15.1 Goal
The goal of this chapter is to provide for the arrangement of control, monitoring and
safety systems that support an efficient and safe operation of the gas-fuelled
installation as covered in the other chapters of this Code.
15.2 Functional requirements
This chapter is related to functional requirements in 3.2.1, 3.2.2, 3.2.11, 3.2.13 to
3.2.15, 3.2.17 and 3.2.18. In particular the following apply:
- .1 the control, monitoring and safety systems of the gas-fuelled installation
shall be so arranged that the remaining power for propulsion and power
generation is in accordance with 9.3.1 in the event of single failure;
- .2 a gas safety system shall be arranged to close down the gas supply system
automatically, upon failure in systems as described in table 1 and upon other
fault conditions which may develop too fast for manual intervention;
- .3 for ESD protected machinery configurations the safety system shall shutdown
gas supply upon gas leakage and in addition disconnect all non-certified safe
type electrical equipment in the machinery space;
- .4 the safety functions shall be arranged in a dedicated gas safety system that
is independent of the gas control system in order to avoid possible common cause
failures. This includes power supplies and input and output signal;
- .5 the safety systems including the field instrumentation shall be arranged to
avoid spurious shutdown, e.g. as a result of a faulty gas detector or a wire
break in a sensor loop; and
- .6 where two or more gas supply systems are required to meet the regulations,
each system shall be fitted with its own set of independent gas control and gas
safety systems.
LR 15.2-01 The gas safety system is to be designed to ‘fail-safe’
such that failure does not result in a hazardous situation. The behaviour and status
on failure and fault detection are to be defined.
LR 15.2-02 The gas safety system and gas fuel control system
shall be provided with:
(a) fault tolerance of sensor inputs, e.g. range checking, wire breaking
monitoring;
(b) self-monitoring capabilities to detect both functional and hardware
failures;
(c) proportional control valves with position feedback;
(d) manual control of remotely controlled equipment (where
appropriate);
(e) instrumentation devices to allow local and remote reading of
essential parameters associated with storage, processing and bunkering;
(f) redundant data communication (where redundancy is required); and
(g) safeguards to prevent unauthorised modification of process-related
parameters.
15.3 Regulations – General
LR 15.3-01 Control, alert and safety systems are to comply with
the relevant requirements of Pt 5 and Pt 6, Ch 1 of the Rules for Ships.
15.3.1 Suitable instrumentation devices shall be fitted to allow a local
and a remote reading of essential parameters to ensure a safe management of the
whole fuel-gas equipment including bunkering.
LR 15.3-02 Arrangements are to be made so that the gas supply to
the gas-fuelled machinery and equipment can be shut off manually from any space or
area containing gas-fuelled machinery and equipment, the engine starting platform or
any other control position.
15.3.2 A bilge well in each tank connection space of an independent
liquefied gas storage tank shall be provided with both a level indicator and a
temperature sensor. Alarm shall be given at high level in the bilge well. Low
temperature indication shall activate the safety system.
LR 15.3-03 The level indicator is required for the purposes of indicating an
alarm status only; a level switch (float switch) is an instrument, for example,
considered to meet this requirement.
15.3.3 For tanks not permanently installed in the ship a monitoring
system shall be provided as for permanently installed tanks.
15.4 Regulations for bunkering and
liquefied gas fuel tank monitoring
LR 15.4-01 As a minimum, each tank is to be provided with the
following monitoring:
(a) Vapour space pressure. Pressure indicators are to be clearly marked
with the highest and lowest pressure permitted in the tank. The high pressure alarms
are to be activated before the set pressures of the pressure relief valves;
(b) Vapour space temperature;
(c) Liquid level.
15.4.1 Level indicators for liquefied gas fuel tanks
-
.1 Each liquefied gas fuel tank shall be fitted with liquid level
gauging device(s), arranged to ensure a level reading is always obtainable
whenever the liquefied gas fuel tank is operational. The device(s) shall be
designed to operate throughout the design pressure range of the liquefied
gas fuel tank and at temperatures within the fuel operating temperature
range.
-
.2 Where only one liquid level gauge is fitted it shall be
arranged so that it can be maintained in an operational condition without
the need to empty or gas-free the tank.
