Fire and Safety Arrangements

Question 1

Describe what to do in the event of a fire?

Answer 1

First of activate the fire alarm. establish the location of the fire and if the fire is small or large and the type of fire. this will help to decide what fire extinguishing media should be used to fight the the fire. if the fire is small use the correct type of portable fire extinguisher to extinguish the fire. if its a large fire start the fire pumps and use local firefighting system on board to extinguish the fire if is hasn’t already been activated automatically. inform the bridge and chief engineer to organise firefighting teams and to decrease engine speed. if possible don’t stop main engine and maintain electrical power. Restrict the fire to prevent it from spreading and to help towards it being extinguished. this can be done by using quick closing emergency valves to stop fuel supply and use fire flaps to restrict air flow. fire team should able to extinguish the fire with the correct fire fighting equipment. if fire gets out of control use CO2 flooding system if necessary.

Question 2

List ways that fire can be prevented onboard

Answer 2

1. No oils, oily rags and wastes should allow in the vicinity of the heat source such as the places of (Boiler, Heaters and M/E exhaust system). They are liable to ignite spontaneously. Dust and cargo residue should be picked up with a broom and scoop and not blown by air into the bilges. These particulate matters could be flammable. Cotton waste or rags should not be left in bilges. Ensure you clean up the surrounding area after any maintenance operation.
2. No oil leak should be tolerated such as from oil tank’s trays and drip pan, fuel and lube oil separator’s trays, fuel and lube oil valves, oil burners and piping connection. Regular rounds of all equipment & inspection to check for leaks/overheating. Used or waste oil should not be intentionally put in the bilges. All oil should be collected and put in the separated oil tank or dirty oil tank. Put drip trays where there are oil leakages and thereafter rectify and stop the leakages
3. Tank top and bilges should be cleaned and hose down frequently. Cleaning could be done with some chemical if oil is accumulated considerably.
4. Tank tops and bilges should be painted white and all places on ship must be well illuminated
5. No naked lights and smoking should be allowed inside the engine room and near the bunker station.
6. Paint should be stored in special well ventilated stored away from machinery space or heat source and automatic water sprinkler system to be provided as per regulation.
7. Welding practice should be done only in workshop and away from combustible material storing spaces carefully, then all the protective cloths to be put on and earthing should be ensured.
8. All engine room members should be properly educated about firefighting appliances and their operation. Fire drills should be carried out at least once a month.

Question 3

What is the purpose of a Davy safety lamp?

Answer 3

Used for detection of the tank atmosphere to check for explosive or toxic gases. If the flame in the lamp burn clearly, the tank atmosphere is free from any fatal or explosive gases. If it develops a faint blue cap above, it is the sign of an explosive gas present. If the lamp burns black or goes out, foul gas such as carbon dioxide is present. The lamp will not burn in an atmosphere containing less than 16% of oxygen

Question 4

Explain the purpose and working principle of an explosimeter?

Answer 4

It’s an instrument used to detect explosive atmospheres. When the lower explosive limit (LEL) of an atmosphere is exceeded, an alarm signal on the instrument is activated. The atmosphere of a tank or pump room can be tested with a combustible gas indicator which is calibrated for hydrocarbons. The scale is represented as the lower explosive or lower flammable limit (LFL) and marked as a percentage of the lower limit. Alternatively, the scale may be marked in parts per million (ppm).

The combustible gas indicator consists of a Wheatstone bridge with current supplied from a battery. When the bridge resistances are balanced, no current flows through. An aspirator bulb and flexible tube are used to draw a gas sample into the chamber. The gas will burn in the presence of the red-hot filament causing the temperature of the filament to rise. Rise of temperature increases the resistance of the filament and this change of filament unbalances the bridge. The current flow registers on the meter which is scaled in percentage of LFL or ppm. A lean mixture will burn in the combustion chamber, because of the filament. False readings are likely when oxygen content of the sample is low or when inert gas is present. The instrument is designed for detecting vapour in a range up to the lower flammable limit and with large percentages of gas (rich mixture) a false zero reading may also be obtained. The instrument and batteries must be tested before use and samples are taken from as many places as possible particularly from the tank bottom. It is possible to obtain a reading for any hydrocarbon but not for other combustible gases on an instrument which is scaled for hydrocarbons. Detection of other vapours must be by devices intended for the purpose. The explosimeter is primarily a combustible gas detector but will also give guidance with regard to safety of a space for entry by personnel. If a space has been ventilated to remove vapours, the remaining concentration can be measured with explosimeter, provided that it is below the lower flammable range. Generally, any needle deflection above zero is taken as indicating a toxic condition.

Question 5

What is a non-combustible material?

Answer 5

A non-combustible material is one which neither burns nor gives off flammable vapours

Question 6

What is the fire control plan?

Answer 6

It is a general arrangement plan which must be on displayed onboard for the guidance of ship personal and the shore fire brigade. The fire control plan provides information about fire stations on each deck of the ship. It will also show any fixed systems/detection equipment.

It can be found:
* On the Bridge
* In the Engine Control Room
* In a prominent location in the Accommodation
* At the fire party muster stations
* In watertight containers on the main deck at the access points.

It consists of details of:

1.Fire control stations
2.Location of various portable fire extinguishers & FFA.
3.Fire detecting and alarming system.
4.Means of escape.
5.Ventilation system.
6.Fixed firefighting instillation system.

Question 7

a.) What is fire Training Manual?
b.) what is included in manual (contents)?

