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DNV-OS-D101 Marine and Machinery Systems and Equipment
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Ch.2
SECTION 1
Design PrinciplesCh.2 Sec.1
A. Arrangement
Ch.2 Sec.1
A 100 General
Ch.2 Sec.1 A
101 All machinery, systems and components that shall be operated
or subject to inspection shall be installed and arranged for easy
access.
Ch.2 Sec.1 A
102 All components in a system shall be satisfactorily matched
with regard to function, capacity and strength. Relative motions
between parts of the machinery shall be allowed for without inducing
detrimental stresses.
Ch.2 Sec.1 A
103 All machinery shall be equipped with control and instrumentation
considered necessary for safe operation of the machinery.
Ch.2 Sec.1 A
104 All spaces in which machinery is operated and where flammable
or toxic gases or vapours may accumulate, or where a low oxygen
atmosphere may occur, shall be provided with adequate ventilation
under all conditions.Guidance note:
By adequate ventilation is meant natural or mechanical ventilation
sufficient to prevent an accumulation of gases above a concentration
of 25% of their Lower Explosion Limit (LEL).---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
Ch.2 Sec.1 A
105 The capacity and arrangement of machinery spaces and emergency
generator room ventilation shall cover demands for operating the
machinery, boilers and emergency generator at full power in all
weather conditions.
On floating installations, ventilation inlets and outlets
shall be located not less than 4.5 m above freeboard deck. Supply
of air to the engine room/main power generation room, emergency
power room and fire pump room shall be ensured even in the event
of failure of one ventilation fan. As an alternative to the redundancy requirements
in B300 alternative provision of
air by adequate openings will be specially considered.
Guidance note:
Necessary capacity of ventilation may be calculated according
to ISO Standard 8861.---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
Ch.2 Sec.1 A
106 Service and utility systems (e.g. steam, heating medium, cooling
medium, compressed air, drains etc.) connected to systems containing
flammable or toxic liquids or gases shall normally not be combined
with similar systems located in non-hazardous areas or connected
to non-hazardous systems.
Ch.2 Sec.1 A
107 Any connection between hazardous and non-hazardous systems
shall be designed to eliminate or control the risk of ingress of
hazardous material from one system to the other due to incorrect
operation or leaks.The following issues shall be evaluated by the designer and
documented before systems are interconnected:
| — | identify possible failure modes
and define a realistic range of leak sizes |
| — | evaluate possible consequences of cross contamination |
| — | describe and evaluate reliability, maintainability and
testability of active and passive protection systems (e.g. liquid
seals, non return valves, detectors, actuated valves, primary and
secondary loops etc.). |
If the potential consequences of cross contamination are found
to be significant or the reliability of protective measures is difficult
to maintain or verify, separated systems shall be specified.
Guidance note:
Investigations following incidents have shown that gas can
migrate backwards against the flow of liquids and past check valves.
Check valves alone are not normally regarded as reliable devices
for prevention of cross contamination where gas is present.---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
Ch.2 Sec.1
A 200 Prevention of inadvertent operations
Ch.2 Sec.1 A
201 The machinery shall be so arranged that inadvertent operation
leading to reduced safety of the unit or installation or personnel,
cannot occur as a consequence of one single operational error.
Ch.2 Sec.1 A
202 The machinery and piping systems shall be arranged to prevent
sea water, stored hydrocarbons or chemicals or ballast from reaching
dry spaces of the installation or stored hydrocarbons or chemicals
from being discharged overboard as a consequence of inadvertent
operations. Measures shall also be taken to prevent inadvertent
movement of ballast or stored fluids internally within these systems.
Ch.2 Sec.1 A
203 Systems and tanks shall be so arranged that leakage or operation
of valves will not directly lead to increased risk of damage to
machinery, installation or personnel due to mixing of different
fluids.
Ch.2 Sec.1 A
204 Open or closed position of valves shall be easily visible.
Ch.2 Sec.1 A
205 If a valve's function in the system is not evident,
there shall be adequate information on a name plate attached to
the valve.
