least one metre to avoid splashing. However, this is not necessary when the slop and cargo tanks are fully inerted.Spraying of WaterThe spraying of water into a tank containing a substantial quantity of static accumulator oil could result in the generation of static electricity at the liquid surface, either by agitation or by water settling. Tanks that contain static accumulator oil should always be pumped out before they are washed with water, unless the tank is kept in an inert condition.

5.3 Purging and gas freeing It is generally recognized that gas freeing is one of the most hazardous periods of tanker operations. This is true whether gas freeing for entry, for Hot Work or for cargo quality control. The cargo vapours that are being displaced during gas freeing are highly flammable.The additional risk from the toxic effect of petroleum gas during this period cannot be over emphasised and must be impressed on all concerned. It is therefore essential that the greatest possible care is exercised in all operations connected with gas freeing.In order to be gas free for entry without breathing apparatus, a tank or space must be ventilated until tests confirm that the hydrocarbon gas concentration throughout the compartment is less than 1% of the LFL, that the oxygen content is 21% by volume, and that there are no hydrogen sulphide, benzene or other toxic gases present, as appropriate

Procedures and PrecautionsThe following recommendations apply to gas freeing generally:A Responsible Officer must supervise all gas freeing operations.All personnel on board should be notified that gas freeing is about to begin.Appropriate No Smoking regulations should be enforced.Instruments to be used for gas measurement should be calibrated and tested in accordance with the manufacturers instructions before starting operations.Sampling lines should, in all respects, be suitable for use with, and impervious to, the gases present.All tank openings should be kept closed until actual ventilation of the individual compartment is about to commence.Venting of flammable gas should be by the ships approved method. Where gas freeing involves the escape of gas at deck level or through hatch openings, the degree of ventilation and number of openings should be controlled to produce an exit velocity sufficient to carry the gas clear of the deck.

Intakes of central air conditioning or mechanical ventilation systems should be adjusted, if possible, to prevent the entry of petroleum gas, by recirculating air within the spaces. If at any time it is suspected that gas is being drawn into the accommodation, central air conditioning and mechanical ventilation systems should be stopped and the intakes covered or closed.Window type air conditioning units which are not certified as safe for use in the presence of flammable gas, or which draw in air from outside the superstructure, must be electrically disconnected and any external vents or intakes closed.Gas vent riser drains should be cleared of water, rust and sediment, and any steam smothering connections tested and proved satisfactory.If several tanks are connected by a common venting system, each tank should be isolated to prevent the transfer of gas to or from other tanks.

If petroleum vapours persist on deck in high concentrations, gas freeing should be stopped.If wind conditions cause funnel sparks to fall on deck, gas freeing should be stopped.Tank openings within enclosed or partially enclosed spaces, such as under forecastles or in centrecastles, should not be opened until the compartment has been sufficiently ventilated by means of openings in the tank that are outside these spaces. When the gas level within the tank has fallen to 25% of the LFL or less, openings in enclosed or partially enclosed spaces may be opened to complete the ventilation. Such enclosed or partially enclosed spaces should also be tested for gas during this subsequent ventilation.

When undertaking gas freeing in port, the following should be observed:As a general rule, gas freeing should not take place concurrently with cargo handling. If for any reason this is necessary, there should be close consultation with, and agreement from, both the Terminal Representative and the port authority.The Terminal Representative should be consulted to ascertain that conditions on the jetty do not present a hazard and to obtain agreement that operations can start.If craft are alongside the tanker, their personnel should also be notified and their compliance with all appropriate safety measures should be checked.

Gas Testing and MeasurementIn order to maintain a proper control of the tank atmosphere and to check the effectiveness of gas freeing, a number of gas measuring instruments should be available on the ship. Atmosphere testing should be undertaken regularly during the gas freeing operation to monitor progress. Ventilating Double Hull Ballast TanksThe complexity of the structure in double hull and double bottom tanks makes them more difficult to gas free than conventional ballast tanks.