Answer 7

a.) SOLAS Chapter 2 requires that all ships should be provided with a Fire Safety Operational Booklet and Fire Training Manual detailing all training on the Fire safety aspects of the ship. it provides guidance on the use of all the Fire Safety systems onboard. Plan is developed in line with IMO Requirements and common marine practice. Approval by the Administration is NOT mandatory; however manual is always inspected by Port state control.

b.) Contents of the Manual

Fire Fighting Theory (Gives an overall description of fire from burning till extinguishing)

On board Fire Prevention (Describes common causes of on-board fires and methods to prevent such accidents)

Fire Fighting Protection Arrangements (Describes vessel’s structural fire protection arrangements as well as fixed firefighting installations.)

Portable Fire Fighting Equipment (Describe the types, uses of portable fire extinguishers on board)

Fire Fighting Safety Equipment (Describe the types, uses of fire safety equipment’s on board)

Safety Equipment Illustrations (Describe the types, uses and illustrations of fire safety equipment on board)

Shipboard Fire Fighting Organization (Responsibilities of crew fire fighting organizations, describes most common firefighting procedures and tactical guidelines as well as fire fighting in port)

Shipboard Training Procedure (Describes proper actions and measures to be taken during a fire accident, in order to assist all involved personnel in proper training)

Vessel Specific Information (Describes procedure of fire fighting with respect to type of ship)

Fire Fighting Equipment Inventory (Contain inventory of fire fighting equipment. It should be updated as per changes)

Firefighting procedures as per vessel specific arrangements

Detailed instructions for every step of training

Question 8

What are examples of fire fighting and detecting equipment?

Answer 8

2 number of fire hydrants at each floor.

3 types of portable extinguisher.(CO2, foam, Dry powder) located in easily accessible position and correct type to deal with expected class of fire in that area.

Non-portable fire extinguisher (136 L foam extinguisher for boiler space.)

Smoke detector and alarm system.

Fixed fire fighting installation system.

Question 9

a) State four actions the EOOW would take on discovering a small fire in the engine room bilge. (8)

b) State four good watch-keeping practices that can help prevent such fires mentioned in Q a) from occurring. (8)

Answer 9

a) Assuming the fire is small enough to be fought with a portable extinguisher the EOOW should:

• Sound the nearest alarm/Inform the Bridge and CE. bilge fires are small oil fires. if possible, remove combustible material near vicinity.
• Assess the situation and find out what class fire it is to know what firefighting installations and extinguishing equipment to use.
• fully extinguish the fire using portable foam extinguisher. operate fire extinguisher by pulling the safety pin and using the handle and then holding the nozzle and doing figure of eights to extinguish fire. Release the foam direct to the fire by deflecting it from another surface. Foam has lower specific gravity than oil or water so it will flow across the surface of oil and cover it.
• once fire is extinguished Inform the bridge and chief engineer of the event. then Logs should be made, and the issue raised at the next safety meeting.

b) * Check tanks for leaks leading to bilges and use drip trays under the tanks and running machinery

• Empty bilges often and maintain proper housekeeping by regularly cleaning the bilges to remove any combustible materials
• Avoid any kind of work that generates sparks or heat near bilges.

Regularly inspection of machinery close to bilge areas and rectify leaks promptly.

Question 9

a) Explain the importance of regular fire drills; (8)

b) Describe how a drill relating to a fire in a purifier room may be organised. (8)

Answer 9

a.) Fire drills can reduce panic and take pressure off in the event of a real-life emergency by teaching crew members what their duties are and how they can be safely executed. All personnel are familiar with the location and operation of firefighting equipment reducing the likelihood of panic. Procedures are put in place which work in real life situations. Everyone is familiar with the fire functions such as correct flow rate and procedure.

b.) for organising a fire drill in the purifier room first have a meeting to discuss and ensure everyone knows their responsibilities for the drill.
Then once its planned someone to raise the alarm and have a crew member investigate if it’s a real fire. Whilst all other crew members would go to their normal fire muster stations. Then have the emergency response team “tackle” the fire with a fire extinguisher hose doing figure of eights to fight fire. Ensure to record the response time and everyone to ear the correct PPE.
Fire support parties know their roles and positions of all firefighting equipment and escape routes. The dangers associated with large quantities of fuel, the requirement for extra cooling and careful application of water must be followed to ensure no flooding. The use of B.A. sets and teams, the possibility for extreme heat, structural damage, and poor visibility. Stand-by teams know how to replenish B.A. set bottles, from solution and how to set up and maintain firefighting foam supply.

Question 10

a.) Describe the immediate action that should be taken in the event of discovering a fire in the accommodation spaces, whilst at sea. (8)

b) Briefly describe the organisation of the two emergency parties on board a ship. For each party define who is in charge, the responsibility of each party and how the efforts of each party are coordinated. (8)

Answer 10

a) Sound the nearest alarm and shout for help in case alarm doesn’t work. Restrict the spread of fire by closing all doors, windows and vents leading to the location of fire if possible. Isolate the electrical supply and close dampers. Quickly decide whether it may be fought with a portable extinguisher or by smothering it using fire blanket, quickly consider boundary starvation too. If not, rush to your muster station and report the condition of the fire so as to help the senior officer(s)-in-charge decide the best plan of attack. state the location of the fire, the type and if any casualties.

b) The two emergency parties on board a ship are normally composed by members of the three departments (the engine department, the deck department, and the galley). The Emergency team # 1 operates at the point of emergency and the second team acts as standby and supporting team. Depending on where the emergency is (e.g.: fire in the ER, in the Accommodation, or fire on main deck) these teams are interchangeable. One of the teams is led by the Chief Officer and the other by the Second Engineer, and the actions of both teams during an emergency are co-ordinated by the command team, which involves the captain and normally one more officer, from the bridge or any other strategic point on board the vessel. the Chief Officer will brief both parties and remain in command at the scene. The 2nd Engineer is in charge of the fire party, their role is to extinguish and prevent the spread of the fire. The 2nd Officer is in charge of the stand-by team, their role is to take care of first aid responsibilities and be on hand to help anywhere needed.

