reet REDUCING THE RISK OF LIQUEFACTION - Mare Forum

REDUCING THE RISK OF LIQUEFACTION

Operational guidance for vessels thatcarry cargoes which may liquefy

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4 GLOSSARY5 INTRODUCTION6 WHAT IS LIQUEFACTION?8 WHAT ARE THE EFFECTS OF LIQUEFACTION?10 THE “CAN TEST”12 LOADING CARGOES WHICH MAY LIQUEFY 13 BEFORE LOADING 14 THE LOADING OPERATION 15 DURING THE VOYAGE17 RECENT DEVELOPMENTS18 APPENDIX 1 - GROUP A CARGOES WHICH MAY LIQUEFY

TABLE OF CONTENTS

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FLOW MOISTURE POINT

The Flow Moisture Point (FMP)means the percentage moisturecontent (wet mass basis) at which aflow state develops under theprescribed method of test in arepresentative sample of thematerial.

GROUP A

Cargoes which may liquefy if shippedat a moisture content in excess ofthe transportable moisture limit.

GROUP B

Cargoes which possess a chemicalhazard which could give rise to adangerous situation on a ship.

GROUP C

Cargoes which are neither liable toliquefy (Group A) nor to possesschemical hazards (Group B).

IMSBC CODE

The International Maritime SolidBulk Cargoes (IMSBC) Code refersto requirements applicable to thetransportation of solid bulk cargoesadopted according to the IMOresolution MSC.268(85).

MOISTURE CONTENT

Moisture Content (MC) means thatportion of a representative sampleconsisting of water, ice or otherliquid expressed as a percentage ofthe total wet mass of that sample.

TRANSPORTABLE MOISTURE LIMIT

Transportable Moisture Limit (TML) of a cargo which may liquefy meansthe maximum moisture content of the cargo which is considered safe for carriage in ships not complyingwith the special provisions ofsubsection 7.3.2 of the IMSBC Code.It is determined by the testprocedures, approved by a competentauthority, such as those specified inparagraph 1 of Appendix 2 of theCode. If the methods of flow tabletest or penetration test is used, theTML is determined as 90% of FMP.

GLOSSARY


The purpose of this booklet is toprovide general guidance andpractical advice to masters, shipowners, shippers and charterers onthe loading and the carriage of bulkcargoes which may liquefy, the risksassociated with liquefaction and theprecautions to minimize these risks.It is not intended to replace, in anyway or form, the official IMOregulations and guidance notes orany document that forms part of avessel’s safety management system.

Millions of tonnes of cargo (iron orefines, coal, manganese ore fines and nickel ore) that are known to be prone to liquefaction have beensuccessfully transported without any incident. Despite animprovement in the awareness ofcarrying such cargoes, incidentswhere cargoes have been known toliquefy unfortunately continue andsometimes with catastrophic/tragic1

results. Therefore the liquefactionphenomenon continues to be asrelevant today in 2017.

While the main requirements for thesafe carriage of solid bulk cargoesare enshrined in the IMSBC Code,this booklet outlines the precautionsyou should take before acceptingcargoes for shipment and theprocedures you should follow for thesafe loading and carriage of thenominated cargo.

You will still need to consult theCode to check whether the cargo you are about to carry or carryingcomplies fully with the Code.

Please note that the IMSBC Code ismandatory under the provisions ofthe SOLAS Convention. However,some parts of the Code continue tobe recommendatory or informativeand therefore in the context of thelanguage of the Code, the words“shall”, “should” and “may”, whenused in the Code, should be taken to mean that the relevant provisionsare “mandatory”, “recommendatory”and “optional”, respectively.


INTRODUCTION

51 E.g. loss of Bulk Jupiter with 18 lives in January 2015

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WHAT IS LIQUEFACTION?


A solid bulk cargo consists of threemain components: a solidcomponent; a moisture component;and an amount of air (void space) inbetween. Vibration and the motion ofa vessel will cause the cargo stowedin the holds to compact the moistureand small particles contained in thecargo. In certain conditions a cargocan compact to such an extent thatthere is no more void space (air)between solid and water particles.

When there is more water inside thecargo than there is space betweenthe particles, and the water hasnowhere to go, then the waterpressure between the particles mayrise and press the particles apart.This will either result in a slidingfailure or the wet base of the cargowill transition from a solid state to aviscous fluid.