6. HEALTH, SAFETY AND EMERGENCY PROCEDURESHealth Hazards Associated with Petroleum Cargoes 6.1.1 GeneralMany substances have harmful effects on the human body. For example, some cargoes are toxic while others disrupt the supply of oxygen and can cause death by suffocation ((asphyxia). Toxicity and asphyxia can be defined as:Toxicity is the ability to cause harm to living issue.Asphyxia is a deficiency of oxygenUsing these definitions, all hydrocarbons, for instance, are harmful if experienced in sufficiently high concentrations: either through toxicity or asphyxia.

6.1.2 Routes in the bodyThere are three main routes by which toxic substances may enter the body:Inhalation, breathing toxic gas into the lungs can cause short and long term effectsIngestion, the swallowing of liquid can also cause short and long term effectsSkin absorption by contact with liquid or gasToxic EffectsMany cargoes have toxic effects like:A) Suffocation due to lack of oxygenB) Anaesthesia due to the presence of toxic vapours

6.1.3 The Toxicity of PetroleumThe toxicity of petroleum and petroleum gases can vary widely depending on the major hydrocarbon constituents and the presence of naturally-occurring impurities such as benzene and hydrogen sulphide. Liquid PetroleumThe risk of swallowing significant amounts of petroleum during normal tanker and terminal operations is very slight. Also petroleum has low oral toxicity to humans, but, when allowed, leads to acute discomfort and nausea.Petroleum Gases The main effect of petroleum gas on humans is to produce NARCOSIS.The symptoms include Head ache And Eye irritation With Diminished responsibility And Dizziness Similar to DrunknessAt higher concentrations, these symptoms are followed by paralysis, insensibility and death.

6.2 DetectionThe smell of petroleum is very variable and, in some cases, can fool the sense of smell. The impairment of smell is especially serious if the cargo contains hydrogen sulphide as the gas bonds strongly with the sensors of the nose preventing any further ability to detect the aroma.Therefore it must be stressed that the absence of smell should never be taken to indicate the absence of gas and the use of on-board instrumental sensors is much more reliable.Benzene and other aromatic hydrocarbonsExposure to benzene in higher concentrations leads to chronic disorders of the blood and bone marrow.Hydrogen sulphide and other sulphur compoundsIf the concentration is high it leads to instantaneous collapse and cessation of breathing.C) Compounds LeadThe effects of the gases from leaded gasolines are similar to those described above for the petroleum gases.

6.3First Aid TreatmentWhen treating a person who has been overcome by toxic gases, oxygen should be given at the point where he was injured usually by using the minuteman or some other type of resuscitator. So when entering a space to rescue someone, it is important that you take the resuscitator with you so that oxygen can be administered immediately while the stretcher etc. is prepared for the victims removal from the space.For cases where poisoning may have occurred, the IMCO Medical First Aid and Guide for use in accidents that involve dangerous goods and, particularly, onboard cargo sheets (safety data sheet) should be referred to. The latter will outline the emergency procedures needed in the event of accidents such as liquid in the eye, vapour inhalation, etc. The second part gives health data such as the acute (short term) and chronic (long term) effects of vapour inhalation.

The first aid treatment is to get oxygen to the victim as soon as possible either using a resuscitator or by mouth-to-mouth resuscitation. However mouth-to-mouth resuscitation should not be performed in a dangerous area as the rescuer runs the risk of inhaling the toxic vapours. It must only be performed when the victim has been removed to a position where fresh air is available. Even then great care must be taken.

Examples of Gassing AccidentsThe procedure when changing certain grades on clean product tankers when arriving in the load port is toGas free with portable fanDrain thoroughly with stripping systemsDispatch personnel into the tanks with initially portable educators to remove the last remnants of waterHand mop the tank bottom with absorbent materialWhile carrying out this procedure, one of the moppers was overcome. The tank was evacuated; the crewman was rescued and fortunately resuscitated. The cause was thought to be due vapours rising from disturbed scale or rust as other crewmen working very close by were unaffected

A cargo pump gland was leaking in the pump room while the pump was discharging gasoline. The pump man went down to investigate and attempted to stop or reduce the leak. He was rapidly overcome by fumes and collapsed. A sailor went WITH NO BREATHING APPARATUS (!) to try and effect a rescue. He was lucky enough to make it back out of the pump room. When a correct procedure was put in place the pump man was rescued. This all happened with the two extraction fans in the pump room in continuous use.

