Ships and marine technology -- Machinery-space flammable oil systems -- Prevention of leakage of flammable oil

ISO 18770:2005 specifies the measures to be taken to reduce fires originating from machinery-space flammable oil systems and to prevent leakage of flammable oil. It is intended for designers, shipyard personnel, engine-room personnel, owners, operators and maintenance personnel. Requirements contained herein address the design, construction, testing, installation, maintenance and inspection of systems containing flammable oil. ISO 18770:2005 is applicable to new and existing vessels, and is intended to be used as a supplement to the regulations for fuel oil, lubricating oil and other flammable oils contained in the International Convention for the Safety of Life At Sea (SOLAS 74), as amended, issued by the International Maritime Organization (IMO).

Navires et technologie maritime -- Systèmes d'huiles inflammables dans les salles de machines -- Lignes directrices pour la prévention de fuites d'huiles inflammables

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Status
Published
Publication Date
30-Aug-2005
Current Stage
6060 - International Standard published
Start Date
04-Jul-2005
Completion Date
31-Aug-2005
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INTERNATIONAL ISO
STANDARD 18770
First edition
2005-09-01
Ships and marine technology —
Machinery-space flammable oil
systems — Prevention of leakage of
flammable oil
Navires et technologie maritime — Systèmes d'huiles inflammables
dans les salles de machines — Lignes directrices pour la prévention de
fuites d'huiles inflammables
Reference number
ISO 18770:2005(E)
ISO 2005
---------------------- Page: 1 ----------------------
ISO 18770:2005(E)
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© ISO 2005

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ii © ISO 2005 – All rights reserved
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ISO 18770:2005(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

1 Scope ..................................................................................................................................................... 1

2 Terms and definitions........................................................................................................................... 1

3 General piping system considerations............................................................................................... 1

3.1 General................................................................................................................................................... 1

3.2 Human element ..................................................................................................................................... 2

3.3 Inspection, maintenance and repairs ................................................................................................. 2

3.4 Operational considerations ................................................................................................................. 2

4 Flexible hose and flexible-hose assemblies ......................................................................................3

4.1 Application ............................................................................................................................................ 3

4.2 Design and construction...................................................................................................................... 3

4.3 Installation ............................................................................................................................................. 3

4.4 Inspection and maintenance ............................................................................................................... 3

5 Spray shields......................................................................................................................................... 4

5.1 Application ............................................................................................................................................ 4

5.2 Design .................................................................................................................................................... 4

5.3 Inspection and maintenance ............................................................................................................... 4

6 Jacketed high-pressure fuel lines....................................................................................................... 4

6.1 Application ............................................................................................................................................ 4

6.2 Design .................................................................................................................................................... 4

6.3 Inspection and maintenance ............................................................................................................... 5

7 Bellows expansion joints..................................................................................................................... 5

7.1 Application ............................................................................................................................................ 5

7.2 Design .................................................................................................................................................... 5

7.3 Installation, inspection and maintenance .......................................................................................... 5

8 Filters and strainers.............................................................................................................................. 5

8.1 Design .................................................................................................................................................... 5

8.2 Installation, inspection and maintenance .......................................................................................... 6

9 Insulation ............................................................................................................................................... 6

9.1 Design .................................................................................................................................................... 6

9.2 Installation, inspection and maintenance .......................................................................................... 6

10 Other mechanical components ........................................................................................................... 6

10.1 Gauges................................................................................................................................................... 6

10.2 Pipe connectors, joints, hangars and supports ................................................................................ 7

11 Operational and maintenance hazards............................................................................................... 7

11.1 General................................................................................................................................................... 7

11.2 High-pressure pulses in fuel oil supply and spill systems .............................................................. 7

11.3 Design considerations ......................................................................................................................... 8

11.4 Installation ............................................................................................................................................. 9

11.5 Maintenance and inspection procedures...........................................................................................9

Annex A (informative) Installation guidelines for hose assemblies ........................................................... 11

Annex B (informative) Installation guidelines for spray shields ................................................................. 16

Bibliography ..................................................................................................................................................... 17