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KEY FACTSKey fact: Liquefaction may occurwithout additional water content(e.g., from rainwater) if theinherent MC is already too high,yet undetected by improperchecks/tests, in which caseagitation alone will causeliquefaction as described.

Space between particles reducesAir is expelledWater pushes particles apartLoss of shear strengthSolid cargo becomes liquidCentre of gravity shiftsFree Surface EffectShips may capsize

Liquefaction process in bulk cargo


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In the liquefied form, the viscous statemay unexpectedly flow from one sideof the cargo hold to the other, whichcauses a shift in the centre of gravityof the vessel. This has a dramatic

effect on the ship’s stability. In heavyseas, the cargo can flow to one side ina roll, and not return with the roll theother way, which progressively leadsto the vessel capsizing.

Liquefied cargoes


8

WHAT ARE THE EFFECTS OF LIQUEFACTION?


Free Surface Effect The most significant consequence of cargo liquefying is the vessel’s loss ofstability (reduction or loss of GM), leading to the vessel listing at a dangerousangle to one side. In some instances, the angle of heel continues to increase,resulting in the vessel listing heavily, down flooding or even capsizing,leading to the loss of the vessel, its cargo and crew.

It is vital that the crew are fully aware and have a complete understanding ofwhat happens when a cargo liquefies, and are able to spot warning signs atthe earliest possible stage.

As the vessel rolls in the oppositedirection the liquefied cargo may nothowever flow back, instead remainingtowards the side of the hold to which ithas already shifted (Step 1.3)

When a bulk cargo liquefies (Step 1.1)

Step 1.1 Liquefied cargo Step 1.2 Ship rolls to port, cargomoves slowly

Step 1.3

it may move towards the lower side ofthe hold when the ship rolls (Step 1.2)

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Step 2.1 Untrimmed bulk cargowith high moisture and low cohesion

Cargo shiftAnother effect is ‘sliding’.Sliding is different fromliquefaction and may occurwhen the moisture contentis too high, in untrimmedcargoes. The cargo losesits cohesion and becomesless sticky.


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This causes a rapid build-up of cargo onone side of the vessel and build-up ofheavy cargo resting on the ship’s side-plating (Step 1.5).

The vessel may progressively reach adangerous angle of heel with downflooding and even capsize quite suddenlywith little or no warning.

Step 1.4

Step 2.3 The top of the cargoseparates and slides to the side

Step 2.4 The cargo has moved tothe side resulting in a list

Step 1.5

On each subsequent roll, the cargo (in aviscous state) may move further to thesame side and build-up (Step 1.4).

The resulting cargo may flow to one sideof the ship with a roll but not completelyreturn with a roll the other way.

Bulk carrier cargo holds are singlecompartments withoutthe centerlinebulkheads. Often withheavy cargo they areonly half full. Thiscreates the largestpossible free surface inthe cargo hold.

Bulk concentratecargoes are a lot denserthan fluids, so themetacentric heightreduction is high whenthe cargo liquefies. Thiscan reduce the stabilityextensively.

When the ship rolls, thetop part of the cargo canseparate and slide to oneside. This transposes thecargo and its verticalcentre of gravity to oneside and affects stability.Liquefaction can alsooccur along with sliding.

When a cargo liquefies, it starts to behave like a fluid. This means that it acquires a free surface. Thedetrimental effect of this free surface (reduction orloss of GM) can be very significant for two reasons:


10

THE “CAN TEST”


Prior to loading a Group A cargo, theactual MC and TML have to bedetermined, as required by Section4.2.2.9 of the IMSBC Code. These scientific (laboratory) tests arecarried out ashore and moreinformation can be found in paragraph1.1.4.4 of appendix 2 of the Code.

Currently, the master or othermembers of the crew can carry out acomplementary test (or check) onboard, known as the “Can Test” inorder to determine approximatelywhether the cargo they are about toload or loading has the possibility offlowing, i.e. whether the FMP isexceeded or not.

How to do a can test?

Take a cylindrical can, preferably atin can or similar container of about0.5 or 1 litre capacity and half fill itwith the cargo.

Cargo stockpile

Half full can

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Hold the can with one hand and bringit down sharply to strike a hardsurface such as the deck or a bollardfrom a height of about 0.2 meters. You need to repeat this procedure 25times at one to two-second intervals.

