cop_mobile crane-English consult.pdf

7/26/2019 cop_mobile crane-English consult.pdf

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F o r e w o r d

MobilecranesarewidelyusedforliftingoperationsintheconstructionindustryinHongKong.Everyyear,therearequiteanumberofaccidentsinvolvingmobile

cranes,suchasoverturningofcranesanddisplacement of loadsbeing lifted.

Propertydamageandbodilyinjuriescanbeavoidediftheyareproperlyused.

ThisCodeofPractice(hereafterreferredastheCode)isapprovedandissued

by the Commissioner for Labour under Section 7A of the Factories and

IndustrialUndertakingsOrdinance(Cap.59). Itprovidespracticalguidanceto

theindustryastohowtousemobilecanessafelyandproperlywithaviewto

assistingthedutyholdersinpreventingaccidents.

TheprovisionsinthisCodeshouldnotberegardedasexhaustingthosematters

whichneedtobecoveredbytherelevantsafetylegislation,norisitintendedto

relieve persons undertaking the work of their statutory responsibilities. It is

important to note that compliance with this Code does not of itself confer

immunityfromlegalobligations.

ThisCodehasaspeciallegalstatus.Althoughfailuretoobserveanyguidance

containedinthisCodeisnotinitselfanoffence,thatfailuremaybetakenbya

courtincriminalproceedingsasarelevantfactorindeterminingwhetherornota

person has breached any of the provisions of the regulations to which the

guidancerelates.

Throughout this Code,wehave quoted the relevant safety standards of the

British Standards Institution. However, if there are some other national,

international standards or provisions which are equivalent, they would beacceptableasalternatives.Inaddition,statutoryprovisionsreferredtoorcited

inthisCodearethoseinforceasat(datetobefixed) .


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1 . S c o p e

1.1 This Code provides guidance on thesafe useandoperationof mobilecranes to ensure the safetyof personnel working at or near by those

cranes.

1.2 It covers management and planning of the lifting operation of mobile

cranes,requirementsforoperators,slingersandsignallers,siting,erection,

dismantling,maintenanceandtestingofmobilecranes. Italsocontains

guidancepertaining to the selection, safeuse and specificprecautions

whenmobilecranesareoperatingwithinaworkplace.

1.3 Reference is also made to relevant Hong Kong legislation in particular

Sections6A&6BoftheFactoriesandIndustrialUndertakingsOrdinance

(Cap.59)(hereafterreferredastheFIUO),theprovisionsintheFactories

andIndustrialUndertakingsRegulations(hereafterreferredastheFIUR),

theFactoriesandIndustrialUndertakings(LiftingAppliancesandLifting

Gear)Regulations(hereafterreferredastheLALGR),theFactoriesand

Industrial Undertakings (Guarding and Operation of Machinery)

Regulations(hereafterreferredastheGOMR)andtheConstructionSites

(Safety) Regulations (hereafter referred as the CSSR). Attention is

drawntotherequirementsandproceduresfortestingandexaminationof

cranesundertheLALGRandtheBritishStandardBS7121.


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2 . D e f i n i t i o n s

Automaticsafeloadindicator

Itmeansadeviceintendedtobefittedtoacranethatautomaticallygives

an audibleandvisiblewarningtothe operatorthereof thatthe crane is

approachingitssafeworkingload,andthatautomaticallygivesafurther

audibleandvisiblewarningwhenthecranehasexceededitssafeworking

load(Regulation3(1)oftheLALGR).

Competentexaminer

A competent examiner, in relation to the carrying out of any test and

examinationrequiredbytheLALGR,meansapersonwhois-

(a) appointedbytheownerrequiredbythoseregulationstoensurethat

thetestandexaminationiscarriedout;

(b) a registered professional engineer registered under the Engineers

Registration Ordinance (Cap. 409) within a relevant discipline

specifiedbytheCommissionerforLabour;and

(c) byreasonofhisqualifications,trainingandexperience,competentto

carryoutthetestandexamination(Regulation3(1)oftheLALGR).

AsatthedateofthisCode,MechanicalEngineeringandMarine& Naval

ArchitecturearethespecifieddisciplinesspecifiedbytheCommissioner.

Competentperson

Acompetentperson,inrelationtoanydutyrequiredtobeperformedby

himundertheLALGR,meansapersonwhois-

(a) appointedbytheownerrequiredbythoseregulationstoensurethat

thedutyiscarriedoutbyacompetentperson;and

(b) byreasonoftrainingandpracticalexperience,competenttoperform

theduty(Regulation3(1)oftheLALGR).


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Conditionoftipping

Aconditionwhenacrane issubjectedtoanoverturningmomentwhich

cannotbeincreasedbyevenasmallamountwithoutcausingthecraneto

fallover.

Owner

In relation to any crane, includes the lessee or hirer thereof, and any

overseer, foreman, agent or person in charge or having the control or

managementofacraneand,inthecaseofacranesituatedonorusedin

connectionwithworkonaconstructionsite,alsoincludesthecontractor

responsiblefor theconstructionsite(Regulation3(1)of theLALGR). Acontractor is responsible for a construction site if he is undertaking

construction work there or, where there is more than one contractor

undertakingconstructionworkatthesite,ifheis theprincipalcontractor

undertakingconstructionworkthere(Regulation3(2)oftheLALGR).


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3.ManagementoftheLiftingOpera t ion

3.1 Safesystemofwork

3.1.1 Asafe system of work should be establishedand documented. This

shouldbefollowedforeveryliftingoperationwhetheritisanindividuallift

oragroupofrepetitiveoperations.Thissafesystemofworkshouldbe

preparedandendorsedbytheowner/contractor,withtheadviceofthe

competent person, safety officer and other relevant personnel. The

same principle should be applied whether the lifting operations are

carriedoutatasite,inafactoryoratadock.Thesafesystemofwork

shouldbeeffectivelycommunicatedtoallpartiesconcerned.

3.1.2 Thesafesystemofworkshouldincludethefollowing:

(a) planningoftheoperation;

(b) selection,provisionanduseofasuitablecraneandequipment;

(c) maintenance,examinationandtestingofthecraneandequipment;

(d) theprovisionofa log-book for thecompetentexaminer/competent

person/mechanic to enter the details of testing, examination,

inspection, maintenance/repairworks whichhave been carriedout

forthecrane;

(e) theprovisionofproperlytrainedandcompetentpersonnelwhohave

been made aware of their relevant responsibilities under the

Sections6A&6BoftheFIUO;

(f) adequatesupervisionbyproperlytrainedandcompetentpersonnel;

(g) observing for any unsafe conditions such as adverse weather

conditionsthatmayariseduringoperation;

(h) ensuring that all necessary test and examination certificates and

otherdocumentsareavailable;

(i) preventingunauthorizedmovementoruseofacraneatalltimes;

(j) the safety of other persons who may be affected by theliftingoperation;


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(k) thecontingencyplanprovidingprocedurestobefollowedincaseof

emergencysituation.

3.1.3 The lifting operation should be taken to include any necessary

preparationofasite,andthesiting,erectionanddismantlingofthecrane.

3.2 Controloftheliftingoperation

3.2.1 Toensuretheimplementationofthesafesystemofwork,a responsible

personshouldbeappointedtohaveoverallcontroloftheliftingoperation.

Thisappointedpersonshouldhaveadequatetrainingandexperienceto

enablethesedutiestobecarriedoutcompetently.


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4.PlanningoftheLiftingOperation

4.1 Allliftingoperationsshouldbeplannedtoensurethattheyarecarriedoutsafely and that all foreseeable risks have been taken into account.

Planning shouldbecarried out by personnel who have the appropriate

expertiseandhavebeenappointedforthispurpose. Incaseofrepetitive

or routine operations, this planning may only be necessary in the first

instance,withperiodicreviewstoensurethatnofactorshavechanged.