Command Team: Operated from the bridge. The Master is the overall in charge and the Third Mate/Navigator assists in relaying the orders of the Master to the respective emergency teams in addition to assisting the Master on Bridge.

Emergency Team: Operates at the point of scenario. Usually headed by the Chief Mate/Second Engineer, comprises 2 fire fighters, BA controller and the remaining crew.

Firefighting Team: Standby team of 2 fire fighters and helping hand for emergency team.

Roving Team: Used to close vents/Isolate Commonly Bosun and 2nd Engineer

Engine room team: This team stand by in ECR, usually the Chief Engineer and 1 MM.

Medical Team: Chief Cook/Galley staff who are conversant with the first aid.

Question 11

What is LFL and HFL?

Answer 11

Lower flammable limit (LFL)

The concentration of hydrocarbon gas, 1% by volume in air below which there is insufficient hydrocarbon gas to support and propagate combustion

Higher flammable limit (HFL)

The concentration of hydrocarbon gas in air 10% by volume, above which there is insufficient air to support and propagate combustion. It is a highest concentration of hydrocarbon gas in air for explosion.

Question 12

List the actions to take for a large fire

Answer 12

• Sound fire alarm system.
• Evacuate all ship crew, count them and assign as per muster list.
• Remote stopping of all fuel pump to be done.
• Remote closing of all quick closing valves to be done.
• Remote closing of skylight door and engine all watertight door to be done.
• Remote closing of all engine room ventilation damper to be done.
• Prime mover and all machinery to be stopped.
• All engine room entry and exit door to be closed.
• All ventilation fan in engine room to be stopped manually.
• Fixed firefighting installation system to be operated by C/E or 2/E in a proper manner.

Question 13

a) Describe each of the different classes of fire indicating which firefighting media should be used to extinguish each. (8)

b) State the document that indicates the location of the fire extinguishers onboard a vessel. (2)

c) State three places where the document stated in Q b) would be found. (6)

Answer 13

a) Class A Fire: This fire involves solid combustible materials such as wood, cloth, paper, rubber and plastics. Effectively extinguished by cooling effect so use foam or water. Water is the best extinguishing medium for Class A fires.

Class B fire: Flammable liquids and solids, such as fuel oil or waxes. Foam and dry powder extinguishers are preferable for this fire class. These extinguishers would have a smothering effect on the fire.

Class C fire: Flammable gases, such as butane, propane, and methane. Dry powder extinguishers are preferable for this fire class. If possible, isolate the source of gas first as if the flammable gas is escaping it making the fire situation more dangerous

Class D: this fire involves the burning of metals such as magnesium, aluminium and titanium. The best fire extinguishing media for this is dry powder. These fire can reach very high temperature therefore no water can come in contact with the burning metal as this can cause the disassociation of water, which feeds the fire instead of putting it out. If the temperature is too hot for dry powder to put the fire out, then use boundary cooling to lower the temperature

Electrical fires – these are considered as a class of fire but not a type of fire. Reason being that electricity isn’t a source of fuel for the fire the surrounding material but of course the cause of the fire is the electrical fault. To extinguish this fire its best to use CO2 but dry powder can be used. CO2 is preferred as it doesn’t cause a mess to the electrical equipment.

Class F: these fire involves cooking oils and fats. The best way to extinguish these fire is with a fire blanket. Water cant be used as it this would turn into steam and expand rapidly taking the burning oil with it. In a confined space this burning oil is carried to the ceiling as a fire ball.

b) The document that indicates the location of the fire extinguishers on board a vessel is the “Firefighting training manual”.

c.) * Crew mess room(s).
* Recreation room(s).
* Navigation Bridge.

Question 14

Why can’t we use just one type of fire detector onboard

Answer 14

Each fire type of fire detector smoke, flame or heat can only identify one aspect of a fire. Smoke detectors based on the ionization chamber are able to recognise combustion products but will not register radiation from a flame or heat. A smoke detector, based on the interruption of light reception by a photo-electric cell, will only identify the shadow effect of dark smoke when it passes through its chamber. It will not identify unseen combustion products, heat or flame. Heat sensors and rate of temperature rise sensors based on the differential expansion of bimetal strips will detect only heat. Flame detectors may not detect a flame which is hidden by equipment and are sometimes caused to operate by sources of radiation other than from a flame. Therefore, various types of fire detectors have to be used to be able to identify the various aspect of a fire such as smoke, heat or flame.

Question 15

a.) List four different types of fire detector heads that may be fitted to the fire detection system. (4)

b) Describe the operation of the fire detector heads listed in part a). (12)

Answer 15

a) Heat detector.
Optical smoke detector.
Infrared flame detector.
photo electric cell smoke detectors

Heat detector, a heat detector responds when the thermal energy of a fire increases the temperature of a heat sensitive element. There are two types of heat detector , “rate-of-rise” and “fixed temperature”.