Ch.2 Sec.1 A
206 All connections to sea shall be marked: SEA
DIRECT.Ch.2 Sec.1
A 300 Communications
Ch.2 Sec.1 A
301 For self propelled units, at least two independent means shall
be provided for communicating orders from the navigating bridge
to the position in the machinery space or in the control room from
which the engines are normally controlled.
Ch.2 Sec.1 A
302 For self propelled units, at least one means of communication
shall be provided between the control station or bridge and any
other control position(s) from which the propulsion machinery may
be controlled.Ch.2 Sec.1
A 400 Engineers' alarm
Ch.2 Sec.1 A
401 For self propelled units arrangement shall be provided at
the main propulsion control station or at the manoeuvring platform
as appropriate for the operation of an engineers' alarm
which shall be clearly audible in the engineers' accommodation.Ch.2 Sec.1
A 500 Fire protection
Ch.2 Sec.1 A
501 Facilities for the safe storage and handling of flammable
fluids shall be found on board.
Ch.2 Sec.1 A
502 All spaces where oil-burning installations, settling tanks
or daily service fuel oil tanks are located, shall be easily accessible
and well ventilated.
Ch.2 Sec.1 A
503 Where small leaks of flammable fluids may occur during normal
service or routine maintenance work, special arrangements shall
be made to prevent these fluids from reaching other parts of the
machinery where danger of ignition may arise.
Ch.2 Sec.1 A
504 Piping and other installations for the transport of flammable
fluids shall be so located that the fire hazard resulting from rupture
and other failures, is acceptably low.
Ch.2 Sec.1 A
505 Exhaust pipes shall not be led in the vicinity of fuel oil
tanks, storage tank bulkheads.
Ch.2 Sec.1 A
506 All surfaces which may reach a temperature of 220°C or more,
shall be insulated or equivalently protected so that flammable fluids
cannot be ignited.
Ch.2 Sec.1 A
507 Where oil absorbing insulating material is used, the insulation
shall be covered by non-combustible vapour-tight sheeting.
Ch.2 Sec.1 A
508 All other possible ignition sources of the machinery shall
be protected in order to prevent ignition of flammable fluids.
Ch.2 Sec.1 A
509 Flammable or oil absorbing materials shall not be used in
floors, gratings etc. in boiler and engine rooms, shaft tunnels
or in compartments where settling tanks are installed.
Ch.2 Sec.1 A
510 Hydraulic power units shall be provided with adequate shielding
in order to avoid potential oil leakage, or spray coming into contact
with any sources of ignition.
Ch.2 Sec.1 A
511 When purifiers for heated fuel oil are not located in a separate
room, consideration shall be given with regard to their lo-cation,
ventilation conditions, containment of possible leakage and shielding
from ignition sources.
Ch.2 Sec.1 A
512 Approved penetrations shall be used where pipes are passing
through fire resistant bulkheads or decks.Ch.2 Sec.1
A 600 Piping systems
Ch.2 Sec.1 A
601 Metallic pipes shall be connected by welding or brazing or
by detachable connections in accordance with Sec.6.
Ch.2 Sec.1 A
602 Plastic pipes shall be connected by welding, gluing, cementing,
lamination or similar methods in accordance with Sec.6 E or by approved detachable
connections in accordance with Sec.2 G.
Ch.2 Sec.1 A
603 Installation of pipes for water, steam or oil behind or above
electric switchboards shall be avoided as far as possible. If this
is impracticable, all detachable pipe joints and valves shall be
at a safe distance from the switchboard or well shielded from it.