Examine the surface for free moistureor fluid conditions. Then turn the canupside down and shake it slightly todislodge the sample. Examine this aswell for free moisture or a fluidcondition. In daylight, the surface willbe glistening.

If possible, photograph each can testfor your own records by marking ondeck the location of the sample fromwhere it was obtained (location incargo pile and depth). Maintain a logof the tests that were carried out andtheir results.

During the course of loading, themaster or a designated crew memberis recommended to frequently ‘CanTest’ the cargo as it is being loaded.This should be from the cargo pile inthe hold (tests on cargo piles inbarges/ashore are additional but notas conclusive for the ‘as loaded’ state).

NOTEEven if a sample remains dry after testing, the MC of thesample may still exceed theTML. The ‘Can Test’ does notdemonstrate that the cargomoisture content is less than the TML but may indicate that the cargo has exceeded itsFMP. Only a laboratory testcan establish this.


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LOADING CARGOES WHICH MAY LIQUEFY


Some of the known cargoes whichmay liquefy (Group A) are mineralconcentrates that have been refinedinto ores by eliminating most of thewaste materials. They are generallyknown to be fine-particled materialwith a moisture content. For example,copper, iron, lead nickel and zincconcentrates. A list of the ‘Group A’cargoes extracted from the currentIMSBC Code can be found at Appendix 1.

Following the tragic loss of BulkJupiter in 2015, bauxite has also beenidentified as a cargo which may liquefyand the IMSBC Code is in the processof being reviewed2.

Any ‘Group A’ cargo whose MC is inexcess of the TML can only be carriedin specially constructed or fitted cargoships that have been approved by theAdministration. For this purpose, inDecember 2016 Bureau Veritas issuedguidelines for the design of shipssubject to bulk cargo liquefaction. See the Bureau Veritas Guidance NoteNI 639 DT R00 E for further details onwhat constitutes a “speciallyconstructed or fitted” cargo ship.

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BEFORELOADING

It is important that the master shouldnot accept concentrates or othercargoes which may liquefy for loadingwithout being provided with theappropriate documentation certifyingthat the moisture content of the cargois less than the TML.

Prior to the commencement ofloading the master should satisfyhimself and confirm that:

The cargo holds are clean and dry,and the bilges have been tested.

The hatch covers close correctlyand are weathertight.

The following should also be carriedout by the shipper and the master:

The shipper should provide themaster well in advance with theappropriate information on thecargo as per requirements found inSection 4.2.2 of the IMSBC Code.

This information should beaccompanied by a declaration by theshipper (Section 4.2.3).

The master should check, based onthe information provided on thecargo declaration, whether thecargo can be safely carried on boardthe vessel or whether additionalinformation is required.

The shipper should provide themaster with a signed certificate ofthe TML, and a signed certificate ordeclaration of the MC issued by anentity recognized by the CompetentAuthority of the port of loading(Section 4.3.2).

The master should check that thelaboratory test undertaken ashoreto determine the TML of a cargo hasbeen conducted within six months ofthe date of loading the cargo3

(Section 4.5.1).

The master should check whetherthe testing of the MC of the cargothat is being presented is as near aspracticable to the time of loading,and not more than seven days(Section 4.5.2).

If there has been significant rain orsnow between the time of testingand loading, check tests (laboratorytests, not can tests) should beconducted to ensure that themoisture content of the cargo is stillless than its TML.

efy” 3 Where the composition or characteristics of the cargo are variable for any reason, a test to determinethe TML shall be conducted again after it is reasonably assumed that such variation has taken place.

NOTEIt is a master’s responsibilityto ensure that his/her vesselis safely loaded. If a shipper’sdeclaration has not beenprovided and has not beenforthcoming, then the mastershould not start loading andimmediately notify thevessel’s owners.


THE LOADINGOPERATION

Although the carriage of ‘Group A’cargoes takes place on a regular basiswithout incident, the potentialconsequence of loading an unsuitablecargo due to an unacceptablemoisture content requires that themaster and crew remain vigilantthroughout the loading operation.

Loading should only commence whenthe shipper has fulfilled therequirements outlined above and themaster is satisfied with the informationhe has been provided with. The mastershould also complete the ship shoresafety checklist as recommended bythe Code of Practice for the SafeLoading and Unloading of BulkCarriers (BLU Code4).