6.4Personal Protection and Safety equipmentPersonal protection and safety equipments are as follows, but not limited to:-Oxygen analyzerGas detectorPPE for entry in to an enclosed spaces.PPE for fire fightingBreathing Equipments, etc.

6.4.1 Entry in to enclosed spaceAn enclosed space is defined as One with restricted access that is not subject to continuous ventilation in which the atmosphere may be hazardous due to the presence of;HDROCARBON GAS TOXIC GASESINERT GASOXYGEN DEFICIENCY

The spaces which are classed as enclosed include the following:CARGO TANKS, BALLAST TANKS, FUEL TANKS, WATER TANKS, L.O. TANKS, SLOP AND WASTE OIL TANKS, SEWAGE TANKS, COFFERDAMS, DUCT KEEL. VOID SPACES AND TRUNKINGS PIPELINES OR FITTINGS CONNECTED TO ANY OF THESE.AND ANY OTHER ITEM OF MACHINERY OR EQUIPMENT NOT ROUTINELY VENTILATED OR ENTERED, INCLUDING MAIN ENGINE CRANKCASES AND BOILER STEAM/ WATER DRUMS.Many of the fatalities in enclosed spaces on oil tankers have resulted from entering the space without PROPER SUPERVISION, ADHERENCE TO AGREED ENTRY PROCEDURES IMPULSIVE AND ILL PREPARED RESCUE ATTEMPTS.

Before entering an enclosed space the atmosphere should be checked by a responsible officer, the order of testing the atmosphere in the tank should be1.OXYGEN 21%2.HYDROCARBONSNOT MORE THAN 1% L.F.L.3.TOXIC GASESLESS THAN T.L.V. OR P.E.L

6.4.2 Oxygen deficiency with particular reference to inert gas plantsAs inert gas causes asphyxiation, great care must be taken to AVOID THE ESCAPE OF INERT GAS INTO ANY ENCLOSED SPACE OR PARTLY ENCLOSED SPACE BEFORE VENTILATED AND GAS FREED. The scrubber and deck seal being the main source of danger.6.4.3 Flammable, toxic and Inert gas atmosphereWhen testing of enclosed space atmospheres this should be achieved using approved instruments and once the Oxygen content of the space has been verified 21% by volume there are no hydrocarbons and toxic gases present then entry can proceed by a person wearing a BREATHING APPARATUS. This persons job is to ensure that no pockets of gas exist at the bottom of the enclosed space. Care should be taken when using personal oxygen meters to prevent people assuming that the oxygen content at the entrance of the tank or enclosed space is the same throughout.

The measurement of Oxygen ContentAtmospheric air contains 21% Oxygen it is this figure that should be in the atmosphere of an enclose space and most Oxygen analysers have the alarm set to 18.5% 6.4.4 RESCUE AND ESCAPE PROCEDURESThe prevention of dangerous situations is far better than having to plan rescues and escape procedures.It is of the utmost importance that the rescuer does not become the RESCUED. Many people have been killed themselves by trying to rescue a person in distress, without bearing the following in mind.1. HAVE ENTERED A HAZARDOUS SPACE WITHOUT A B.A.SET2. HAVE ATTEMPTED TO CARRY OUT THE RESCUE WITHOUT INFORMING ANYONE ELSE.

When it is required to work or enter a hazardous space for any reason it is imperative that a back up team is at the entrance standing by in constant communication with the person/persons in the space concerned.In any hazardous space personnel should be in possession of escape B.A. set once the atmosphere has been tested for satisfactory entry. A secondary escape route should be available if possible.No one should enter a cargo tank cofferdam, double bottom. Or other enclosed spaces unless an entry permit has been issued by a responsible officer who has ascertained immediately before entry that the atmosphere is within the space is in all respects safe for entry. Before issuing an entry permit, the responsible officer should ensure that.