-
.3 Liquefied gas fuel tank liquid level gauges may be of the
following types:
-
.1 indirect devices, which determine the amount of fuel
by means such as weighing or in-line flow metering; or
-
.2 closed devices, which do not penetrate the liquefied
gas fuel tank, such as devices using radio-isotopes or ultrasonic
devices;
15.4.2 Overflow control
-
.1 Each liquefied gas fuel tank shall be fitted with a high
liquid level alarm operating independently of other liquid level indicators
and giving an audible and visual warning when activated.
-
.2 An additional sensor operating independently of the high
liquid level alarm shall automatically actuate a shutoff valve in a manner
that will both avoid excessive liquid pressure in the bunkering line and
prevent the liquefied gas fuel tank from becoming liquid full.
-
.3 The position of the sensors in the liquefied gas fuel tank
shall be capable of being verified before commissioning. At the first
occasion of full loading after delivery and after each dry-docking, testing
of high level alarms shall be conducted by raising the fuel liquid level in
the liquefied gas fuel tank to the alarm point.
LR 15.4-02 The expression ‘each dry-docking’ refers to:
- (a) for cargo ships, the survey of the outside of the
ship's bottom required for the renewal of the Cargo Ship Safety Construction
Certificate and/or the Cargo Ship Safety Certificate; and
- (b) for passenger ships, the survey of the outside of
the ship's bottom to be carried out according to paragraphs 5.10.1 and
5.10.2 of the Survey Guidelines under the Harmonized System of Survey and
Certification.
-
.4 All elements of the level alarms, including the electrical
circuit and the sensor(s), of the high, and overfill alarms, shall be
capable of being functionally tested. Systems shall be tested prior to fuel
operation in accordance with 18.4.3.
-
.5 Where arrangements are provided for overriding the overflow
control system, they shall be such that inadvertent operation is prevented.
When this override is operated continuous visual indication is to be
provided at the navigation bridge, continuously manned central control
station or onboard safety centre.
15.4.3 The vapour space of each liquefied gas fuel tank shall be
provided with a direct reading gauge. Additionally, an indirect indication is to be
provided on the navigation bridge, continuously manned central control station or
onboard safety centre.
LR 15.4-03These reading gauge(s) are to be provided for both
pressure and temperature measurement and are to be located in the tank connection
space or a space meeting the requirements for a tank connection space, close to the
storage tank.
15.4.4 The pressure indicators shall be clearly marked with the highest and lowest
pressure permitted in the liquefied gas fuel tank.
15.4.5 A high-pressure alarm and, if vacuum protection is required, a low-pressure
alarm shall be provided on the navigation bridge and at a continuously manned
central control station or onboard safety centre. Alarms shall be activated before
the set pressures of the safety valves are reached.
15.4.6 Each fuel pump discharge line and each liquid and vapour fuel manifold shall
be provided with at least one local pressure indicator.
15.4.7 Local-reading manifold pressure indicator shall be provided to indicate the
pressure between ship's manifold valves and hose connections to the shore.
15.4.8 Fuel storage hold spaces and interbarrier spaces without open connection to
the atmosphere shall be provided with pressure indicator.
15.4.9 At least one of the pressure indicators provided shall be capable of
indicating throughout the operating pressure range.
15.4.10 For submerged fuel-pump motors and their supply cables,
arrangements shall be made to alarm in low-liquid level and automatically shutdown
the motors in the event of low-low liquid level. The automatic shutdown may be
accomplished by sensing low pump discharge pressure, low motor current, or
low-liquid level. This shutdown shall give an audible and visual alarm on the
navigation bridge, continuously manned central control station or onboard safety
centre.
15.4.11 Except for independent tanks of type C supplied with vacuum insulation system
and pressure build-up fuel discharge unit, each fuel tank shall be provided with
devices to measure and indicate the temperature of the fuel in at least three
locations; at the bottom and middle of the tank as well as the top of the tank below
the highest allowable liquid level.
15.5 Regulations for bunkering
control
15.5.1 Control of the bunkering shall be possible from a safe location
remote from the bunkering station. At this location the tank pressure, tank
temperature if required by 15.4.11, and tank level shall be monitored. Remotely
controlled valves required by 8.5.3 and 11.5.7 shall be capable of being operated
from this location. Overfill alarm and automatic shutdown shall also be indicated at
this location.