Fixed Temperature Heat Detector
works when the heat exceeds a pre-determined temperature, the bi-metallic element deflects and closes the contact, triggering the fire signal. The bi-metallic switch is normally composed of two metals, each having a different temperature coefficient of expansion. As this bi-metallic element heats the metal with higher coefficient of expansion, it causes the switch to bend or curve, closing the switch; thus, indicating an alarm condition.

Rate-of-Rise (ROR) heat detectors
operate on a rapid rise in element temperature of 6.7°C to 8.3°C increase per minute, irrespective of the starting temperature. This type of heat detector can operate at a lower temperature fire condition than would be possible if the threshold were fixed. It has two heat-sensitive thermocouples or thermistors. One thermocouple monitors heat transferred by convection or radiation while the other responds to ambient temperature. The detector responds when the first sensing element’s temperature increases relative to the other. Rate of rise detectors may not respond to low energy release rates of slowly developing fires. To detect slowly developing fires combination detectors add a fixed temperature element that will ultimately respond when the fixed temperature element reaches the design threshold.

Optical smoke detectors relay on the smoke particles to obstruct an IR or other light source within the device, obstructing the light sensor thus causing an alarm. smoke scatters a light source towards its sensor causing an alarm condition

Infrared flame detectors work by sensing a flame, flickering at less than 25Hz and after a time delay of 5-20 seconds an alarm sounds. Sensor looks for infra-red or ultraviolet radiation emitted by a fire. The radiation increases the conductivity so that the current flow increases and causes the alarm circuit to be triggered. To reduce the chance of false alarms from light sources other than flame, a capacitor and a coil are connected in series, such that current fluctuations, with frequency similar to the of flames, are passed. Flame detectors are normally found near to fuel handling equipment in the machinery spaces but not normally at boiler fronts as boilers sometimes need to have naked flame torches to ignite them.

Photo electric cell smoke detectors: There are three types of this detector in use, light scatter, light obscuration and photoelectric. These types of detectors give a very early warning, but they can be vulnerable to vibration and dirt.
Photoelectric type smoke detector
Smoke produced by a fire affects the intensity of a light beam passing through air. The smoke can block or obscure the beam. It can also cause the light to scatter due to reflection off the smoke particles. Photoelectric smoke detectors are designed to sense smoke by utilizing these effects of smoke on light.

Obscuration type of smoke detector
employs a light source and a photosensitive receiving device such as a photodiode. When smoke particles partially block the light beam, the reduction in light reaching the photodiode alters its output. The change in the photodiode’s output is detected by the detector’s circuitry, and when the threshold is crossed, an alarm is initiated. This type of detector can be tested by blocking the incident light with a piece of paper or with a test gas contained within a test canister.

Light Scattering type smoke detector
This type of smoke detector employs a light emitting diode (LED). The LED is beamed onto an area not normally “seen” by a photosensitive element such as photodiode. When smoke particles enter the light path, light strikes the particles and is reflected onto the photodiode which cause the detector’s circuitry to respond and raise the alarm. This type of smoke detector is tested with the aid of test gas contained in the canister.

Question 16

Describe the testing of fire detectors

Answer 16

• Heat detectors – These are normally tested by means of a portable hot air blower. The air outlet temperature should be gradually brought up to just the minimum activation temperature of the detector. Watch for insensitivity or oversensitivity.
• Smoke detectors – These are normally tested by using an aerosol can which has been specially formulated for testing purposes. A simple one- or two-second spray, from 2 to 4 feet away, will set off the alarm on a properly functioning smoke detector. Watch for detector delay.

Inform and obtain permission from the Bridge before starting to inspect/testing the fire detectors. depending on the detectors used, actual inspection may be carried out as follows:

• After completion of inspection inform the Bridge and carry out any corrective action as applicable.

Question 17

What is the Purpose of siphon Tube in CO2 Extinguisher?

Answer 17

Whether it is portable CO2 fire extinguisher or cylinder in CO2 flooding system, a siphon tube or dip tube is necessary inside bottle. The function of dip tube is to deliver liquid carbon dioxide outside the bottle. If dip tube in not provided, CO2 evaporates from the surface while discharge taking latent heat of vaporization and remaining liquid CO2 will freeze inside and hence failure of CO2 discharge. Therefore, it is necessary to operate CO2 fire extinguishers in upright position.

Question 18

a) Name four types of portable fire extinguishers that may be found in the
machinery space on board ships. (8)

b) State the Fire Classifications, including the type of material involved with EACH (8)

Answer 18

a) The four types of portable fire extinguishers that may be found in the machinery space on board ships are:
Dry powder 45L
Foam 9L
Water
CO2

b) Class A – Wood/paper textiles.
Class B – Flammable liquids and solids.
Class C – Fires involving gases.
Class D – Fires involving metals.
Class E or ↯ – All electrical fires.
Class F – High temperature cooking oils

Question 19

a) With reference to contents and use, describe how a portable fire extinguisher is identified. (4)

b) State, with reason, the type of fire extinguisher normally found in the engine control room. (4)

Answer 19

a) According to BS EN 3 guidelines, every fire extinguisher is to be red in colour. However, a band or circle of a second colour covering between 5-10% of the surface area of the extinguisher should be used to indicate its contents. most modern fire extinguishers also specify on the label whether they should be used on electrical equipment.

b) Fire hazards associated with the Engine Control Room mainly involve electrical equipment, due to the switchboards and all of the electrical equipment there. Accordingly, CO2 and dry powder extinguishers are normally provided for these spaces. CO2 due to its ability to be used on live electrical equipment whilst being non-corrosive.