4.2 Planningshouldincludetheconsiderationof:

(a) theloadsuchasitscharacteristicsandthemethodoflifting;

(b) theselectionofasuitablecraneappropriatetotheoperationensuring

thatadequateclearancesaremaintainedbetweentheloadandthe

cranestructure;

(c) theselectionofliftinggear,theweightofwhichshouldbetakeninto

accountwhenassessingtheloadonthecrane;

(d) thepositionofthecraneandthe loadbefore,duringandaftertheoperation;

(e) thesiteoftheoperation,takingintoaccountproximityhazards,space

availability and suitability of the ground or foundation such as the

allowablebearingcapacityoftheground;

(f) anynecessaryerection,alterationanddismantlingofthecrane;

(g) theenvironmentalconditionsthatexistormayoccuratthesiteofthe

operation, which may necessitate stopping the operation whenconditionsareunsuitable;and

(h) theeffectivenessofcommunicationamongrelevantparties,suchas

thatbetweentheoperatorandthesignaller/s.


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5.Responsibilities/RequirementsofPersonnel

5.1 Ownersresponsibilities

5.1.1 Itistheresponsibilityofownertoensurethatthemenwhopreparethe

equipment,erectit,operate it,andworkwithit arewell trainedinboth

safetyandoperatingprocedures.

5.1.2 Theownermustensurethatall mobilecranesareoperatedbytrained,

experienced,competentandqualifiedcraneoperator.

5.1.3 Theownermustalsoensurethatthemenwhodirect,rigandhandlethe

loadshavereceivedpropertrainingintheprinciplesoftheoperation,are

abletoestablishweightsandjudgedistances,heightsandclearances,

arecapableofselectingtackleandliftinggearaswellasriggingmethod

suitable for the loads to be lifted, and are capable of directing the

movementofthecraneandloadtoensurethesafetyofallpersonnel.

5.1.4 The owner is also responsible for putting together a crane safety

programme,educatingall related personnel in safe practices and the

assignmentofdefinite,individualsafetyresponsibilities.Theownermust

planallphasesoftheoperationinvolvingthecrane.

5.2 Mobilecraneoperator

5.2.1 The mobile crane operator should be responsible for the correct

operationofthecraneinaccordancewiththemanufacturersinstructions

andwithin thesafe system of work. He should at anyone time only

respond to thesignals fromoneslinger/signallerwhoshouldbe clearly

identified.Inparticular,themobilecraneoperatorshould:

(a) haveattainedtheageof18yearsandholdavalidcertificateissued

by the Construction Industry Training Authority or by any other

personspecifiedbytheCommissionerforLabour(Regulation15A(1)ofLALGR);


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(b) havebeenadequatelytrainedintheoperationofthetypeofcrane

he is driving and have sufficient knowledge of the crane and its

safetydevices;

(c) understand fully theduties of theslinger andbe familiar with the

signal code shown in Table 1 in order to implement safely the

instructionsoftheslingerorsignaller;and

(d) understand fully the radio/tele-communicationsignalsbetweenthe

partiesconcerned.

5.3 Slinger

5.3.1 Theslingershouldberesponsibleforattachinganddetachingtheloadto

andfromthecrane,andfortheuseofcorrectliftinggearinaccordance

withtheplanningoftheoperation. Inparticular,theslingershould:

(a) haveattainedtheage18years;

(b) befit,withparticularregardtoeyesight,hearingandreflexes;

(c) beagileandhavethephysiquetoenablehimtohandleliftingtackle;

(d) havebeentrainedinthegeneralprinciplesofslingingandbeableto

establishweightsandjudgedistances,heightsandclearances;

(e) be capable of selecting tackle and lifting gear as well as rigging

methodsuitablefortheloadstobelifted;

(f) understand thesignal code shownin Table1andbeable to give

clearandprecisesignals;

(g) becapableofdirectingthemovementofthecraneandloadinsuch

amannerastoensurethesafetyofpersonnelandplant;and

(h) understand fully the radio/tele-communicationsignalsbetweenthe

partiesconcerned.


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5.4 Signaller

5.4.1 Wherethecraneoperatorofthemobilecranedoesnothaveaclearand

unrestricted view of the load carried by the crane or the point of

attachmentfora loadwhereno load isbeingcarried andsuchview is

necessaryforthesafeworkingofthecrane,asignallershallbeemployed

torelaytheslinger'sinstructionstothecraneoperator(Regulation15B(1)

ofLALGR).

5.4.2 Thesignallershouldberesponsibleforrelayingthesignalfromtheslinger

to the crane operator. He is also responsible for directing the safe

movementofthecrane. Inparticular,heshould:

(a) haveattainedtheage18years(Regulation15B(2)ofLALGR);

(b) befitwithparticularregardtoeyesight,hearingandreflexes;

(c) understandthesignalcodeshowninTable1andbeabletotransmit

theinstructionsoftheslingerinaclearandprecisemanner;

(d) be easily identifiable to the crane operator (e.g.by wearing `high-

visibility'clothing,orothermeans);and

(e) understand fully the radio/tele-communicationsignalsbetweenthepartiesconcerned.


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6.SelectionofMobileCranes

6.1 General

6.1.1 Eachclassofcranespossessescertainbasiccharacteristicswhichwill

usually dictate the one most suited toa particular application. Mobile

cranes must be selected to suit the job. If the crane's basic

characteristicsdonotmatch the job's requirements,unsafeconditions

willbecreatedandaccidentspronetohappen.

6.1.2 Referenceshouldthereforebemadetothefollowingsub-section6.2for

detailsofdifferentcranetypesandtheiroperationalcharacteristics.

6.1.3 Thetypeofmobilecranestobeusedshouldbeconsideredagainstthe

jobrequirementsforaparticularapplication. Pointstobeconsideredin

makingtheselectioninclude:

(a) weightsanddimensionsofloads;

(b) heightsofliftanddistances/areasofmovementofloads;

(c) numberandfrequencyoflifts;

(d) lengthoftimeforwhichthecranewillberequired;

(e) siteconditions,includinggroundconditionsforcranestanding,and

space available for crane access, erection, operation and

dismantling;and

(f) anyspecialoperationalrequirementsorlimitationsimposedincluding

theexistenceofothercranesincloseproximity.

6.1.4 Ingeneral,allthepointsinsub-section6.1.3caninfluencethechoiceof

thecrane. Withtheconsiderationoftheabovepoints,thecranetobe

selectedshouldbe:

(a) capableofmakingallitsliftsinitsstandardconfiguration;

(b) havingatleasta5%working/safetymarginwithrespecttotheload

capacityoneverylift;

(c) havingsufficientclearancefortheboom;and


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(d) havingadequateheadroombetweentheloadandriggingrequiredto

makethelift.

6.2 Typesofmountingandjibconfiguration

6.2.1 Theoperatingcharacteristicsofamobilecranearelargelydeterminedby

itstypeofmountingandtypeofjib(seeFig.1&2).

6.2.2 Crawler-moun ted crane-acranewhichismountedoncrawler-tracked

chassis. Thecranecan travelunder its ownpower. Acranecabin is

usuallyprovidedforthecranedrivingandoperationpurposes.Asingle

powerunitisprovidedforboththecranedrivingandoperationmodes.

Thistypeofcraneshouldbeconsideredunderthefollowingconditions:

(a) thegroundispoortotraveloverorsloped;or

(b) operationinareasoflimitedaccess.

The tracks of the crane which provide large ground-bearing areahas

prevented the sinkageof iton softor unpavedground to enhance its

operational stability. Crawler-mounted crane is highly manoeuverable

andcanbeturnedvirtuallyaboutitsowncentre.

6.2.3 Truck-mountedorwheel-mountedcrane

Truck-mounted crane-acranewhichismountedonatruckorlorry

chassiswithorwithoutaspring suspension. Adrivingcabinisusually

providedonthetrucktodrivethecranefromonelocationtotheother.

Besides,thecranecanbeoperatedfromaseparatecontrolcabinorjustfrom the samedriving cabin. Inpractice, the craneand truckcanbe

operatedbyeitherasinglepowerunitorbyseparatepowerunits.

Whe el-mounted crane - a crane which is mounted on wheeled or

crawler-trackedchassis.Thecranecantravelunderitsownpower.A

crane cabin is usually provided for the crane driving and operation

purposes. Asinglepowerunitisprovidedforboththecranedrivingand

operationmodes.


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Thefollowingconditionsarerequiredforthesetypesofcrane:

(a) operationonhardorcompactedground;and

(b) goodaccesstotheoperatingareaisprovided. Inthisrespect,load

bearingcapacityofaccessroutesshouldbeproperlyassessed.