© ISO 2005 – All rights reserved iii
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ISO 18770:2005(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the

International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 18770 was prepared by Technical Committee ISO/TC 8, Ships and marine technology, Subcommittee

SC 3, Piping and machinery.
iv © ISO 2005 – All rights reserved
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ISO 18770:2005(E)
Introduction

Fuel oil, lubricating oil and other flammable oil system failures are a major source of shipboard fires. This

International Standard specifies the measures that shall be taken to reduce fires originating from

machinery-space flammable oil systems, and is intended for designers, shipyard personnel, engine-room

personnel, owners, operators and maintenance personnel. Requirements contained herein address the design,

construction, testing, installation, maintenance and inspection of systems containing flammable oils.

It is the intent of this International Standard to supplement and provide guidance in support of the following

International Maritime Organization circulars, with the eventual goal of replacing these circulars.

 MSC/Circular 647 (1994), “Guidelines to Minimize Leakages from Flammable Liquid Systems”, a

supplement for SOLAS Regulation II/2-15 (“Arrangements for Flammable Oils”). It addresses several

aspects of the fuel oil, lubricating oil and other flammable oil systems, such as hoses, spray shields,

insulation, connectors, joints and supports.

 MSC/Circular 851 (1998), “Guidelines on Engine-Room Oil Fuel Systems”, a supplement to

MSC/Circular 647. This circular addresses causes of oil fuel leakage, which sometimes result in

machinery space fires. It discusses design, installation, maintenance and inspection issues, and explains

some contributing factors such as frequent dismantling, short-duration pressure pulses, and vibration.

© ISO 2005 – All rights reserved v
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INTERNATIONAL STANDARD ISO 18770:2005(E)
Ships and marine technology — Machinery-space flammable oil
systems — Prevention of leakage of flammable oil
1 Scope

This International Standard specifies the measures to be taken to reduce fires originating from machinery-

space flammable oil systems and to prevent leakage of flammable oil. It is intended for designers, shipyard

personnel, engine-room personnel, owners, operators and maintenance personnel. Requirements contained

herein address the design, construction, testing, installation, maintenance and inspection of systems

containing flammable oil.

This International Standard is applicable to new and existing vessels, and is intended to be used as a

supplement to the regulations for fuel oil, lubricating oil and other flammable oils contained in the International

Convention for the Safety of Life At Sea (SOLAS 74), as amended, issued by the International Maritime

Organization (IMO).
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
flammable oil
oil easily ignitable and burned, generally found in machinery spaces
EXAMPLE fuel oil, lubricating oil, thermal oil or hydraulic oil
3.2
machinery space

space, generally containing main and auxiliary propulsion equipment and associated systems, as defined in

the International Convention for the Safety of Life At Sea (SOLAS 74), as amended, issued by the

International Maritime Organization
3.3
hot surface
surface whose temperature exceeds 220 °C
3.4
electrical component

switchboard, instrument panel, electrical controller, instrumentation cabinet or other shipboard electrical

equipment, whose wetting or spray by liquids could result in fire or loss of propulsion

3 General piping system considerations
3.1 General

Based on past experience, it is known that the combination of flammable materials and sources of ignition is

the main cause of machinery-space fires. The flammable materials involved in the majority of cases are oils,

i.e. fuel oil, lubricating oil or hydraulic oil. There are many potential ignition sources in a machinery space, the

© ISO 2005 – All rights reserved 1
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ISO 18770:2005(E)

most common being hot surfaces, e.g. exhaust pipes and steam pipes. Overheating of machinery, ignition

from electrical installations due to short-circuiting or arcing of switchgear and other fault conditions can result

in fire. Other frequent ignition sources are those associated with human activities, e.g. smoking, welding and

grinding.
3.2 Human element

The role of the human element shall always be considered. Personnel shall be properly trained and follow

established procedures. Knowledge of the operation of engine fuel systems and other flammable oil systems,

as well as the magnitude of pressures generated within them and hazards associated with leaks, should be

included in training for engineer officers. These topics should receive detailed attention when candidates sit

for their Certificate of Competency examinations.
3.3 Inspection, maintenance and repairs

Inspection, maintenance and repairs to flammable oil systems shall be carried out in a professional manner.