A RISK OR HAZARD ASSESSMENT HAS BEEN CARRIED OUT. THE HYDROCARBON CONTENT IS NOT MORE THAN 1% OF THE L.E.L. NO TOXIC GASES ARE PRESENT.CONTINOUS VENTILATION OF THE SPACE IS BEING CARRIED OUT AND THAT RESCUE HARNESSESS ARE IN POSITIONTHE ENTRY OF THE SPACE:APPROVED POSITIVE PRESSURE BREATHING APPARATUS AND RESUSCITION EQUIPMENT ARE READY FOR USE AT THE ENTRANCE TO THE SPACE.

WHERE POSSIBLE A SEPARATE MEANS OF ACCESS IS AVAILABLE FOR USE AS AN ALTERNATIVE MEANS OF ESCAPE IN AN EMERGENCY.EFFECTIVE COMMUNICATION FOR TANK ENTRY AND RESCUE OPERATIONS IS VERY IMPORTANT MORE SO IN THE DAYS OF CREWS BEING MULTI NATIONAL.6.4.6 Breathing apparatus and tanker evacuating equipment.The types of breathing apparatus found on oil tankers are listed below:1. AIR LINE BREATHING APPARATUS: ( small diameter hose connected to compressed air bottle.) 2. HOSE MASK (FRESH AIR BREATHING APPARATUS): not recommended due to poor sealing effect on the face.3. EEBD used for emergency exit only

4. THE SELF CONTAINED BREATHING APPARATUS It consists of a steel cylinder containing compressed air at a pressure of about 207 bar. From the bottle air passed through a reducing valve which reduced the pressure to about 6 bar. The face mask demand valve reduces this pressure to about 1400mm water gauge for breathing. The duration of the air supply depends upon the size and task the wearer is carrying out but it is usually about 30 minutes. The apparatus is fitted with an alarm which informs the wearer there is about 10 minutes air left. The following are also provided.1. A luminous pressure gauge.2. A canvas jacket shrouding the bottle to prevent metallic sparks.3. A waist belt that fastens on the side to prevent fouling.

6.4.7 PROTECTIVE CLOTHINGProtective clothing consists of a suit manufactured from lightweight fire resistant fabric incorporating an aluminum covering, and is sometimes referred to as fire proximity suit. It must be noted that this type of suit is not suitable for direct entry into fire areas.Heavier weight suits, termed fire suits permits personnel actually to enter the fire area wearing breathing apparatus.The protective clothing is accompanied by GOOGLES, BOOTS, GLOVES FIRE AXE, LIFELINE AND A TORCH. It is important that no item from the list is borrowed for other tasks.

6.4.8 THE RESUSCITATORSResuscitators must be carried by law, they are used to treat victims who have inhaled obnoxious substance and cardiac arrest patient briefly they consist of bottle which is filled with medical Oxygen to pressure of 137 bar which gives the length of duration at adult setting of 25 minutes.6.5Fire fighting principles and controlFire requires a combination of fuel, oxygen, a source of ignition and a continuous chemical reaction, commonly referred to as combustion.Fires are extinguished by the removal of heat, fuel or air, or by interrupting the chemical reaction of combustion. The main objective of fire-fighting is to reduce the temperature, remove the fuel, exclude the supply of air or interfere chemically with the combustion process with the greatest possible speed.

6.5.1Types of Fire and Appropriate Extinguishing Agents:Class A Ordinary (Solid) Combustible Material FiresClass B Fires Involving Flammable and Combustible Hydrocarbon LiquidsClass B fires are those that occur in the vapour/air mixture over the surface of flammable and combustible liquids such as crude oil, gasoline, petrochemicals, fuel and lubricating oils, and other hydrocarbon liquids. Fires involving flammable gases are generally included in this classification.These fires are extinguished by isolating the source of fuel (stopping the flow of fuel), inhibiting the release of combustible vapours or by interrupting the chemical reaction of the combustion process. Since most Class B materials burn with greater intensity and re-ignite more readily than Class A materials, more effective extinguishing agents are generally required.