6.2.4 Ingeneral, local liftingoperationswouldusewheel-mountedorcrawler-

mountedcrane. While thoseinvolving considerable travelling between

sitesduringliftingoperationswouldusetruck-mountedcrane.

6.2.5 Telescopingjib

Itsoperationally-variablejiblengthcangreatlyfacilitatemanoeuvringand

placing the load in confined areas. The operational set-up andstripdowntimesof thiskindof jibsareshorten thanother type. However,

workingloadsatlongerradiiarelessthanthoseatcomparableradiiofa

lattice-constructionstrutjibandthemaximumlengthofthejibisrestricted

duetothejib'srelativeheavierweight(seealsoFig.2a).

6.2.6 Cantileverjib

Itwouldgivethegreatestclearanceunderthejibforhandlingbulkyloads

(seealsoFig.2b).

6.2.7 Strut-typejib

Itwouldprovidegreaterheightsofliftandmaximumoperatingradii,and

hencesuitableforlongrangeworkorhighlifts(seealsoFig.2c).

6.2.8 Fly-jib

Itwouldbesuitableforoperationsinvolvingthehandlingofrelativelylight

loadstoextremesofheightandoutreach(seealsoFig.2c).


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Fig.1 Typesofmountingformobilecranes

Truck driving cabin


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Fig.2 Typesofjibonmobilecranes(notrelativelyscaled)

Fig.2aTelescopingjib(hydraulic)

Fig.2bCantileverjib(lattice)

Fig.2cStrut-typejibandflyjib(lattice)


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7.MarkingsandDocumentation

7.1 Identif ication

7.1.1 The crane should have a permanent durable plate bearing the

manufacturer's name, machine model, serial number, year of

manufactureandweightoftheunitforidentificationpurpose.

7.1.2 Every major structural, electrical and mechanical component of the

machine should have a permanent durable plate bearing the

manufacturers' name, machine model number, serial number, year of

original sale by the manufacturer and weight of the unit. Besides,

identificationnumbersshouldbeclearlymarkedonall basicremovable

componentsandattachmentsofthemachine(suchascounterweights

etc.)toshowthattheybelongtothatmachine.Itisimportantthatthese

componentsshouldbeusedonlyonthatmachineoridenticalmodelsor

an equipment for which they were specifically intended by the

manufacturer.

7.2 Safeworkingloadcharts

7.2.1 The crane should have asubstantial/durable safeworking loadchart

which:

(a) has clearly legible characters in English and Chinese and figures

displayedinsidethecrane(Regulation11(1)oftheLALGR);and

(b) iseasilyvisibletothecraneoperator.

7.3 Instructionmanualsandlogbook

7.3.1 Manufacturersmanualscontainingallpertinentdatarelatingtooperation

andmaintenanceforthespecificmodelofcraneinusemustbeprovided

witheachmachine.


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7.3.2 The language used in the majority of the workforce in Hong Kong,

especiallyamong theshop-flooroperationsand themiddlesupervisory

staff, is Chinese. It is essential that all the written instructions, the

documentsandliteraturesgivenbythecranemanufacturersinrelationto

thesafeuseofthecranes(suchastheloadcharts),ifnotinChinese,be

translated into Chinese so that the operatives have no difficulty in

understanding them. Suitable arrangement should also be made to

enhance communication in workplace where people would use

languagesotherthanChineseorEnglish.

7.3.3 If the equipment is not supplied with a logbook then one should be

started,maintainedand keptonthe worksite for the regular,periodic

recording of all inspections, tests, repairs, maintenance, and hours ofservicerelatedtothemachine.Allentriesshouldbedatedandsigned

by the operator, repairman and supervisor. The crane owner should

ensurethatthelogbookremainswiththecraneandiskeptup-to-date

throughouttheworkinglifeofthecrane(seesection14).


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8.OperationalFeaturesofMobileCranes

8.1 Automaticsafeloadindicator

8.1.1 Alltypesofcrane,exceptthosewithamaximumsafeworkingloadof1

tonneorlessorthoseoperatewithagraborbyelectromagneticmeans,

shallbefittedwithanautomaticsafeloadindicator(Regulation7Bofthe

LALGR). The automatic safe load indicator is usually used in

association with overloading cut-out. The specification of automatic

safeloadindicatorshouldconformtoBritishStandard7262orequivalent

standards.

8.2 Brakes

8.2.1 Brakes should be automatically applied if there is a loss of power or

pressure. Theycannot bereleased until the restorationof powerand

onlywhendeliberatelyreleased.

8.2.2 Fail-safebrakesshouldbeprovidedsothatitwillappliedautomaticallyto

preventanyfreefallofthehookorloadwheneverthehookorloadis

notinapowerraisingorpowerloweringcondition.

8.2.3 Swingbrakesshouldconsistofafail-safemechanicalunitcapableofnot

onlystoppingtheswingwithfullloadbutalsoholdingthefulljib/boomin

windsofupto50kilometresperhour.

8.2.4 Besides, a positive swing lock or house lock designed to prevent

accidentalengagementordisengagementshouldbeprovided.

8.2.5 Forwheel-mountedcranes:

Thefail-safebrakesprovidedshouldbeabletobringthecranetoastop

onlevelgroundwithinadistanceof9.6mfromaspeedof25kilometres

per hour, and hold it stationary on the maximum grade for travel

recommendedbythemanufacturer.


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8.2.6 Forallmobilecranesotherthanwheel-mountedcranes:

Fail-safebrakesshouldbeprovidedtoholdthecranestationaryunder

normal working conditions, and on the maximum grade for travel

recommendedbythemanufacturer.

8.3 Cabinsforoperators

8.3.1 Theoperatingcabinattachedtothestructureofthemobilecraneshould

meetthefollowingrequirements:

(a) be designed and constructed to protect the operator and the

controlsfromtheweather(Regulation10(1)ofLALGR);

(b) beprovidedwitharoofofadequatestrengthtoprotecttheoperator

fromfallingobjects;

(c) beproperlyventilatedbyartificialmeanswherenecessary;

(d) befittedwitha locktopreventunauthorizedentrywhentheunitis

leftunattended,unlessthecontrolunitcanbeseparatelylocked;

(e) beconstructedtogivetheoperatoraclearandunrestrictedviewthat

willenablehimtousethecranesafely(Regulation10(1)ofLALGR);

(f) haveasafeaccesstoandegressfromthecabin. Themeansof

access to the cabinshould ensurethat thereisno dangerof the

operatorbeingtrappedinthecabin;

(g) haveguardrailsprovided onall outsideand accessplatforms (see

Regulation38B(1)oftheCSSR,Regulation24oftheFIUR);

(h) havehandholdsandstepstofacilitateentrancetoandexitfromthe

cabin;and

(i) Allwalkingsurfacesonthecraneshouldbeofanti-skidtype.

8.4 Operatingcontrols

8.4.1 Allcontrolsmustbelocatedwithineasyreachoftheoperatorandallow

himample room foroperation. The controls should be of dead man

switchesinthattheyreturntoneutralautomaticallywhenreleased. Themainpowerswitchshouldbelockableandlocatedwithineasyreachof


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theoperator. Eachcontrolmustbeclearlylabelledandmarkedtoshow

the motion and the direction of movement that it controls. Where

practicable,controlsshouldbearrangedsothataccidentaldisplacement

ispreventedandinadvertentpressureonthemdoesnotcausethecrane

tobesetintomotion.

8.5 Jib/boomstops

8.5.1 Jib/boomstopsshouldbeprovidedtopreventthejib/boomfromtoppling

orbeingpulledbackwardsoverthetopofthecabin. Thestopsshould

disengage the master clutch and physically stop the jib/boom as it

reachesapredeterminedmaximumangle.

8.6 Guardsandprotectivestructures

8.6.1 Allexposedmovingpartsofamobilecranesuchasgears,pulleys,belts,

chains,shafts, flywheels,etc. which might constitutea hazard under

normaloperatingconditionsshallbeeffectivelyguarded(seeRegulation

5oftheGOMR).

8.7 Outriggers

8.7.1 Outriggers should be capable of being securely held in the retracted

positionwhiletravelling.

8.7.2 Theyshouldalsobesecurelyheldintheextendedpositionwhenblocked

forhoisting.