LR 15.5-01 A method of providing communication with the bunker
supply system is to be provided. Where practicable, this system is to be of a linked
type system and is to connect to the ship’s gas safety system, see 8.5.7.
15.5.2 If the ventilation in the ducting enclosing the bunkering lines stops, an
audible and visual alarm shall be provided at the bunkering control location, see
also 15.8.
15.5.3 If gas is detected in the ducting around the bunkering lines an audible and
visual alarm and emergency shutdown shall be provided at the bunkering control
location.
15.6 Regulations for gas compressor monitoring
15.6.1 Gas compressors shall be fitted with audible and visual alarms both on the
navigation bridge and in the engine control room. As a minimum the alarms shall
include low gas input pressure, low gas output pressure, high gas output pressure
and compressor operation.
15.6.2 Temperature monitoring for the bulkhead shaft glands and bearings shall be
provided, which automatically give a continuous audible and visual alarm on the
navigation bridge or in a continuously manned central control station.
15.7 Regulations for gas engine monitoring
In addition to the instrumentation provided in accordance with part C of SOLAS
chapter II-1, indicators shall be fitted on the navigation bridge, the engine
control room and the manoeuvring platform for:
LR 15.7-01 Where machinery is arranged to start automatically or
from a remote control station, interlocks are to be provided to prevent start-up
under conditions that could introduce an unsafe situation.
15.8 Regulations for gas
detection
15.8.1 Permanently installed gas detectors shall be fitted in:
-
.1 the tank connection spaces;
-
.2 all ducts around fuel pipes;
-
.3 machinery spaces containing gas piping, gas equipment or gas consumers;
-
.4 compressor rooms and fuel preparation rooms;
-
.5 other enclosed spaces containing fuel piping or other fuel equipment
without ducting;
-
.6 other enclosed or semi-enclosed spaces where fuel vapours may accumulate
including interbarrier spaces and fuel storage hold spaces of independent
tanks other than type C;
-
.7 airlocks;
-
.8 gas heating circuit expansion tanks;
-
.9 motor rooms associated with the fuel systems; and
-
.10 at ventilation inlets to accommodation and machinery spaces
if required based on the risk assessment required in 4.2.
LR 15.8-01 In addition to the areas identified in 15.8.1, the
following areas are also to be fitted with gas detection:
(a) any spaces requiring gas detection as identified as part of RBC and
the safety concept for gas-fuelled machinery;
(b) vent outlet from lubricating oil purifiers;
(c) vent outlet from engine cooling water expansion tank.
15.8.2 In each ESD-protected machinery space, redundant gas detection
systems shall be provided.
15.8.3 The number of detectors in each space shall be considered taking
into account the size, layout and ventilation of the space.
15.8.4 The detection equipment shall be located where gas may accumulate
and in the ventilation outlets. Gas dispersal analysis or a physical smoke test
shall be used to find the best arrangement.
LR 15.8-02 The detector or sampling heads of the fuel gas
detection systems are not to be located where liquid can collect. Pipe runs from
sampling heads are not to be led through non-hazardous spaces, except as permitted
by LR 15.8-09.
15.8.5 Gas detection equipment shall be designed, installed and tested
in accordance with a recognized standard.footnote
LR 15.8-03 In addition, the equipment is to be designed to be
self-monitoring such that failure of the control panel, detector heads or sampling
unit can be detected and an audible and visual alarm provided.
LR 15.8-04 Gas detection equipment is to be designed so that it
may be readily tested. Testing and calibration is to be capable of being carried out
at regular intervals. Arrangements are to be made for suitable equipment and span
gas for testing and calibration purposes to be carried on board. Wherever
practicable, provision is to be made for permanent connections for attachment of
testing and calibration equipment.
LR 15.8-05 In the selection of detectors for locations identified
in 15.8.1.8 and LR 15.8-01 due consideration is to be taken of temperature
and humidity of the environment in which gas is being detected. For sampling
systems, the system is to include a method to dry and cool the sampled environment
to that in which gas can be accurately detected.
