Section
12 Control, alarm and safety systems of machinery
12.1 General
12.1.1 Where
machinery is fitted with automatic or remote controls so that under
normal operating conditions it does not require any manual intervention
by the operators, it is to be provided with the alarms and safety
arrangements required by Pt 5, Ch 14, 12.2 Thermal fluid heaters to Pt 5, Ch 14, 12.4 Miscellaneous machinery, as appropriate. Alternative
arrangements which provide equivalent safeguards will be considered.
12.1.2 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.
12.1.3 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.
12.1.4 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.
12.2 Thermal fluid heaters
12.2.1 Alarms
and safeguards are indicated in Pt 5, Ch 14, 12.2 Thermal fluid heaters 12.2.2 to Pt 5, Ch 14, 12.2 Thermal fluid heaters 12.2.8 and Table 14.12.1 Thermal fluid heaters: Alarms and
safeguards.
Table 14.12.1 Thermal fluid heaters: Alarms and
safeguards
| Item
|
Alarm
|
Note
|
| Expansion tank level*
|
Low
|
Fuel oil burners to be shut off
automatically
|
| Thermal fluid flow
|
Low
|
Fuel oil burners to be shut off automatically,
see Note 5
|
| Thermal fluid pressure
|
Low
|
Fuel oil burners to be shut off
automatically
|
| Thermal fluid outlet
temperature*
|
1st stage high
|
—
|
|
|
2nd stage high
|
Fuel oil burners to be shut off automatically,
see
Pt 5, Ch 14, 12.1 General 12.1.4
|
| Combustion air pressure*
|
Low
|
Fuel oil burners to be shut off automatically in
operation or not released during start-up, see Note 3. Purge sequence
to be inhibited see
Pt 5, Ch 14, 3.1 Oil burning units 3.1.9
|
| Fuel oil pressure*
|
Low
|
—
|
| Fuel oil temperature or
viscosity*
|
High and low
|
Heavy oil only
|
| Fuel oil atomising steam/air pressure
|
Low
|
—
|
| Burner flame*
|
Failure
|
Each burner to be monitored. Fuel oil to burner
to be shut off automatically, see
Pt 5, Ch 14, 3.1 Oil burning units 3.1.11 to Pt 5, Ch 14, 3.1 Oil burning units 3.1.12 , and Note 3
|
| Flame monitoring device(s)*
|
Failure
|
See
Pt 5, Ch 14, 12.2 Thermal fluid heaters 12.2.6 and Note 3
|
| Igniter power supply*
|
Failure
|
Each igniter to be checked before fuel oil is
supplied to burner(s), see
Pt 5, Ch 14, 12.2 Thermal fluid heaters 12.2.5 and Note 3
|
| Forced draft fan*
|
Power failure
|
Fuel oil burners to be shut off automatically in
operation or not released during start-up, see Note 3
|
| Air register and dampers (including
those in the uptake)*
|
Not fully open
|
Purge sequence to be inhibited, see
Pt 5, Ch 14, 3.1 Oil burning units 3.1.9
|
| Control system*
|
Power failure
|
Fuel oil burners to be shut off automatically.
Control using alternative arrangement is to remain available, see
Pt 6, Ch 1, 2.5 Control systems, general requirements 2.5.7
|
| Uptake temperature
|
High
|
To monitor for soot fires. Fuel oil to the burner is to be
shut off, see Notes 4 and 6
|
Note
1. Special consideration may be given to
the requirements for oil-fired hot water heaters.
Note
2. For heaters not supplying thermal oil
for services essential for the safety or the operation of the ship at
sea, only the items marked* are required.
Note
3. These safeguards are to remain
operative during automatic, manual and emergency operation.
Note
4. Alarm and fuel oil shut-off is only
required where exhaust gas economisers/boilers are fitted.
Note
5. For exhaust gas economisers/boilers
requiring thermal fluid forced circulation, the low flow alarm is to
be fitted with provision to override the alarm if the exhaust gas
economiser/boiler is to be operated in the dry condition. See
also
Pt 5, Ch 14, 6.2 Feed and circulation pumps 6.2.5.
Note
6. Alternatively, details of an
appropriate fire detection system are to be submitted for
consideration.
|
12.2.2 The
standby pumps for fuel oil and thermal fluid circulation are to start
automatically when the discharge pressure from the working pump falls
below a predetermined value. The standby pumps for thermal fluid circulation
are to start before shut-off due to low thermal fluid pressure, see
Table 14.12.1 Thermal fluid heaters: Alarms and
safeguards, is
activated.
12.2.3 The
following heater services are to be fitted with automatic controls
so as to maintain steady state conditions throughout the operating
range of the heater:
-
Combustion system.
-
Fuel oil supply
temperature or viscosity (heavy oil only).
-
Thermal fluid
temperature.
12.2.4 Burner
controls are to be arranged such that light-off is only possible at
the minimum firing rate compatible with flame establishment. If ignition
is set to occur at a fuel rich condition then the burner is to revert
to the correct operating air/fuel ratio on establishment of a stable
flame.
12.2.5 Arrangements
are to be such that burner fuel oil valve(s) do not open:
-
prior to completion
of required warm up times for residual fuel oil; or
-
when the power
supply to the igniter has failed, as applicable; or
-
until a pilot
flame is established, as applicable; or
-
prior to the
completion of furnace purging, see
Pt 5, Ch 14, 3.1 Oil burning units 3.1.7.