Low expansion foam is an effective agent for extinguishing most hydrocarbon liquid fires.It should be applied so as to flow evenly and progressively over the burning surface, avoiding undue agitation and submergence. This can best be achieved by directing the foam discharge against any vertical surface adjacent to the fire, both in order to break the force of discharge and to build up an unbroken smothering blanket. If there is no vertical surface, the discharge should be advanced in oscillating sweeps, in the direction of the wind when possible, taking care to avoid foam plunging into the liquid. Foam spray streams, while limited in range, are also effective.Volatile liquid fires of limited size can be rapidly extinguished with dry chemical agents, but are subject to re-ignition when hot surfaces are in contact with flammable vapours.Non-volatile liquid fires that have not been burning for an extended period can be extinguished by water fog or water spray if the whole burning surface is accessible. The surface of the burning oil transfers its heat rapidly to water droplets, which present a very large cooling surface area.

Class C Electrical Equipment Fires Class D Combustible Metal Fires Extinguishing Agents Extinguishing agents act by heat removal (cooling), by smothering (oxygen exclusion) or by flame inhibition (interfering chemically with the combustion process).Cooling Agents Water: Foam:Smothering Agents Foam: Carbon Dioxide: Steam:Flame inhibiting AgentsDry ChemicalAll personnel on board should know their place in the emergency organization and their duty in case an emergency procedure is being initiated.

Basic emergency actions to be taken in case of:1.fire: Sound the alarm and if possible advice to Engineer or Officer on watch (OOW) the location of seat of fire and combustibles involvedMake voice warning via public communication System Inform Master and Duty Engineer and if in the port to Advise to Port AuthorityStart to put fire before Emergency Team come if it is containable.2.Cargo hose burstRaise alarm (internal and external, give agreed signal on the whistle (if applicable)Activate Emergency Shut Down (ESD) if applicableStop main cargo pump if applicableClose manifold valves

Accident involving personnelYou can find in the Integrated System of Contingency Plans for shipboard emergencies. Module IV RESPONSE ACTIONS provides guidance for shipboard personnel relating to an emergency when the ship is UNDERWAY, berthed, MOORED, at anchor, IN PORT or dry dock.The correct emergency procedures for accidents involving dangerous chemicals are given in the recommended guide lines or Cargo Data Sheets (CDS).FIRST AID TREATMENTFirst-aid procedures for accidents involving dangerous chemicals are given in the ICS or other Cargo Data Sheets (CDS).For ex. ACRYLONITRILE (Inhibited):EMERGENCY PROCEDURES:

Liquid in eye:DO NOT DELAY: Wash eye gently, keeping eyelids wide open, with copious amounts of clean water for at least 10 minutes. If there is doubt that the chemical has not been completely removed, continue washing for a further 10 minutes. Consult the MFAG (Medical first aid guide) or OBTAIN MEDICAL ADVICE IMMEDIATELY.Liquid on skin:DO NOT DELAY: HIGHLY TOXIC BY SKIN ABSORPTION: Remove contaminated clothing and wash affected area with copious amounts of water for at least 10 minutes. If there is any doubt that the chemical has not been completely removed, continue washing for a futher 10 minutes.OBTAIN MEDICAL ADVICE IMMEDIATELY.