Question 20

In order of preference, identify two types of portable fire extinguishers that may be used to fight a fire in the following shipboard cases:

a) The galley;
b) An accommodation space;
c) The machinery space control room;
d) The main electrical switchboard.

Answer 20

a) The galley; CO2 and foam. Foam, in the event of oil-based fire. CO2, in the event of a fire with live electrical equipment.

b) An accommodation space; Water and foam. Water, in the event of a combustible materials fire. Dry Powder, in the event of a fire involving live electrical equipment.

c) The machinery space control room; CO2 and dry powder. Foam in the event of an oil based electrical fire. Dry Powder in the event of a fire involving live electrical equipment non-critical.

d) The main electrical switchboard. CO2 and dry powder. CO2 in the event of a fire involving live electrical systems that are critical. Dry Powder in the event of a fire involving live electrical equipment non-critical.

Question 21

a) Describe the maintenance required by each of the following fire extinguishers:

i) CO2: (6)

ii) Dry powder. (6)

b) Describe the routine inspections of the portable fire extinguishers found in the machinery spaces (4)

Answer 21

a) i.) Other than the yearly basic servicing, CO2 extinguishers, which are subject to pressure vessel safety legislation due to their high operating pressure, must be hydraulic pressure tested, inspected internally and externally every 10 years. Check the hoses are not perished. Check the weight of the bottle within 10% of stated volume. Check the bottle for visible damage. They are serviced ashore but onboard inspection consists of checking the body for corrosion or damage and weighing the cylinder to see if any contents have been lost.

ii.) Other than the yearly basic servicing, dry powder extinguishers require every five years a detailed examination including a test discharge of the extinguisher and recharging; on stored pressure extinguishers this is the only opportunity to internally inspect for damage/corrosion. Weigh the appliance for stated weight. Check the CO2 canister for damage. Rotate the canister 180deg and shake to free powder. All maintenance must be done in the driest of conditions as the powder will absorb any moisture. Agitate powder to avoid compaction. Weigh the whole extinguisher to see if any powder has been lost.

b.) Examine the extinguisher body for corrosion and damage. Carefully check the plastic head cap for signs of UV degradation Check the condition of the discharge hose and make sure that it meets the manufacturer’s specifications. Weigh the extinguisher to check that the weight corresponds with previous value.
Check Safety pin and seal is in place and
pressure gauge indicating needle is in the green area. Check that the operating instructions on the extinguisher are clear and legible.

Question 22

Describe the construction of a portable fire extinguisher?

Answer 22

a standard potable fire extinguisher is constructed of steel with a plastic stand fitted to the bottom. the newest fire extinguishers are now made of lightweight composite material because this material will not corrode and therefore extinguisher will not need servicing as long as they remain pressurised. whatever the construction material the fire extinguisher must be of sufficient strength to contain the pressure and must meet certain standards.

fire extinguishers nozzle will differ slightly depending upon type fire extinguishing medium.

for example

• foam extinguishers have a special nozzle to assist with introducing air into the mixture to form the foam jet that’s aimed at a fire.
• CO2 extinguishers have a shallow tapered nozzle that slows the velocity and concentrates the CO2 gas in the right direction and prevents it from mixing with the air
• water extinguishers have a rounded end that helps to form a jet that can be directed towards the fire

Question 23

Describe the operation and maintenance of a portable water extinguisher

Answer 23

Normally Found only in accommodation area. It has a 9-litre capacity, a minimum range of 6m and a discharge time of 65s. It is operated in the upright position, to operate pull the pin and press the handles together, this pierces the CO2 cartridge and pressurises the extinguisher body, which forces water up the siphon tube. Releasing the handles will stop the discharge. Once used, de-pressurize the container and extinguisher to be recharged. The jet of water coming from the nozzle should be aimed at the base of the fire and kept moving around the whole area until fire is extinguished.

Additives maybe be included in the water such as salts to reduce freezing point and or anti-freeze. Do not use It cannot on live electric equipment since water is a good conductor of electricity and do not to keep the extinguisher in high temperature areas, since increase in temperature causes pressure of carbon dioxide gas to increase and it may result in accidental release of the CO2 gas which then forces the water up the siphon tube. Water extinguishes the fire in two ways. One is the water has a cooling effect on the fire which removes the heat. Second is it covers the material on fire with a blanket of steam as the water evaporates, this cuts the oxygen supply due to smothering. Water is best used on class A fires.

Maintenance

• inspection is carried out Monthly/annually.
• Inspect pressure gauge for correct reading (in the green)
• Inspect the inside and outside of the extinguisher body for corrosion or damage.
• Examine the gas cartridge and weigh it, compare this with the weight stamped on the cartridge.
• Clean the vent holes.
• Check the mechanism.
• The extinguisher body and the gas bottle must be hydraulically tested every 10 years

Question 24

Describe the operation and maintenance of Foam (AFFF) Extinguisher

Answer 24

Found in Machinery
spaces/accommodation and galley. It has a 9-litre capacity, minimum range of 4m and a discharge time of 40s. It is of the same construction as the water extinguisher except that it is filled with a foam solution and has an aspirator nozzle on the end of the discharge hose, which induces the air, this is how the foam is created. The extinguishing effect of the foam is a combination of smothering and cooling. The foam is designed to float on oil, forming a space between the oil and the flame. The AFFF type a significant amount of water content which will help reduced heat but because of the water content the AFFF type shouldn’t be used on electrical fires. Foam fire extinguishers are designed for use on Class A and Class B fires. The technique for extinguishing a fire with foam is to aim the foam jet at a structure close to the fire so that the foam then spreads and covers the fire and then due to smothering and cooling effect the fire is extinguished.