8.7.3 Ifpoweractuatedjacksareused,theyshouldneverlosepressureorleak

whileunderload.

8.7.4 Theoutriggerbeamsshouldbemarkedorpaintedinamannertoindicate

thefullyextendedposition.


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8.8 Drumassemblies

8.8.1 Thedrumassembliesshouldhaveadequatepower.

8.8.2 Indicatorsfordrumrotationshouldbeprovided.

8.8.3 Ropeshouldbecorrectlyinstalledondrum.

8.9 Sheaves

8.9.1 Groovesshouldbesmoothandslightlylargerthantheropetopreventit

frombeingpinchedorjammedinthegroove.

8.9.2 Jib/boomhoistingsheavesshouldhavepitchdiameterofnotlessthan15

timesthenominaldiameteroftheropeused.

8.9.3 Load hoisting sheaves should have pitch diameters not less than 18

timesthenominaldiameteroftheropeused,andtheloadblocksheaves

should also have pitch diameters not less than 16 times the nominal

diameteroftheropeused.

8.9.4 Depthofsheavegroovesshouldbeatleast1.5timestheropediameter,

andthetaperedsidewallsofthegroovesshouldnotmakeanangleof

morethan18degreeswithrespecttothecentreline.

8.9.5 Bearingsshouldbepermanentlylubricatedor beequippedwithmeans

forlubrication.

8.9.6 Sheaveshouldbeequippedwithcablekeepersorclosefittingguardsto

preventtheropefromleavingthegroove.

8.10 Other safetyfeatures

8.10.1 Thefollowingsshouldbeprovidedtomobilecranesforthesakeofsafe

operation:


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(a) Fuel tanks should be equipped with self-closing filler caps and

flamearrestors.

(b) A metal receptacle for storing tools and lubricatingequipment

shouldbeprovidedandsecuredpermanentlyonthecrane.

(c) For night operation if required, adequate lighting and back-up

lightsshouldbeinstalledonthecrane.

(d) For wheel-mounted crane, wheelchocks should beprovided to

blockmovementonslopeswhenthecraneisleftunattendedor

undergoingrepair/maintenance.

(e) Rear view mirrors of each at least 625 cm2 in area should be

equippedonbothsidesofcrane.

(f) A suitable fire extinguisher should be installed and properly

maintained.

(g) Jib/boomangleindicatorsshouldbeinstalledforjib/boomwhichis

capableofmovingintheverticalplane.Theindicatorshouldbe

clearlyvisibleandreadablebytheoperatorathiscontrolstationto

thenearestdegree.

(h) For telescopic jib/boom, jib/boom length indicator should beprovided andclearly visible and readableby the operatorathis

controlstation.

(i) With the exception of the telescopic jib/boom, shock absorbing

jib/boomstopsandjib/boomsafetyshutoffsshouldbeprovided.

(j) Motionlimitdevices:Thesedevicesshouldbefittedtolimithoisting,

derricking, travelling, slewing or any other crane motion. For

example, automatic device should be installed to stop jib/boom

drum motion when the maximum permissible jib/boom angle is

reached.

(k) Overloadcut-outdevices,ifprovided,shouldcutoutcranemotions

whenthe crane is inanoverload situation. Thisshouldnotbe

achievedbystoppingtheprimemover. Only motions,thatpermit

thecranetoreturn toasafecondition,should remain operative.

Besides,theoverloadcut-outdeviceshouldbeeitheroffail-safe

designorprotectedfromdamagebyexcessiveoverloading.


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(l) Aspiritlevelforlevellingtheoutriggersshouldbeprovidedatthe

outriggercontrols.

(m) Acarpenter'slevelshouldbeequippedatthemachinedsurfaces

ontherevolvingdeckwhichareparalleltothejib/boomfootpinsinthehorizontalplaneforfinalprecisionlevellingofthecrane.

(n) Aplateshouldbeinstalledinthevicinityofthejib/boomfootpins

whichcanclearlyshowthedistanceofawelldefinedpointfrom

thecentreofrotation.


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9.SitingofMobileCranes

9.1 General

9.1.1 Insitingamobilecraneforoperation,particularattentionshouldbepaid

to two factors: the crane standing or support conditions and the

presenceofproximityhazards. Considerationshouldalso begiven to

the projection of the mobile cranebeyond the site boundary to avoid

potentialhazardstothepublicincludingthoseinprivateareasandpublic

areas.

9.2 Cranestandingorsupportingconditions

9.2.1 Mobilecranesshouldonlybeoperatedonuniform,levelandfirmground

withsufficientloadbearingcapacitytowithstandthemaximumin-service

loadings of the crane. It should be noted that wind loadings and

dynamiceffectshouldalsobetakenintoaccount.

9.2.2 Forthewindeffectonstructureofmobilecranes,referencecanbemade

to theCode of Practice on Wind EffectsHong Kong 1983. Crane

manufacturersdatarelatingtothedeadweightofthemobilecraneand

the dynamic forces, which can occur during operation of the crane,

should always be obtained for determining the maximum in-service

loadings.

9.2.3 Incalculatingthemaximumbearingpressuresofthecraneontheground

orsupportingsurface,itisincorrecttoassumeanaveragevalueequaltototalweightdividedbythegroundcontactareabecausethemaximum

valueswouldgenerallybefarinexcessofthisaveragebearingpressure.

9.2.4 Inordertoavoidthesinkageorcollapseofthesupportingsurfaceand

overturningorcollapseof the crane, the loadingshouldbedistributed

over a sufficiently large area. Steel plates of adequate strength,

suitablematsorsuitabletimberblockingshouldthereforebeused.

9.2.5 Ifoutriggersareprovided,thebeamsshouldbefullyextendedasfaras


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practicable (Fig.3). The jacks shouldbe suitably extendedso thatall

thecranetyresareclearoftheground.

9.2.6 Some mobile cranes can lift loadswith partially extended outriggers.

However,useofpartiallyextendedoutriggersshouldbeavoidedasfaras

practicablebecausethestability of the cranemay begreatly reduced.

Where the use of partially extended outriggers cannot be avoided, it

shouldbecarefullyplannedandcontrolledbytheresponsibleperson.

9.2.7 Itshouldbenotedthatpartialandfullextensionofoutriggersshouldnot

beusedsimultaneously. Outriggerbeamsshouldalsonotbesetatany

other intermediate points apart from the designated partial or full

extensionposition.

9.2.8 Thematortimberblockingshouldbeatleast3timeslargerinareathan

thefloat (unlessasmallerarea isspecifiedby the manufacturer) and

completelysupport the float. For timber blocking, it should be tightly

spacedand level toguaranteea rightangle (90degrees)betweenthe

cylinderandthefloatoftheoutrigger.

Fig.3 Typicaltruck-mountedcraneshownwithoutriggersset


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9.2.9 Advice should be sought from the manufacturers regarding the

particulardataand informationonweightsand loadingsof thecrane.

Besides, thesupportingsurfaceshouldbe frequentlyexaminedduring

theoperationtoensure thattherehasbeennomovementorsinkage

affectingthecrane'sstability.

9.2.10 Theoverallstabilityandsafetyofacraneshouldbecarefullycheckedin

relationto localconditionsand particularly when the cranehas tobe

operated on bridge decks, partially completed building frames, other

structuralsupports,orclosetoexcavationsandembankments.

9.2.11 When operating close to the edge of a slope or an unsupported

excavation,amobilecranemaycollapseasthe loadbearingcapacitythereismuchlowerthanthoseawayfromtheedge.Asafetydistance

atleast4timesthewidthofthefoundation(thematortimberblocking

oftheoutriggerorthecrawler)shouldthereforebemaintainedbetween

thefoundationandtheedge(seeFig.4).Thedistancebetweenthe

foundationandthetoeoftheslopeorexcavationshouldalsobeatleast

2timesthedepthoftheslopeorexcavation.

9.2.12 Beforeamobilecraneisputintooperationinalandfilling,reclamationordemolition site, a thorough investigationon the ground conditions

shouldbeconductedtoensurethatthecranewillnotbepositionedin

areaswhichhaveinsufficientloadbearingcapacity.