15.8.6 An audible and visible alarm shall be activated at a gas vapour concentration
of 20% of the lower explosion limit (LEL). The safety system shall be activated at
40% of LEL at two detectors (see footnote 1 in table 1).
15.8.7 For ventilated ducts around gas pipes in the machinery spaces containing
gas-fuelled engines, the alarm limit can be set to 30% LEL. The safety system shall
be activated at 60% of LEL at two detectors (see footnote 1 in table 1).
15.8.8 Audible and visible alarms from the gas detection equipment shall be located
on the navigation bridge or in the continuously manned central control station.
15.8.9 Gas detection required by this section shall be continuous without delay.
LR 15.8-06 Where gas detection not used to activate safety
shutdown functions required by these Rules, sampling type detection may be accepted
in agreement with the National Administration.
LR 15.8-07 When sampling type gas detection equipment is used,
the following requirements are to be met:
(a) the gas detection equipment is to be capable of sampling and
analysing for each sampling head location sequentially at intervals which are as
short as possible but do not exceed 30 minutes;
(b) individual sampling lines from sampling heads to the detection
equipment are to be fitted; and
(c) pipe runs from sampling heads are not to be led through
non-hazardous spaces, except as permitted by LR 15.8-09.
LR 15.8-08 Sampling type gas detection equipment may be located in
a non-hazardous space, provided that the detection equipment such as sample piping,
sample pumps, solenoids and analysing units are located in a fully enclosed steel
cabinet with the door sealed by a gasket. The atmosphere within the enclosure is to
be continuously monitored. At gas concentrations above 30 per cent LEL inside the
enclosure, the entire gas detection unit is to be automatically shut down including
all power to external equipment.
LR 15.8-09 Additionally, where sampling type gas detection
equipment is located in a non-hazardous space, the following conditions are also to
be satisfied:
(a) fuel gas sampling lines are to have shut-off valves or an equivalent
arrangement to prevent cross communication with hazardous spaces; and
(b) exhaust gas from the detector is to be discharged to the atmosphere
in a safe location.
15.9 Regulations for fire detection
Required safety actions at fire detection in the machinery space containing
gas-fuelled engines and rooms containing independent tanks for fuel storage hold
spaces are given in table 1 below.
LR 15.9-01 A fire detection and alarm system, satisfying the
requirements of Pt 6, Ch 1,2.8 of the Rules for Ships, is to be
fitted in all spaces containing potential sources of gas leakage and ignition.
LR 15.9-02 Fire detection is to be arranged such that the
activation of any fire detectors in hazardous areas, spaces containing gas-fuelled
equipment, spaces adjacent to hazardous areas or gas-fuelled equipment,
automatically shuts down the gas supply system.
15.10 Regulations for
ventilation
15.10.1 Any loss of the required ventilating capacity shall give an
audible and visual alarm on the navigation bridge or in a continuously manned
central control station or safety centre.
LR 15.10-01 Acceptable means
to confirm that the ventilation system has the required ventilating capacity in
operation are, but not limited to:
- a) Monitoring of the ventilation electric motor or fan
operation combined with underpressure indication; or
- b) Monitoring of the ventilation electric motor or fan
operation combined with ventilation flow indication; or
- c) Monitoring of ventilation flow rate to indicate that the
required air flow rate is established.
15.10.2 For ESD protected machinery spaces the safety system shall be
activated upon loss of ventilation in engine-room.
15.11 Regulations on safety functions of fuel supply systems
15.11.1 If the fuel supply is shut off due to activation of an automatic valve, the
fuel supply shall not be opened until the reason for the disconnection is
ascertained and the necessary precautions taken. A readily visible notice giving
instruction to this effect shall be placed at the operating station for the shutoff
valves in the fuel supply lines.
15.11.2 If a fuel leak leading to a fuel supply shutdown occurs, the fuel supply
shall not be operated until the leak has been found and dealt with. Instructions to
this effect shall be placed in a prominent position in the machinery space.
15.11.3 A caution placard or signboard shall be permanently fitted in the machinery
space containing gas-fuelled engines stating that heavy lifting, implying danger of
damage to the fuel pipes, shall not be done when the engine(s) is running on gas.