The master and owners may considerthe appointment of an experienced,independent cargo surveyor in order tocheck the shore-side stockpile and ifnecessary take samples. In most portsthe master may not be allowed to goashore to inspect the stock pile.

During loading the master should:

Arrange for the deck to beadequately manned so as to carryout a visual inspection of the cargobeing loaded.

Be aware of the build-up of waterpools or splatter on the bulkheads -this indicates excessive moisture.

Continue to systematically carry outand record ‘Can Tests’ as describedabove.

Restrict the ingress of water and notload during periods of rain fall.

Make sure that the hatch covers ofall non-working holds are kept shut.

Ensure that, if the cargo is beingloaded from barges, the barges areadequately covered during periods ofprecipitation and water ingress. Ifthis is not the case, the mastershould not accept any cargo fromthese barges unless the moisturecontent has been re-established.

If the vessel encounters prolongedperiods of precipitation during theloading period, request check teststo ensure that the MC of the cargo isstill less than its TML.

Prior to completion of loading,ensure that the cargo is reasonablytrimmed (as per dry bulk cargo goodpractice).

On completion of loading, ensurethat the hatch covers are closed andsecured as required.

NOTEIf during loading the master hasreason to suspect that the MC isin excess of the TML, he/sheshould stop loading the cargoand inform the owners. Themaster may issue a ‘Letter ofProtest’ and seek further advicefrom the P&I Club.

144 The BLU Code can be found as a supplement to the IMSBC Code

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DURING THE VOYAGE

During the voyage the master andcrew should continue to monitor thestate of the cargo even if they aresatisfied about the condition of thecargo they loaded. Someprecautionary measures to minimiseany potential incidents of cargoliquefaction are as follows:

Monitor the cargo holds regularly tocheck for any sign of accumulation offree water in the cargo. Althoughthese inspections may not provide atrue representation of the cargocondition, they may provide anindication of how the cargo hasbehaved since it was loaded. However,this should only be carried out if it issafe to enter the holds, as mineralcargoes tend to deplete oxygen levels.It should be remembered that severalfatalities have occurred in recentyears.

If it is not already part of the ship’sroutine, sound the cargo hold bilgeson a daily basis. Although free water isexpected to drain it can hold themoisture towards the bottom of thehold and develop a wet base.

If necessary, consider ventilation ofcargo as and when appropriate. This will depend on the advicecontained in the IMSBC Code for thatparticular cargo loaded.

Monitor the vessel’s motion, inparticular the rolling period. A change in the rolling period mayprovide a warning of a reduction in the vessel’s GM.

If the master or owner has any reasonto suspect that the cargo is/hasliquefied, they should immediately:

Contact their P&I Club

Contact the nearest coastal stateauthority

Consider heading to the nearestport or place of refuge

Consider measures to reduce thevessel’s vibration/motion


FLOW DIAGRAM TO BE FOLLOWED PRIOR TO AND DURING LOADING

16

LOAD

YES

YES

YES NO

YES

YES

YES

YES

Has the shipper provided all the cargo information?

Has the IMSBC Codebeen consulted?

Does the Master have sufficient informationto plan the loading?

Has the cargobeen correctly identified?

Is the MC lowerthan the TML?

Are the cargo spacesfree of liquids?

Loading visually monitored?Measures against water ingress taken?

Trimming at the end ofloading considered?

NO

NO

NO

NO

NO

NO

STOP LOADING

DO NOTLOAD

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RECENT DEVELOPMENTS


On 1st January 2017, the latestamendment, 03-15, to the IMSBCCode entered into force. The amendments are aimed atdealing with the latest advancementsin the transport of cargoes, and arebriefly summarised below.

There are 18 new individualschedules of solid bulk cargoes, amajority of which are for Group Acargoes. These schedules provideclarity on the carriage requirementsfor cargoes that in the past may havecreated uncertainty. A list of all GroupA cargoes and the recent additions tothe Group contained in the IMSBCCode can be found in Appendix 1 ofthis booklet.

The Code now provides newschedules for iron ore fines and scalegenerated from the iron and steelmaking process. In the past theseGroup A cargoes have beenassociated with a significant numberof ship casualties and cargo disputesdue to liquefaction.