9.3 Proximityhazards

9.3.1 Considerationshouldbegiventotheproximityhazardssuchasoverhead

electric lines and conductors, power cables, radio frequency wave

transmitting tower, nearby structure and building, hoists, stacked

materials,otherconstructionworks,theflightpathsofairfields,theroute

of aerial ropeway and other cranes, public access areas including

highwaysandrailways,etc.


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Fig.4 Positionofmobilecrane

9.3.2 Asfaraspossiblemobilecranesshouldbesited to avoid loads being

handledoveroccupiedpremises,highways,therouteofaerialropeway,

other construction works, or railways. The danger to or from

undergroundservices,suchasgasmainsorelectriccables,shouldnot

beoverlooked.Precautionsshouldbetakentoensurethatthemobile

cranestandingisclearofanyundergroundservices. Wherethisisnot

possible, the services should be adequately protected to safeguard

againstanydamage.


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9.3.3 Overheadelectriclinesandcables

9.3.3.1 Fatalaccidentsmayoccurwhenacranecomes intocontactwithor

neartooverheadelectriclinesorcables.Whereamobilecranehasa

chanceofcomingclosetoanyliveoverheadelectriclinesorcables,the

craneownershouldliaisewithownersoftheoverheadlines,e.g.the

power companies, to work out the exact safety requirements and

devise the safe work plans. Reference should be made to the

Electricity Supply Lines (Protection) Regulation (Cap. 406 sub. leg.)

and the Code of Practice on Working near Electricity Supply Lines

issuedbytheElectricalandMechanicalServicesDepartment.

9.3.3.2 Alloverheadlinesorotherelectricapparatusshouldbetreatedasliveunlessdeclareddeadandsafebytherelevantauthority.

9.3.3.3 Anypersonworkinginthevicinityofanyelectricitysupplylineshouldbe

properlytrainedtoensurethattheyarecapableoftakingnecessary

safetymeasuresandsafesystemofwork.

9.3.3.4 Whenworking paralleltooverheadpowercables,astringofwarning

markersshouldbeerectedatasafedistancefromthecables.Thestringshouldbesupportedonpostsatconvenientintervalsandeach

postshouldcarrythewarningnoticestating:

DANGER!OVERHEADELECTRICLINES!

u MI ! [ qu ! v

9.3.3.5 Acraneshouldnotbeoperatedinthevicinityofoverheadelectriclines

unless guided by an experienced slinger or signaller. The crane

operator should always try to keep theoverhead lines in view whenmaneuvering the crane. It is worthwhile to note the difficulty to

estimatetheheightsordistancesof the linesbynormalmethodsof

observation.

9.3.3.6 Whereacranemusttravelunderneathanoverheadline,thecrossing

routeshouldbeplainlymarkedandgoalpostserectedeachsideof

the crossing approach to ensure that the jib or moving parts are

loweredtoasafeposition(seeFig.5).


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Fig.5Travellingunderoverheadelectriclinesandcables

9.3.3.7 Thedimensionsofthegoalpostsandtheirdistancesfromthenearest

powercablearetobedecidedinconsultationwiththeEMSDandthe

relevant electric power company. Large notices in English and

Chineseshouldbepostedstating:

DANGER!OVERHEADELECTRICLINES!

u MI ! [ qu ! v

9.3.3.8 In the absence of this expert advice, a general safe rule for crane

operationsistopositionthemachinewithasafeclearancedistance

from the overhead lines. The distance should be larger than the

lengthofthecranejibfitted,plussixmetres(20feet)measuredalong

thegroundandtheplumbofthenearestlineorcable(seeFig.6). It

shouldbenotedthatincertaincasesofoverheadlineswithlongspans,

the line may swing laterally due to the wind. Allowanceshould be

madetomaintainthesafeclearancedistanceatalltimes.

9.3.3.9 The operator of the crane should operate under the direction of a

slinger or signaller who has a clear view of the crane and the

obstruction.

9.3.3.10 The slinger or signaller should be able to assess whether there isadequateheadroomandclearance.


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9.3.3.11 Thepointof the jiband the front and rearof the craneshould be

painted in a distinctive manner for visual sighting and warning

purposes.

Fig.6Overheadelectriclines

9.3.4 Proximityofothercranes

9.3.4.1 Whenconsideringthepositionofthecraneforoperation,careshould

beexercisedregardingtheproximityofothercranes,theoverlappingof

theworkingareasandthepossibilityofthehoistingropeorsuspended

load fouling the lower crane even though they are operating withdifferentjiblengthsoratdifferentlevels.

9.3.4.2 Craneshouldbesitedinsuchawaythattheoperatorhasaclearview

ofanyothercraneoperatinginthecollisiondangerarea.


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10.Erection,Dismantlingand Transportation

10.1 Generalprecautionsforerectionanddismantling

10.1.1 Accidentsmayoccurduringcraneerectionanddismantlingoperations

due to failure to follow the correctproceduresspecifiedbythe crane

manufacturers,useofincorrectparts,thewrongsizeortypeofbolt,the

incorrect assembly or sequence of assembly, or taking apart of

components. Toavoiddangerousand expensiveconsequences,the

followingpointsshouldbeobserved:

(a) It is essential that crane manufacturer's instructions should be

strictlyadheredto. Anydeparturesfromthespecifiedprocedures

mayimposeexcessiveloadingsonstructuralandmechanicalparts

leadingtoafailureorcollapseofthecrane.

(b) The erection or dismantling operation shall be supervisedby a

competentpersonofanerectioncrew whohavebeenadequatelytrainedandhaveexperienceoferecting/dismantlingtheparticular

typeofcraneinvolved(Regulation7HoftheLALGR).

(c) Fortheerection/dismantlingoperation,aroped-offareaisrequired

whichhasbeenclearofotherpersonnelnotinvolved andstacked

materials, etc. The area should be large enough to permit the

components to be stacked and handled, and the crane to be

erected/dismantledwithoutinterferingwithor riskingtheothersite

personnel. Sufficientareamustbesetasideforthemobilecrane

orother liftingappliance that will beused toerect/dismantle the

mobilecrane.Provisionsmustbemadeforgoodaccessfortrucks

delivering or taking away the components. Adequate lighting

shouldbeprovidedforalltheseworkingareas.

(d) All major components, particularly those that are load bearing,

shouldbeclearlymarked forproper identification. Bolts andnuts

manufacturedfromhightensilesteelorotherspecialsteelsshould


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also carry clear identification marks. The re-use of high tensile

bolts and nuts should be strictly in accordance with the

manufacturersspecificationsandinstructions.

(e) Allstructuralcomponentsshouldbe inspectedtoensuretheyare

freefromdamageordefects.

(f) Itisprohibitedtoimproviseortotryshort-cutsinhandlingthecrane.

Onlythecorrecttackleandtoolsshouldbeused.

(g) Acopyofthemanufacturersinstructionmanualfortheparticular

machine shouldbe carried atall timesonthe crane(thisshould

bear the manufacturer'smachine serial number and the owner'splantnumber).

(h) Assembliesshouldbeslungfromthepointsrecommendedbythe

manufacturerandinsuchawaythattheywillnotswingorbecome

unstableorsustaindamagewhenlifted.

(i) Erection/dismantlingstaffshouldbefullybriefedonandfamiliarwith

theprescribedprocedures.

(j) Approvalshouldbeobtained fromthecranemanufacturerbefore

anydepartureismadefromtheprescribedprocedures.

10.2 Foldingorhingingj ibs

10.2.1 Forjib whichcanbefoldeddown-and-underorhingedsideways, the

manufacturer'sinstructionsshouldbefollowedwhenthejibissetting

upforoperationsorperformingjibfoldingoperations.

10.2.2 Itshouldbeensuredthatthejibisrestrainedbythehoistropeorother

specifiedmeanstopreventitfromswinginguncontrollablyonrelease

fromitsstowedpositionorwhenpinsareremovedforfolding.

10.2.3 Integralpinnedfolding-hingesshouldbeprovidedinthejibsections.


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10.2.4 Beforeerectionoftheassembledjib,anygateorhingesectionshould

bepositionedorremovedinthemannerspecifiedbythemanufacturer.

10.3 Jibassembly

10.3.1 The followings should be noted for jibs which are designed to be

extendedbytheadditionofintermediatesectionsintothebasicjib:

(a) Onlycorrectsectionsfortheparticularcraneshouldbeused.