15.11.4 Compressors, pumps and fuel supply shall be arranged for manual remote
emergency stop from the following locations as applicable:
- .1 navigation bridge;
- .2 cargo control room;
- .3 onboard safety centre;
- .4 engine control room;
- .5 fire control station; and
- .6 adjacent to the exit of fuel preparation rooms.
The gas compressor shall also be arranged for manual local emergency stop.
Table 1: Monitoring of gas supply system to engines
Parameter
|
Alarm
|
Automatic shutdown of tank valve6)
|
Automatic shutdown of gas supply to machinery space containing
gas-fuelled engines
|
Comments
|
Gas detection in tank connection space at 20% LEL
|
X
|
|
|
|
Gas detection on two detectors1) in tank connection
space at 40% LEL
|
X
|
X
|
|
|
Fire detection in fuel storage hold space
|
X
|
|
|
|
Fire detection in ventilation trunk to the tank
connection space and in the tank connection space
|
X
|
|
|
|
Bilge well high level in tank connection space
|
X
|
|
|
|
Bilge well low temperature in tank connection space
|
X
|
X
|
|
|
Gas detection in duct between tank and machinery space containing
gas-fuelled engines at 20% LEL
|
X
|
|
|
|
Gas detection on two detectors1) in duct between tank
and machinery space containing gas-fuelled engines at 40%
LEL
|
X
|
X2)
|
|
|
Gas detection in fuel preparation room at 20% LEL
|
X
|
|
|
|
Gas detection on two detectors1) in fuel preparation
room at 40% LEL
|
X
|
X2)
|
|
|
Gas detection in duct inside machinery space containing
gas-fuelled engines at 30% LEL
|
X
|
|
|
If double pipe fitted in machinery space containing gas-fuelled
engines
|
Gas detection on two detectors1) in duct inside
machinery space containing gas-fuelled engines at 60% LEL
|
X
|
|
X3)
|
If double pipe fitted in machinery space containing gas-fuelled
engines
|
Gas detection in ESD protected machinery space containing
gas-fuelled engines at 20% LEL
|
X
|
|
|
|
Gas detection on two detectors1) in ESD protected
machinery space containing gas-fuelled engines at 40% LEL
|
X
|
|
X
|
It shall also disconnect non certified safe electrical equipment
in machinery space containing gas-fuelled engines
|
Loss of ventilation in duct between tank and machinery space
containing gas-fuelled engines
|
X
|
|
X2)
|
|
Loss of ventilation in duct inside machinery space containing
gas-fuelled engines5)
|
X
|
|
X3)
|
If double pipe fitted in machinery space containing gas-fuelled
engines
|
Loss of ventilation in ESD protected machinery space containing
gas-fuelled engines
|
X
|
|
X
|
|
Fire detection in machinery space containing gas-fuelled
engines
|
X
|
|
|
|
Abnormal gas pressure in gas supply pipe
|
X
|
|
|
|
Failure of valve control actuating medium
|
X
|
|
X4)
|
Time delayed as found necessary
|
Automatic shutdown of engine (engine failure)
|
X
|
|
X4)
|
|
Manually activated emergency shutdown of engine
|
X
|
|
X
|
|
1) Two independent gas
detectors located close to each other are required for redundancy
reasons. If the gas detector is of self-monitoring type the
installation of a single gas detector can be permitted.
|
2) If the tank is supplying
gas to more than one engine and the different supply pipes are
completely separated and fitted in separate ducts and with the
master valves fitted outside of the duct, only the master valve on
the supply pipe leading into the duct where gas or loss of
ventilation is detected shall close.
|
3) If the gas is supplied to
more than one engine and the different supply pipes are completely
separated and fitted in separate ducts and with the master valves
fitted outside of the duct and outside of the machinery space
containing gas-fuelled engines, only the master valve on the supply
pipe leading into the duct where gas or loss of ventilation is
detected shall close.
|
4) Only double block and
bleed valves to close.
|
5) If the duct is protected
by inert gas (see 9.6.1.1) then loss of inert gas overpressure shall
lead to the same actions as given in this table.
|
6) Valves referred to in 9.4.1.