Ch.2 Sec.1 A
604 Routing of water pipes and air and sounding pipes through
freezing chambers shall be avoided.Ch.2 Sec.1
A 700 Operation of valves
Ch.2 Sec.1 A
701 Sea suction and discharge valves located in dry compartments,
bilge valves and valves on the fuel oil and lubricating oil tanks
which are situated higher than the double bottom tanks, shall be
arranged for local manual operation. The change over to manual operation
from possible remote control arrangement shall be simple to execute.Guidance note:
For remotely controlled sea suction and discharge valves located
in engine room each actuator should be fitted with a hand pump ready
for use or an equivalent arrangement.---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
Ch.2 Sec.1 A
702 For remotely controlled valves failure in power supply or
control signal shall not cause:| — | opening of closed valves |
| — | closing of open valves on fuel oil tanks and in cooling
water system for propulsion and power generating machinery. |
Ch.2 Sec.1 A
703 All valves in storage and ballast tanks which are hydraulically
or pneumatically controlled shall also be arranged for manual operation,
e.g. with a hand-pump connected to the control system.
Ch.2 Sec.1 A
704 Spindles of sea suction valves, discharge valves below the
load line, emergency bilge valves in engine rooms and blow down
discharge valves shall extend above the floor plates or by other
means be easily accessible and visible. For vessels with class notation E0 see also Rules for
Classification of Ships Pt.3 Ch.3 Sec.6.
Ch.2 Sec.1 A
705 Remotely controlled valves shall be provided with indications
for open and closed valve positions at the control station. In cases
where the possibility of local manual operation is required in addition
to the remote control, means of observing the valve position at
the valve location shall be provided.
Ch.2 Sec.1 A
706 When the valves are designed for actuator, the system transmitting
the torque to the valve stem, or the valve stem itself shall be
equipped with an interchangeable safety device such as breaking
pins or equivalent.
Ch.2 Sec.1 A
707 In addition, requirements for weathertight and watertight
integrity as given in DNV-OS-C301, shall be complied with.Ch.2 Sec.1
A 800 Valves on sides and bottom of floating
units and installations
Ch.2 Sec.1 A
801 All sea inlet and overboard discharge pipes shall be fitted
with easily accessible valves or cocks secured direct to the shell
or sea chest.
Ch.2 Sec.1 A
802 If it is impractical to fit the valves or cocks directly to
the shell or sea chest, distance pieces of steel may be accepted.These shall be made as short, rigid constructions, and shall
not be of a thickness less than given in DNV-OS-C301, Ch.2 Sec.2
F200.
Ch.2 Sec.1 A
803 For units or installations with double side and/or
bottom, the following requirements apply:
- The valve may be fitted to
the inboard tank boundary.
- The pipe wall thickness between side and bottom and
inner boundary shall be minimum 11 mm, regardless of pipe diameter
and regardless the shell plating thickness.
- Due attention shall be paid to the detail design to
avoid high stresses being introduced at pipe fixations, as for example
where the outer and inner boundary are connected by a short and
straight pipe.
- Outlet- or inlet-pipes passing through heated fuel oil
tanks or lubricating oil tanks shall be surrounded by cofferdams.
Ch.2 Sec.1 A
804 All outlets and sea inlet valves shall be fitted to the shell
in such a way that piping inboard of the valves may be disconnected
without interfering with the watertight integrity of the shell.
Ch.2 Sec.1 A
805 Valves and cocks for blow down of boilers shall have a protection
ring fitted on the outside of the shell plating through which the
spigot shall be carried.The spigot shall terminate flush with the outer side of the
ring.
Ch.2 Sec.1 A
806 Suction and discharge valves of steel and sea chests and distance
pieces shall be protected against corrosion by an efficient coating
or equivalent.
Ch.2 Sec.1 A
807 All suction and discharge pipes shall be adequately protected
where they are liable to be damaged by cargo and equipment.
Ch.2 Sec.1 A
808 Sea inlets shall be so designed and arranged as to limit turbulence
and to avoid entry of air due to the unit/installation's
movements.
Ch.2 Sec.1 A
809 Scuppers and sanitary discharges shall be arranged in accordance
with DNV-OS-C301, Ch.2 Sec.2, as applicable.
Ch.2 Sec.1 A
810 Sea inlets and discharge valves for systems where plastic
piping is used shall be arranged with remote closing arrangement.