(b) The sections should be in good conditions and free of bent

bracings/mainchords,brokenwelds,etc.

(c) Jiblengthshouldbemadeupofminimumnumberofintermediate

sectionsaccordingtothemanufacturer'sspecifications.

(d) sections should be assembled in the correct manner and

sequence as specified in the manufacturer's instructions and

procedures,andthatthebracingpatterncontinuityismaintained

throughoutthejiblength.

(e) certaindesignsofjibemployingpinconnectionsinsteadofbolted

jointsto linkjibsectionstogether,thejibshouldbesupportedatthe appropriate sections according to the manufacturer's

instructions. Allpersonnelshouldneverworkorpassunderneath

ajibduringthisoperation. Besides,allthejibsectionpinsshould

preferablybeinsertedfromtheinsideofthejibpointingoutwards.

Alsothesuspensionropesor tiesshouldnotfoulthelockingpins

orclipsofthepinconnectionswhenthe jib isbeingraisedfrom

groundlevel,andallthelockingpinsorspringclipsshouldbein

goodconditionandoffereffectivesecurityofthejibsectionpins.

(f) Otherthanmanufacturersinstruction,whenextendingthelength

of a strut jib no attempt should be made to lift the jib on the

suspension.Shouldthispracticebeunavoidable,thesuspension

ropeshouldattachtotheextremityofthepart-assembledorfully-

assembledjib.


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(g) Whenafly-jibistobefitted,theangleand/orlengthofsuspension

tiesbetweenthefly-jibandthemainjibshouldbeinaccordance

with the manufacturer's recommendations. Also, the safety

ropes or arrestors should be installed to prevent backwards

instabilityofthefly-jib.

10.4 Jibsuspension(seeFig.7)

10.4.1 Correct lengthof derricking rope andties shouldbe used for the jib

fittedaccordingtothemanufacturer'sinstructions.

10.4.2 Longerjibsmayrequirespecialorauxiliarysuspensionequipmentsuchasahighgantry,mast, intermediatesuspension,etc. Checkshould

bemade for themaximumlengthofjibwhichcanbe raisedwiththe

craneasspecifiedbythemanufacturer.

10.5 Loadhoistrope

10.5.1 Theropesystemshouldbestrongenoughtohandlethemaximumloadrequired to be liftedon a jib, and the rope is of sufficient length to

performtheloadliftingorloweringoperation.

10.5.2 Correcttypeandlengthofhoistropeasspecifiedbythemanufacturer

shouldbefitted.ThesteelropeshouldbemadetoBS302:Stranded

SteelWireRopesorequivalentnationalstandards.

10.5.3 The number of falls of hoist rope according to the jib length or

maximum load to be fitted should be the same as required by the

manufacturer.

10.5.4 Forthecaseofanautomaticsafeloadindicatorinstalled,theindicator

camand/orsettingshouldcorrespondwiththejiblengthfittedandthe

numberoffallsofthehoistropeused.


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Fig.7Typicalropeandsuspensionsystemsonmobilecranes


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10.5.5 Notlessthantwocoilsshouldalwaysremainonthedrumandthedrum

capacityshouldnotbeexceeded.

10.5.6 Reference should be made to the rope manufacturer's manual or

craneinstructionmanualfordetailsregardingtheropeexamination.

10.6 Safetydevices

10.6.1 Before thecraneisputintouse,acheckshouldbemadetoensure

that all disconnected or by-passed safety devices such as load

indicator,overloadcut-outormotion limitswitch,etc.during previous

erection or dismantling operations have been reconnected and arefunctioningproperly.

10.6.2 Adjustment should be made to the visual load-radius indicatorand

automaticsafeloadindicatoreachtimewhenthecraneconditionor

front-endequipmentisvaried. Forexample,suchvariationwouldbe

for changes in jib length, fly-jib length, falls of hoist rope (main or

auxiliary),angleoffly-jiboff-set,andalsobetweenmobile(ontyres)and

withoutriggerssetoperations.

10.7 Cranestability,erectionanddismantlingprocedures

10.7.1 Thecorrectamountofcounterweightshouldbefittedonthecraneand

at the appropriate location as specified by the manufacturer's

counterweightchartpriortoelevateajib.

10.7.2 When additional counterweight for longer booms/jibs are fitted, it

shouldberemovediftheoperatinglengthofjibisrestoredtooriginal

length.

10.7.3 Erectingorloweringoflongjibsshouldbeperformedwiththejibaxisin

the longitudinal axis of the mounting, i.e. in the position offering

greatestmachinestability. Besides, forthecaseofcrawler-mounted

craneoperatingonahardconcretesurface,woodenpackersshould

beplacedundertheendsofthecrawlertrackstoreducethetendency


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forthemachinetorockduringtheloweringoflongjibtotheground.

10.7.4 Appropriateprecautionsincludingthere-settingofauxiliaryoutriggers

shouldbetakenpriortotheloweringoflongjibstotheground.

10.7.5 Thehookblockshouldbe loweredandrestedon thegroundbefore

loweringthejibtogroundlevelinordertomaintainthebestmarginof

stability.

10.8 Tyres

10.8.1 Forwheel-mountedcranes including the truck-mountedcraneswhich

arefittedwithpneumatictyres,checkshouldbemadetoensuretheconditionsofthetyresandthattheyareinflatedtotherecommended

pressurepriortoanyliftingoperation.

10.8.2 Any replacement tyres fitted should conform to the manufacturer's

specificationregardingthesize,constructionandrating.

10.9 Travellingandtransportationofmobilecrane10.9.1 Sitetravellingwithlongjibfitted:

(a) When it is necessary to travel long jib crane which has been

assembledanderectedataremotelocationtotheplaceofwork,

itshouldbehandledwithgreatcareandundersupervisionofa

competentperson.

(b) Thegroundtobetraversedshouldbefirmandlevel.

(c) Theoperationshouldbeperformedatcreepspeedswiththejibin

linewiththedirectionoftravelandwiththeslewinglocksand/or

swingbrakeengaged.

10.9.2 Loadingcranesfortransportation

(a) Whenloadingandoff-loadingcrawler-mountedcranesandwheel-

mountedcranes onto the transporter, careshould beexercised

whennegotiatingtheshortestanddeceptivelysteeprampsontothevehicletoensurethatthecranedoesnottipoverbackwards.


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(b) The specified maximum gradient for stability of the crane as

equippedfortransportationshouldnotbeexceeded.

10.9.3 Securityofcranefortransportation

(a) Incasethatthemobilecraneistransportedbyroad,itshouldbe

stowedonandsecurelyattachedtothecarryingvehiclesoasto

preventanymovementofcrane,oranypartofitoritsequipment

duringtransit.

(b) Additionally, themanufacturer'sinstructionsor recommendations

for crane transportation should be followed regarding the

restrictionsinjiblength,jibsuspensionandcounterweights.

10.9.4 Generalprecautionstobetakenwhentransportingcranes

(a) Asuitabletransportingvehicleofadequate loadingcapacityand

beddimensionstoaccommodatethecraneshouldbeemployed.

(b) Thecrane'soperationalbrakesandwhenfitted,propelordigging

locksshouldbeengagedandthecraneshouldbefullychocked

againstallmovement.

(c) Thecraneshouldbesecurelylashedtothevehicletopreventthe

cranefrombouncing,tippingorslidingoffthebed.

(d) Theupperworksshouldbecross-chainedagainstpossiblerotation

inaddition tosettingtheswingbrakeand/or slewing lockofthe

slewingcrane.

(e) Hookblockandanyotherlooseitemsshouldbesecurelylashed

topreventanymovementduringtransit.

(f) Forthecaseoftruckcrane,theoutriggerbeamsandfeetshouldbe securely stowed and fastened in position to prevent any

movementduringtransit.

(g) It should be noted that the statutory requirements on the

movementofcranesonroadsundertheRoadTrafficOrdinance,

Cap.374shallalsobecompliedwith.


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11.ProceduresandPrecautions

11.1 Suspensionofload

11.1.1 Noloadisallowedtobeleftsuspendedunlessacompetentpersonis

inchargeofthecraneduringtheperiodofsuspension(Regulation12A

oftheLALGR)andtheoperatorshouldremaininthedrivingposition.