The most noteworthy amendment tothe existing cargo schedules is thereplacement schedule for iron ore(Group C). Iron ore cargoes are nowdefined in terms of particle size andgoethite content. The new section 1.4of Appendix 2 includes a ModifiedProctor/Fagerberg test procedure foriron ore fines. This method is used fordetermining the TML of iron ore fines.

For the purpose of incorporating therequirements of MARPOL Annex Vthat apply to the management of solidbulk cargo residues, a newregulation, Section 14, has beenadded which addresses themanagement of residues of solid bulkcargoes, in relation to the “2012Guidelines for the implementation ofMARPOL Annex V”. As per MARPOLAnnex V, the management of theresidues of solid bulk cargoesdepends primarily on theclassification of a solid bulk cargo aseither harmful to the marineenvironment (HME) or non-HME. The responsibility for classifying anddeclaring whether a solid bulk cargois HME or non-HME lies with theshipper now. This classification willnow be included in the cargoinformation provided by the shipperas per section 4.2.2.2.

A new Appendix 5 containing all theBulk Cargo Shipping Names (BCSN)can be found in the IMSBC Codeappendix under three languages.


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APPENDIX 1 GROUP A CARGOES THAT MAY LIQUEFY5


Aluminium fluoride*

Alumina hydrate (can also be B)

Aluminium smelting/remelting by-products, processed (can also be B)

Blende (zinc sulphide)

Calcined pyrites (can also be B)

Cement copper

Chalcopyrite

Chemical gypsum*

Clinker ash, wet (can be also B)

Coal (can be also B)

Coal slurry

Coke breeze

Copper concentrate

Copper nickel

Copper ore concentrate

Copper precipitate

Copper slag*

Fish (in bulk)

Fluorspar (can be also B)

Fly ash, wet

Galena (lead sulphide)

Ilmenite clay

Ilmenite sand (can be also C)

Ilmenite (upgraded)

Iron and steel slag and its mixture*

Iron concentrate

Iron concentrate (pellet feed)

Iron concentrate (sinter feed)

Iron ore (concentrate, pellet feed,sinter feed)

Iron ore fines*

Iron oxide technical*

Lead and zinc calcines (mixed)

Lead and zinc middlings

Lead concentrate

Lead ore concentrate

Lead ore residue

Lead silver concentrate

Lead silver ore

Lead sulphite

Lead sulphite (galena)

Manganese concentrate

Manganese ore fines*

Metal sulphide concentrates (can be also B)

Mineral concentrates

Nefeline syenite (mineral)

Ni

Ni

Ni

Pe

Pe

Py

Py

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Py

Py

Py

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Sil

Sil

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* New individual schedules of solid bulk cargoes as per amendment 03-15 of the IMSBC Code5 Extracted from Appendix 4 of the IMSBC Code and includes the amendments in force on 1 January 2017


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Nickel concentrate

Nickel ore

Nickel ore concentrate

Peat moss (can be also B)

Pentahydrate crude

Pyrites calcined (can be B)

Pyrites

Pyrites (cupreous, fine, flotation or sulphur)

Pyritic ash (can be B)

Pyritic ashes (iron)

Pyritic cinders

Sand, heavy mineral

Scale generated from the iron andsteel making process*

Silver lead concentrate

Silver lead ore concentrate

Slig (iron ore)

Spodumene (upgraded)*

Zinc and lead calcines (mixed)

Zinc and lead middlings

Zinc concentrate

Zinc ore, burnt

Zinc ore, calamine

Zinc ore, concentrates

Zinc ore, crude

Zinc sinter

Zinc slag*

Zinc sludge

Zinc sulphide

Zinc sulphide (blende)

Zircon kyanite concentrate*

NOTES

ode017


Move Forward with Confidence

Bureau Veritas - Marine & Offshore Le Triangle de l'Arche - 8 Cours du TriangleCS 50101 - 92937 Paris La Défense Cedex

Phone: +33 (0)1 55 24 70 00Corporate website: www.bureauveritas.com/marine-and-offshore

Client portal: www.veristar.com

BC

046

DC

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01 –

Oct

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7 -

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50 Leman Street London E1 8HQ - UK

Telephone: +44 (0)20 7772 8000 Email: [email protected]

www.londonpandi.com

Standon House - 21 Mansell Street London E1 8AA - UK

Telephone: +44 (0)20 7237 2617 Email: [email protected]

www.tmcmarine.com


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