The adequacy of this system shall be documented.
Ch.2 Sec.1
A 900 Fittings on watertight bulkheads
Ch.2 Sec.1 A
901 Where a collision bulkhead is provided, any pipes penetrating
collision bulkhead to be arranged in accordance with DNV Rules for
Classification of Ships Pt.4 Ch.6 Sec.3.
Ch.2 Sec.1 A
902 No drain valve or cock shall be fitted to watertight bulkheads
unless they are accessible at all times and capable of being closed
from above the deep load line. Alternatively the valve shall be
of the self-closing type. Indication of open and closed position
of the valves and cocks shall be provided.
Ch.2 Sec.1 A
903 Fastening of fittings, pipes, etc. to bulkheads or tunnel
plating by means of bolts passing through clearing holes in the
plating is not acceptable.Ch.2 Sec.1
A 1000 Requirements dependent upon damage
stability calculations
Ch.2 Sec.1 A
1001 For units or installations where damage stability requirements
apply, precautions shall be taken to prevent intercommunication
through damaged pipe lines between flooded and intact compartments. For this purpose, where any part of a pipe system is situated
within the defined damaged area and the pipe line has an open end
in a compartment assumed to be intact, then an isolating valve shall
be fitted. The valve shall be situated outside the damaged area
and shall be operable from the freeboard deck or from another position and
accessible when the unit or installation is in damaged condition.
For bilge lines, the remotely operated stop valves may be substituted
by a non-return valve.
Guidance note:
For compliance with IMO MODU Code bilge lines may only be
fitted with a positive closable valve from above the waterline.---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
Ch.2 Sec.1
A 1100 Refrigeration systems
Ch.2 Sec.1 A
1101 Fixed refrigeration plants (including air condition plants)
with a total prime mover rated effect of 100 kW and above, shall
comply with safety requirements as given in the Rules for Classification
of Ships Pt.5 Ch.10.Refrigeration plants using Group 2 refrigerants (e.g. ammonia)
shall comply with the safety requirements as given in Pt.5 Ch.10
irrespective of size.
Ch.2 Sec.1 A
1102 Spaces containing refrigeration installations and not fitted
with mechanical ventilations, shall be provided with an oxygen deficiency
monitoring system. Alarm indication shall be located at the entrance
to the space. Regarding routing of alarm to a manned control station,
see also DNV-OS-D202, Ch.2 Sec.2 A400.
Ch.2 Sec.1
B. Construction and Function
Ch.2 Sec.1
B 100 General
Ch.2 Sec.1 B
101 The machinery shall be so designed, installed and protected
that risks of fire, explosions, accidental pollution, leakages and
accidents thereof are acceptably low.
Ch.2 Sec.1 B
102 Reliability and availability of the machinery shall be adapted
according to considerations of the consequences from machinery failures
and disturbances.
Ch.2 Sec.1 B
103 The design arrangement of machinery foundations, shaft connections,
piping and ducting shall take into account the effects of thermal
expansion, vibrations, misalignment and hull interaction to ensure
operation within safe limits. Bolts and nuts exposed to dynamic
forces and vibrations shall be properly secured.Ch.2 Sec.1
B 200 Environmental conditions
Ch.2 Sec.1 B
201 All machinery, components and systems essential to the safe
operation of a unit should be designed to operate under the following
static conditions of inclination: | — | stabilized units - from upright to an
angle of inclination of 15° in any direction; |
| — | self-elevating units - from upright to an angle
of inclination of 10° in any direction; |
| — | surface units - from upright and in level trim
to an angle of inclination of 15° either way and simultaneously trimmed
up to 5° by the bow or stern. |
Ch.2 Sec.1 B
202 Deviations from these angles may be required or considered,
taking into consideration the type, size and service conditions
of the unit.