|
LR Table 1: Monitoring of gas
supply system to engines
Parameter
|
Alarm
|
Automatic shutdown of tank
valve6)
|
Automatic shutdown of gas supply to machinery
space containing gas-fuelled engines
|
Comments
|
Gas detection in tank connection space at 20%
LEL
|
X
|
|
|
|
Gas detection on two detectors1) in tank
connection space at 40% LEL
|
X
|
X
|
|
|
Fire detection in fuel storage hold space
|
X
|
|
|
(See LR 1-3 & 5)
|
Fire detection in ventilation trunk for fuel
containment system below deck
|
X
|
|
|
(See LR 1-3 & 5)
|
Bilge well high level in tank connection
space
|
X
|
|
|
|
Bilge well low temperature in tank connection
space
|
X
|
X
|
|
|
Gas detection in duct between tank and machinery
space containing gas-fuelled engines at 20% LEL
|
X
|
|
|
|
Gas detection on two detectors1) in duct
between tank and machinery space containing gas-fuelled engines at
40% LEL
|
X
|
X2)
|
|
|
Gas detection in fuel preparation room at 20%
LEL
|
X
|
|
|
|
Gas detection on two detectors1) in fuel
preparation room at 40% LEL
|
X
|
X2)
|
|
|
Gas detection in duct inside machinery space
containing gas-fuelled engines at 30% LEL
|
X
|
|
|
If double pipe fitted in machinery space containing
gas-fuelled engines
|
Gas detection on two detectors1) in duct
inside machinery space containing gas-fuelled engines at 60%
LEL
|
X
|
|
X3)
|
If double pipe fitted in machinery space containing
gas-fuelled engines
|
Gas detection in ESD protected machinery space
containing gas-fuelled engines at 20% LEL
|
X
|
|
|
|
Gas detection on two detectors1) in ESD
protected machinery space containing gas-fuelled engines at 40%
LEL
|
X
|
|
X
|
It shall also disconnect non certified safe
electrical equipment in machinery space containing gas-fuelled
engines
|
Loss of ventilation in duct between tank and
machinery space containing gas-fuelled engines
|
X
|
|
X2)
|
(See LR 1-3)
|
Loss of ventilation in duct inside machinery space
containing gas-fuelled engines5)
|
X
|
|
X3)
|
If double pipe fitted in machinery space containing
gas-fuelled engines
(See LR 1-3 &
6)
|
Loss of ventilation in ESD protected machinery space
containing gas-fuelled engines
|
X
|
|
X
|
|
Fire detection in machinery space containing
gas-fuelled engines
|
X
|
|
|
(See LR 1-3 & 5)
|
Abnormal gas pressure in gas supply pipe
|
X
|
|
|
(See LR 1-3)
|
Failure of valve control actuating medium
|
X
|
|
X4)
|
Time delayed as found necessary
|
Automatic shutdown of engine (engine
failure)
|
X
|
|
X4)
|
|
Manually activated emergency shutdown of
engine
|
X
|
|
X
|
|
1) Two
independent gas detectors located close to each other are required
for redundancy reasons. If the gas detector is of self-monitoring
type the installation of a single gas detector can be
permitted.
|
2) If the tank is
supplying gas to more than one engine and the different supply pipes
are completely separated and fitted in separate ducts and with the
master valves fitted outside of the duct, only the master valve on
the supply pipe leading into the duct where gas or loss of
ventilation is detected shall close.
|
3) If the gas is
supplied to more than one engine and the different supply pipes are
completely separated and fitted in separate ducts and with the
master valves fitted outside of the duct and outside of the
machinery space containing gas-fuelled engines, only the master
valve on the supply pipe leading into the duct where gas or loss of
ventilation is detected shall close.
|
4) Only double
block and bleed valves to close.
|
5) If the duct
is protected by inert gas (see 9.6.1.1) then loss of inert gas
overpressure shall lead to the same actions as given in this
table.
|
6) Valves
referred to in 9.4.1.
|
NOTES
|
LR 1 Gas fuel
supply shutdown by automatic operation of gas supply line double
block-and-bleed valves.
|
LR 2 Alarms
associated with gas fuel supply and ventilation arrangements are to
be given in the machinery space and machinery control
station.
|
LR 3 See
10.3.4 for alternative gas fuel supply requirements.
|
LR 4 High
temperature alarm to operate at all times when tank is in
operation.
|
LR 5 Fire
detection in spaces containing gas-fuelled equipment or in adjacent
spaces to result in gas fuel supply shutdown.
|
LR 6 Actual
valve position is to be positively indicated at the required remote
control position.
|
LR 7 Arrangements are to
prevent automatic or remote starting under conditions which could
cause a hazardous situation.
|
LR 15.11-01 Any additional alarms and shutdowns determined on the
basis of RBD are to be provided as necessary.