Owners shall ensure that the necessary training, equipment and parts are available. Records of significant

repairs and maintenance to these systems shall be noted in the engineer's daily log and/or maintenance log.

3.4 Operational considerations

3.4.1 Many fires have been caused by pipe connections and fittings working loose. The fuel, lubricating and

hydraulic oil pipes, their fittings, connections and securing arrangements shall be routinely checked as part of

a preventive maintenance plan. Care shall be taken not to overtighten fittings during checks.

3.4.2 When completing maintenance or repairs to main or auxiliary engines, checks shall be made to

ensure that the insulation covering hot surfaces has been properly replaced. Regular checks of the engines

shall be made to confirm that the insulation is in place.

3.4.3 Any fuel, lubricating- or hydraulic-oil leak shall be dealt with promptly. In the event of a major leak,

every effort should be made to stop the pump or source of the oil pressure. When underway, the navigation

bridge shall be immediately informed of major flammable-liquid leaks.

3.4.4 Serious fires have originated because of a failure to recognize potential hazards (such as burning oil

running out of furnace fronts onto the tank top, a spray of oil from a defective gland, joint or a fractured pipe) in

areas where these may not be readily noticeable, but can be easily ignited. It is essential to avoid the

dangerous situation in which a small fire could spread to waste oil in the bilges or on tank tops, where it could

rapidly spread out of control. Cleanliness is essential for safety, and a high standard of cleanliness shall

always be maintained.

3.4.5 Woodwork or other readily combustible materials shall not be used in machinery spaces where

flammable oil is used. No combustible material shall be stored near any part of oil installations. The use of

bituminous or similar flammable compounds shall be kept to a minimum in machinery and boiler spaces.

3.4.6 When repairs, however temporary, are carried out to oil lines, special attention shall be paid to fire

risks. All repairs shall be adequate to prevent any danger of leakage and shall be to a standard which would

endure exposure to fire.

3.4.7 If there is a leakage of fuel, lubricating or hydraulic oil, the chances of preventing the outbreak of fire

or quickly extinguishing one which has started, will be greatly improved if all affected or adjacent machinery

which may have heated surfaces, including ancillaries, can be immediately shut down. The prevention of

further leakage will reduce the probability of fire, or reduce the intensity of one that has already started and

can help to avoid permanent disablement of the ship.
2 © ISO 2005 – All rights reserved
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ISO 18770:2005(E)
4 Flexible hose and flexible-hose assemblies
4.1 Application

The limited use of flexible hose in flammable oil systems is permitted. This clause provides guidance

concerning the safe application of flexible-hose assemblies. Flexible-hose assemblies, which are flexible

hoses with end fittings attached, shall be as short in length as practicable and only used where necessary to

accommodate relative movement between fixed piping and machinery parts.
4.2 Design and construction

Hoses shall be constructed to a recognized standard and be approved as suitable for the intended service,

taking into account pressure, temperature, fluid compatibility and mechanical loading including impulses

where applicable. Each hose assembly shall be provided with a certificate of hydrostatic pressure testing and

conformity of production. In addition, non-metallic hoses shall be provided with a certificate of fire-resistance

[1]
testing; guidance for fire-resistance testing is provided in ISO 15540 .
4.3 Installation

Hoses shall be installed in accordance with the manufacturer's instruction, with regard to minimum bend

radius, twist angle and orientation, as well as support where necessary. In locations where hoses are likely to

suffer external damage, adequate protection shall be provided. After installation, the system shall be operated

at maximum working pressure and checked for malfunctions and leaks. General installation guidelines are

given in Figures A.1 and A.2.
4.4 Inspection and maintenance

Hose assemblies shall be periodically inspected according to the manufacturer's or ship's maintenance

programme. Results of periodic inspections shall be documented. Hose assemblies shall be replaced when

there is evidence of distress likely to lead to failure, or doubt as to their continued suitability for service.