Maintenance

• inspection is carried out Monthly/annually.
• Inspect pressure gauge for correct reading (in the green)
• Inspect the inside and outside of the extinguisher body for corrosion or damage.
• Examine the gas cartridge and weigh it, compare this with the weight stamped on the cartridge.
• Clean the vent holes.
• Check the mechanism.
• The extinguisher body and the gas bottle must be hydraulically tested every 10 years
• Check the quality of the foam solution, replace it if it smells bad or has gone black.
• Foam has a limited life span and has to be replaced at approximately 4 yearly intervals

Question 25

Describe the operation and maintenance of a CO2 fire extinguisher

Answer 25

Found in the Machinery spaces near switch boards/electrical rooms. It commonly has a 2kg or 6kg capacity, which gives a discharge time of 10/19sec, the gas is stored at 55 bar. The extinguisher is designed to release liquid CO2 which is turned into a gas in the nozzle which can ice up as the liquid expands. They are fitted with high pressure relief devices and for this reason are not allowed in accommodation spaces. They are serviced ashore but onboard inspection consists of checking the body for corrosion or damage and weighing the cylinder to see if any contents have been lost. The cylinder should be hydraulically tested every 10 years. To operate remove the safety pin and then the handle lever is squeezed to pierce the disc. The liquid CO2 leaves into the discharge nozzle and emerges as a cloud of CO2. The technique is to cover the area with CO2 to smoother the fire and so that oxygen is excluded. The CO2 extinguisher shouldn’t be used on confined spaces as it will endanger crew. The better option for electrical fires as won’t leave as much damage or mess to electrical equipment as oppose to dry powder extinguisher. Can be used on class B or C type fires.

Maintenance

• inspection is carried out Monthly/annually.
• Inspect pressure gauge for correct reading (in the green)
• Inspect the inside and outside of the extinguisher body for corrosion or damage.
• Examine the gas cartridge and weigh it, compare this with the weight stamped on the cartridge.
• Clean the vent holes.
• Check the mechanism.
• The extinguisher body and the gas bottle must be hydraulically tested every 10 years

Question 26

Describe the operation and maintenance of a dry powder fire extinguisher

Answer 26

Found in the machinery spaces/Switchboards rooms & Accommodation.

These come in 2 types:

• Stored pressure, where the extinguisher is pressurised with nitrogen or dry air.
• Cartridge type, where the gas charge is inside a cartridge inside the extinguisher.
  The extinguisher incorporates a balance valve, the purpose of this is to ensure that the gas passes through the powder and completely fluidises it. The extinguisher is operated in the same way as the water type. The extinguishing effect of the powder is mainly by inhibition (chain reaction breaking) and effective mainly against fires in flammable liquid, gases and electrical equipment. Extinguisher is best used by pointing the discharge jet/cloud at the fire and driving it towards the far corner of the area that is alight.

Maintenance

• inspection is carried out Monthly/annually.
• Inspect pressure gauge for correct reading (in the green)
• Inspect the inside and outside of the extinguisher body for corrosion or damage.
• Examine the gas cartridge and weigh it, compare this with the weight stamped on the cartridge.
• Clean the vent holes.
• Check the mechanism.
• The extinguisher body and the gas bottle must be hydraulically tested every 10 years
• All maintenance must be done in the driest of conditions as the powder will absorb any moisture.
• Agitate powder to avoid compaction.
• Weigh the whole extinguisher to see if any powder has been lost

Question 27

In the event of discovering a fire in the machinery space, list the actions to be taken after deciding that the fire has become too fierce to fight and the fixed CO2 installation is to be used. (10)

Answer 27

the CO2 system is the last resort for fighting fire and no more firefighting method is available after using that (CO2 system can be used only once). The CO2 operator in-charge i.e. Chief engineer (or 2nd engineer in C/E’s absence) has to be extremely careful when it comes to following procedure to avoid fire from spreading or any casualty.

• On outbreak of fire, the fire alarm is sounded, and bridge is informed about the location of fire. All crew should be gathered in muster stations for head count.
• If the fire is too fierce to be fought with portable extinguishers, the chief engineer should take the decision in consent with the master to flood the engine room with CO2 to extinguish the fire.
• The Emergency generator and fire pump should be started as 𝐶𝑂2 flooding requires all engine room machinery, including the auxiliary generator to be stopped. Make sure emergency generator is running and on load. Power is required for running emergency fire pump for boundary cooling.
• Reduce ship speed and stop the main engine at a safe location. The Master should inform the nearest coastal authority if the ship is in a coastal zone
• a crew member should open the cabinet of the 𝐶𝑂2 operating system in the fire station with the “Key” provided nearby in the glass case. This will give an audible 𝐶𝑂2 Alarm in the engine room. Some systems and machinery including engine room blowers and fans etc. will trip with opening of 𝐶𝑂2 cabinet. Check all these have tripped.
• Operate all remote closing/Shutdown switches for quick closing valves, funnel flaps, fire flaps, engine room pumps and machinery, watertight doors etc.
• Close all the entrance doors of the engine room and make sure the room is airtight. All access doors, vent flaps, blower flaps, skylights, hatches, fire flaps, to be closed. All machinery in engine room to be stopped
• Ensure there is no one left inside the engine room by repeating a head count and once all persons are present at the muster station, the entire CO2 system may be released.
• In the CO2 release cabinet, open pilot cylinder valve first. Now open master valve first. Then open valve for CO2 releasing mechanism. Co2 will be released after 60-90 seconds of time delay. If CO2 is not released, then follow emergency releasing procedure. Open master valve manually and open each CO2 main bottle by manual actuation lever.
• When Co2 is released there will be a loud noise of gas escaping. CO2 bottles can be felt cold after releasing. Visual inspection of the operation of, pressure operated cylinder valves also can be carried out.
• CO2 has very little cooling effect. So, there is a danger of re-ignition of fire when engine room is ventilated immediately. Keep the boundary cooling running to reduce the temperature of the engine room.
• Ventilation of engine room should not be started until it has been definitely established that the fire has been extinguished completely, which can take several hours.
• Engine room to be sufficiently ventilated for a period of 24hours before re-entering. Entry to be carried out by trained personnel wearing breathing apparatus.
• Back up team or support team to be ready in case any difficulties happens inside.
• An attendant should be instructed to remain at the entrance of the engine room.
• An agreed and tested system of communication to be established between attendant and team inside engine room.
• In case any emergency occur to the team inside engine room, the attendant is not supposed to enter inside before the help has arrived.
• In the event of ventilation system fails, the personnel in the space should leave immediately.

