8.1 General
8.1.1 General
8.1.1.1 The machinery, associated piping systems and fittings relating to main machinery
and auxiliary power units should be of a design and construction adequate for the
service for which they are intended and should be so installed and protected as to
reduce to a minimum any danger to persons on board, due regard being paid to moving
parts, hot surfaces and other hazards. The design should have regard to materials used
in construction, the purpose for which the equipment is intended, the working conditions
to which it will be subjected and the environmental conditions on board.
8.1.1.2 All surfaces with temperatures exceeding 220°C where impingement of
flammable liquids may occur as a result of a system failure should be insulated using
firewalls, shrouds or other equivalent systems. The insulation should be impervious to
flammable liquids and vapours.
8.1.1.3 Special consideration should be given to the reliability of single essential
propulsion components and a separate source of propulsion power sufficient to give the
craft a navigable speed, especially in the case of unconventional arrangements, may be
required.
8.1.1.4 Means should be provided whereby normal operation of propulsion machinery can be
sustained, restored or safely shut down if one of the essential auxiliaries becomes
inoperative. Special consideration should be given to the malfunctioning of:
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.1 a generating set which serves as a main source of electrical power; and
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.2 a source of essential service or supply to a main propulsion engine or main
source of electrical power, such as fuel oil supply, pressurised lubricating oil,
aspiration air, cooling water or engine starting or control systems.
However, for assisted and cargo craft, a partial or complete reduction in propulsion
capability from normal operation may be accepted if the failure does not directly or
indirectly lead to a condition that endangers the craft or personnel.
8.1.1.5 Means should be provided to ensure that the machinery can be brought into
operation from the dead craft condition without external aid.
8.1.1.6 All parts of machinery, hydraulic, pneumatic and other systems and their
associated fittings which are under internal pressure should be subjected to appropriate
tests including a pressure test before being put into service for the first time.
8.1.1.7 Provision should be made to facilitate cleaning, inspection and maintenance of
main propulsion and auxiliary machinery including pressure vessels.
8.1.1.8 The reliability of machinery installed in the craft should be adequate for its
intended purpose.
8.1.1.9 The Administration may accept machinery which does not show detailed compliance
with the present Guidelines where it has been used satisfactorily in a similar
application, provided that it is satisfied:
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.1 that the design, construction, testing, installation and prescribed maintenance
are together adequate for its use in a marine environment; and
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.2 that an equivalent level of safety will be achieved.
8.1.1.10 A system safety assessment should include machinery systems and their
associated controls.
8.1.1.11 Such information as is necessary to ensure that machinery can be installed
correctly regarding such factors as operating conditions and limitations should be made
available by the manufacturers.
8.1.1.12 Main propulsion machinery and all auxiliary machinery essential to the
propulsion and the safety of the craft should, as fitted in the craft, be designed to
operate when the craft is upright and when inclined at any angle of trim, heel, roll or
pitch the craft may achieve in any normal operational mode within the range of allowable
operating conditions.
8.1.1.13 All pressure vessels and associated piping systems should be of a design and
construction adequate for the purpose intended and should be so installed and protected
as to minimise danger to persons on board. In particular, attention should be paid to
the materials used in the construction and the working pressures and temperatures at
which the item will operate and the need to provide an adequate margin of safety over
the stresses normally produced in service. Every pressure vessel and associated piping
system should be fitted with adequate means to prevent over-pressures in service and be
subjected to a hydraulic test before being put into service, and where appropriate at
subsequent specified intervals, to a pressure suitably in excess of the working
pressure.
8.1.1.14 Arrangements should be provided to ensure that any liquid cooling system is
rapidly detected and alarmed (visual and audible) and means instituted to minimize the
effects of such failures on machinery serviced by the system.
8.1.2 Engine (general)
8.1.2.1 The engines should be fitted with adequate safety monitoring and control devices
in respect of speed, temperature, pressure level and other operational functions.