Vapour inhaled:With rescuers wearing breathing apparatus, remove casualty to fresh air. Check that casualty is breathing if stopped give artifical respiration at once by the Silvester method or, immediately available, by using resuscitation equipment to avoid inhaling any toxic vapour expired by the casualty. Give cardiac compression if the pulse is absent. OBTAIN MEDICAL ADVICE IMMEDIATELY.All personnel should be familiar with the first-aid procedure set out in the Data Sheets for the cargoes carried

6.6.General Safety PrecautionsDanger can always be present regardless of the type of tanker. Most of the risk is removed by the designer however what risks remain can only be avoided by taking care, this must be exercised by everyone on board. TO AVOID THE RISKS YOU MUST KNOW WHAT THEY AREREAD, LEARN AND PUT IN TO PRACTICE ALL THE SAFE WORKING PRACTICES YOU CANYOUR SHIP WILL HAVE MANY SAFETY PUBLICATIONS ON BOARD READ THEM AND WATCH THE SAFETY VIDEOSYOUR SHIP WILL ALSO HAVE SENIOR OFFICERS WITH AWEALTH OF EXPERIENCE ASK THEMTAKE DRILLS SERIOUSLYIF IN DOUBT DO NOT DO IT ASK SOME BODY

7. POLLUTION PREVENTIONPollution of marine environmentCAUSES OF MARINE (AIR AND WATER) POLLUTIONOil PollutionMarine pollution at sea can occur as a result of:Strandings and collisionsLightering operationsNormal operations such as tank washing and line flushingDeballastingThermal expansion of oil in tanks and piping

Marine pollution in port can occur as a result of:Leaking hoses and loading armsOverflow from tanksEquipment failureProcedural failures, e.g. improperly set sea valves Operational requirements to prevent pollutionTo prevent hazards to the environment, the following should be observed:For oil tankers in port:Ship movements alongside must be restricted by adjusting mooringsAll pipelines, joints and must be kept under observation whilst handling cargo

All valves in the cargo system should be treated as precision equipment. They should be regularly inspected and maintained to ensure safe and efficient operation.Catchment must be fitted or placed at vulnerable points (hose connections, for example)Strict control must be exercised whilst loading to prevent tanks overflowingAll scuppers must be closed to prevent a discharge of oil from the deck overboardAll valves and blanks must be checked prior to cargo operationsValves not used should be secured if possibleSea valves not in use should be closed by double valves or blanked offIf oil is spilt, cargo operations must be stopped and warnings given to all involved

Air pollutionAir pollution may be caused by inert gas, hydrocarbon gas or any other cargo vapour finding their way into the atmosphere because of:The breathing or venting of loaded tanksPurging or gas-freeing operationsLoading or ballasting cargo tanksHydrocarbon vapour collects above the surface of the oilThe vapour/air mixture is displaced during loading, ballasting, gas-freeing and tank-washing operations.Hydrocarbon gas, chemical gas and inert gas may be considered air pollutantsNo measures are usually taken against air pollution at sea, apart from the necessary safety precautions:have good communicationhave the best possible co-operation between ship and terminal.Some ports have regulations restricting air pollution from tankers.Certain displacement and containment measures can be taken to restrict air pollution.

7.2.Response to Marine SpillsGeneralThe measures to be taken in the event of spillage, including the need to:Immediately report all relevant information to the appropriates officials when a spill is detected or when a malfunction has occured which poses a risk of a spill: 2 .Properly implement shipboard spill-containment proceduresSOPEP (Shipboard Oil Pollution Emergency Plan)As per the MARPOL Convention, most tankers shall carry a Shipboard Oil Pollution Emergency Plan (SOPEP)The Shipboard Oil Pollution Emergency Plan (SOPEP) covering the requirements of Reg. 26 of Annex I of MARPOL 73/78 and following the guidelines of IMO Resolution MEPC 54(32).

The aforementioned manuals exist onboard all vessels and cover issues dealing with, reporting procedures, response procedures, training and drill procedures.As a general rule it must be emphasized that all actions must be executed quickly, precisely and efficiently.In brief form the concept of the plan is to assist personnel in dealing with an unexpected discharge of oil and to assist the ships officers to take quick action in an event of oil spillage.The SOPEP consists of at least:The procedure to be followed to report an oil pollution incidentThe list of authority or persons to be contacted in an event of an oil pollution incidentDescription of action to be taken by persons on board to control the discharge of oilThe procedures and point of contact on the ship for co-ordinating shipboard action with national and local authority.