Question 28

Explain the Foam flooding installation system

Answer 28

Onboard ships we use only high and low expansion foam. There are three types of foam

Low expansion foam – These foam solutions are having expansion ratio less than 12:1. these are used for cargo deck area.

Mid expansion foam – These foam solutions are having an expansion ratio of more than 20:1, but less than 100:1 The system is designed to deliver a blanket of foam on top of the fire. Foam concentrate is mixed with water in a correct proportion to form a foam solution. This foam solution when agitated with air produces foam.

High expansion foam – These foam solutions have an expansion ratio above 100:1. They are light in weight than other mid and low expansion foams and are used only in machinery space/engine room. Low expansion foam has a higher weight to volume ratio as compared to high expansion foam. If we use high expansion foam on deck, then it would be possible for wind to blow away the foam. Low expansion foam has sufficient weight to counter the wind force effect, so it is easier for low expansion foam to form a blanket over fire properly. In the engine room, wind effect is not present, so it is effectively easier to suppress the flammable gases and to give a cooling effect in the large volume of the engine room. So high expansion foam is used to cover more space in a short time. The maximum expansion ratio of high expansion foam is 1000:1 and the foam must be able to fill a space at the rate of 1m depth per minute. High expansion foam concentrate, and water are mixed in the correct proportions (3% to 6% concentrate) to form a foam solution. This solution flows to the high expansion foam generator and is then discharged through a nozzle onto a fine mesh stainless steel screen. The fan in the high expansion foam generator forces large volumes of air through the stainless-steel screen as the foam solution is sprayed onto it. The air mixes with the foam solution to a large discharge mass of stable bubbles at a controlled rate. This highly expanded foam mass quickly fills large areas flowing around obstacles and thus smothers the fire. To operate the system the foam concentrate line is opened, and the fire pump started. Foam mixing is carefully metered by the mixing device which is a venturi device. Both the fire pump and the foam concentrate tank must be located outside the engine room. Air is drawn into the foam solution at the discharge device which then generates foam

Question 29

What is the function of a Bursting Disc in CO2 Flooding System?

Answer 29

The pressure of CO2 inside the bottle depends on the temperature of the surroundings. As temperature increases, pressure also increases. Therefore, to safeguard against abnormally high pressures inside the bottle, a bursting disc is provided on the head assembly. When the CO2 pressure inside the bottle increases to about 200 bar, bursting disc bursts and releases CO2 to the CO2 room it also means there is a fire in engine room. Here, CO2 released from the bottle itself extinguishes fire inside the room.

Question 30

Explain one type of time delay unit used in a CO2 flooding system?

Answer 30

The time delay can be achieved in different ways. Out of these, two types of time delay unit is commonly used in CO2 flooding system on board ships. One is electrical type, which has an AC 220 V power supply, a pressure switch, timer and a solenoid valve. Solenoid valve is normally in closed position. When CO2 from pilot cylinder (CO2 release cabinet) reaches the time delay unit, the pressure acts on the pressure switch. This closes the pressure switch. But the timer allows power supply to the solenoid only after 60-90 seconds, the timing can be adjusted as required. As soon as the specified time is reached, solenoid becomes energized and the solenoid valve will open. This allow passage of CO2 to the pressure operated cylinder valve of main bottle. Normally a bypass valve is also fitted across this time delay unit which can be used in case the unit goes defective.

Question 31

What is the function of a Time Delay Unit in CO2 Flooding System?

Answer 31

CO2 from the pilot bottles in release cabinet reaches main CO2 bottle head assembly through a time delay unit. Function of this time delay unit is to delay the supply of CO2 for 60 – 90 seconds. Reason for providing such a delay in CO2 flooding system are as soon as CO2 release cabinet opens, alarm is sounded in the protected space. A time delay of 60 to 90 seconds give sufficient time for any personnel in the protected space to escape.

Question 32

Explain the CO2 flooding system.