Control of the machinery should be from the craft's operating compartment and should be
arranged so that no single failure causes loss of control of machinery. The machinery
installation should be suitable for operation as in an unmanned machinery spacefootnote, including automatic fire detection system, bilge alarm
system, remote machinery instrumentation and alarm system.
8.1.2.2 The engines should be protected against overspeed, loss of lubricating oil
pressure, loss of cooling medium, high temperature, malfunction of moving parts and
overload. Safety devices may provide warnings but should not cause complete engine
shutdown. Such safety devices should be capable of being tested.
8.1.2.3 At least two independent means of stopping the engines quickly from the
operating compartment under any operating conditions should be available. Duplication of
the actuator fitted to the engine should not be required.
8.1.2.4 The major components of the engine should have adequate strength to withstand
the thermal and dynamic conditions of normal operation. The engine should not be damaged
by a limited operation at a speed or at temperatures exceeding the normal values but
within the range of the protective devices.
8.1.2.5 The design of the engine should be such as to minimise the risk of fire or
explosion and to enable compliance with the fire precaution requirements of chapter 6.
8.1.2.6 Provision should be made to drain all excess fuel and oil to a safe position so
as to avoid a fire hazard.
8.1.2.7 Provision should be made to ensure that, whenever practical, the failure of
systems driven by the engine should not unduly affect the integrity of the major
components.
8.1.2.8 The ventilation arrangements in the machinery spaces should be adequate under
all envisaged operating conditions. Where appropriate, arrangements should ensure that
enclosed engine compartments are forcibly ventilated to the atmosphere before the engine
can be started.
8.1.2.9 Any engines should be so installed as to avoid excessive vibration within the
craft.
8.1.3 Gas turbines
8.1.3.1 Gas turbines should be designed to operate in the marine environment and should
be free from surge or dangerous instability throughout its operating range up to the
maximum steady speed approved for use. The turbine installation should be arranged to
ensure that the turbine cannot be continuously operated within any speed range where
excessive vibration, stalling, or surging may be encountered.
8.1.3.2 The gas turbines should be designed and installed such that any reasonably
probable shedding of compressor or turbine blades will not endanger the craft, other
machinery, occupants of the craft or any other persons.
8.1.3.3 The provisions of 8.1.2.6 should apply to gas turbines in respect of fuel which
might reach the interior of the jet pipe or exhaust system after a false start or after
stopping.
8.1.3.4 Turbines should be safeguarded as far as practicable against the possibility of
damage by ingestion of contaminants from the operating environment. Information
regarding the recommended maximum concentration of contamination should be made
available. Provision should be made for preventing the accumulation of salt deposits on
the compressors and turbines and, where appropriate, for preventing the air intake from
icing.
8.1.3.5 In the event of a failure of a shaft or weak link, the broken end should not
hazard the occupants of the craft, either directly or by damaging the craft or its
systems. Where necessary, guards may be fitted to achieve compliance with these
provisions.
8.1.3.6 Each engine should be provided with an emergency overspeed shutdown device
connected, where possible, directly to each rotor shaft.
8.1.3.7 Where an acoustic enclosure is fitted which completely surrounds the gas
generator and the high pressure oil pipes, a fire detection and extinguishing system
should be provided for the acoustic enclosure.
8.1.3.8 Details of the manufacturers' proposed automatic safety devices to guard against
hazardous conditions arising in the event of malfunction in the turbine installation
should be assessed as part of the SSA specified in part C.
8.1.3.9 The manufacturers should demonstrate the soundness of the casings. Intercoolers
and heat exchangers should be hydraulically tested on each side separately.
8.1.4 Diesel engines for main propulsion and essential auxiliaries
8.1.4.1 Any main diesel propulsion system should have satisfactory torsional vibration
and other vibrational characteristics verified by individual and combined torsional and
other vibration analyses for the system and its components from power unit through to
propulsor.
8.1.4.2 All external high-pressure fuel delivery lines between the high-pressure fuel
pumps and fuel nozzles should be protected with a jacketed tubing system capable of
containing fuel from a high-pressure line failure. The jacketed tubing system should
include a means for collection of leakages and arrangements should be provided for an
alarm to be given of a fuel line failure.