Themachineshouldbefullyoperationaltomeetanyemergencyarising

andwiththehoistbrakelock,theboomderrickingsafetypawlandthe

swinglock/brake,wherefitted,allengaged. Undernocircumstances

shouldthecranebeleftunattendedwiththeloadsuspended.

11.2 Leavingthecraneunattendedforashortperiod

11.2.1 Amobile craneshouldnotbe leftunattendedeven forshortperiods

unlessthefollowingprecautionsareadopted:

(a) Theloadshouldberemovedfromthehook.

(b) Thehookshouldberaisedtoahighpositionatwhichitwouldbe

safelyclearofotheroperations.

(c) The engineofcraneshould bestoppedand appropriatemotion

brakes and locks including those preventing rotation of the

upperworks have been applied to put the machine in a safe

condition.

(d) Theignitionkeyandanyotherkeysshouldberemovedfromthe

craneandkeptbytheoperator.(e) Fordetailsof methods to safeguardparticular types of cranes,

referenceshouldbemadetothecranemanufacturersinstruction

book.


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11.3 Leaving the crane unattended for a long period oftime

11.3.1 For longer periods and for out-of-service conditions, the following

precautionsshouldbeadopted:

(a) Isolation should be more permanent, e.g. switches should be

locked off, fuel suppliescut off and any doorsgiving access to

machinery or control cabins should be locked to prevent

unauthorizedaccess.

(b) The jib should be secured or lowered according to the

manufacturer'sinstructionsforout-of-serviceconditions.

(c) Ifit isnotpossible tolower the jibdue tospacerestrictions, the

hookblockshouldbeloweredneartogroundlevelandsecuredto

asubstantialanchorageverticallybelowthejibpoint.

(d) Theignitionkeyandanyotherkeysshouldberemovedfromthe

crane.

(e) For detailsof methods to safeguard particular types of cranes,

referenceshouldbemadetothecranemanufacturer'sinstruction

book.

11.4 RoutineChecks

11.4.1 At the beginning of each shift or working day, the operator, if

competent for thepurpose,or acompetentperson,shouldcarryout

thefollowingroutinechecks,asappropriate:

(a) checksasrequiredbythemanufacturersinstructions;

(b) checkthattheautomaticsafeloadindicatoriscorrectlysetand/or

fittedwiththecorrectjiblength(orjibandfly-jiblengths)andfalls

ofhoistrope;

(c) checkthatthecorrect load-radiusscaleappropriatetothejib(or

fly-jib)lengthisfittedonthevisualindicator;

(d) checkthelevellingofthecranetoconfirmthattherehasbeenno

change in the original levelling, no sinking of outrigger feet orsettlingofthefoundation;


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(e) checkthesecurityofthecounterweightorballastwherethisisin

the form of removable weights, check that the weights fitted

correctlycorrespondtothoseshownonthecounterweightchart

fortheoperatingcondition[Note:Wherethestabilityofacraneis

secured by means of removable weights, a diagramor notice

indicatingthepositionandamountoftheweightsshallbeaffixed

tothecraneinaplacewhereitcaneasilybeseen(Regulation7F

oftheLALGR);

(f) checktheoillevel(s),fuellevelandlubrication;

(g) checkhookforsignsofcracksandwear;

(h) checklooseningofpins,boltsandnuts;

(i) check the ropes, and rope terminal fittings andanchorages for

obviousdamageandwear;

(j) check the condition and inflation pressure(s) of tyres (where

applicable);

(k) checkthatallwaterisdrainedfromanyairreceivers;

(l) checkthejibstructurefordamage;

(m)checktheoperatingpressuresinanyairand/orhydraulicsystem(s);

(n) checkleakageofbrakefluidandhydraulicoil;

(o) check the operation of the crane through all motions with

particularattentiontobrakes toensure that theseareoperating

efficiently;

(p) checktheoperationofalllimitswitchesorcut-outs(usecautionin

makingthechecksincaseofnon-operation);

(q) checktheoperatingpressuresinanyairand/orhydraulicsystem(s);

(r) checkleakageofbrakefluidandhydraulicoil;and

(s) forsafetyandtopreventtheriskoffire,thecranecabinisinatidy

state,isfreefromtinsofgreaseandoilorotherfluids;fromrags,

tools,shackles,andothermaterials,andthata fireextinguisher

suitableforextinguishingbothelectricalandothertypesoffireis

availableinaconvenientplaceinthecranecabin.

11.4.2 Atleastonceaweekafullinspectionofthecraneshallbecarriedout

byacompetentperson.Apartfromthoseitemscoveredinthedaily


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inspection,attentionsshouldalsobepaidtoallanchorages,fixingand

structural members. The check should include identifying of

significantcracksandflakingofthepaintonstructuralmembersand

joints, which are usually signs of permanent deformation and loose

joints. Bolts should be checked for tightness and welded joints

inspected for cracks. Check the slewing rings, slewing gears and

gussetplatesinthemobileringforcracks.Thissectionofthecrane

takesthedirecttorsionloadofbrakingandaccelerationoftheslewing

motionswhichconstituteahighproportionofthecrane'sdutycycle;

further, the load is a cyclically reversing head, the worst possible

condition for producing fatigue failures. The competent person

shouldalsocheckforanyabnormalnoisewhilethecraneisinmotion

asthisisusuallythesignofcranedamage.

11.4.3 Use of "Check List" for carrying out the abovementioned routine

checks is recommended. A certificate in anapproved form stating

thatthemobilecraneisinsafeworkingordershallbesubmittedtothe

owner by the competent person when no defect was found in the

weeklyinspection.

11.4.4 Shouldthepersoncarryingoutaninspectionfindanydefect(such astwisted/brokenwires,etc.)orabnormalityinthe mobilecraneor inthe

operation of the mobile crane, or should the mobile crane be

accidentally damaged, this should be reported immediately to the

personresponsibleforthesafeuseofthemobilecrane. Themachine

shouldbetakenoutofserviceuntilthefaultshavebeenrectifiedand

clearanceisgivenbytheresponsibleperson.Sufficientspaceonthe

"CheckList"forreportingthedefectsarerecommended.


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11.5 Permittowork

11.5.1 Beforeanymajorrepairs,adjustmentsorinspectionsarecarriedouton

a crane, a proper system ofgranting permission towork should be

considered. Suchapermit toworksystemproperlyimplementedwill

ensure that thenecessaryprecautionsaretaken tomake thecrane

safeformaintenanceorrepairwork,etc.(e.g.byisolationandlock-off

ofelectricalequipment,removalofignitionkeys,etc.)andwillnotifyall

affectedpersonsthatthecranemaynotbeused.

11.5.2 A permit to work is a specially designed form issued only by a

responsibleperson. It indicates thatspecialprecautionshavebeen

taken to make it safe for work on the machine to proceed for aspecifiedperiodoftime. Theformshouldalsospecifyanyadditional

precautions which should be observed by persons carrying out the

work. Theresponsiblepersonshouldbethepersoninchargeofthe

site.

11.5.3 Most system requires that the person performing the work should

retainthepermitinhispossessionwhilecarryingoutthiswork. Where

several persons are involvedon thesame job, the permit should beheldbytheseniorperson(e.g.aforeman). Acommendablepractice

inthis respect isfor the permit tobe placed inaspeciallydesigned

carrier(e.g.weatherprooftransparentplasticjacket)anddisplayedina

prominentpositiononthecraneinvolved,suchasontheaccessdoor

oratthecraneoperator'sstation,toindicatethatmenareworkingon

themachine.

11.5.4 Whentheworkiscompleted,allpermitsshouldbereturnedtoandduly

endorsedbythepersonwhoissuedthembeforethecraneis`handed

over'fornormaluse. This procedure is as importantas the original

certification. Theresponsiblepersoninchargeshouldensurethatall

personswhoworkedunderthepermitareclearofthemachineorarea.

Heshouldalsoensureequipmentthatwas brought infor thework is

removed,allsafetyguardsonthecranearereplacedandthemachine

isinallrespectssafefornormaluse,subjecttotheconditionsspecified

insection14.


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11.6 Safemeansofaccess

11.6.1 Provisionshouldbemadeforsafeaccess to thecranecabinorany

other areas necessitating periodic maintenance, inspection, or

adjustmentpurposes.