Ch.2 Sec.1 B
203 The emergency generator and its prime mover and any emergency
accumulator battery shall be designed to function at full rated
power when upright and when inclined up to the maximum angle of
heel in the intact and damaged condition, as determined in accordance
with chapter 3. In no case need the equipment be designed to operate
when inclined more than:| — | 25° in any direction on a column-stabilized unit; |
| — | 15° in any direction on a self-elevating unit; and |
| — | 22.5° about the longitudinal axis and/or when
inclined 10° about the transverse axis on a surface unit. |
Ch.2 Sec.1 B
204 All components and systems covered by this standard shall
be designed to operate under the following environmental conditions
unless otherwise specified in the detailed requirements for the
component or system:- Ambient air temperature in
the machinery space between 0°C and 45°C.
- Relative humidity of air in the machinery space up to
96%.
- Sea water temperature up to 32°C.
Guidance note:
Environmental conditions for instrumentation are given in
DNV-OS-D202 Ch.2 Sec.4.---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
Ch.2 Sec.1 B
205 Where the standard gives requirements for capacity or power
of machinery, these shall be determined at the ambient reference
conditions stated in Table B1.Ch.2 Sec.1 B
| Table B1 Ambient reference
conditions for machinery |
| Parameter | Value | Total barometric pressure | 1 bar | | Ambient air temperature | 45°C | | Relative humidity of air | 60% | | Sea water temperature | 32°C | |
Ch.2 Sec.1 B
206 The engine manufacturer shall not be expected to provide simulated
ambient reference conditions at a test bed unless specified in the
relevant standards.Ch.2 Sec.1
B 300 Functional
capability and redundancy (floating units)
Ch.2 Sec.1 B
301 Components and systems shall be arranged with redundancy so
that a single failure of any active component or system does not
cause loss of any main function, as specified in DNV-OSS-101 Ch.1
Sec.3 A and DNV-OSS-102 Ch.1 Sec.3 A, with the exceptions listed
in 305.
Ch.2 Sec.1 B
302 Redundancy can either be arranged as component redundancy
or system redundancy as defined in Ch.1 Sec.1
D200.
Ch.2 Sec.1 B
303 For redundancy on a component level a single failure of an
active component shall not lead to a reduction of the output power
for the main function served, as long as the main function is served
by one system only.
Ch.2 Sec.1 B
304 For duplicated systems a single failure of an active component
or a system shall not reduce the output power for the main function,
served by the duplicate system, to less than 40% of the
nominal output rated power. 301 and 302 shall be considered as general
requirements. For evaluation of deviations or equivalent solutions
reference should be made to the relevant standard for the component
or system in question.Guidance note:
For single engine propulsion plants all active components
must be duplicated to satisfy 301 and 307. Multi engine propulsion
plants or propulsion plants with combinations of diesel engines,
gas turbines and/or electrical motors are considered to
provide redundancy on a system level. For these plants, duplication
of the active components is not necessary provided that at least
40% of output rated power for the main function is remaining
in case of a single failure. For propulsion plants where less than
40% of output rated power remains, after a single failure,
duplication of the active components will be required. 'Output
rated power' is in this context the total rated propulsion
power for the driven unit (e.g. one or several propellers).
All other main functions shall be treated accordingly.---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
Ch.2 Sec.1 B
305 The following active components are general exceptions to
301 and are not required as part of the designed redundancy, unless
otherwise specified in the rules:| — | main engine |
| — | shafting, gear, driven unit (e.g. propeller) |
| — | anchor windlass |
| — | machinery for emergency power supply |
| — | auxiliary thrusters. |
Ch.2 Sec.1 B
306 Components and systems forming part of the designed redundancy
are normally to be arranged as system availability R2 (see Ch.1 Sec.1 D200). When the interruption
of the function, of a duplicated component or system, entails considerable
hazard to other components or systems, or to the unit or installation,
system availability R1 shall be arranged. The installation can be
arranged as system availability R3 if accepted in the relevant standard.