Answer 32

CO2 flooding system floods the protected space under fire with carbon dioxide, which displaces oxygen, thereby removing one part of fire triangle for the extinction of fire. CO2 flooding system consist of main CO2 bottles, common manifold, master valve or distribution valve and distribution pipelines with nozzles as shown in the system drawing below. Main CO2 bottles contain carbon dioxide in liquid state with a pressure of 56 bar at 20 degree Celsius. Pressure of CO2 at 25 and 30 degree Celsius are 64 bar and 71 bar respectively. So, it is important to keep the temperature of CO2 bottles low for limiting the pressure inside bottles. The operator in the control position releases the gas from master cylinders in the CO2 room by means of a manual pull wire. The CO2 from these cylinders acts on the piston release system. Movement of the piston actuates a system of levers attached to the cylinder head valve, which releases the gas to the manifold. The released gas then passes to a control valve at the control station and then to the diffuser heads in the protected spaces. A pressure transducer with an alarm is fitted to the main discharge line in order to identify any leakage of CO2 gas from bottles to the manifold. The pressure switch activates warning alarm for the leakage. Before the CO2 gas is released the space must be clear of personnel and sealed against entry and the ingress of air which could feed the fire. All access doors and ventilation dampers should be closed before the CO2 is discharged.

Question 33

Explain the operation of the water mist firefighting system?

Answer 33

Automatic Operation

The water mist firefighting system consists of two detectors placed over the area to be protected (such as main engine, auxiliary engines, incinerator, auxiliary boiler, purifiers, etc.). Out of these two detectors, one is a smoke and other is a flame detector. If only one detector is activated in a protected area, it gives a fire alarm as a pre warning. In case both the detectors are activated, the information is transmitted to the main control panel of the water mist fire extinguishing system and it starts the water pump and opens the solenoid valve to the particular protected area. Water at high pressure (around 10 bar at the nozzle) reaches water mist nozzles and forms fine mist which is sprayed over the area under fire. Water mist is discharged until stop. If the fire is not extinguished, the water mist can be discharged for 20 minutes according to international rule regulations. Solenoid valves are electrically operated by the main control panel for directing high pressure water to the nozzles placed in protected area.

Manual Operation

In case water mist is to be manually sprayed over any protected area, the ‘START’ push button on the local or remote-control panel for the particular area can be activated, which will start the pump and activate the solenoid valve for the respective area.

Question 34

Describe the water mist firefighting system?

Answer 34

The water mist firefighting system basically consists of fire detection part and firefighting part. The fire detection part monitors and detects the fire condition of the protected area. If any fire is detected, it transits the information on fire location to the main control panel. activates the pump and solenoid valve (for the protected area) and discharges the water mist through the nozzles over the protected area. The water mist fire detection and firefighting system can be operated automatically or manually.

System Components

1.Main Control Panel
2.Water Pump (For High Pressure Water)
3.Fire Detectors (Detects Fire in Protected Area)
4.Solenoid Valve (One for Each Protected Area
5.Water Nozzles (Produces Water Mist)

Question 35

Explain the Automatic Water Sprinkler System

Answer 35

The automatic water sprinkler system is an automatic fire detecting, alarm and extinguishing system which can deal quickly and effectively with any outbreak of fire that may occur in accommodation or other spaces on ships. The system consists of several sections comprising a number of sprinkler heads mounted on the pipes, each section being connected through a section control valve to a sprinkler main which in turn is connected to a pressure tank and a pump. Number of sprinkler heads per section to be not more than 200. Each section has an alarm system. The entire system is initially charged with fresh water at a pressure of about 8 bar by a tank (tank is half filled with fresh water), maintained under pressure by compressed air. This should be such that the pressure at the highest sprinkler head in the system is not less than 4.8 bar. It is also connected to an independent sea water pump with its own sea water suction. Each sprinkler head has a quartzoid bulb which retains a diaphragm seal in the outlet of the water pipe. This bulb is partially filled with a special fluid so arranged that a rise in temperature in the compartment concerned will cause the liquid to expand and entirely filled the space, the bulb burst, the water pressure forces the diaphragm out and water flow out from the sprinkler. Under the specific pressure maintained in the tank by air pressure, the water from the sprinkler is deflected outwards and broken into a fine spray and will adequately cover a floor area. When the sprinkler head comes into operation, the non-return alarm valve for the section opens and water flows to the sprinkler head. This non return valve also uncovers the small-bore alarm pipe lead and water passes through this small-bore alarm pipe to a rubber diaphragm. The water pressure acts on this diaphragm and this operates a switch which causes a break in the continuously live circuit. Alarms both visible and audible, fitted in engine room, bridge and crew space are then automatically operated. Thus, the pressure drop at the release of the water causes an alarm to sound on the bridge and indicates on the board, the zone in which the ruptured sprinkler heads are situated. When the system pressure dropped to 5 bar, the sea water pump will start automatically and continue supply with sea water. A hose connection is also provided so that water can be supplied to the system from shore when ship is in dry dock. The sprinkler heads are spaced not more than 4 meters apart and 2 meter from any bulkhead or part of the ship’s side which forms a boundary of the protected space. Stop valves ‘A’ and ‘B’ are locked open and if either of these valves are inadvertently closed, a switch will be operated that brings the alarms into operation. The alarm system can be tried by opening valve ‘C’ which follows delivery of water similar to that of one sprinkler head to flow to drain. At least two sources of power must be provided to operate the sea water pump and automatic alarms.

Question 36

What is an emergency fire pump?

Answer 36

• It is a fixed pump independently driven by self-cooled compression ignition engine or an electric motor for which power is supplied from emergency generator. can be fitted at steering flat, shaft tunnel, or forward part of the ship.
• It is fitted as alternative means of providing water for firefighting if a fire in anyone compartment could put all the fire pumps out of action either by disabling the pumps of their source of power.