co2 system for engine room assignment

7/28/2019 CO2 System for Engine Room Assignment

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Fire extinguishing equipment fixed

The fixed fire extinguishing system r installed to protect large areas like the

machinery spaces and cargo holds. Smaller areas such as the paint store and the

ventilation duct to the galley are protected with a fixed system due to the high

potential risk of fire.

Fixed gas fire extinguishing system

Locating and extinguishing a fire in large enclosed compartments by conventional

means may be very time consuming. Taking into consideration that even small fires

can cause severe damage to vital machinery and/or cables, the decision to release the

fixed gas fire extinguishing medium into nay enclosed compartments should not be

delayed by manual fire fighting unless this is deemed as being the quickest and most

effective option.

In any protected space to which personnel have access an automatic audible warningof the release shall be provided.

The alarm shall operate for the length of time needed to evacuate the space.

During fire drills all crewmembers shall be made familiar with the sound of the alarm

and all must be instructed to:

When the alarm sounds leave the room immediately

This applies to all situations the room must be evacuated even if the alarm is believe

to sound due to technical, electric or other failures.

CO2 system GINGE KEER

GENERAL DESCRIPTION

A low pressure carbon dioxide system is designed to protect the cargo holds, the

hazardous store forward(paint store), the emergency generator room and the engine

room with the auxiliary machinery spaces, is provided in a separate CO2 room.

The liquid CO2 is stored in a tank with a capacity of 10,000 kg of CO2. The CO2 iskept cooled by refrigerating machinery at a temp of 18 C corresponding to a pressure

in the tank of 21 Bar.

Two complete refrigerating units, separated fm each other, and each having sufficient

capacity to keep the tank cooled, and provided together with the tank.

Each unit is controlled by a pressure switch which, when activated by the tank

pressure, governs start and stop of the refrigerating compressor. Furthermore, each

refrigerating unit is connected to a separate evaporator built into the top part of the

CO2 tank, and provided with air-cooled condensers


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To protect the CO2 tank against increased pressure in case of power failure or fire ,the

tank is fitted with two safety valves, each one with sufficient capacity to protect the

tank form bursting.

A three way valve is fitted under the safety valves to ensure that only one safety valve

is shut off at a time. In case of power failure the blow off loss is limited to 300-400 kgof CO2 per 24 hrs after blow off has started.

To check the quantity of CO2 in the tank a liquid level meter, a liquid level gauge

pipe and level test valves for 100%,95%,75% and 0% levels r fitted.

AUXILIARY EQUIPMENT AND UTILITES

THE FIRE EXTINGUISHING PLANT COMPRISES OF THE FOLLOWING:

1. One CO2 storage tank.

2. Two refrigerating compressors.3. One instrument panel.

4. Three master control units.

5. One electronic liquid level meter.

6. Safety equipment.

OPERATION FROM THE INSTRUMENT PANEL

The system is controlled fm the instrument panel. During normal operation only green

lamps are on. In case of a fault or abnormal operation , red lamps come on , and the

alarm is sounded.

For control, the instrument panel contains the following equipment :

1. Change over switch for the refrigerating compressors.

2. Various indicators and warning lights for operation and fault.

3. Liquid level meter with indicator and alarm at low liquid level.

4. Tank pressure gauge.

5. Pressure switches controlling compressors and alarms.6. Circuit breakers, relays, terminal boards and fuses.

The change over switch at the instrument panel enables switching fm one compressor

to the other. The change over switch has the following four(4) positions:

0 both compressors are stopped.

I compressor 1 is connected.

II compressor 2 is connected.

I+II both compressors are connected.


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During normal operation the change over switch shall be in either position I or II. If

the change over switch is in e.g. position I , compressor 1 will be engaged and started

and stopped by signals respectively fm the high and low pressure switches.

In case of a failure and compressor 1 will not start, the start signal automatically is

transmitted to compressor 2, which thus will start. Exactly the same applies to thechange over switch when in position II.

If one compressor cannot manage the cooling on its own, and the pressure in the CO2

tank continues to rise, an extra pressure switch will automatically connect the other

compressor and the red lamp CO2 pressure over max./below min. comes on in the

instrument panel.

