Section
8 Control, alarm and safety systems
8.1 General
8.1.2 All
gas turbines intended for essential services are to be provided with
means of indicating the lubricating oil pressure supply to them. Where
such turbines are of more than 37 kW (50 shp), audible and visual
alarms are to be fitted to give warning of an appreciable reduction
in pressure of the lubricating oil supply. Further, these alarms are
to be actuated from the outlet side of any restrictions, such as filters,
coolers, etc.
8.2 Overspeed protection and shutdown system
8.2.1 The
gas turbine is to be protected against overspeed by the provision
of a suitable device(s) capable of shutting-down the gas turbine safely
before a dangerous overspeed condition occurs.
8.3 Power turbine inlet over-temperature control
8.3.1 The
power turbine is to be protected against over-temperature by the provision
of a suitable device(s) capable of controlling the temperature within
acceptable limits or shutting-down the gas turbine safely to prevent
damage.
8.4 Flameout
8.5 Lubricating oil system
8.5.1 Means
are to be provided to accurately determine the pressure and temperature
of the lubricating oil supply to the various parts of the gas generator
and power turbine, and scavenge oil and return systems to ensure safe
operation.
8.5.2 Means
are to be provided to ensure that the temperature of the lubrication
oil supply is automatically controlled to maintain steady-state conditions
throughout the normal operating range of the gas turbine.
8.5.3 Where
the oil supply to the power turbine is fed from a separate supply
system, similar arrangements to those detailed above are to be provided.
8.6 Hand trip arrangement
8.6.1 Means
are to be provided, at both the local and remote control/operating
positions, to manually initiate the shutdown of the gas turbine in
an emergency.
8.7 Fire detection, alarm and extinguishing systems
8.8 Unattended machinery
8.8.1 Where
gas turbines are fitted with automatic or remote controls so that
under normal operating conditions they do not require any manual intervention
by the operators, they are to be provided with the alarms and safety
arrangements required by Pt 5, Ch 4, 8.8 Unattended machinery to Pt 5, Ch 4, 8.9 Gas turbine machinery as appropriate. Alternative arrangements
which provide equivalent safeguards will be considered.
8.8.2 Where
machinery is arranged to start automatically or from a remote control
station, interlocks are to be provided to prevent start-up under conditions
which could hazard the machinery.
8.8.3 Where
machinery specified in this Section is required to be provided with
a standby pump, the standby pump is to start automatically if the
discharge pressure from the working pumps falls below a predetermined
value.
8.8.4 Where
a first stage alarm together with a second stage alarm and automatic
shutdown of machinery are required in the relevant Tables of this
Section, the sensors and circuits utilised for the second stage alarm
and automatic shutdown are to be independent of those required for
the first stage alarm. LR will consider alternative arrangements which
provide an equivalent level of safety.
8.9 Gas turbine machinery
8.9.1 Alarms
and safeguards are indicated in Pt 5, Ch 4, 8.9 Gas turbine machinery 8.9.2 to Pt 5, Ch 4, 8.9 Gas turbine machinery 8.9.4 and Table 4.8.1 Gas turbine machinery: Alarms and
safeguards.
Table 4.8.1 Gas turbine machinery: Alarms and
safeguards
| Item
|
Alarm
|
Note
|
| Overspeed
|
High
|
Automatic shutdown see also
Pt 5, Ch 4, 8.2 Overspeed protection and shutdown system
|
| Power turbine inlet temperature
|
1st stage high
|
Automatic power reduction
|
|
|
2nd stage high
|
Automatic shutdown see also
Pt 5, Ch 4, 8.3 Power turbine inlet over-temperature control
|
| Flame failure
|
Failure
|
Automatic shutdown, see also
Pt 5, Ch 4, 8.4 Flameout
|
| Failure to ignite
|
Failure
|
Automatic shutdown, see also
Pt 5, Ch 4, 8.4 Flameout
|
| Lubricating oil pressure
|
1st stage low
|
—
|
|
|
2nd stage low
|
Automatic shutdown, see also
Pt 5, Ch 4, 8.5 Lubricating oil system
|
| Lubricating oil temperature
|
High
|
See also
Pt 5, Ch 4, 8.5 Lubricating oil system
|
| Lubricating oil filter differential pressure
|
High
|
—
|
| Scavenge oil temperature
|
High
|
—
|
| Scavenge oil pressure
|
Low
|
Automatic shutdown
|
| Bearing temperature
|
High
|
—
|
| Turbine vibration
|
1st stage high
|
—
|
|
|
2nd stage high
|
Automatic shutdown, see also
Pt 5, Ch 4, 4.2 Vibration
|
| Fuel oil supply pressure
|
Low
|
—
|
| Fuel oil supply temperature
|
High
|
—
|
| Fuel oil leakage
|
High
|
See also
Pt 5, Ch 4, 5.2 Fuel oil systems
|
| Automatic starting
|
Failure
|
Automatic shutdown
|
| Control system
|
Failure
|
Automatic shutdown
|
| Air intake pressure
|
Low
|
See also
Pt 5, Ch 4, 4.4 Intake and exhaust ducts 4.4.4
|
| Feed water or water/thermal fluid forced
circulation flow (if fitted)
|
Low
|
See
Pt 5, Ch 14, 6.2 Feed and circulation pumps 6.2.7 and Note 4
|
| Uptake temperature
|
High
|
To monitor for soot fires. See Notes 4 and 5
|
Note
3. Where a requirement for disabling the
automatic protection and safety system devices for machinery and
engineering systems has been defined by the Owner, the consequences of
using the disabling arrangements are to be established and included in
the operations procedures and orders provided on board ship. Details
of any disabling arrangements are to be submitted to LR for
consideration in each instance.
Note
4. Alarm is required only when suitable
for operation on residual fuel grades and an exhaust gas
economiser/boiler/thermal oil heater is fitted.
Note
5. Alternatively, details of an
appropriate fire detection system are to be submitted for
consideration.
Note 6. The Table contains the minimum list of alarms and
shutdowns required for a gas turbine. Additional alarms and shutdowns
may be necessary as determined through risk-mitigating activities in
response to the completed Risk-Based Analysis (e.g. FMEA) for the gas
turbine.
Note 7. If specific alarms and shutdowns
are not applicable for the gas turbine, sufficient evidence shall be
produced to support such claims (e.g. Risk-Based Analysis such as
FMEA).
|
8.9.2 The
following turbine services are to be fitted with automatic temperature
controls so as to maintain steady state conditions throughout the
normal operating range of the turbine:
-
Lubricating oil
supply.
-
Fuel oil supply, see also
Pt 5, Ch 4, 8.9 Gas turbine machinery 8.9.3.
-
Exhaust gas.
8.9.4 A means
of manually shutting off the fuel in an emergency is to be provided
at the manoeuvring station.
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