Any of the following conditions can require replacement of a hose assembly:
 leaks at fitting or in flexible hose;
 damaged, cut or abraded cover;
 kinked, crushed, flattened or twisted flexible hose;
 hardened, stiff, heat-cracked or charred flexible hose;
 blistered, soft, degraded or loose cover;
 cracked, damaged or badly corroded fittings;
 fitting slippage on flexible hose.

It is expected that hose assemblies may need to be replaced several times during the life of the ship.

Manufacturer's recommendations for maximum hose service life shall be followed.
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ISO 18770:2005(E)
5 Spray shields
5.1 Application

Spray shields prevent the impingement of leaked or sprayed flammable liquid onto a hot surface or other

source of ignition. Fuel oil, lubricating oil and other flammable oil piping shall be screened or otherwise

suitably protected to avoid, as far as practicable, oil spray onto hot surfaces, into machinery air intakes, or

other sources of ignition. Spray shields are intended for use on flanged joints, flanged bonnets and other

flanged connections in oil pressure systems which are located above the floor plates and which are not lagged

(insulated). The number of joints in such systems shall be kept to a minimum. Spray shields shall be installed

for pressurized flammable-liquid systems in the main and auxiliary machinery spaces if the joint is within 3 m

(10 ft) of an electrical component or a hot surface.
Spray shields are not required for the following:
 suction piping, or piping not subject to pump discharge pressures;
 piping located in voids or cofferdams;
 tank-sounding tubes, air escapes, vents and overflows;

 piping located inside gas-turbine modules, reduction-gear enclosures, or otherwise protected by barriers

such as lockers, decking or foundations;

 union-type fittings, consisting of a threaded three-piece (male, female, nut) assembly.

5.2 Design

Many types of spray shields are possible. An example of a spray shield that provides a total enclosure of a

joint is given in Figure B.1. This spray shield is designed to wrap completely around the joint and is long

enough to provide an overlap equal to one-quarter of the joint's circumference. The shield is wrapped around

the sides of the flange far enough to cover the heads of the bolts. The shield is laced tightly with wire and the

overlap is pointed away from potential ignition sources.
5.3 Inspection and maintenance

Spray shields shall be inspected regularly for their integrity, and any which have been removed for

maintenance purposes shall be refitted on completion of the task. Oil-soaked spray shields normally indicate

the presence of leaks. They shall be replaced as soon as possible, and the cause of the leak repaired.

6 Jacketed high-pressure fuel lines
6.1 Application

All external high-pressure fuel delivery lines between the high-pressure fuel pumps and fuel injectors shall be

protected with a jacketed piping system capable of containing a high-pressure fuel line failure. A jacketed pipe

incorporates an outer pipe into which the high-pressure fuel pipe is placed, forming a permanent assembly.

The jacketed piping system shall include a means for collection of leakage, and arrangements shall be

provided for a fuel line failure alarm.
6.2 Design

Two systems have been successfully used in meeting this requirement, namely, rigid-sheathed fuel pipe and

flexible-sheathed fuel pipe. In either case, the sheathing shall fully enclose the pipe and resist penetration by

the spray of oil from a pipe failure during service. Also, the annular space and drainage arrangements shall be

sufficient to ensure that, in the event of a complete fracture of the internal pipe, an excessive build-up of

4 © ISO 2005 – All rights reserved
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ISO 18770:2005(E)

pressure cannot occur and cause rupture of the sheath. The suitability of such pipes shall be demonstrated by

prototype testing, appropriate design analysis, or class-society-type approval. The drainage arrangement shall

prevent contamination of lubricating oil by fuel oil.
6.3 Inspection and maintenance

Regardless of the system selected, little additional maintenance or periodic inspection is required to keep the

jacketed fuel lines in proper working order. However, jacketed pipes shall be inspected regularly and any

drainage arrangement which may have been disconnected for maintenance shall be properly refitted.

Inspection and maintenance to these systems shall be noted in the engineering log or maintenance log.

7 Bellows expansion joints
7.1 Application

This clause refers specifically to metallic expansion joints used in flammable-oil systems. To ensure adequate

piping system flexibility, bends, loops, offsets or bellows expansion joints are required in most piping systems.