8.1.4.3 Engines of a cylinder diameter of 200 mm or a crankcase volume of
0.6 m3 and above should be provided with crankcase explosion relief valves of
an approved type with sufficient relief area. The relief valves should be arranged with
means to ensure that discharge from them is directed so as to minimise the possibility
of injury to personnel.
8.1.4.4 The lubrication system and arrangements should be efficient at all running
speeds, due consideration being given to the need to maintain suction and avoid the
spillage of oil in all conditions of list and trim and degree of motion of the craft.
8.1.4.5 Arrangements should be provided to ensure that visual and audible alarms are
activated in the event of either lubricating oil pressure or lubricating oil level
falling below a safe level, considering the rate of circulation of oil in the engine.
8.1.4.6 Where diesel engines are arranged to be started, reversed or controlled by
compressed air, the arrangement of the air compressor, air receiver and air starting
system should be such as to minimise the risk of fire or explosion.
8.1.5 Transmissions
8.1.5.1 The transmission should be of adequate strength and stiffness to enable it to
withstand the most adverse combination of the loads expected in service without
exceeding acceptable stress levels for the material concerned.
8.1.5.2 The design of shafting, bearings and mounts should be such that hazardous
whirling and excessive vibration could not occur at any speed up to 105% of the shaft
speed attained at the designed overspeed trip setting of the prime mover.
8.1.5.3 The strength and fabrication of the transmission should be such that the
probability of hazardous fatigue failure under the action of the repeated loads of
variable magnitude expected in service is extremely remote throughout its operational
life. Compliance should be demonstrated by suitably conducted tests, and by designing
for sufficiently low stress levels, combined with the use of fatigue resistant materials
and suitable detail design. Torsional vibration or oscillation likely to cause failure
may be acceptable if it occurs at transmission speeds which would not be used in normal
craft operation, and it is recorded in the craft operating manual as a limitation.
8.1.5.4 Where a clutch is fitted in the transmission, normal engagement of the clutch
should not cause excessive stresses in the transmission or driven items. Inadvertent
operation of any clutch should not produce dangerously high stresses in the transmission
or driven item.
8.1.5.5 Provision should be made such that a failure in any part of the transmission, or
of a driven component, will not cause damage which might hazard the craft or its
occupants.
8.1.5.6 Where failure of lubricating fluid supply or loss of lubricating fluid pressure
could lead to hazardous conditions, provision should be made to enable such failure to
be indicated to the operating crew in adequate time to enable them as far as practicable
to take the appropriate action before the hazardous condition arises.
8.1.6 Propulsion and lift devices
8.1.6.1 The provisions of this section are based on the premise that:
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.1 Propulsion arrangements and lift arrangements may be provided by separate
devices, or be integrated into dual-function devices.
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.2 Propulsion devices are those which directly provide propulsive thrust and
include machinery items having a primary function of contributing to that thrust,
including any associated ducts, vanes, and nozzles.
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.3 Lift devices are those devices which generate lifting force on the craft and
include arrangements which direct air flow from propellers or gas jets from
engines to produce such force.
8.1.6.2 The propulsion and lift devices should be of adequate strength and stiffness.
The design data, calculations and trials, where necessary, should establish the ability
of the device to withstand the loads which can arise during the operations for which the
craft is to be certificated, so that the possibility of catastrophic failure is
extremely remote.
8.1.6.3 The design of propulsion and lift devices should pay due regard to the effects
of allowable corrosion, electrolytic action between different metals, erosion or
cavitation which may result from operation in environments in which they are subjected
to spray, debris, salt, sand, icing, etc.
8.1.6.4 Design and testing of propulsion and lift devices should pay due regard, as
appropriate, to any pressure which could be developed as a result of any duct blockage,
in terms of steady and cyclic loadings, loadings due to external forces and of the use
of the devices in manoeuvring and reversing and to the axial location of rotating parts.
8.1.6.5 Appropriate arrangements should be made to ensure that: