Maintenance Course for Junior Officers

KGJSContinuous

Improvement

KRISTIAN GERHARD JEBSEN SKIPSREDERI AS

Maintenance course for Junior Officers’

Maintenance course for Junior Officers’

GENERALterotechnology - the branch of technology and engineering concerned with the maintenance of equipment.

In recent years, there has been an increase in the use of proactive maintenance techniques for repair and maintenance onboard vessels.There have been numerous advances in condition monitoring technology, trending, and increasingly more powerful planned maintenance software. However, machinery systems have continued to become larger and more complex, requiring skilledoperators with specialized knowledge of the machinery and systems onboard.Maintenance is particularly vulnerable to error because the work is often complex, involving the frequent removal and replacement of a variety of components. Certain tasks also require high levels of vigilance and skill to detect faults that can be infrequent and difficult to spot. Maintenance is also commonly performed in difficult working conditions and often under time pressure. Maintenance errors have been contributory factors in a number of high profile accidents across different industries. The maritime industry is no exception.Attention to Human Factors is a proven way to enhance performance and reduce the risks of accidents and incidents. Human Factor takes a human centered approach when considering the design and operation of the workplace. This helps to control the factors that influence and shape behavior which can lead to error and rule violation.

Due to the operation of the ship and exposure to environmental conditions, such as air, humidity, heat and seawater, the ship and its equipment deteriorate. Further, as the time passes by, certain documentation, services and equipment become invalid, out dated or non-compliant. This makes maintenance necessary in order to maintain compliance with the applicable requirements on safety and pollution prevention. Company carry out maintenance either as corrective maintenance or preventive maintenance. Corrective maintenance means taking corrective actions after deficiencies have occurred. Corrective maintenance is an unacceptable approach as it implies that at times deficiencies can be found on board compromising the safety of the ship, its personnel and the environment. When serious deficiencies are found during class surveys, Flag State inspections or Port State inspection, the ship may be detained until rectification.

Preventive maintenance means taking preventive actions before deficiencies occur. This means continuous compliance, no deficiencies on board and therefore no ground for detention.

!“Ships do not move cargoes, people do”.

Competence is the knowledge, skills and attitude utilised to fulfil a defined role, safely

and successfully to a defined standard.

One of the primary responsibilities of a ship owner and ship management Company is that the ship hull structures, machinery and equipment are maintained and operated in conformity with the applicable rules and regulations and any relevant additional requirements, procedures and standards established by the Company.

That responsibility starts from the top Managers of the Company, who should be committed to direct efforts, resources and investments in order to ensure that their ships are properly maintained and operated by qualified and competent crew. Such a Company’s commitment from the top is the first element to be verified by the ISM Auditors.

The objectives of a responsible Company should be to ensure, as required bythe ISM Code, that the procedures for ship maintenance established by theCompany are properly implemented ashore and on board. The identificationof factual evidences and possible non-conformities related to theimplementation of ship maintenance procedures ashore and on board is thesecond step of verification against the relevant requirements of the ISM Code.The Company shall not limit its maintenance and repair interventions to theones strictly required by Flag and Port State Authorities, classificationsocieties and other interested parties during periodical and renewal- of certificatessurveys. In accordance with the requirements of the ISM Code, the Company is theparty which is solely responsible for the daily maintenance of the ship, including the hull structure, machinery and equipment and for the safe and environmentally responsible operation of the ship.

WHAT THE ISM CODE SAYS ABOUT MAINTENANCE ?

Clause 10.1 of the ISM Code states, “The Company should establish procedures to ensure that the ship is maintained in conformity with

the provisions of the relevant rules and regulations and with any additional requirements which may be established by the Company”.

Clause 10.2 of the ISM Code states, that the company should ensure that any

non-conformity is reported, with its possible cause, if known, and thatappropriate corrective action is taken.

Clause 10.3 of the ISM Code states, “The Company should establish procedures in its SMS to identify equipment and technical systems

the sudden operational failure of which may result in hazardous situations. The SMS should provide for specific measures aimed at

promoting the reliability of such equipment or systems. These measures should include the regular testing of stand-by

arrangements and equipment or technical systems that are not in continuous use”.

1. Introduction2. Industry mistakes and Port State

Control3.Equipment Failure4.Planned Maintenance5.Predictive Maintenance6.Testing & Inspections7.Hatch covers8.Bearings9.Wire ropes10.Greasing11.Hydraulic12.Coating13.Pipes14.Risk Assessment – Safe Job Analysis15.Human Factor

1. Introduction2. Industry mistakes and Port State

Control3.Equipment Failure4.Planned Maintenance5.Predictive Maintenance6.Testing & Inspections7.Hatch covers8.Bearings9.Wire ropes10.Greasing11.Hydraulic12.Coating13.Pipes14.Risk Assessment – Safe Job Analysis15.Human Factor

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A is the sample surface [m2],

Tc is the exposure time [hours]

ρ is the sample density [kg/m3].

Vc is the rate of penetration [mm/year]

What is the 8760 ???

By understanding the risk of losses associated with equipment failures, a maintenance program can be optimized. This optimization is achieved by allocating maintenance resources to equipment maintenance according to risk impact on the vessel.

For example:

1) Identify functional failures with the highest risk, which will then become the focus for further analyses

2) Identify equipment items and their failure modes that will cause high-risk functional failures

3) Determine maintenance tasks and maintenance strategies that will reduce risk to acceptable levels

Does it sounds complicated?

You have to understandYou have to understand

1)1) Equipment functionsEquipment functions

2) The failure modes of its equipment that support these 2) The failure modes of its equipment that support these functionsfunctions

3) How then to choose an optimal course of maintenance to 3) How then to choose an optimal course of maintenance to prevent the failure modes from occurring or to detect the prevent the failure modes from occurring or to detect the failure mode before a failure occursfailure mode before a failure occurs

4) How to determine spare holding requirements4) How to determine spare holding requirements

5) How to periodically refine and modify existing maintenance 5) How to periodically refine and modify existing maintenance over timeover time

Number of claims by claim type per 1000 vessels

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400

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Heavy weather

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Fire/ Explosion

Contact

Collision

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Insurance perspective

PSC Procedure Boarding Procedures PSC Inspectors are boarding a ship without announcement and primarily check the ship's documents for completeness and validity. If there are any grounds to believe that the ship is substantially not conforming with the international conventions, the inspector will carry out an expanded inspection of the ship's condition and the required equipment. The Master will receive an official inspection report consisting of Form A and B. Form A lists the ship's details and the validity of the relevant certificates. Form B shows the list of deficiencies found (if any), with an action code which describes a timeframe for rectification for each deficiency. If clear grounds are established that the ship forms a hazard to safety and/or the environment, the PSCO has the right to detain the ship in port until the respective deficiencies have been rectified and resurveyed. The PSC authority will either resurvey by own inspectors or ask for a survey report from the Classification surveyor to verify the rectification. Any detention has to be reported as soon as possible by the authority to the flagstate, the classification society and IMO. The data about the inspection and the given timeframe for rectification are entered in a computer system used by all members of a regional PSC agreement.

Deficiency Codes The PSC authorities within the main MOU regions are using deficiency codes for the various defects they are listing in the inspection reports. They are defining the kind of deficiency and are used for statistical evaluations. We must not mix them with an Action Codes

Action Codes The given timeframe for rectification of each deficiency is commonly given in a coded form in the inspection report, called "action code".

Following codes are mainly used:

30 = Grounds for detention 17 = Master instructed to rectify deficiency before departure 16 = to be rectified within 14 days 15 = to be rectified at next port of call 19 = rectify major non-conformity before departure 18 = rectify non-conformity within 3 months 10 = deficiency rectified 40 = next port informed 47 = as in agreed class conditions 50 = Flagstate informed 70 = Classification society informed 80 = temporary repair 99 = to be specified in free text .

Extract from PSC inspection reports - AUSTRALIA

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Extract from PSC inspection reports - JAPAN

Extract from PSC inspection reports – U K

Extract from US Coast Guard inspection reports – U S A

Extract from PSC inspection reports – CHINA

Extract from PSC inspection reports – HONG KONG

Extract from PSC inspection reports – KOREA

Extract from PSC inspection reports – GERMANY

Definitions Used In Connection WithDefinitions Used In Connection WithPort State ControlPort State Control Inspection Inspection

Clear grounds: Evidence that the ship, its crew or its safety management system does not comply with the requirements of the relevant conventions. Such evidence needs not necessarily be a deficiency, but may be an incident, and accident or and indication of substantial non-compliance/detainable deficiencies.

Deficiency: Non-compliance, discrepancy or deviation from the requirements of the relevant instruments/conventions.

Non-conformity: means an observed situation where the objective evidence indicates the non-fulfilment of a specified requirement.

Observation: means a statement of fact made during an inspection and substantiated by objective evidence. It may also be a statement made by the inspector referring to the competence management system which, if not corrected, may lead to a non-conformity in the future.Detainable Deficiency: A deficiency that presents an immediate threat to the ship, its personnel

or the environment, which renders the ship unsafe to proceed to sea. Detention: Intervention action taken by the port State in case of detainable deficiencies or substantial non-compliance to ensure that the ship does not sail until detainable deficiencies have been rectified.

The following factors usually influence equipment failure:

1) Design error2) Faulty material3) Improper fabrication and construction4) Improper operation5) Inadequate maintenance6) Maintenance errorsNote that maintenance does not influence many of these factors.

Therefore, maintenance is merely one of the many approaches to improving equipment reliability and, hence, system reliability. In addition, maintenance analysesidentifying premature equipment failures introduced by maintenance errors. In these cases, management may recommend improvements for specific maintenance activities, such as improving maintenance procedures, improving worker performance, or adding quality assurance/quality control tasks to verify correct performance of critical maintenance tasks. To effectively improve equipment reliability through maintenance, design changes or operationalimprovement, Officer must have an understanding of potential equipment failure mechanisms, their causes and associated system impacts. Equipment failure should be defined as a state or condition in which a component no longer satisfies some aspect of its design intent (e.g., a functional failure has occurred due to the equipment failure).

To develop an effective failure management strategy, the strategy must be based on an understanding of the failure mechanism. Equipment will exhibit several different failure modes (e.g., how the equipment fails). Also, the failure mechanism may be different for the different failure modes, and the failure mechanisms may vary during the life of the equipment. To help understand this relationship, Table 1 examines typical hardware-related equipment failure mechanisms.

Table 1

Equipment Failure Rate and Patterns

Depending on the dominant system failure mechanisms, system operation, system operating environment and system maintenance, specific equipment failure modes exhibit a variety of failure rates and patterns.1) Infant mortality or wear-in2) Random3) Early wear-out4) Wear-out

Wear-in failure – dominated by “weak” members related to problems such as manufacturing defects and installation/maintenance/startup errors. Also known as “burn in” or “infant mortality” failures.

Random failure – dominated by chance failures caused by sudden stresses, extreme conditions, random human errors, etc. (e.g., failure is not predictable by time).

Wear-out failure – dominated by end-of-useful life issues for equipment

Equipment Life Periods

By simply identifying which of the three equipment failure characteristics is representative of the equipment failure mode, Officer gains insight into the proper maintenance strategy. For example, if an equipment failure mode exhibits a wear-out pattern, rebuilding or replacing the equipment item may be an appropriate strategy. However, if an equipment failure mode is characterized by wear-in failure, replacing or rebuilding the equipment item may not be advisable. Finally, a basic understanding of failure rate helps in determining whether maintenance or equipment redesign is necessary. For example, equipment failure modes that exhibit high failure rates (e.g., fail frequently) are usually best addressed by redesign rather than applying more frequent maintenance.

Japanese Statistical Study on Reliability of Ship Equipment and Safety Management from 1982 to 1997 ( 15 years ), the total number of 376 ships as the object of investigation. The collected data is of 2 kinds, the one concerned with the failure, the other concerned with the alarm. And the total number is 114402 [case]Among these, the amount of data as the occurrence of ship equipment failure is 77114 [case],

The basic principle of planned maintenance is that restoring or discarding the item at a specific time before failure is expected can best manage the probability of failure. Following this principle, the planned-maintenance tasks are performed at set intervals, regardless of whether or not a failure is impending. Restoring the item or discarding it and replacing it with a new item prevent the failure.

Our tool for planned maintenance on board is AMOS software

Maintenance Planning Work Flow Maintenance Planning Work Flow DescriptionDescription

When department Chief issues work order

1 ) An Officer needs to have a thorough understanding of the work order’s requirements such as the following:

· Correct equipment position / number / marks· Work description request or equipment symptoms · Urgency of work · Initial safety considerations

Officer reviews AMOS to determine if the job has been performed previously and history is available.

2.) Officer visits the job location area to plan the work order. Observing physical restraints

· Access to work area · Equipment removal requirements · Space for lifting devices or mobile equipment · Proximity of other jobs going on at potentially the same time

· Identify environmental condition · Wet · Hot · Cold · Heights · Depths · Escaping Steam · Product · Chemicals

· Identify safety issues · Permits – Hot Work, Enclosed Space Entry · PPE requirements · Blowers · Fall protection harnesses · Monitoring devices · Extra safety watch people

· Prepare field drawings or sketches · Take digital pictures with supporting notes · Prepare any type of notations that will help plan the job · Specify special tolls and/or equipment

· Cranes · Fire protection · Welding/cutting tools · Scaffolding

3.) Crew receives verbal instructions from the Officer regardingexpectations and the planned maintenance work order.

Officer constantly supervise correct application of safety mesures and maintenance work order

4.) Upon completion of the maintenance work order, Officer is expected to provide a brief written description of work performed on the work order form.

Although many failure modes are not age-related, most of them give some sort of warning that they are in the process of occurring or about to occur. If evidence can be found that something is in the final stages of a failure, it may be possible to take action to prevent it from failing completely and/or to avoid the consequences.

The time interval between Point P and Point F in above diagram is called the “P-F interval”. This is the warning period (e.g., the time between the point at which the potential failure becomes detectable and the point at which it deteriorates into a functional failure). It should be noted that the P-F interval can vary in practice, and in some cases, it can be very inconsistent. In these cases, a task interval should be selected that is substantially less than the shortest of the likely P-F intervals.

WarningPeriod

For a condition-monitoring maintenance task to be considered applicable and effective, the following considerations must be made:

1) Onset of failure must be detectable. There must be some measurable parameter that can detect the deterioration in the equipment’s condition. In addition, maintenance personnel must be able to establish limits to determine when corrective action is needed.

2) Reasonably consistent P-F interval. The P-F interval must be consistent enough to ensure that corrective actions are not implemented prematurely or that failure occurs before corrective actions are implemented.

3) Practical interval in which condition-monitoring tasks can be performed. The P-F interval must be sufficient to permit a practical task interval. For example, a failure with a P-F interval of minutes or hours is probably not a good candidate for a condition-monitoring maintenance task.

4) Sufficient warning so that corrective actions can be implemented. The P-F interval must be long enough to allow corrective actions to be implemented. This can be determined by subtracting the task interval from the expected P-F interval and then judging whether sufficient time remains to take necessary corrective actions.

5) Reduces the probability of failure (and therefore the risk) to an acceptable level. The tasks must be carried out at an interval so that the probability of failure allows an acceptable risk level to be achieved. Agreed-upon risk acceptance criteria should be determined and recorded.

6) Must be cost-effective. The cost of undertaking a task over a period of time should be less than the total cost of the consequences of failure.

This is so called failure-finding maintenance, and it is included in onboard planned maintenance software – AMOS. Testing and inspections tasks are designed to discover equipment faults that are not detected during normal crew operations (e.g., hidden failures)For example, a standby electrical generator failing to start on loss ofpower may only be discovered when the primary generator fails and power is lost.Basically, the Inspection – means visiting all accessible areas of the ship, assessment of the sea worthiness, cargo worthiness, the quality of the manning, service and maintenance, safety standards, (particularly crew safe working practices), the operational performance of the ship and pollution control.Inspection plays a vital role in vessel quality control and day to day maintenance

Competence is required to detect and characterise the defect which is expected

Some of the common negative factors expressed by individuals involved in ISM implementation are:

• Too much paperwork• Voluminous procedures manuals• Irrelevant procedures• No feeling of involvement in the system• Ticking boxes in checklists (without actually carrying out the required task)• Not enough people/time to undertake all the extra work involved• Inadequately trained/motivated people• No perceived benefit compared with the input required• ISM is just a paperwork exercise

Kristian Gerhard Jebsen Skipsrederi A/S 300 Shipboard Main Manual All Vessels/06 Management of Safety and Quality: SMM -06.07 KGJS MANUALS (Nautilus) rev: 00

Document title: Master/ Ship Management’s Verification ------------------------------------------------------------------------------------------------------------------------- Procedure In order to verify that the SQM System is functioning as intended, Master, in co-operation with the Ship Management shall complete the following Check List once a month. Completed Check List shall be filed in CHECK LIST FILE. Verification Checklist NO ITEM Yes Comment 1 Deck Log Book and GMDSS log properly kept and signed by

officers. Bridge and Deck Check Lists being used as described in SMM

2 Oil Record Book and Log book for Chemical used onboard kept in accordance with instructions, updated and signed by Chief Engineer

3 Engine Room Log Book kept in accordance with instructions and signed by Chief Engineer. Bunkering Procedure being followed.

4 Familiarisation Check Lists properly completed for all new personnel (Filed in Personnel file)

5 Safety Check Lists (Enclosed Space), Procedures followed and Check Lists Filed

6 Chart Corrections completed up till last received Notice to Mariners

7 Voyage/ Passage Planning carried out in accordance with instructions and Company Policy

8 Ships Medicine Chest. Stock in accordance with regulations and use of medicines recorded properly.

9 Planned Maintenance System (PMS) Up to date and in accordance with procedure given in SMM.

10 Master’s weekly inspection of accommodation/ galley/ food store performed and recorded in Bahamas Official Log Book

11 Work Planning Meetings/ PEC activity kept as pr SMM 12 Drills planned and performed as in accordance with

instructions in SMM and PMS

Date: Master

.........................................

It is generally accepted that leaking hatch covers are a principal cause of cargo wetting.Hatches leak for a variety of reasons, but mainly because of poor maintenance or failure to close them properly. There is a degree of confusion as to whether hatches areconstructed to be watertight or weathertight. This is apparent when surveyors checkfor watertightness during statutory inspections. Minor leakage during a test is often accepted as being within the standard for weathertightness; in fact, no leakage is the requirement. We think hatches are robust, monolithic structures, thereby failing to appreciate the small tolerances on panel alignment and gasket compression.For example, 4mm wear on the steel-to-steel contact is sufficient to damage rubber sealing gaskets beyond repair; 5mm sag along the cross-joint can cause a large gap between the compression bar and gasket. It is better to think of hatches as complex, finely-made structures, to be handled with care.

What is weathertightness?We always refer to hatch covers needing to be ‘weathertight’, but what does this actually mean?The statutory requirement contained in Regulation 3(12) of the International Convention on Load Lines 1966, states:‘ “weathertight” in relation to any part of a ship other than a door in a bulkhead means that the part is such that water will not penetrate it and so enter the hull of the ship in the worst sea and weather conditions likely to be encountered by the ship in service’.

Always• Rectify any steel-to-steel fault before renewal of rubber packing. Renewal will not be effective if steel-to-steel contact points are defective, and expensive rubber packing will be ruined after only a few months of use;• Replace missing or damaged hatch gaskets (rubber packing) immediately. The minimum length of replaced gasket should be 1 metre;• Keep hatch coaming tops clean and the double drainage channels free of obstructions. (Open hatch covers to clean coaming tops and the double drainage channels after loading bulk cargo);• Keep cleats and wedges in serviceable condition and correctly adjusted;• Keep wheels, cleats, hinge pins, and other elements well greased;• Test hydraulic oil regularly for contamination and deterioration;• Keep hydraulic systems oiltight;• Ensure the oil tank of the hydraulic system is kept filled to the operating level and with the correct oil;• Clean up oil spills. If the leak cannot be stopped immediately, construct a save-all to contain the oil and empty it regularly;• Remember that continuing and regular maintenance of hatches is more effective and less expensive than sporadic inspection and major repair.

Common False Beliefs about Hatch Covers

• It is the rubber seal that keeps the water out of the cargo.The double drainage system is as important in keeping water away from cargo.

• Renewing a worn rubber seal is all that is needed to keep a hatch watertight.Worn rubber is usually the result of worn steel-to-steel contact surfaces or a deformed structure. Rubber renewal alone is futile unless the steel-to-steel contact surface is repaired.

• Watertight is the same as weathertight.From a hatch cover design perspective, watertight means that water cannot get in or out; weathertight (as required by the 1966 Load Line Convention) means that water cannot pass through the seal.

• Hatch covers will always leak in heavy weather.Hatch covers are designed to withstand the rigours of the sea. Provided the cleats are correctly adjusted, hatch gaskets are in good condition and the construction material sound, then hatch covers should not leak, regardless of the weather.

• Screwing cleats down hard will ensure watertightness.No amount of tightening of cleats beyond their correct position will improve hatch watertightness. Hatch cover manufacturers usually test for watertightness without engaging cleats. The weight of a hatch is sufficient to create the required gasket compression.

• Drain valves are not important; it does not matter if they are blocked.Drain valves are an essential feature of the double drainage system as they allow water that has penetrated the hatch gasket (rubber packing) to drain away. If the valve is blocked or closed, water will spill from the drainage channel into the cargo hold.

• When carrying a cargo on top of a hatch it is not necessary to fasten cleats.Cleats prevent excessive movement of the hatch as a ship bends and flexes in a seaway. They allow limited movement to ensure correct contact between the hatch and its coaming, preventing hatch damage. Cargo loaded on the hatch does not secure the hatch to its coaming.

• Sealing tapes (popular Ramneck)– to use or not to use?The use of sealing tapes at the cross-joints of hatch covers is common, sometimes even being expressly called for by the shipper or charterer. On the face of it, this seems like a sensible additional precaution to enhance weathertightness. However, there arenegative aspects to using hatch cover sealing tape, which include:

• it can lead to a false sense of security• the tape can wash off in heavy seas, just when it is needed most• the tape can obstruct drain holes trapping water in the cross-joint• complete sealing may be difficult due to the presence of cross-joint cleats or other fittings• the tape can cause accelerated corrosion and associated deterioration of the structure due tothe removal of coatings.

Proprietary tape or other material should not be used between compression bars and rubber seals as an alternative to proper repairs. It may be that rather than paying for expensive tape, the money could be better spent on maintenance ofthe rubber seals and associated steelwork.Similarly, high-expansion foam is often used as a ‘belt and braces’ measure to achieve reliable weathertightness. This type of foam is hard to control in practice and can block drain holes and drain channels, such that water leaking in can find its way to the cargo rather than draining out as the system designers intended.

Maintenance of Hatchcovers

Maintenance of the steel-to-steel contact surfaceHatch covers are designed to make steel-to-steel contact between a defined part of the hatch cover and coaming when closed. This steel-to-steel contact determines the amount of compression between the hatch gasket and compression bar. Contact might be nothing more than the hatch skirt sitting on the horizontal coaming plate, although some hatches are fitted with metal landing pads. When the horizontal coaming plate or hatch landing pad is worn, pressure on the hatch gasket (rubber packing) increases. If this wear is greater than 4mm, increased pressure on the gasket will cause damage. Landing pad repair is essential.

Maintenance of rubber packing – surface damageRubber packing that is physically damaged, cut or chafed should be renewed immediately.The minimum length of replaced packing should be 1 metre.

Maintenance of rubber packing – permanent setRubber packing that is permanently impressed to 75% of its design compression should be completely replaced. The manufacturer will provide details of the design compression. A rule of thumb to estimate design compression is to use 30% of the packing’s thickness.Permanently impressed rubber packing indicates worn steel-to-steel contact surfaces.Never replace permanently impressed gaskets without checking the steel-to-steel contact points for wear and doing repairs if they are worn.

Maintenance of rubber packing – aged gasketsOzone will age rubber. It becomes hard and loses elasticity. The entire length of aged gasket should be replaced.

Maintenance of the double drainage systemHatches are designed to drain away water that has penetrated the gasket. Drainage channels should always be cleaned before hatches are closed, and kept free from rust scale and cargo debris. Damaged channels should be repaired immediately and then painted to prevent corrosion. Drainage channels are located along the cross-joint and on the coaming between the compression bar and the inner coaming.

Maintenance of non-return drain valvesHatch coaming non-return drain valves are an essential feature of the hatch double drainage system. They let water that has come through the hatch cover drain away. Damaged, missing or defective non-return drain valves should be repaired or renewed.

Maintenance of rubber seals on cement feeders, access hatches and ventilator flapsWater can enter the cargo hold through cement feeders, hatches and ventilator covers.Maintain them in the same way as you would hatch covers.

Maintenance of hatch cleatsCleats and wedges hold the hatch in position with adequate gasket compression.(Cleats are fitted with a rubber washer or ‘grommet’ to aid compression). Compression of the washer determines tension in the cleat. Washers are prone to both physical damage and age hardening (weathering). When damaged or aged the washer loses its elasticity and should be replaced. Some operators protect the washer and screw threads with a layer of grease or by application of ‘denzo’ tape.

Maintenance of landing padsThe size and dimensions of a landing pad are dependent on the size and weight of the hatch cover. Landing pads are normally located adjacent to cleats. The pads are fitted to the top of the coaming and to the side of the hatch panel. Landing pads should always be repaired to their original design height. Correct adjustment of them can only be achieved during repair when the ship is out of service. Some ships are provided with cassette type landing pads, these are easily replaceable.

Bearing failures and their causesThe general classifications of failures and deficiencies requiring bearing removal are overheating, vibration, turning on the shaft, binding of the shaft, noise during operation, and lubricant leakage, bearing failures are rarely caused by the bearing itself.Defective bearings that leave the manufacturer are very rare and it is estimated that defective bearings contribute to only 2 per cent of total failures. The failure is invariablylinked to symptoms of misalignment, imbalance, resonance and lubrication – or the lack of it.

Wires have for many years played an integral role in the daily operation and function of nearly every commercial vessel afloat.

Wire constructionWire rope is fabricated from strands of precise individual wires. The configuration of the wires and strands making up the wire rope is designed and manufactured to be able to work together and move with respect to one another to ensure the rope has the flexibility necessary for successful operation under tensile loading. In addition to properties such as material strength, minimum breaking load and corrosion protection, wire rope is identified by its construction - typically, the number of strands in the rope and the number of wires in each strand. For example, a wire rope of 6 x 36 construction denotes a 6-strand rope, with each strand having 36 wires. The core running through the centre of the wire may be fibre, or of wire construction itself. For example, crane wires on ships are commonly configured with an independent wire rope core (IWRC) or wire strand core (WSC) as opposed to a fibre core (FC).

Strength is referred to as minimum breaking force or minimum breaking load.

Resistance to rotation Some applications require use of a low rotation or rotation resistant rope. Examples would be lifeboat fall wires, and main and auxiliary hoist crane wires. Such ropes are often referred to as multi-strand ropes.

Fatigue resistance Steel wire ropes will suffer from fatigue when working around a sheave or drum. The rate of deterioration is influenced by the number of sheaves in the system, the diameter of the sheaves and drum, and the loading conditions

Resistance to abrasive wear Abrasive wear can take place between wire rope and sheave, and between wire rope and drum, but the greatest cause of abrasion is often through ‘interference’ at the drum.

Corrosion resistance ropes When the wire rope is to be used in a corrosive environment – which applies broadly across the marine environment – then a galvanized coating may be recommended, and where moisture can penetrate the rope and attack the core, plastic impregnation could be considered. In order to minimise the effects of corrosion, it is important to select a wire rope with a suitable manufacturing lubricant. This should be reapplied regularly while the rope is in service.

Wire rope layThe helix or spiral of the wires and strands in a rope is known as the lay and there are several basic types.

Routine Inspection

The time interval and extent of inspection and maintenance for wires will vary depending on their construction and use. These should be documented by the manufacturer and incorporated into the vessels planned maintenance system by a responsible officer. Although wires of six or eight strand construction hold up to 90% of their strength in their outer strands, it is the support provided by the core which maintains the wires efficiency and performance. Internal examination is therefore a vital component of any inspection regime and may be carried out by a competent person on board Discard Criteria

Stress, abrasion, bending, crushing and corrosion are the most common sources of damage to wires. However, rotation, vibration, cabling and elongation may also occur under certain circumstances. These can in extreme cases lead to catastrophic wire failure. A detailed external examination should compare the wire against the discard criteria for each type of wire. These criteria are determined in consultation with the manufacturer and include:• Number of broken wires – The number of permissible broken wires will depend on thefunction of the wire and will include the rate of breakage occurrence and grouping of broken wires. For example, a single layer 6 x 7 fibre core wire rope used for a cargo wire should be discarded if 2 or more wires are visibly broken in a length equivalent to 6 diameters.• Fractured strands – A strand that has completely fractured will require the wire to be discarded• Decrease in elasticity – This can be quite difficult to detect and it may be necessary toconsult a wire specialist if it is suspected. Warning signs can include a reduction in the diameter of the rope, elongation of the lay length, signs of compression between strands along with the appearance of fine brown powder, and an increase in the stiffness of the wire.

• External and internal corrosion – External corrosion is easier to detect than internal.

Discolouration will be accompanied by an apparent slackness between wires, which is a

result of a reduction in the cross-sectional area of the wire. Corrosion can rapidly accelerate

fatigue damage by causing surface deformation which can lead to stress cracking.Other discard criteria may include:• Heat damage.• Rate of permanent elongation.• Reduction in tensile strength.• Length of service.• Number of life-cycles.• Broken wires at termination points.• Reduction in diameter.

In addition to other consideration relative to the condition of a wire rope such as corrosion or distortion of lay, the wire rope may be assessed as follows:

1. Wear limit 40% of the diameter of the individual outer wires where the condition is fairly general. (International Standard 4309)

This condition may be recognized by the virtual elimination of the valley between adjacent wires at the crown of the strand, or examination of the section of a broken wire.

In examining a wire rope for wear, compare a working section with a nonworking part so that flattened wire types are recognized.

2. 10% of the wires broken in a length of 8 diameters.

3. Reduction in diameter of the wire rope in excess of 7% when elongation of the lay has occurred or a strand is becoming buried, or reduction in wire rope diameter in excess of 10% with the lay still uniform.

4. Combination of wear and broken wires, as follows:

% Wear on Outer Wire % Broken Wires in 8 x D 40% Nil up to 35% 1% up to 30% 5% up to 25% 9% under 25% 10%

The above table is aimed at preserving 80% of the strength of the wire rope so long as the wire rope is not corroded or suffering numerous internal breaks which have not been considered. The lay of the wire rope shall be opened at one or two places if its internal condition is doubtful.

Maintenance and RecordsThe lifespan of any wire will depend to a great extent on the way that it is maintained on board. The technical nature of wire manufacture demands that planned maintenance programmes be developed in collaboration with the manufacturer before the wire is supplied tothe vessel. Where lubrication or dressing of the wire is required this should be applied prior to the wires installation on board and reapplied at pre-determined intervals determined by themanufacturer. Lubricants may need to be worked into the core of the rope during application if they are to serve their intended purpose.

Greasing or lubrication plays a vital role in the operation of any merchant vessel.

Why a lubricant? When the surfaces of two solid bodies are in contact a certain amount of force must be applied to one of them if relative motion is to occur. Taking a simple example, if a dry steel block is resting on a dry steel surface, relative sliding motion will not start until a force approximately equal to one fifth the weight of the steel block is applied. In general, the static friction between any two surfaces of similar materials is of this magnitude, and is expressedas a coefficient of friction of 0.2. As soon as the initial resistance is overcome, a very much smaller force will keep the slider moving at uniform velocity. This second frictional condition is called dynamic friction. In every bearing or sliding surface, in every type of machine, these two coefficients are of vital importance. Static friction sets the force required to start the machine and dynamic friction absorbs power that must be paid for in terms of fuel consumed. Also, friction resistance of non-lubricated surfaces causes heating, rapid wear and even, under severe conditions, actual welding together of the two surfaces.Lubrication, in the generally accepted sense of the word, means keeping moving surfaces completely separated by means of a layer of some liquid. When this is satisfactorily achieved, the frictional resistance no longer depends on the solid surfaces but solely on the internal friction of the liquid, which, in turn, is directly related to its viscosity. The more viscous the fluid, the greater the resistance, but this is never comparable with that existing between non-lubricated surfaces.In simple terms, it provides a measure of the thickness of lubricating oil at a given temperature; the higher the viscosity, the thicker the oil. Accurate determination of viscosity involves measuring the rate of flow in capillary tubes, the unit of measurement being the centistoke (cSt). As oils become thinner on heating and thicker on cooling a viscosity figure must always be accompaniedby the temperature at which it was determined.

Types of lubricationLubrication exists in one of three conditions:1. Boundary lubrication2. Elastohydrodynamic lubrication3. Full fluid-film lubricationBoundary lubricationBoundary lubrication is perhaps best defined as the lubrication of surfaces by fluid films so thin that the friction coefficient is affected by both the type of lubricant and the nature of the surface, and is largely independent of viscosity. A fluid lubricant introduced between two surfaces may spread to a microscopically thin film that reduces the sliding friction between the surfaces.Elastohydrodynamic lubricationThis type of lubrication provides the answer to why many mechanisms operate under conditions that are beyond the limits forecast by theory. It was previously thought that increasing pressure reduced oil film thickness until the aspirates broke through, causing metal-to-metal contact.Research has shown, however, that the effect on mineral oil of high contact pressure is a large increase in the viscosity of the lubricant. This viscosity increase combined with the elasticity of the metal causes the oil film to act like a thin solid film, thus preventing metal-to-metal contact.Full fluid-film lubricationThis type can be illustrated by reference to the conditions existing in a properly designed plain bearing. If the two bearing surfaces can be separated completely by a fluid film, frictional wear of the surface is virtually eliminated. Resistance to motion will be reduced to a level governedlargely by the viscosity of the lubricating fluid

AdditivesMuch highly stressed modern machinery runs under conditions in which a straight mineral oil is not adequate. Even the highest quality mineral oil can be unsatisfactory in response of its resistance to oxidation and its behavior under pure boundary conditions, but it is possible to improve these characteristics by the addition of relatively small amounts of complex chemicals. Types of Additives:Anti-oxidants, Anti-foam, Anti-corrosion, Anti-wear, Extreme pressure, Detergent/dispersant

Lubricating-oil applicationsThere is a constant effort by both the supplier and consumer of lubricants to reduce the number of grades in use. The various lubricant requirements of vessel not only limit the extent of this rationalization but also create the continuing need for a large number of grades with differentcharacteristics. It is not possible to make lubricants directly from crude oil that will meet all these demands. Instead, the refinery produces a few basic oils and these are then blended in varying proportions, together with additives when necessary, to produce oil with the particular characteristics required.

General machinery oilsThese are lubricants for the bearings, where circulating systems are not involved. The viscosity of these oils will vary to suit the variations in speed, load and temperature.

Engine lubricantsThe oils for engines have several functions to perform while in use. They must provide a lubricant film between moving parts to reduce friction and wear, hold products of combustion in suspension prevent the formation of sludge and assist in cooling the engine. Unless the lubricant chosen fulfils these conditions successfully, deposits and sludge will form with a consequent undesirableincrease in wear rate and decrease in engine life.

Engine frictional wear If the effects of friction are to be minimized, a lubricant film must be maintained continuously between the moving surfaces. Two types of motion are encountered in engines, rotary and linear. A full fluid-film between moving parts is the ideal form of lubrication, but in practice, even with rotary motion, this is not always achievable. At low engine speeds, for instance, bearing lubrication can be under boundary conditions. The linear sliding motion between pistons, piston rings and cylinder walls creates lubrication problems that are some of the most difficult to overcome in an engine. The ring is exerting a force against the cylinder wall while at the same time the ring and piston are moving in the cylinder with a sliding action. Also, the direction of piston movement is reversed on each stroke. To maintain full fluid oil film on the cylinder walls under these conditions is difficult and boundary lubrication can exist. Frictional wear will occur if a lubricant film is either absent or unable to withstand the pressures being exerted. The lubricant will then be contaminated with metal wear particles, which will cause wear in other engine parts as they are carried round by the lubricant.

Engine chemical wear Another major cause of wear is the chemical action associated with the inevitable acidic products of fuel combustion. This chemical wear of cylinder bores can be prevented by having an oil film which is strongly adherent to the metal surfaces involved, and which will rapidly heal when a tiny rupture occurs. This is achieved by the use of a chemical additive known as a corrosion inhibitor. As it is not possible to maintain perfect combustion conditions at all times, contamination of the oil by the products of combustion is inevitable. These contaminants can be either solid or liquid. When an engine idles or runs with an over-rich mixturethe combustion process is imperfect and soot will be formed. A quantity of this soot will pass harmlessly out with the exhaust but some will contaminate the oil film on the pistons and cylinders and drain down into the crankcase. If there is any water present, these solids will emulsify to form sludge which could then block the oilways. Filters are incorporated into the oil-circulation system to remove the solid contaminants together with anyatmospheric dust, which bypasses the air filters. One of the liquid contaminants is water, the presence of which is brought about by the fact that when fuel is burnt it produces approximately its own weight in water. When the engine is warm, this water is converted into steam, which passes harmlessly out of the exhaust. However,with cold running or start-up conditions this water is not converted and drains into the sump. Having dissolvedsome of the combustion gases, it will be acidic in nature and will form sludge. Another liquid contaminant is unburned fuel. A poor quality fuel, for example, may contain high boiling point constituents that will not all burn off in the combustion process and will drain into the sump

Gear lubricantsExtremely high pressures are developed between meshing teeth as, in theory, they only have point or line contact. Together with the sliding between mating surfaces, which is always present, it is clear that, if there is metal-to-metal contact, rapid wear will occur. The function of the lubricant is to provide and maintain a separating film under all the variations in speed, load and temperature. It must also act as a coolant and protect the gears against corrosion. The lubrication of gears is not a simple matter, because of their shape and variability of motion. Fundamental factors which affect their lubrication are gear characteristics, materials, temperature, speed, loading, method of applying the lubricant and environment.

Surface speed It is generally true to say that, as speed increases, the oil viscosity decreases, that is, if hydrodynamic conditions exist. Relatively low viscosity oil will allow the oil to spread rapidly over the tooth surfaces before meshing and, in the case of forced lubrication, ease circulation. In the case of bath lubrication, it will eliminate the oil drag effect.Loading If a gear is subjected to shock loading, the high pressures that are rapidly applied may rupture the oil film. These peak pressures are of greater importance than average tooth loading. To prevent sudden wear of the teeth it is essential to maintain a lubricant film, and using extreme pressure additives does this. Continuous and severe overloading may cause the oil film to break down with disastrous resultsOil or grease? In summary, it can be said that the best choice of lubricant for a gearbox depends on the service conditions. If leakage is a problem, or if, during shutdown, the maintenance of a thick film of lubricant is necessary to inhibit corrosion and prevent ‘dry-state’ operation, greases show to advantage. If generation of heat and consequent excessive temperatures are a problem, users will find it better to use liquid lubricants, which have the advantage of high rates of heat transfer.Gear wear and failureA gearbox can be regarded as having four main components:– gears, casing, bearings and lubricant – and failure can be caused by shortcomings in any one of them. Gear teeth that are inaccurate through design or manufacture can cause poor meshing, noisy running, overheating or surface failure due to overloading. Excessive flexing of the casing would allow misalignment of the gear shafts, which would also lead to surface failure due to overheating.Unsuitable or badly fitted bearings may fail because of their own surface damage, and this creates shaft misalignments and produces debris that can quickly damage the gear teeth. Lubrication failure can arise from unsuitable lubricant or from the inability (through bad design) of the lubricant to get where it is needed. Gear failure is rarely attributable to the type of materials selected. More often, it is the result of defects such as cracks, casting inclusions and poor heat-treatment. Badly casehardened steel might fail by the flaking of its hardouter layers and a through-hardened gear might have hard or soft patches. Distortions due to sub-standard hardening can modify tooth profiles to such an extent that load concentrations will break the ends of teeth.The term ‘failure’ is relative, because severe operating conditions affect different materials in different ways. Anexample of this might be seen in a high-reduction gear unit whose pinion is very small and is therefore made of harder material, to avoid premature wear relative to the larger gear. In arduous running, the two gears might notdisplay the same kind of wear pattern

Operation failuresThe three most likely types of operational service misuse are: overloading, incorrect lubrication and the presence of contaminants. Overloading is primarily due to the use of too small or too weak a gear unit, and this may be the result of false economy (installing an available unit for an application beyond its capacity) or failure to cater for the effects of shock loads in calculations of power rating. Incorrect lubrication can take many forms. One example is the use of oil that is too thick or too thin, or is incompatible with the metal of the gears. Others include unsuitable methods of application, bad filtration, inadequate maintenance, filling to the wrong level, and poor standards of storage and handling.

Backlash gear backlash is the play between teeth measured at the pitch circle. It is the distance between the involutes of the mating gear teeth, as illustrated:

Backlash is necessary to provide the running clearance needed to prevent binding of the mating gears, which canresult in heat generation, noise, abnormal wear, overload, and/or failure of the drive. In addition to the need toprevent binding, some backlash occurs in gear systems because of the dimensional tolerances needed for cost effective manufacturing. The increase in backlash that results from tooth wear does not adversely affect operation with non-reversing drives, or drives with continuous load in one direction. However, for reversing drives and drives where timing is critical, excessive backlash that results from wear usually cannot be tolerated.

Fluid power systems have developed rapidly over the past thirty-five years. Today, fluid power technology is usedin every phase of human existence. The extensive use of hydraulics to transmit power is due the fact that properly constructed fluid power systems possess a number of favorable characteristics. They eliminate the need for complicated systems of gears, cams, and levers. Motion can be transmitted without the slack or mechanical looseness inherent in the use of solid machine parts. The fluids used are not subject to breakage as are mechanical parts, and the mechanisms are not subjected to great wear.Hydraulic pumpsThe purpose of a hydraulic pump is to supply the flow of fluid required by a hydraulic system. The pump doesnot create system pressure. System pressure is created by a combination of the flow generated by the pump andthe resistance to flow created by friction and restrictions within the system. As the pump provides flow, it transmits a force to the fluid. When the flow encounters resistance, this force is changed into pressure. Resistance to flow is the result of a restriction or obstruction in the flow path. This restriction is normally the work accomplished by the hydraulic system, but there can also be restrictions created by thelines, fittings or components within the system. Thus, the load imposed on the system or the action of a pressure regulatingvalve controls the system pressure.Hydraulic fluidsSelection and care of the hydraulic fluid for a machine will have an important effect on how it performs and on the life of the hydraulic components. As a power transmission medium, the fluid must flow easily through lines and component passages. Too much resistance to flow creates considerable power loss. The fluid also must be as incompressible as possible so that action is instantaneous when the pump is started or a valve shifts.Hydraulic fluid contamination may be described as any foreign material or substance whose presence in the fluid is capable of adversely affecting system performance or reliability. It may assume many different forms, including liquids, gases, and solid matter of various composition, sizes, and shapes. Solid matter is the type most often found in hydraulic systems and is generally referred to as particulate contamination. Contamination is always present to some degree, even in new, unused fluid, but must be kept below a level that will adversely affect system operation. Hydraulic contamination control consists of requirements, techniques, and practices necessary to minimize and control fluid contamination.

There are many types of contaminants which are harmful to hydraulic systems and liquids. These contaminantsmay be divided into two different classes – particulate and fluid.

Particulate contamination This class of contaminants includes organic, metallic solid, and

inorganic solid contaminants.

Organic Wear, oxidation, or polymerization produces organic solids or semisolids found in hydraulic systems.Minute particles of O-rings, seals, gaskets, and hoses are present, due to wear or chemical reactions. Synthetic products, such as neoprene, silicones, and hypalon, though resistant to chemical reaction with hydraulic fluids, produce small wear particles.

Metallic solids Metallic contaminants are usually present in a hydraulic system and will range in size from microscopic particles to particles readily visible to the naked eye. These particles are the result of wearing and scoring of bare metal parts and plating materials, such as silver and chromium. Because of their continuous high-speed internal movement, hydraulic pumps usually contribute most of the metallic particulate contamination present in hydraulic systems.

Inorganic solids This contaminant group includes dust, paint particles, dirt, and silicates.For example, the wet piston shaft of a hydraulic actuator may draw some of these foreign materials into the cylinder past the wiper and dynamic seals, and the contaminant materials are then dispersed in the hydraulic fluid. Contaminants may also enter the hydraulic fluid during maintenance when tubing, hoses, fittings, and components are disconnected or replaced

Fluid contamination Air, water, solvent, and other foreign fluids are in the class of fluid contaminants.

Air - Hydraulic fluids are adversely affected by dissolved, entrained, or free air. Air may be introduced throughimproper maintenance or because of system design. Any maintenance operation that involves breaking into the hydraulic system, such as disconnecting or removing a line or component, will invariably result in some air beingintroduced into the system. Another lesser-known but major source of air is air that is sucked into the system past actuator piston rod seals. This occurs when the piston rod that is stroked by some external means while the actuator itself is not pressurized.

Water - Water is a serious contaminant of hydraulic systems. Hydraulic fluids are adversely affected by dissolved,emulsified, or free water. Water contamination may result in the formation of ice, which impedes the operation ofvalves, actuators, and other moving parts. Water can also cause the formation of oxidation products and corrosion of metallic surfaces.

Solvents - Solvent contamination is a special form of foreign fluid contamination in which the original contaminating substance is a chlorinated solvent. Chlorinated solvents or their residues may, when introduced into a hydraulic system, react with any water present to form highly corrosive acids.

Foreign-fluids Foreign fluids other than water and chlorinated solvents can seriously contaminate hydraulic systems. This type of contamination is generally a result of lube oil, engine fuel, or incorrect hydraulic fluid beingintroduced inadvertently into the system during servicing.

Important - It is extremely important that the different types of hydraulic fluids are not mixed in one system. If different types hydraulic fluids are mixed, the characteristics of the fluid required for

a specific purpose are lost. Mixing the different types of fluids usually results in a heavy, gummy deposit that will clog passages and require a major cleaning. In addition, seals and packing installed for use with one fluid are usually not compatible with other fluids and damage to the seals will result.

Steel structure of a vessel is prone to corrosion throughout its service life. Due allowance must be made at the new-building stage, and by periodic maintenance to provide effective corrosion protection to ensure continued structural integrity of the vessel. PAINT TECHNOLOGYPaints are mixtures of many raw materials, each of which in turn has been manufactured to give certain specific properties. Basically, however, paints consist of three major components and many additives which are included in minor properties. The major components are:• Binder (other terms used include: vehicle, medium, resin, film, polymer)• Pigment and extender• SolventOf these, only the first two form the final dry paint film. Solvent is necessary purely to facilitate application and initial film formation; it leaves the film by evaporation and can therefore be considered an expensive waste product.

BINDERSBinders are the film forming components of paint. They are predominant in determining the principle characteristics of the coating, both physical and chemical. Paints are generally named after their binder component (e.g. epoxy paints, chlorinated rubber paints, alkyd paints, etc.). The function of the binder is to give a permanent continuous film which is responsible for adhesion to the surface and which will contribute to the overall resistance of the coating to the environment. Binders used in the manufacture of paints fall into two classes, Thermoset and Thermoplastic. This classification is solely dependent upon how they form a film, and whether that film formation is reversible. In the case of liquid paints, they change state, i.e. from a liquid to a solid. This transformation in paint is known as drying or curing. It will be readily appreciated that a Thermoset coating when dry will be chemically quite different from the paint in the can.Thermoset coatings are not affected by solvent wipe, once cured. With a Thermoplastic coating, the dry film and the wet paint differ only in solvent content, but chemically these remain essentially similar. If solvent is applied to a thermoplastic coating, it will soften and try to return to its original state.

THEROSET COATINGSAir Drying ResinsOleoresinous VarnishesAlkyd ResinsEpoxy Ester ResinsUrethane Oil/Alkyd ResinsSilicone Alkyd ResinsEpoxy ResinsPolyurethane Resins

THERMOPLASTIC COATINGSChlorinated Rubber ResinsVinyl ResinsBituminous BindersCellulose Derivatives

In liquid paints where solvent is involved, drying is considered a two stage process. Both stages actually occur together but at different rates.• Stage One: Solvent is lost from the film by evaporation and the film becomes dry to touch.• Stage Two: The film progressively becomes more chemically complex by one of the following methods:1) Reaction with atmospheric oxygen, known as oxidation.2) Reaction with an added chemical curing agent.3) Reaction with water (moisture in the atmosphere).4) Artificial heating.5) Radiation curing (e.g. ultraviolet).The films formed by the above methods are chemically different to the original binders and will not re-dissolvein their original solvent.

These types of paint binders are simple solutions of various resins or polymers dissolved in suitable solvent(s). Drying is simply effected by the loss of the solvent by evaporation. This is termed physical drying as no chemical change takes place.The resulting film is therefore always readily soluble in the original solvent and can also be softened by heat.

PIGMENTS AND EXTENDERSPigments and extenders are used in paints in the form of fine powders. These are dispersed into the binder to particle sizes of about 5-10 microns for finishing paints and approximately 50 microns for primers.These materials can be divided into the following types:

Type PurposeAnticorrosive pigments To prevent corrosion of metals by chemical and electrochemical means.Barrier pigments To increase impermeability of the paint filmColoring pigments To give permanent colorExtending pigments To help give film properties required

SOLVENTSSolvents are used in paints principally to facilitate application. Their function is to dissolve the binder and consequently reduce the viscosity of the paint to a level which is suitable for the various methods of application, i.e. brush, roller, conventional spray, airless spray, dipping, etc. After application, the solvent evaporates and plays no further part in the final paint film, the solvent therefore becomes a high cost waste material. Liquids used as solvents in paints can be described in one of three ways:True SolventsA liquid which will dissolve the binder and is completely compatible with it.Latent SolventA liquid which is not a true solvent. However, when mixed with a true solvent, the mix has stronger dissolving properties than the true solvent alone.Diluent SolventA liquid which is not a true solvent. Normally used as a blend with true solvent/latent solvent mixes to reduce the cost. Binders will only tolerate a limited quantity of diluent.

CORROSIONCorrosion of metals may be defined as an electromechanical process in which the metal reacts with its environment to form an oxide, or other compound, similar to the ore from which it was originally won. The majority of metals are found in nature in the mineral state, that is, in their stable oxidized condition as oxides, chlorides, carbonates, sulfates, sulfides, etc. The extraction of a metal from the appropriate mineral involves a reduction process in which a great deal of energy is absorbed. As a consequence of this large energy input the metal is in a high energy condition and will endeavor to return to its former stable oxidized low energy state as quickly as environmental conditions will allow. It is this energy difference between the pure metal and its oxidized forms which is the driving force for corrosion of the metal. Many corrosion products show a chemical similarity to the corresponding minerals. Iron, for example, is extracted from its ores, mainly oxide and carbonate, by reduction with carbon in a blast furnace. In the presence of moisture the iron metal so obtained is oxidized rust, which if analyzed is found to have a composition similar to the mineral ore.

Types of CorrosionUniform CorrosionThe most common type of corrosion encountered is the general attack of a more or less uniform nature. The loss of metal over the entire surface is fairly uniform. This is the easiest form of corrosion to combat or allow for because structural life time can be predicted, a feature which is not possible with the following corrosion forms.

Pitting CorrosionThe characteristic of this type of attack is that it is extremely localized and the penetration is deep in relation to the area attacked. Pitting is one of the most dangerous forms of corrosion and often occurs in places where it cannot be readily seen. Pitting corrosion is one of the most common forms that can be noted in ballast tanks. It is a localised corrosion that occurs on bottom plating, other horizontal surfaces and at structural details that trap water, particularly the aft bays of tank bottoms. For coated surfaces the attack produces deep and relatively smalldiameter pits that can lead to hull penetration. Pitting of uncoated tanks, as it progresses, forms shallow but very wide scabby patches (e.g. 300m mm diameter); the appearance resembles a condition of general corrosion.

Crevice CorrosionIntense localized corrosion, ranging from small pits to extensive attack over the whole surface. The mostcommon case occurs in cracks and generally on steel surfaces covered by scales and deposits. Typical examples are ship welding seams, pipe supports and bolts.

Erosion corrosionCorrosion due to erosion occurs when abrasives (i.e. sand or mud) held in the sea water impinges, with a certain velocity, an existing corrosion cell. The abrasives remove the accumulation of corrosion products keeping the metal clean and the corrosion active.

Microbiologically Influenced Corrosion (MIC)All metals, even stainless steel, may incur corrosion from microbiologically influenced corrosion, MIC. This type of corrosion has been in existence for a long time and is either completely overlooked or goes unrecognized. However, it is gaining attention in the marine environment as a leading cause of corrosion in cargo, ballast and void spaces

Heat transferIn many cases where heat transfer is involved the metal wall temperature experienced in service is higher than the surrounding atmosphere temperature. This, and the actual heat transfer through the material, must be taken into account since both factors can increase corrosion rates significantly. Fuel oil tanks adjacent to ballast tanks.

Condensation corrosionCondensation can form on cargo hold bulkheads, under hatch covers, at the top sections of ballast tanks, as heat is lost. This condensation can absorb corrosive gases, creating localized corrosion effects of greater severity than the standard environment that is normally present.

Corrosive atmospheresCorrosive species in the atmospheres include water, salts and gases. Clean atmospheres contain little other than oxygen, nitrogen, water vapour and a small quantity of carbon dioxide. These species are virtually non-corrosive to any of the common constructional materials for vessel at normal temperatures. Steel is susceptible to corrosion in even fairly clean air where water can exist as liquid.

Corrosion under laggingThermal insulation of vessels and pipework usually employs glass fiber or foamed polyurethane products. In their pure forms these pose little corrosion risk. Generally, they are contaminated with leachable acids and/or chloride ions. Chloride-free lagging can be specified and this should be used for contact with metals which are susceptible to chloride pitting or chloride-induced stress corrosion cracking.

Corrosion when carrying timber on deckMetals in contact with or in the proximity of timber can suffer enhanced corrosion attack. Some species of timber, especially oak, contain high levels of acetic acid. These are volatile and cause corrosion of nearby metals, especially iron, steel and lead alloys. Metals in contact with timber can be corroded by the acetic acid of the timber and by treatment chemicals present in it. Treatment chemicals include ammonium sulfateand ammonium phosphate flame-retardants. These are particularly corrosive towards steel.

Special types of Corrosion

Stress CorrosionThe presence of tensile stress in a metal surface renders that surface more susceptible to many kinds of corrosionthan the same material in a non-stressed condition. Similarly, the presence of compressive stress in the surfacelayer can be beneficial for corrosion behavior. Tensile stresses can be residual, from a forming or welding operation, or operational from heating–cooling, filling–emptying or pressurizing–depressurizing cycles.The presence of a tensile stress from whatever origin places some materials at risk from stress corrosion cracking. The presence of stress raisers, including sharp corners and imperfect welds, produces locally high stress levels. These should be taken into account when inspecting the ships structure.

Cargo Hold Coating There is no paint available on the market today that is capable of withstanding the type of physical damage inflicted in cargo holds by grabs, bobcats, bulldozers, etc, particularly where such damages result in the deformation of the steel itself. As a result of these impacts and abrasions, paint is damaged or removed from the cargo holds and also from the reverse side of the steel plating, in areas such as the ballast tanks, stools and outer hull.

Failure of Cargo Hold Coatings by “Active” Cargoes The number of coating damages and sags varies depending upon the local conditions within the cargo hold. Factors such as coating type and the extent of cure, cargo type and shape and cargo corrosivity will all have an influence on the extent of damage. Other factors such as the method of loading the cargo, the sea states during the voyage and the quantity of water applied to or

associated with the cargo are also important. What is an “active” cargo? Iit can be defined as one that physically affects the cargo hold coating and directly influences the corrosion reaction on the underlying steel. Examples of active cargoes are coal, coke, bauxite, sulphur and petcoke.

There are many cargoes transported by vessels that will cause accelerated corrosion of the steel if they are in direct contact with the metal. However cargoes that are soft and of low density are unlikely to cause direct physical damage to the paint and therefore they will only accelerate corrosion of the steel and subsequent coating breakdown at sites of existing coating damage or failure. Hard, dry cargoes such as ingots or ferrochrome do not tend to produce this type of damage, but cargo cycles that include iron ore can exacerbate the damage caused by the previous cargoes.

Active cargo corrosion occurs in a sequence of events that results in coating damage, often with the characteristic tree pattern, together with steel corrosion. The first stage of the damage to the paint occurs when the sharp, hard and angular cargo scratches into the coating due to settlement during both loading and the voyage. Eventually the cargo cuts through sites of weak paint to the steel and exposes the metal to the cargo environment.

It is first seen as a small puncture in the coating, which creates a pathway for water to reach the steel. Water associated with the cargo can permeate along the interface between the paint and the steel at the site where the coating has been damaged, resulting in the loss of adhesion of the coating.

How do the active cargoes cause coating failure?

Two major factors are required, a suitably hard and abrasive cargo and a coating in a susceptible condition. The cargo hold coating may be susceptible to damage by active cargoes due to a number of factors.

1. An incorrect choice of paint (that is a coating that is not designed to withstand abrasions and impacts) will quickly fail in a cargo hold environment when active cargoes are carried.

2. If the application and/or curing conditions for the coating were not suitable, for example the curing temperature was too low or there may have been inadequate ventilation during the curing period, then the coating may remain soft when it enters service and will fail prematurely.

3. If the quality of the surface preparation of the steel is not sufficiently good, then contamination may remain on the steel and be over coated by the paint. When suitable conditions of water and oxygen are present, corrosion can quickly initiate and propagate at contamination sites, generating rust under the paint and ultimately levering the coating from the steel.

4. The presence of water in the coating can also result in plasticisation of some paints, making them easier to deform.

5. Increased temperatures can cause some types of coating to soften and again this will result in deformation and sags when in contact with active cargoes.

Paints for Purposes

Most of the important properties of a paint are determined by its binder and the manner in which the film is formed. Function according basic characteristics:• Anticorrosives• Shop Primers/Holding Primers• AntifoulantsANTICORROSIVESIn corrosion prevention with paints, three main principles are employed:• Create a barrier that keeps out charged ions and retards the penetration of water and oxygen.• Ensure that water on its passage through the paint coating takes on special properties or compounds inhibiting it’s corrosive action.• Ensure metallic contact between the steel and a less noble metal, such as zinc, affords cathodic protection of the steel by utilizing the galvanic effect.Typical representatives are:• Bitumen• Coal tar epoxy• Epoxy

SHOP PRIMERSShop primers, also referred to as pre-construction primers, are anticorrosives designed for

application in automated plants to plates or profiles prior to assembly or construction.Types of Shop PrimersThe most widely accepted shop primers are:• Poly Vinyl Butyral (PVB)• Epoxy Iron Oxide• Zinc Epoxy• Zinc Silicate

ANTIFOULINGSShips’ underwater hulls are painted to protect the building material, usually steel, and prevent undue roughness. The effect of roughness on the hull area is an increase in resistance to movement, resulting in reduced speed and/or increased fuel consumption. The penalty is a higher operating cost.FoulingThe most severe hull roughness is that caused by fouling, the growth of various marine plants, animals, and organisms. Some 10% of the fuel bill for the merchant vessel, it is estimated, is caused by fouling.Antifoulant PaintsThe antifouling paints used today are based on physically drying binders. They prevent fouling by releasing bioactive materials that interfere with the biological processes of the fouling organisms.Classification of Antifouling PaintsAntifouling paints differ basically in their load or concentration of bioactive material and in the mechanism controlling the release of that material. According to the manner in which bioactive material is leached from the coating, antifoulants may be grouped as the following:• Soluble Matrix Types (non polishing)• Insoluble Matrix Types (non polishing)• Self Polishing TypesSoluble Matrix (non polishing)General Properties• Effective protection rather limited (up toapproximately 12 months).• Only antifoulant type that can be safely applied oversoft, bitumen, primers.• The binder oxidizes and is sensitive to sunlight.Therefore the vessel must be launched or floatedsoon after curing.• Sensitive to oil pollution (mineral and fish oils)

Insoluble Matrix (non polishing)General Properties• Medium extended effective protection (up to 24 to 30months, depending on trading pattern).• Re-activation (removal of empty matrix) possiblethrough scrubbing • An empty matrix, because of its sponge like properties,should be scaled off prior to a fresh ornew coat of antifoulant is applied.

Self PolishingGeneral Properties• Medium to very high effective protection against fouling (up to 48 months).• Excellent mechanical strength and stability.• Effective life is directly proportional to applied film thickness.• No sealer coat required at subsequent dry dockings .• Remaining antifoulant becomes an effective part of the new system (can overcoat).

Surface Preparation

Good surface preparation is, perhaps, the most important part of the entire coating job, in that the greatest percentage of coating failures can be traced directly to poor surface preparation. No paint system will give optimum performance over a poorly prepared surface. All paint systems will fail prematurely unless the surface has been properly prepared to receive the coating material. If contaminants such as oil, grease, dirt, salts, chemicals, etc. are not removed from the surfaceto be coated, adhesion will be compromised, and/or osmotic blistering will occur. Loose rust left on the surface will cause a loosening of the coating and eventual loss of adhesion. Also, good surface preparation roughens the surface to assist in obtaining the proper surface profile, thereby promoting better coating performance in the areas of adhesion, abrasion resistance, chemical and water resistance, as well as the long term cosmetic appearance of the paint system.

PREPARATION STANDARDS

Nonabrasive Blast Cleaning Solvent Cleaning Hand Tool Cleaning Power Tool Cleaning Power Tool Cleaning to Bare Metal

Abrasive Blast CleaningWhite MetalNear-White Metal Commercial Brush-Off

Water Blasting

Solvent CleaningA process of using solvents, expanded more recently to include other cleaning compounds, to remove oil, grease, and other contaminants. This process is best utilized as a preliminary step in the total surface preparation procedure.Solvents are no longer the recommended cleaner, as they may become an impediment rather than a help, if not properly removed.

Hand Tool Cleaning This method is the slowest and usually the least satisfactory method of surface preparation. Wire brushing, in fact, can make the surface worse by polishing rather than cleaning the rusted surface. Scrapers, chipping hammers, or chisels can be used to remove loose, non adherent pain, rust or scale, but is usually considered incomplete. For this reason, the area to be prepared should be sufficiently small to allow for the time requiredPower Tool Cleaning The advantage of power (electrical or air) tool methods over hand tools, is that they are generally less laborious, but, as with manual, easier to feather loose coatings back to tight impact paint. The effectiveness of cleaning will depend on the effort and endurance of the operator, and becomes especially tiring when working above shoulder height. Some of the more popular methods are as follows:

Rotary Wire BrushingThis method does have some value, depending upon the condition of the surface. Loose “powdery” rust can be removed but hard scale will resist the abrasion of the wire bristles. When rust scale is intact and adherent to the substrate, rotary wire brushing tends to merely burnish the surface of the rust scale, but does not remove it. Care should be exercised, in that the burnished surface may give the appearance of a well cleaned surface, which is often misleading.

Mechanical DescalingNeedle Guns, Jet Chisels, and other pounding type instruments are effective to some degree in removing thick rust and scale. The action of these types of devices is dependent upon cutting blade or point pounding the surface and breaking away the scale. Cleaning is only effective at the actual points of contact. The intermediate areas are only partially cleaned, because the brittle scale disintegrates, but the lowermost layer of rust and scale remains attached to the substrate. This may be sufficient for surface tolerant epoxies.

Rotary Power DiscingOf the power tool methods, this one is the most effective in producing a surface suitable for the application of most types of coating systems, especially for most on-board maintenance. While effective, discing should generally be limited to localized areas of fairly severe corrosion or more widespread light corrosion, because, once again, this method can be quite slow and labor intensive. Normally silicon carbide discs are used and the grade selected to suit the conditions of the surface to be abraded. It is important to change the discs at regular intervals in order to maintain efficiency. Care should be exercised in the selection of the grit size and type of disc to be utilized, so that the surface is not excessively smoothed, thereby reducing the ability of the paint to adhere. Irregular and pitted surfaces may require a combination of the various power tool cleaning methods to maximize effectiveness.

Abrasive Blast Cleaning (Sandblasting)This is by far the most efficient and effective method of removing paint, rust, mill scale, etc. from substrates, also, it is generally considered to provide the proper surface profile to promote coating adherence. However, compared to the methods discussed above, it is also the most expensive method. For this reason, it is chosen to reduce the time for surface preparation, or to achieve standards of cleanliness that are only attainable by some type of abrasive blasting.

Swedish Sa 3White Metal Blast Cleaned Surface Finish.

Swedish Sa 2 1/2Near White Blast Cleaned Surface Finish.

Swedish Sa 2Commercial Blast Cleaned Surface Finish.

Swedish Sa 1Brush Off Blast Cleaned Surface.

Water Jetting and HydroblastingAs discussed previously dry abrasive blasting is the most commonly used method of surface preparation. Accompanied with this style of preparation are some known problems. In general with abrasive blasting the resultant flying abrasive particles and drifting dust may damage equipment, clog filters and create possible environmental problems.

Also, it is possible to trap contaminants on the surface of the substrate being cleaned.It should be noted that hydroblasting does not produce a profile on the steel surface as does abrasive blasting. It does, however, expose the original abrasive blast surface profile. To be an effective agent the water being used should be pure enough that it does not contaminate the surface being cleaned.In general however, water-jetting will only remove loose rust, loose scale and loose paint at an acceptable production rate. It will not remove mill-scale or "black rust“ (magnetite-scale). Painting over such scale will bring the performance expectation down to that of hand chipping.

Water treatments below 68 bar (1000 psi) are not surface preparation methods but cleaning methods. They are defined as Low-pressure Washing, having water pressure below 68 bar while High-pressure Water Cleaning (HPWC) are termed the treatments having pressures from 68 to 680 bar (1000 to 10000 psi).Ultra-high-pressure water-jetting (UHP-WJ) is defined as having a pressure in excess of 1500 bars (22,000 psi). Normally, such tools operate at 2000 bars (30,000 psi) or more. UHP-WJ produce better and faster cleaning than the water-jetting method does. This pressure removes most contaminants, such as salts, dirt, grease and rust scale. Utilized sometimes in this type of preparation are inhibitors which are added to the water to help prevent flash rusting prior to coating being applied.

The service life expectancy span for UHP-WJ can be 2 to 10 years depending onthe cleanliness achieved, the amount of re-rusting and moisture control during painting.

Advantages to hydroblasting are:• Water as a cleaning material is generally available in inexpensive large quantities.• Lack of contamination of surrounding areas because there are no abrasive particles.• Lack of dust.

Methods of Paint Application

The objective in applying paint coatings are to provide films which will give protection and, normally to a lesser extent, decoration to the structure being painted. The variables which govern the success of any application are:• Surface preparation• Film build and total thickness of system• Methods of application• Atmospheric conditions during application

Methods of ApplicationThe normal methods of application of paint coatings are by:• Brush• Roller• Conventional Spray• Airless Spray• High-Volume, Low Pressure spray (HVLP)Other methods may also be encountered, such as: electrostatic, powder coatings application, dipping and pouring

Brush ApplicationThe “historical” method of paint application is not as fast as spraying or rolling and is generally used for the coating of small complicated or complex areas or where the need for ‘clean’ working with no overspray precludes the use of spray application. When painting it is important to dip the brush in paint frequently and not to ‘over-brush’ the surface, as this will result in large variations in film thickness, the inherent problem with brush application. Choice of brush, both size, length and type of bristle, and shape, are important, and the type of paint being applied will modify the selection. Thus, large flat brushes are normally used for the majority of purposes, but round brushes are better for painting bolt-heads and ‘difficult’ areas. Special brushes are available with offset heads and long handles to facilitate painting the ‘backs’ of structures and inaccessible areas.Brush application is most suited to the slower drying, normal build type of coatings, and will not always be suitable for the more sophisticated ‘fast-drying’ or ‘hi-build’ materials. It is often not possible to achieve the required film thickness in the same number of coats as with spray application, and multi-coat applications are necessary to give the specified film build. Stripe coats on weld seams of new buildings.

Roller ApplicationRoller application is faster than brush on large, flat surfaces, such as tank sides and tops and walkways and deck areas, but it is not so good for ‘difficult’ areas. It is hard to control film thickness, however, and care must always be taken that the coating is not ‘over-rolled’ in the same manner that it can be ‘over-brushed’. Choice of roller pile (short or long hair, sponge or lambs wool) is dependent on type of coating and roughness and irregularity of surface being coated. Not recommended way of paint application if Spray equipment is available.

Conventional SprayThe equipment is relatively simple, paint and air are fed separately to the spray gun and mixed at the nozzle, where the paint is atomized and air is mixed with these droplets forming a fine mist of paint which is carried by the air pressure to the work surface.

Airless SprayBy far the most important and efficient method for the application of heavy duty marine coatings.As the name implies, it is a technique of spray application which does not rely on the mixing of the paints with air to provide atomization, which is achieved by forcing the paint through a specially designed nozzle or ‘tip’ at very high pressures

Coating failures

The coating failures is the coating degradations within the intended coating service life. The main types are identified in the following items.

CrackingThis is a break-down in which the cracks penetrate at least one layer and which may be expected to result ultimately in complete failure. Such cracks may result from:• over thicknesses of paint,• plastic structural deformations exceeding the elongation properties of the paint film• localised fatigue stress, due to non appropriate design

Flaking (loss of adhesion)It consists in the lifting of the paint from the underlying surface in the form of flakes or scales. The causes of a loss of adhesion may be the following ones:• unsatisfactory surface preparation,• incompatibility with underlayer,• contamination between layers,• excessive curing time between layers

BlisteringIt appears as a bubble formation scattered on the surface of a paint film, with a diameter ranging from 3-4 mm to 20-30 mm. Blisters contain liquid, vapour or gas.Blistering is a localised loss of adhesion and lifting of the film, coming generally from osmosis due to one of the following causes:• Solvent retention,• Improper coating application,• Soluble salt contamination under the paint film, due to an insufficient cleaning of the surface.

It is to be noted that in most cases there is no corrosion in an unbroken blister andmany years of protection can be obtained if these blisters are left untouched.

Examples of assessment of coating conditions

Everyone knows about the effect of corrosion on a ship’s hull, but few people consider the effect of corrosion on piping. Pipes pose a hidden danger, a danger that is often forgotten about.Pipes are silent workers, conveying fluid or allowing air to enter or to leave a space, and are the means by which many control systems operate. They are unnoticed until pipe failure occurs and a machine stops operating, a space floods or oil is spilled. Pipespenetrate almost every enclosed space, as well as the shell both above and below the waterline, and the weather deck. There is no system on a ship that has such enormous potential to cause fire, pollution, flooding or even total loss.The majority of ships’ pipes are constructed of ferrous material, a material that isattacked by all forms of corrosion. As a ship ages, so does the piping system. Maintenance is not always easy, because pipes, unlike the hull, are difficult to examine because of their numbers and inaccessibility. It is practically impossible to maintain them internally, where most corrosion takes place, and at times just as difficult to maintain a pipe’s external surface. As a result, pipes can receive minimum maintenance, and pipe failure is often the result. ????? “When is it necessary to replace a pipe?”, “When it bursts.” Agree or Not ?

• The majority of ships’ pipes are made of mild steel.• Flow rate, viscosity and pressure of fluid being carried determine a pipe’s diameter.• The water circulating in cooling pipes will corrode them over time.• Pipes passing through tanks containing liquid are exposed to corrosive attack on both surfaces.• Visual checks of the external surfaces of a pipe will not indicate its condition because it could be internally corroded and have a reduced wall thickness.• Most abrasive corrosion and consequent internal thinning happens where the pipe bends and at elbows.• Liquid flowing quickly will be turbulent as a result of fluid separation and cavitation. Flow turbulence in a pipe will cause pitting. A pipe with the correct diameter for the job will eliminate turbulence.• A pressure test of 1.5 times design pressure is a strength test; a test at the design pressure is a tightness test. Pressure testing can show the small cracks and holes that will not be found by a visual examination.• Pipes are held in place by supports or clips that prevent movement from shock loads and vibration. Pipe failure is common when pipes are allowed to vibrate.• Pipes carrying flammable liquids have as few joints as possible and these are shielded to prevent leaks from coming into contact with hot surfaces.• Mechanical joints are not normally fitted on pipes carrying flammable liquids.

Bilge systemThe bilge system is used to remove small quantities of fluid that have leaked or condensed into a dry space. The system serves the machinery spaces, cargo holds, cofferdams, voids, stores, tunnels and pump rooms. Each space has its own piping but the pump is likely to be shared.The capacity of a bilge system is defined by the diameter of the bilge main and pump capacity for the volume of the enclosed space.In cargo ships where the engine room provides bilge pumping, the whole ship is the ‘enclosed space’. The diameter of the bilge main is:d = 25+1.68√L(B+D)where,d = internal diameter of bilge main, in millimetresL = length between the ship’s perpendiculars, in metresB = extreme breadth, in metresD = moulded depth, in metresCargo ships are required to have two bilge pumps with non-returnvalves fitted to prevent back-flow or cross-flow.Mud boxes and strum boxes (line filters) are fitted at the ends andin bilge lines to stop debris being sucked into the pipe.

Ballast systemBallast is taken on to increase a ship’s draught, particularly the stern draught, when sailing without cargo. Ballast piping is usually made of ordinary mild steel. A ship’s size determines the capacity of its ballast system.

Ships’ firefighting systemsPiping is used extensively throughout a ship for fire control purposes. The specific features of ships’ fire-fighting equipment are governed by the Safety of Life at Sea Convention (SOLAS). Many SOLAS requirements have been put into classification society rules. They include:

• Fire mainMild steel piping fitted with hydrants for hoses where saltwater is used for manual firefighting. The fire main is designed for a typical working pressure of about 10 bar. Pipes in the fire main are affected by corrosion both externally and internally. Pipes are joined with flanged connections.

• CO2 pipingRelatively small bore hot galvanised mild steel piping designed to withstand the surge loads that occur with the release of CO2. Main CO2 lines are designed to withstand the same pressure as that of CO2 bottles, while distribution lines off the main valve are designed for a lower pressure. Typically, the main line is pressure tested to 200 bar, the design pressure being at least 160 bar.

Pipes carrying fuel oil and flammable liquidsThere are two principal types of pipes that carry fuel and they are categorised by the pressure the pipe is designed to withstand. Low-pressure pipes are used to move fuel from a storage tank to a service tank to an injection pump; high-pressure pipes are used to deliver fuel from an injection pump to an engine combustionchamber. Ships’ fuel is usually stored in double-bottom tanks, deep tanks, side bunker tanks, settling tanks or service tanks. Piping between a service tank and a fuel transfer or booster pump is rated as low pressure. However, between each pumping stage, pressure increases.It is a mistake to assume that even if a pipe’s pressure is relatively low, fuel will not spray from a crack or small hole.Pipes from fuel tanks can pass through ballast tanks and pipes serving ballast tanks can pass through fuel tanks. Because of pollution risks, classification societies have stringent rules restricting the length of any oil pipe passing through a ballast tank(and vice versa); it must be short, have increased wall thickness and stronger flanges. SOLAS includes requirements for fire safety in engine rooms. In particular, special double-skinned pipes must be used to deliver fuel to engine combustion chambers. These are made of low carbon steel alloys and operate at high pressure, between 600 and 900 bar. Double skins are necessary because pipe fracture will cause fuel to spray in a fine aerosol. Fuel will ignite on contact with a hot surface,such as a turbocharger casing or exhaust pipe. The second skin is to guard against direct spraying. The pipe is designed so that fuel will be contained in the space between the outer skin and the main pipe, and will drain into a collecting tank fitted with a high-level alarm.

Low-pressure lubricating and fuel oil pipes passing close to a hot surface have to be secured against the possibility of oil spraying from a flange. To prevent this, the flange is usually taped. In addition, and whenever possible, the pipes are routed clear of hot surfaces. Similarly, to prevent leaking oil falling onto a hot surface,pipes should never be allowed to run above a hot surface.Regular thermographic surveys of hot surfaces will identify those risk areas that are sufficiently hot to ignite spraying or leaking fuel.Preventive measures to be taken include additional lagging, spray or drip shields.Fuel oil transfer pipes are usually mild steel and may corrode. The calculation for minimum wall thickness includes a small allowance for corrosion. As a pipe ages and corrodes, leakage can occur. Inspection programmes should concentrate onidentifying worn or corroded pipes.

Engine cooling systemWater carried in pipes is used to cool machinery. The main engine is cooled by two separate but linked systems: an open system (sea-to-sea) in which water is taken from and returned to the sea (seawater cooling), and a closed system where freshwater is circulated around an engine casing (freshwater cooling).Freshwater is used to cool machinery directly, whereas seawater is used to cool freshwater passing through a heat exchanger. The particular feature of an engine cooling system is continuous fluid flow. Fluid in motion causes abrasive corrosion and erosion. To reduce the effects of turbulent flows, seawater systems incorporate large diameter mild steel pipes, the ends of which open to the sea through sea chests where gate valves are fitted.

If a seawater cooling pipe bursts, both suction and discharge valves will have to be closed to prevent engine room flooding. In order to make sure the valves operate correctly when you need them to, open and close them at regular, say monthly, intervals. Seawater pipes are usually mild steel, but galvanised steel, copper or copper alloy are also used. Freshwater cooling pipes are generally made of mild steel.

Air and sounding pipesAir pipes allow an enclosed space to ‘breathe’. They prevent over-or under-pressure by letting air in or out of the space when liquid is pumped in or out, or when temperature changes cause air or fluids to expand or contract. Cargo holds are ventilated by air pipes passing through the weather deck and these are fitted withself-closing watertight covers (headers). This is a Load Line requirement.Sounding pipes are small-bore mild steel pipes used to measure the quantity of fluid in a tank or a hold bilge. The pipe allows a tape or sounding rod to pass through to the bottom of a tank or hold. Deck sounding pipes pass through the weather deck and are fitted with screw-down caps. Sounding pipes for engine room double-bottom tanks are fitted with self-closing cocks. It is imperative that sounding pipe caps or cocks be kept shut. Sounding pipes are a potentially dangerous source of progressive flooding. An engine room can be flooded through an open soundingpipe if a ship’s bottom is holed. A cargo hold can be flooded through an open deck sounding pipe when water is washed on deck in heavy weather. Holes in weather deck air pipes also cause hold flooding during heavy weather.

Air and sounding pipes are normally constructed of mild steel. Most of the time, these pipes do not come into contact with liquid, either inside or outside. The size of an air pipe serving a tank is determined by comparison of the pipe’s cross-section area with that of the pipe that will fill or empty the tank. This determination, by the designer, is to avoid the risk of over- or under-pressure. Air and sounding pipes that pass through other compartments are a potential source of progressive flooding. It is difficult to inspect air and sounding pipes located inside cargo spaces or ballast tanks. However, the integrity of air pipes for ballast tanks can be checked by overfilling the tanks. Pipes passing through a dry cargo space must be inspected for damage caused by contact with grabs, bulldozers, etc. It is advisable to open and to inspect air pipe headers on the exposed weather deck once every five years following the first special survey. This is necessary because corrosion on the inside of an air pipe header will not be noticeable externally. Screw-down caps are fitted on the top of sounding pipes. These caps should never be mislaid or replaced withwooden plugs. To extend the life of air pipe headers, they should be galvanised. The self-closing cocks on engine room sounding pipes should never be tied open.

Hydraulic piping systemsHydraulic pipes are high-pressure pipes. Hydraulics are used for:• Manoeuvring the steering gear• Actuating controllable pitch propellers and thrusters• Control of watertight doors and valves• Lifting appliances and deck equipment• Opening stern, bow or side doors• Moving mobile ramps for hatch covers• Driving cargo and ballast pumps and for many other minor shipboard utilities.It is a requirement that hydraulic systems for steering, pitch control and watertight doors have dedicated piping and pumps. Some hydraulic fluids are highly flammable. As a result, hydraulic equipment and pipework must be kept clear of hot surfaces. Alternatively, hot surfaces must be protected by spray shields. It is important to prevent the external corrosion of hydraulic piping located on deck. Hydraulic pipes operate at very high pressure and corrosion-induced weakness frequently causes hydraulic pipes to burst. A high standard of cleanliness is necessary when working with, or replacing, hydraulic piping. Check the systems regularly for leaks, corrosion or mechanical damage.Use only good-quality and clean hydraulic fluid.

PIPE DESIGNClassification societies publish rules for design and fabrication of ships’ piping. The rules consider how the pipe will be used, the fluid conveyed, materials for construction, and welding and test procedures. Ships’ piping is grouped into three categories, each of which has different technical requirements.Class I pipes have to comply with the most stringent rules. They include fuel oil pipes operating above 16 bar pressure or above 150ºC, and steam pipes where the temperature exceeds 300ºC.Class II pipes fall between the two rule requirements.Class III pipes have the lowest requirements. They include fuel pipes that operate at or below 7 bar pressure and 60ºC.During design of piping systems, fluid temperature, pressure and the type of fluid conveyed have to be considered.Pipe dimensionsA pipe is sized by its internal diameter. The required diameter of a pipe depends on the minimum cross-section area necessary to permit passage of a fluid of given viscosity at a given velocity. A pipe’s wall thickness depends on the pressure, the temperature of the fluid conveyed and construction materials. Pipes operating at high pressure, such as hydraulic pipes, have thick walls, while pipes that operate at low pressure, such as ballast water pipes, can be designed to classification society rule ‘minimum thickness’. Pipes that connect direct to the ship’s shell have thicker walls. During design calculations, an allowance for corrosion is factored into the wall thickness. However, the calculated wall thickness can never be less than rule minimum thickness. It is a mistake to believe that the corrosion allowance is enough to prevent failure from uniform corrosion before the pipe is ‘design life-expired’.

Minimum wall thickness for steel pipesThe graph shows the classification society required minimum wall thickness for low-pressure steel pipes.

Connection to pumpsPipes are connected to pumps by flanges. Flanges are a potential weak point in a piping system. Occasionally, and to provide the correct pressure from a pump, a calibration orifice is fitted in the delivery piping. This can result in turbulent fluid flow and causeabrasive corrosion or erosion. Welded flanges are prone to accelerated corrosion in the weld metal or in the heat-affected zone. Pipes in wet areas where corrosion is likely need to be examined at regular intervals (six-monthly).

Pipe jointsThe preferred method for connecting two lengths of steel pipe, whether a straight, elbow or tee joint, is with a flange. With the possible exception of small-bore pipes in low-pressure systems, pipes are not normally connected by threaded joints. Mechanical,expansion or sliding joints are fitted in longitudinal pipes to allow the pipe to move when a ship bends and flexes, or to cater for thermal expansion. Expansion joints are not fitted where there is regularly high stress, nor are they used inside cargo holds or tanks. Expansion joints should never be used as a permanent connection for corroded pipes after a temporary repair. Classification society rules define which piping systems to use and the positions where expansion joints can be fitted. Only approved expansion joints are allowed.

Clips and supportsClips and supports are used to hold pipes in position and to prevent movement or vibration. A vibrating pipe can ‘work harden’ and fail. Pipes can fracture when there is insufficient support. There are no hard and fast rules about the number of clips required in a length of pipe as this will depend on the pipe’s diameter, length, its position and the density of fluid conveyed. The contact area at the surface of the pipe requires protection. Failures often occur as a result of mechanical wear when the cliploosens, allowing the pipe to move. Inspection procedures must be designed to ensure that all clips are checked regularly, including those hidden from sight behind insulation or under engine room floor plates. Special attention should be paid to clips in concealed places.

ValvesValves are fitted to isolate sections of pipe and will typically be found at suction points, crossovers, feed lines, delivery lines and where pipes need to be removed. Valves connected to the shell are flanged and made of steel or other ductile material. Grey or nodular cast iron cannot be used for boiler blow-down valves, for valvesfitted to fuel oil or lubricating oil tanks, or for shell valves. Shell valves should be tested regularly, on a monthly basis, by opening them. Marking valve handles with high-visibility paint will help with identification during an emergency. Cast iron valves have a service life shorter than those made from cast steel. Consequently, they need careful examination during a special survey.

CAUSES OF PIPE FAILURE

Pipes have a hard life: they carry abrasive and corrosive fluids; they are exposed to atmospheric corrosion and to general wear and tear; they sometimes operate at extremely high temperatures. The most common cause of pipe failure is corrosion-induced weakness. Pipes corrode internally and externally. Internally, they may beaffected by erosion, uniform and abrasive corrosion, fatigue and galvanic action. Externally, corrosion is caused mainly by atmospheric conditions, but pipes can corrode locally where liquids drip onto them.

Uniform corrosionUniform corrosion is the most common form of attack on metal. Its aggressiveness depends on relative humidity, temperature, oxygen content and salt content. It is widespread in pipes carrying saltwater. Pipes on deck, in locations prone to wetting, in bilges and in ballast tanks, as well as pipe supports are at risk of uniform corrosion. It is a good policy to replace a pipe when the corrosion measuredis equal to or greater than the design allowance.

Pitting corrosionPitting corrosion is defined as the localised breakdown of the inert surface layer that protects metal against the formation of cavities or small diameter holes in the material. Such corrosion can occur in mild steel and stainless steel. It has a random pattern, as the formation of a pit is dependent on the breakdown of a pipe’s protective film. Pitting happens more readily in a stagnant environment.As a general rule, any badly pitted pipe needs replacing.

Abrasion and erosionAbrasion and erosion are the wearing away of material by a fluid flow. Material that has been abrasively corroded or eroded looks pitted. To determine whether material has been lost by either abrasion or erosion, it is necessary to examine the processesinvolved in both. Abrasion happens when solid particles, such as sand, suspendedin a fluid flow scour a pipe. It is therefore a mechanical process. If the oxidised surface protecting a pipe’s base metal is abraded by such flows, uniform corrosion or pitting can result. The main characteristic of abrasion is the appearance of cracking in thedirection of flow. Filters are fitted in ballast and bilge lines to prevent debris from being sucked into a pipe. A slower than expected pumping rate may indicate that filters are clogged and that they need cleaning. Worn or damaged filters must be replaced.Erosion is caused when turbulent fluid flows hit a pipe’s inner surface; it is most common at points where a pipe bends and at elbows where fluid flow changes direction, or where an orifice, valve, welded joint or any other blockage impinges on fluid flow tocause turbulence. Prevention of turbulence is the key to prevention of erosion. The use of larger diameter pipes, together with a reduced pumping rate, can eliminate flow turbulence and erosion.

Fatigue damageFatigue damage is the rapid deterioration of metal, the results of which are cracking and collapse. It is caused by cyclical mechanical stress, or when pipes are connected to machinery or other pipes that vibrate.

Galvanic corrosionGalvanic corrosion is the electro-chemical process between different metals. It is most common where pipes connect to equipment made from a different metal and where there is an electrically conductive path between the metals through an electrolyte.

Graphitic corrosionCast iron pipes and fittings are affected by graphitic corrosion that is most commonly found at bends and elbows, locations where boundary layers cause water to flow at different velocities, or where water accumulates. Graphitic corrosion attacks the inside of a pipe by oxidation and leaching of iron. It results in the formation of rust supported by graphitic flakes. The process occurs over aperiod of time and, if the pipe is not replaced, will continue until the pipe weakens and eventually fails, usually catastrophically. The risk of failure through graphitic corrosion can be reduced by:• Identifying every cast iron pipe or fitting that has a connection to the sea.• Using ultrasonic equipment to measure the wall thickness of pipes over ten years old; this should be done annually.• During a docking survey, removing for internal examination all iron pipes over ten years old that are located in high-risk areas likely to be affected by graphitic corrosion, such as elbows, where flow velocity changes or where water canaccumulate.

Water hammerWater hammer can affect any pipe but is most common in steam pipes. It is a problem in pipes where internal condensation occurs.Water hammers are impulse pressures that happen when steam enters a cold pipe containing a small amount of water. The resulting stresses, along with possible rapid expansion, can cause pipe joints to fail. Prevent water hammers by draining fluid from pipes before injecting steam gradually. Steam systems are most prone to damage by water hammer because they operate at high temperature and pressure, and because condensed steam will remain in them, unless regularly drained.Steam heating coils on tankers are particularly susceptible to damage by a water hammer.

Pipe alignmentIrregular stress affects pipes that are forced into alignment. If they have been weakened by corrosion, stresses caused by thermal expansion or impulse loading, the pipes will fail. Forcing pipes into alignment is bad engineering practice. Failures are most likely at flange connections or valves.

Low temperatureVery low temperatures cause water to freeze and to expand in uninsulated pipes. In cold conditions, high-viscosity or solidifying substances will become difficult to pump because of their tendency to constrict the flow in pipes. Care must be taken toavoid over-pressurising the pipe in an attempt to increase flow. It may be necessary to add anti-freeze to a pipe system, or to arrange external heating, if conditions get really cold.

ExpansionMetallic pipes expand and contract as the temperature changes. A ship’s movement will cause them to stretch and bend, and unless these stresses are absorbed by an expansion joint, pipes can fail. Bulkheads pierced by pipes present special problems.The bulkhead’s strength has to be maintained and the stresses resulting from a pipe’s movement have to be absorbed. If the bulkhead forms part of a fire zone, insulation has to be repaired or replaced to ensure that fire integrity is notcompromised.

PIPE MAINTENANCE

DO’S DON’TS

IMO defines risk as: “The combination of the frequency and the severity of the consequence.”In other words, risk has two components: likelihood of occurrence and severity of the consequences.

A hazard is a substance, situation or practice that has the potential to cause harm. Briefly, what we are concerned with, therefore, is:• the identification of hazards• the assessment of the risks associated with those hazards• the application of controls to reduce the risks that are deemed intolerable• the monitoring of the effectiveness of the controls

TerminologyIncident An unplanned sequence of events and/or conditions that results in, or could have reasonably resulted in, a loss event.

Incidents are a series of events or conditions that contain a number of structural / machinery / equipment / outfitting problems, human errors, external factors as well as positive actions and conditions.

AccidentAn incident with unexpected or undesirable consequences. The consequences may be related to personnel injury or fatality, property loss, environmental impact, business loss, etc. or a combination of these.

Near Miss An incident with no consequences, but that could have reasonably resulted in consequences under different conditions.

Consequences Undesirable or unexpected outcomes may result in negative effects for an organization. These consequences can range from minor injuries to major events involving loss of life, extensive property loss, environmental damage, and breaches related to security.

All too often, companies carry out risk assessment exercises as separate, isolated activities. The process is regarded as complete once the forms are filled in and filed away. But if new or enhanced controls have been identified, they must be implemented, usually by inclusion in the company’s documented procedures.

If it is to make a real, practical contribution to improving safety and preventing pollution, the management of risks must be continual and flexible. A risk assessment is nothing more than a “snapshot”. The organization, the technology, working practices, the regulatory environment and other factors are constantly changing, and subsequently arising hazards will not be included. Assessments must be reviewed regularly and in the light of experience; for example, an increase in the number of accidents or hazardous occurrences may indicate that previously implemented controls are no longer effective. Additional risk assessments will be needed for infrequent activities or those being undertaken for the first time.

The formal risk assessment exercise is only one of many contributions to risk management. Much more important are flexibility and responsiveness to a dynamic environment and its dangers. The organization (Company) must ensure that it is sensitive to the signals provided by internal audits, routine reporting, company and Masters’ reviews, accident reports, etc., and that it responds promptly and effectively.

A Safe Job Analysis(SJA) is a systematic and step-by-step review of all elements of risk carried out prior to a specific task or operatoin so that measures can be taken to remove or control any elements of risk identified during the preparation for or performance of the said task or operation.It is important to remember the subjective nature of risk perception; for

example, one person swinging 30m above the deck in a bosun’s chair may have a very different view of the risks involved from that of another person in the same situation. This divergence in responses to risk arises from differences in experience, training and temperament, and it can be considerable. Who decides what is tolerable and what is acceptable? Because the judgements of the people engaged in an activity may not coincide with those of the assessors, it is essential that operational staff be involved in the assessment process.They have knowledge of the activities and experience in their conduct, and they have tolive with the consequences of the decisions that are taken.Furthermore, different levels of experience and training mean that the hazards and risksassociated with an activity can vary greatly with the people who carry it out, and conditions may be very different from those prevailing at the time of the assessment.

Documentation and experience

Is this a familiar work operation for the crew?

Is there an adequate procedure/instruction/work permits?

Is the group aware of experiences/incidents from similar activities/SJA?

exercise, HOW TO PLAN ANY JOB?

Competence

Do we have the necessary personnel and skills for the job?

Communication and coordination

Is this a job where several departments/crews must be coordinated?

Is good communications and suitable means of communication in place?

Are there potential conflicts with simultaneous activities (cargo/ballast/bunker)?

Has it been made clear who is incharge for the work?

Has sufficient time been allowed for the planning of the activities?

Key physical safety systems

Are barriers,to reduce the likelihood of unwanted incidents maintained intact(safety elements of any kind)?

Equipment worked on/involved in the job

Is the necessary isolation from energy provided(rotation,pressure,electrical voltage etc.)?

May high temperature represent a danger?

Equipment for the execution of the job

Is lifting equipment,special tools,equipment/material for the job available,familiar to the users,checked and found in order?

Do the involved personnel have proper and adequate protective equipment?

Is there danger of uncontrolled movement/rotation of equipment/tools?

The area

Is it necessary to make a worksite inspection to verify access, knowledge about theworking area working conditions etc.?

Has work at heights/at several levels above eachother/falling objects been considered?

Has flammable gas/liquid/material in the area been considered?

The workplace

Is the workplace clean and tidy?

Has the need for tags/signs/barriers been considered?

Has the need for additional guards/watches been considered?

Has weather,wind,waves,visibility and light been considered?

Has access/escape been considered?

Maintenance and inspection procedures are largely dependant on humans and although no one intends for errors to happen, experience informs us that by ournature humans are prone to error and it is inevitable that mistakes will be made from time to time.Maintenance and inspection work is particularly vulnerable to error because the work is often complex involving the frequent removal and replacement of a variety of components. Certain tasks also require high levels of vigilance and skill to detect faults that can be infrequent and difficult to spot. Maintenance and inspection work is also commonly performed in difficult working conditions, and often under time pressure.

Most people would agree that human beings are frequent violators of the ‘rules’ whateverthey might be. But violations are not all that bad – through constant pushing at acceptedboundaries they got us out of the caves!

It is no surprise that most small claims are caused by small human errors. You mightexpect, therefore, that most really large claims would result from major human errors. They do not! They, too, are caused by minor errors.

We must prevent the next incident occurring, not the last one. Latent failures are a greater threat as they create conditions in which accidents are more likely and more serious

Human ErrorsPerformance of humans that deviates from the desired performance.

Notes:• This definition is not a failure to perform as directed, but failure to perform as desired. An individual can follow the procedure precisely and still perform a human error, because the individual does not perform as desired (i.e., there is a gap between actual and desired performance). In this situation, the procedure specifies the incorrect method for performing the task.

Definition of Human Error

Basically they are procedures written to shape people’s behaviour so as to minimiseaccidents. They are, if you like, standards designed to form part of the system defences against accidents. Defences are installed to protect the individual, the asset or the natural environment (all ‘objects of harm’) against uncontrolled hazards

The rules

Assuming that the rules, meaning safe operating procedures, are wellfounded, anydeviation will bring the violator into an area of increased risk and danger. The violation itself may not be damaging but the act of violating takes the violator into regions in which subsequent errors are much more likely to have bad outcomes. This relationship can be summarised quite simply by the equation:

Violations + errors = injury, death and damage

Factors leading to deliberate non-compliance extend well beyond the psychology of the individual in direct contact with working hazards and include such organisational issues as:

The nature of the workplace The quality of tools and equipment Whether or not supervisors or managers turn a ‘blind eye’ in order to get the job done The quality of the rules, regulations and procedures The organisation’s overall safety culture, or indeed its absence

Other reasons for Human Error

Can we see any reasons here?

Classifying violations

Routine violations – almost invisible until there is an accident (or sometimes as theresult of an audit), routine violations are promoted by a relatively indifferent environment; i.e. one that rarely punishes violations or rewards compliance – “we do it like this all the time and nobody even notices”.EXAMPLE?

Optimising violations – corner-cutting; i.e. following the path of least resistance,sometimes also thrill seeking – “I know a better way of doing this”.EXAMPLE?

Situational violations – standard problems that are not covered in the procedures – “we can’t do this any other way”. EXAMPLE?

Exceptional violations – unforeseen and undefined situations – EXAMPLE?.

Routinisation – the individual becomes so expert at exercising a particular skill, that he no longer consciously thinks about it allowing the mind to wander and the unexpected to happen – drivers who regularly travel the same route to the station each day suffer from this – ‘am I here already?’

Normalisation – the process of forgetting to be afraid – interestingly most accidents on mountains happen on the way down from the summit – only a relatively smallnumber happen on the way up.

Intrinsic hazard – no matter how well you defend yourself the dangers ‘out there’never go away – move outside your protective ‘bubble’ and something or someone will get you!

Creeping entropy – systems, policies and procedures grow old or fail to adjust to changing external factors thus increasing the propensity for accidents to happen.

Murphy’s Law – if it can happen it will happen, but there is also Schultz’ Law. Mr Schultz merely said that Murphy was an optimist!

Types of errors

Fire in Machinery Spaces

Based on past experience it is known that the combination of combustible materials andsources of ignition are the main cause of machinery space fires. The combustible material involved is in the majority of cases oil, i.e. fuel oil, lubricating oil, thermal oil or hydraulic oil. However, plastic materials in electrical installations may also be combustible material causing outbreak of fires.

There is a large variety of potential ignition sources and the most common are hot surfaces, e.g. exhaust pipes and steam pipes, over-heating of machinery or ignition from electrical installations due to short circuiting or sparks caused by operation of switchgear. Other frequent ignition sources are those associated with human activities, e.g. smoking, welding and grinding.

Contributing Factors to Machinery Space Fires

1. Failures resulting from the daily use of machinery space installations, such as e.g. oil leakages, breakage of flexible pipes.

2. Lack of adequate cleanliness adds to the fire hazard in two ways.

a) In the first place the probability of occurrence of fire, in particular due to ignition caused by human activities is increased because of the widespread presence of the combustible material in the form of oil spill/oily deposits.

b) Secondly, an unclean machinery space may cause a small fire to spread, e.g. a fire in an electrical switchboard or panel may develop into a full machinery space fire due to the presence of oil spills/oily deposits.

Measures to Reduce the Fire Risk

Shielding of high pressure fuel oil pipesTypical defects found may be of the following nature:– Partially lacking or damaged shielding.– Loose or defective end attachments of shielding.– Flexible pipes used for shielding fitted in such a way that contact between high pressure fuel pipe and flexible pipe causes wear damage.– Defective drainage arrangements.– Partially lacking insulation, typically in way of flanges or at locations where removal ofinsulation is necessary for maintenance.– Oil soaked insulation due to damage or the lack of steel sheeting.

Oil leakages into electrical equipment may be ignited due to sparks normally generated by operation of switchgear (fine oil spray is probably most susceptible to ignition). Water leakages may cause short circuiting and ignition of insulation or other material of plastic type. The owner and operating personnel should in particular look for signs of leaking flanges, deterioration of pipes and leakages from other machinery which may come into contact with subject electrical equipment.

Attention at the condition of flexible pipes used in oil systems, e.g. in connection with hydraulic power arrangements, flexible pipes are used to prevent harmfulvibrations and noise. High pressures in combination with pulsations may cause breakage of the flexible pipes, particularly in way of end attachments.

Also, flexible pipes for connecting fuel oil supply to oil burners are extensively used. Any signs of deteriorating conditions being revealed, should be replaced or at least temporarily repaired.

Broken or loose fastenings of oil pipes should be repaired immediately because they may result in future damage and possible fire.

It is your responsibility to ensure that the machinery space is maintained in a cleancondition.

A cleanliness level is not acceptable in cases where floor plates are slippery from extensive oil spills, or oil is seeping from machinery, or if painted surfaces have an oil layer, or when a fire hazard exists due, for instance, to accumulation of rags or other similar materials or presence of oil on bilge water surface

1) Everyone is fallible and capable of bending the rules

2) All systems have techical and procedural shortcomings

3) Whatever you do, there is always something beyond your control that can hurt you

1) Everyone is fallible and capable of bending the rules

2) All systems have techical and procedural shortcomings

3) Whatever you do, there is always something beyond your control that can hurt you

The best safeguard against accidents is a genuine safety culture -awareness and

constant vigilance on the part of all those involved

The best safeguard against accidents is a genuine safety culture -awareness and

constant vigilance on the part of all those involved