The use of non-metallic expansion joints shall be limited, and the requirements of Clause 4 for flexible hose

shall apply, particularly fire-resistance testing.
7.2 Design

Expansion joints are designed to accommodate axial and lateral movement and shall not be used to

compensate for pipe misalignment. Design shall be based on an acceptable code or on testing of expansion

joints of similar construction, type, size and use. Thermal expansion and contraction and the fatigue life due to

vibration are also important points to consider. Where external mechanical damage is possible, the bellows

shall be suitably protected. Each bellows expansion joint shall be provided with a certificate of hydrostatic

pressure testing and conformity of production. The manufacturer's name, the month and the year of

manufacture shall be permanently marked on expansion joints.
7.3 Installation, inspection and maintenance

Bellows expansion joints shall be installed in accordance with the manufacturer's instructions and examined

under working conditions, and shall be inspected regularly and be replaced whenever there is doubt as to their

suitability to continue in service.
8 Filters and strainers
8.1 Design

In general, filters and strainers used in fuel-oil, lubricating-oil or other flammable-oil systems shall have

metallic housings and bodies with a melting point above 930 °C. Other metallic housing and body materials

[1]

may be acceptable provided they have successfully completed a fire test according to ISO 15540 . All

pressure-retaining parts shall be suitable for the maximum operating temperature and pressures. The filter or

strainer design and construction shall facilitate cleaning, and prevent or minimize spillage during maintenance.

Where filters and strainers are required to be opened for cleaning during operation, they shall be fitted with a

means of depressurization before being opened.
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ISO 18770:2005(E)
8.2 Installation, inspection and maintenance

Filters and strainers shall be located as far away as practicable from hot surfaces and other sources of ignition.

They shall not be located in positions where spillage could fall onto a flywheel, or other rotating machinery

parts, and be sprayed. Suitable drip trays shall be provided under filters and strainers. Filters and strainers

shall be inspected every time they are opened for cleaning, and the cover gaskets or seals shall be renewed

when necessary. Satisfactory seating and tightening of the cover shall be verified before the system is put

back into service. Nuts, bolts, screws and studs associated with the filter covers and holding-down

arrangements shall be inspected every time the filter is opened for cleaning. The nuts, bolts, screws and studs

shall be replaced with the correct type as soon as they show signs of wear, crossed threads, stretching, or

rounded hexagonal heads. Studs shall be inserted into the casing to the correct depth of thread.

Vent plugs shall be replaced whenever they show signs of wear or blockage. Vent plugs should not be

replaced by valves or solid plugs.

Drain plugs shall be replaced when they show signs of wear or blockage. Open-ended drain lines shall be

plugged or effectively sealed against inadvertent release of oil prior to the filter being put back into service.

9 Insulation
9.1 Design

All surfaces with temperatures above 220 °C, that can be impinged as a result of a flammable-oil system

failure, shall be properly insulated. Insulation of hot surfaces reduces the risk of fire by keeping the

temperatures of these surfaces below the auto-ignition temperature of the oil fluids. The insulating material

shall be non-combustible and impervious to oil impingement. If the insulation is not impervious to oil, it shall be

encased in a metallic sheath.
9.2 Installation, inspection and maintenance

Manufacturer's installation instructions shall be followed. Permanent insulation shall be used to the greatest

extent possible. Insulation shall be provided with readily removable sections that allow access for normal

maintenance. Regular checks of equipment shall confirm that insulation is properly in place, particularly

following maintenance or repair.
10 Other mechanical components
10.1 Gauges
10.1.1 Design and installation

10.1.1.1 Pressure, temperature and oil-level gauges, and similar instrumentation have featured in many

fires aboard ships. All pressure gauges and other similar instruments in oil systems shall, wherever possible,

be fitted with an isolating valve or cock at the connection to the pressure take-off point. The number of

pressure take-off points shall be kept to a minimum and gauge piping runs shall be as short as practicable.

Copper pipes should not be used and, where already fitted, should be replaced by steel. As an interim

measure, existing copper pipe should be properly secured against damage from vibration. Gauge pipes

should incorporate an expansion loop to accommodate changes in temperature and to assist in resisting the

...

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