LR 15.11-02
Table 1.15.1 Gas fuel supply
and storage: Alarms, monitoring and safeguards
Item
|
Alarm
|
Note
|
Gas fuel storage tanks
|
High level, high
temperature
|
Gas fuel bunkering alarms are
to be given in the bunkering control station, (See LR
4)
|
Gas fuel storage tanks
|
High pressure, high-high
level, overfill, low pressure (if vacuum insulated tank)
|
Gas fuel bunkering
shutdown
|
Bunkering
|
Bunker line high pressure, loss
of communication
|
Gas fuel bunkering
shutdown
|
Fire
|
Fire detection
|
Gasfuel supply shutdown.
(See LR 1-3 & 5)
|
Space ventilation
system
|
Failure
|
|
NOTES
|
LR 1 Gas fuel
supply shutdown by automatic operation of gas supply line double
block-and-bleed valves.
|
LR 2 Alarms
associated with gas fuel supply and ventilation arrangements are to
be given in the machinery space and machinery control
station.
|
LR 3
See 10.3.4 for alternative gas fuel supply
requirements.
|
LR 4 High
temperature alarm to operate at all times when tank is in
operation.
|
LR 5 Fire
detection in spaces containing gas-fuelled equipment or in adjacent
spaces to result in gas fuel supply shutdown.
|
LR 6 Actual
valve position is to be positively indicated at the required remote
control position.
|
LR 7
Arrangements are to prevent automatic or remote starting under
conditions which could cause a hazardous situation.
|
LR 8 Alarm
is to be given at the gas fuel bunkering control station.
|
LR 9 For high pressure
alarm, see 6.3.2.
|
LR 15.11-03
Table 1.15.2 Gas-fuelled
machinery: Alarms, monitoring and safeguards
Item
|
Alarm
|
Note
|
Engine crankcase
protection
|
High oil mist concentration,
see (See LR 1)
|
See safety concept, LR
10.3-03
See 15.8.5 for gas detection
equipment requirements as applicable
|
Engine gas supply
pressure
|
Low
|
Automatic closing of gas
supply manifold isolating valve
See 10.3.4
foralternative gas fuel supply requirements
|
Engine gas fuel
injection
|
Cylinder misfire
Gas fuel or pilot fuel injection valve failure
|
(See LR 3)
|
Exhaust gas temperature
|
High
|
Per cylinder, (See LR
3)
|
Exhaust gas temperature
deviation from average
|
High
|
Per cylinder, (See LR
3)
|
Cylinder pressure
|
Low
|
Alternatively, ignition failure
monitoring and alarms of each cylinder are permitted, (See LR
3)
|
Engine shutdown
|
|
Automatic closing of gas supply
manifold isolating valve
|
Burner flame and
ignition
|
Failure
|
Each burner to be monitored,
(See LR 5)
|
Boiler shutdown
|
|
(See LR 4 &
5)
|
Fuel injection valve cooling
water pressure
|
Low
|
|
Fuel injection valve cooling
water temperature
|
High
|
|
NOTES
|
LR 1 Bearing
temperature monitoring is permitted in lieu of oil mist monitoring
for dual fuel crosshead type engines.
|
LR 2 Alarm
set point to allow sufficient time for corrective action necessary
to avoid increased risk of explosion. Alarm set point not to exceed
LEL.
|
LR 3
Automatic operation of gas supply line double block-and-bleed valves
and closing of supply line master gas fuel valve.
|
LR 4
Automatic operation of gas supply line double block-and-bleed
valves.
|
LR 5
Combustion spaces are to be purged automatically before re-ignition
takes place in the event of flame-out on all burners.
|
LR 6 Machinery alarms
are to be given in the machinery space and the machinery control
station, in accordance with Pt 6, Ch 1,2.3.1 of the Rules for
Ships.
|