The pressure switches are adjusted as follows:

Type of switch pos set pressure disconnection at

Control pressure 2 22 bar (2.2 MP a) 20 bar (2.0 MP a)

High pressure 1 24 bar (2.4 MP a) 22 bar (2.2 MP a)

Low pressure 1 20 bar (2.0 MP a) 18 bar (1.8 MP a)

For distr. Pipe 1 6 bar (0.6 MP a)

Safety Equipment

The storage tank is provided with two safety valves, which will open when the

pressure in the tank reaches a pressure of 24.5 Bar. They are fitted on a three way

valve ensuring that one of the safety valves will always be connected.

In addition, six small safety valves are fitted to pipe sections where it is possible for

the liquid CO2 to be trapped. These valves open at a pressure of 35 bar.

Pipe sections that are protected by safety valves are as follows:

1. Main outlet pipe between main isolation valve and main valve.

2. Main outlet pipe between main valves.

3. Valve register for cargo holds.

4. Valves register for emergency generator room and paint store.5. Filling line, liquid side.

6. Filling line, vapour side.

An alarm will indicate the following faults:

- Main fuses blown.

- CO2 pressure over max. /below min.

- Pressure in distribution manifold.

- Co2 liquid level below min.

- Fault compressor I

- Fault compressor II


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Measuring of liquid level

The tank is provided with an electronic liquid level meter, an electronic limit

controller, an indicating instrument and a probe stick with an electronic pre-amplifier

unit.

The probe is arranged in a level measuring pipe placed at the middle of the tank. The

level measuring pipe placed at the middle of the tank. The level measuring pipe is

connected with the tank by a pipe at the top and the bottom.

On the measuring pipe itself four (4) valves are fitted:

- One at the bottom at operating pressure 21 bar.

- One at 75% level at operating pressure 21 bar.



By opening one of these valves the level can be checked:

- If CO2 gas comes out, the liquid level is below the valve.

- If CO2 snow comes out, the liquid level is above the valve.

Releasing of CO2

The plant is provided with two separate master control units, placed in the fire control

station and the aft end of the starboard box grinder on the 2nd deck. From these two

places CO2 can be released to the main engine room and to the auxiliary machinery

space. CO2 can also be released from the CO2 room to the following places:

- Main engine room.

- Auxiliary machinery space.

- Emergency generator room.

- Cargo holds 1-11

- Paint store forward.

Before releasing CO2, always make sure that everybody has left the compartment. To

release CO2 from one of the master control units to the engine room or auxiliarymachinery room the following steps must be taken:

- Open the master control unit door.

- Open screw valve on one of the master cylinders.

- Open master control valve no. 1

- Open the master control valve no. 2

For releasing of CO2 from the CO2 room to the engine room or auxiliary machinery

room:

- Open the door for either control box engine room valve or control box auxiliarymachinery room valve.


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- Open the pilot valve for main valve (19).

- Open the pilot valve for engine room distribution valve respectively pilot valve

for aux. machinery space distribution valve (20).

For releasing of CO2 from the CO2 room to the emergency generator room or the

paint room.

- Open distribution valve in manifold for the room in question. The valves are marked

Emergency Generator Room and Paint Room.

- Open pilot valve (20) placed in box marked control box for emergency generator

room and paint room valve.

- Open pilot valve for main valve (19).

The main valve (4) will close automatically after the calculated release time, which is

for:

1. Engine room - two (2) minutes2. Auxiliary machinery room - two (2) minutes

3. Emergency generator room - two (2) minutes

4. Paint store - two (2) minutes

5. Cargo holds - sixty (60) minutes

If more Co2 is needed after the release time has ended; press button CO2 re-release.

The CO2 alarm will automatically be released, when:

- Master control valve no. 2 is opened in nay of the master control units.

- Pilot valve no.20 is opened in any of the control boxes in the CO2 room.

When the CO2 system is activated for the engine room or the auxiliary machinery

room the supply and exhaust fans will automatically stop. The fire flaps will be

activated simultaneously and close.

CO2 quantity

Co2 quantity calculated for the various spaces:

Engine room 7100 Kg

Auxiliary machinery space 1650 Kg

Emergency generator room 90 Kg

Paint room 120 Kg

Cargo hold No. 1 2250 Kg






Cargo hold No. 7 8400 KgCargo hold No. 8 8400 Kg


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co2 system for engine room assignment

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