12.2.6 Arrangements
for flame failure detection are to be provided with self-monitoring
capabilities which ensure that the flame detector is not erroneously
indicating the presence of a flame. In the event of failure being
detected by these self-monitoring capabilities:
- an alarm is to be activated;
- In the event of loss of flame detection capability for a burner;
- fuel oil to the burner is to be shut off automatically; and
- an alarm is to be activated.
12.2.7 Where
established as necessary by Pt 5, Ch 14, 3.1 Oil burning units 3.1.8,
means are to be provided to prevent starting of the ignition sequence
following multiple flame failures until completion of the identified
lock-out period.
12.2.8 Following
burner shutdown, the furnace is to be purged automatically for at
least the required pre-purging time. In event of shutdown due to activation
of a required safeguard, this purging is to be manually initiated.
12.3 Incinerators
12.3.1 Alarms
and safeguards are indicated in Pt 5, Ch 14, 12.3 Incinerators 12.3.2, Pt 5, Ch 14, 12.3 Incinerators 12.3.3 and Table 14.12.2 Incinerators: Alarms and
safeguards.
Table 14.12.2 Incinerators: Alarms and
safeguards
| Item
|
Alarm
|
Note
|
| Fuel oil temperature or
viscosity
|
High and low
|
Heavy oil and sludge
|
| Fuel oil pressure
|
Low
|
—
|
| Combustion air pressure
|
Low
|
Fuel oil and/or sludge to burners to be shut off
automatically
|
| Burner flame and ignition
|
Failure
|
Fuel oil and/or sludge to burners to be shut off
automatically, see Note
|
| Furnace temperature
|
High
|
Fuel oil and/or sludge to burners to be shut off
automatically
|
| Furnace temperature
|
Low
|
If applicable
|
| Exhaust temperature
|
High
|
—
|
Note Combustion spaces are to be purged automatically before
re-ignition takes place in the event of a flame-out on all
burners.
|
12.3.2 Where
arrangements are provided to introduce solid waste into the furnace,
these are to be such that there is no risk of a fire hazard.
12.3.3 The
combustion temperature is to be controlled to ensure that all liquid
and solid waste is efficiently burned without exceeding predetermined
temperature limits.
12.4 Miscellaneous machinery
12.4.1 Alarms
and safeguards are indicated in Pt 5, Ch 14, 12.4 Miscellaneous machinery 12.4.2 to Pt 5, Ch 14, 12.4 Miscellaneous machinery 12.4.6 and Table 14.12.3 Miscellaneous machinery: Alarms
and safeguards.
Table 14.12.3 Miscellaneous machinery: Alarms
and safeguards
| Item
|
Alarm
|
Note
|
| Exhaust gas temperature after water
injection
|
High
|
See
Pt 5, Ch 2, 8.3 Exhaust systems 8.3.6
|
| Sterntube lubricating oil tank level
|
Low
|
—
|
| Sterntube bearing
temperature (oil lubricated)
|
High
|
—
|
| Coolant tanks level
|
Low
|
—
|
| Fuel oil service tanks
level
|
High and low
|
Where a common overflow tank is
fitted, a high level alarm in the common overflow tank may be
accepted
|
| Fuel oil service tanks
temperature
|
High
|
Where heating arrangements are
fitted
|
| Fuel oil settling tanks
temperature
|
High
|
Where heating arrangements are
fitted
|
| Sludge tanks level
|
High
|
—
|
| Feed water tanks level
|
Low
|
Service tank only
|
| Purifier water seal
broken
|
Fault
|
—
|
| Purifier oil inlet
temperature
|
High
|
—
|
| Air compressor
lubricating oil
|
Failure
|
Automatic shutdown
|
| Air compressor discharge
air temperature
|
High
|
—
|
| Hydraulic control system
pressure
|
Low
|
—
|
| Pneumatic control system
pressure
|
Low
|
—
|
| Oil heater temperature
|
High
|
—
|
| Control environmental conditions
|
Abnormal
|
See also
Pt 6, Ch 1, 1.4 Control, alarm and safety equipment 1.4.3
|
12.4.2
Dual
fuel systems. Oil and gas dual-fired systems for boilers and
engines are to be provided with indication to show which fuel is in
use.
12.4.4
Oil
heaters. Fuel oil or lubricating oil heaters are to be fitted
with a high temperature alarm which may be incorporated in the temperature
control system. In addition to the temperature control system, an
independent sensor with manual reset is to be fitted, which will automatically
cut off the heating supply in the event of excessively high temperatures
or loss of flow, except where the maximum temperature of the heating
medium remains limited to a value below 220°C.
12.4.5
Oil
tank electric heating. Fuel oil and lubricating oil tanks that
are provided with electric heating elements are to be fitted with
a high temperature alarm, which may be incorporated in the temperature
control system, a low level alarm and an additional low level sensor
to cut off the power supply at a level above that at which the heating
element would be exposed.
12.4.6
Fuel
oil tanks. Means are to be provided to eliminate the possibility
of overflow from fuel oil service tanks into the machinery space and
to safeguard against overflow of oil from fuel oil service tanks through
the air pipe. See
Pt 5, Ch 13 Ship Piping Systems regarding the termination of air pipes.
|