Ch.2 Sec.1 B
307 Active components, arranged as part of the designed redundancy,
shall be so dimensioned that in the event of a single failure sufficient
capacity remains to cover demands at the maximum continuous load
of the component served.Guidance note:
Only relevant for plants where it is required to have redundancy
on a component level (e.g. single engine plants, see 302).---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
Ch.2 Sec.1 B
308 When two or more components are performing the same function,
these shall be mutually independent and at least one shall be independently
driven. Components arranged as part of the designed redundancy,
yet only performing auxiliary functions to a main unit, can be directly
powered by the main unit through separate power transmissions, on
the condition that these components are not necessary for the starting
of the main unit.
Ch.2 Sec.1 B
309 The machinery shall be so arranged and designed that all main
functions can be maintained simultaneously in normal service.
Ch.2 Sec.1 B
310 For self-propelled units maintenance tasks normally expected
to occur at short intervals, for example weekly, shall be carried
out without loss of propulsion or steering.
Ch.2 Sec.1 B
311 Change over from one normal operational mode to another normal
operational mode of the machinery shall be possible without interruption
in propulsion or steering.
Ch.2 Sec.1 B
312 Machinery or equipment having remote or automatic control,
shall have additional alternative provisions for attendance and
operation.
Ch.2 Sec.1 B
313 For mobile offshore units the machinery shall be so arranged
that it can be brought into operation from the «dead ship» condition
within 30 minutes using only the facilities available on board. «Dead
ship» condition is understood to mean that the entire machinery
installation, including the power supply, is out of operation and that
auxiliary services (such as compressed air, starting current from
batteries etc.) for bringing the main propulsion into operation
and for the restoration of the main power supply are not available.In order to restore operation from the «dead ship» condition,
an emergency generator may be used provided that it is ensured that
the emergency power supply from it is available at all times. It
is assumed that means are available to start the emergency generator
at all times.
For units without a designated emergency engine, in accordance
with the 1989 MODU code, all main engines doubling as emergency
engines are considered to be available for start.
Ch.2 Sec.1 B
314 Requirements for cold starting arrangements of floating offshore
installations shall be especially determined depending on project
specific assessment of the safety hazards involved.
Ch.2 Sec.1 B
315 The performance and capacity of auxiliary systems shall be
adapted to the needs of the machinery installations served.
Ch.2 Sec.1
B 400 Failure effects
Ch.2 Sec.1 B
401 In the event of failure, components and systems shall enter
the least hazardous of the possible failure states with regard to
machinery, personnel and environment.
Ch.2 Sec.1 B
402 The probability that failure in a component causes damage
or failure to other components, shall be acceptably low.
Ch.2 Sec.1 B
403 Failure of one component in a system arranged as part of the
designed redundancy shall not lead to failure or damage to backup
or parallel components or systems.Ch.2 Sec.1
B 500 Component design
Ch.2 Sec.1 B
501 Where no specific requirements are given in these standards
regarding dimensioning and choice of materials, generally recognised
standards and engineering principles may be applied.
Ch.2 Sec.1 B
502 If acceptable accuracy cannot be obtained by strength calculations,
special tests for the determination of the strength of the design
may be required.
Ch.2 Sec.1 B
503 When it is of essential significance for the safety of the
unit or installation that the function of a component is maintained
as long as possible in the event of fire, materials with high heat
resistance shall be used.
Ch.2 Sec.1 B
504 Materials with low heat resistance shall not be used in components
where fire may cause outflow of flammable or health hazardous fluids,
flooding of any watertight compartment or destruction of watertight integrity.Guidance note:
Materials with high heat resistance are materials having a
melting point greater than 925°C. Materials with low heat resistance
are all other materials. Deviations from the above requirement will
be subject to special considerations.---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
Ch.2 Sec.1
C. Personnel Protection
Ch.2 Sec.1
C 100 General
Ch.2 Sec.1 C
101 Machinery, boilers and associated piping systems shall be
so installed and protected as to reduce to a minimum any danger
to persons onboard, due regard being paid to moving parts, hot surfaces
and other hazards.
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