11.6.2 Onlythecraneoperatorortheauthorizedpersonshouldbeallowedto

climbonthecraneinordertogainaccesstothecabinortocarryout

taskssuchasmaintenanceorinspection.


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12.SafeWorkingLoadsandOperating Conditions

12.1Modeofoperationandcontrol

12.1.1 Eachcranecontrolshallbeclearlyidentifiedtoindicateitspurposeand

themodeofoperation (Regulation16(2)(b) of the LALGR). When

practicable,thecranecontrolshallalsobeprovidedwithsuitablespring

or other locking arrangement to prevent accidental movement or

displacement(Regulation16(2)(a)oftheLALGR).

12.1.2 Beforestartinganyliftingoperationwithacrane,theoperatorshould

ensure:

(a) that he has a clear and unrestricted view of the load and

operationalarea;ifnot,heshouldactunderthedirectionsofan

authorized signallerwho is positionedtohavesuchaclearand

uninterruptedview;

(b) wheretelephoneorradiocommunicationsarebeingused,thatthe

calling signal is functioning and that verbal messages can be

clearlyheard;and

(c) that all gauges are reading correctly and that air or hydraulic

systemsareuptooperatingpressure.

12.1.3 Handlingofloadsnearpersons

12.1.3.1 When loadshave tobehandled in thevicinityofpersons,extremecareshouldbeexercisedandadequateclearancesallowed.

12.1.3.2 Liftingofloadsoverhighways,railways,orotherplacestowhichthe

publichaveaccessshouldbeavoided.

12.1.4 Slewing/travellingclearances

12.1.4.1 Adequateclearanceofatleast600mmshouldbeallowedbetween

anypartofacraneandthenearestobstructiontopreventtrappingof


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personnelwhenthecraneisslewedorstartsthetravellingmotion.

12.1.4.2 Whereitisnotpracticabletomaintainsuchclearanceorwhereonly

limited slewingor travelling motionof the craneispossible, special

precautionsshouldbetakentoavoidatrappinghazard:

(a) Personnel should not be allowed to approach near a crane

whenitisoperatingortravellingasthereisadangerofbeing

struckortrappedbetweenfixedandmovingpartsofthecrane.

(b) 'KeepClear 'noticesinEnglishandChinesewhich

are visible from the sides and rearof the machineshouldbe

paintedontheslewingupperworks.

(c) Forsafetyawarenesspurpose,thecounterweightorrear-endof

thecraneshouldbepainteddistinctively.

(d) AfurthernoticeinEnglishandChineseshouldalsobedisplayed

onthecranetotheeffect:

'NOPERSONISALLOWEDACCESSTOANYPARTOF

THE CRANE WITHOUT THE PERMISSION OF THE

OPERATOR

S rp \i, Hh iJ_ '.

12.2 Safeworkingloads

12.2.1 The safe working load of a crane is defined in the LALGR as the

appropriatesafeworking loadforoperatingthecrane asspecifiedin

thecurrentcertificateoftestandthoroughexaminationdeliveredinthe

approved form by a competent examiner in respect of that crane(Regulation 3(1) of the LALGR). In other words, the safe working

loadisthemaximumloadunderspecifiedconditionsforwhichacrane

maybeused.

12.2.2 Thesafeworkingloadofamobilecraneisthehookloadspecifiedfora

givenradius,withtheappropriateropereevingandlengthofjib,and

withthecranestandingonafirm,levelbase. Inassessingtheweight

oftheusefulload,allowanceshouldthereforebemadefortheweightof slings or other tackle used to attach the load to the hook.


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Considerationshouldalsoincludethedynamiceffectssuchasjerking

andimpact.

12.2.3 Safe working loadsaregenerallycalculated as apercentage of the

ultimateloadofacrane. Theultimateloadwillbethetippingloadfor

certaincranes.

12.2.4 But for others, a structural failure would occur before the crane

reachedatippingcondition,and,inthesecasestheultimateloadwill

relatetothemanufacturer'sdesigncapacityofthecrane.

12.2.5 Themarginbetweenthesafeworkingloadandtheultimateload isa

safetymargintoallowforthevariousforceswhichwillactonthecranein operation. These include allowances for wind loading and for

dynamicforcessetupbynormaloperationalmovementofthecrane

andload.

12.2.6 Mobilecranesandtheirassociatedliftinggearshallbeclearlymarked

withtheirsafeworkingloads. Meansofidentificationshallbeprovided

(Regulations11(2)and18oftheLALGR).

12.2.7 Safe working loads apply only to freely-suspended loads. Before

liftingaloadthehoistlineshouldbeplumb. Itisexpresslyforbidden

tousethecranehookorslewingmotionofa cranetodraganyload

along the ground, etc. Similarly, sideward pushing/pulling the load

whetherwithbarehandsorbychainblock/sorbysimilarequipment

should be discouraged. Failure to observe these points may

endangerthestabilityofthecraneorintroduceloadings(stresses)into

thejibforwhichithasnotbeendesignedfor. Evenwithanautomatic

safeloadindicatorfitted,astructuralfailuremayresultwithoutanyprior

warningbeinggiven.

12.2.8 Incaseamobilecraneisusedtodragaloadnotinaverticaldirection,

stepsshallbetakentoensurethatnounduestressisimposedonany

partofthestructureormechanismofthecranetherebyendangering

thestabilityofthecraneandsuchuseissupervisedbyacompetent

person(Regulation15(1)oftheLALGR).


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12.2.9 Reference should always be made to the crane manufacturer's

handbook of appropriate machine specification to establish the

restriction, limitations or special conditions applicable to a particular

crane.

12.2.10 Cranemanufacturerssafeworkingloadsmaybelimitedeitherby:

(a) stabilityofthecranewhichisafunctionoftheweightandweight-

distribution ofa craneand the physicalsize of the supporting

base;or

(b) thestructuralormechanicalstrengthofthecraneorcomponents,

i.e.thejib,machinery,ropes,etc.

Therefore,thepublishedsafeworkingloadsshouldnotbeexceeded

underanycircumstances.

12.2.11 Onlythecorrecttableofsafeworkingloadsappropriatetothedesign

capacityofthejib,thecounter-weightfittedandthespecificationof

themountingshouldbeused.

12.2.12 Duetothevariationsintheweightofthehookblocksandslingswhich

canbeusedonmobilecraneliftingoperations,theweightofthehook

blockand slings should beconsideredaspart of the safeworking

load.

12.2.13 Allowanceonthesafeworkingloadshouldbemadeaccordingtothe

manufacturer'sinstructionswhenauxiliaryequipmentsuchasfly-jibor

additionalliftingattachmentsareused.

12.2.14 Whenworkingatdepthsbelowgroundlevel,deductionsonthesafeworkingloadshouldalsobenecessaryfortheweightofhoistrope.

12.2.15 Workingatextremesorreachofsafeworkingloadshouldbeavoided

whereverpossible.

12.2.16 Thecraneshouldbepositionedinthemostfavourablepositionsoas

tooperatewithasshortajibaspossibleandatamid-radiusposition.


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12.2.17 The safe working load at any given radius generally varies with jib

lengthandanyextensioninjibwouldreducethesafeworkingload.

12.2.18 Derricking-out the jib to increase the radius of the load would

generallyresultinareducedliftingcapacity.

12.2.19 The load-radius dimension is the radius of the hook with the safe

workingloadsuspended,unlessotherwisespecified. Whenaloadis

picked-up,owingtothestretchofthe guyropesof loadedjiband/or

deflectionofthejibstructure,thehookradiuswillincrease. Withthe

approachofmaximumsafeworkingload,thisincreasemaytakethe

loadoutsidethepermittedradius. Before the lift is made, the jib

shouldbederricked-intobringtheloadbackintoradius,asnecessary(see Fig. 8). Conversely when settling down loads with the jib

positioned atsteepangles, itshould beensured that the jib isnot

damagedbycontactingtheclosedjibsafetybackstopsorbyextreme

tensioninginthejibguyropes. Suddensettling-downor releaseof

loadsshouldalwaysbeavoidedinordertopreventthejibspringing

backwardorthemachinebecomingunstableinabackwarddirection.

12.2.20 Fiercemovementsofanyoperationalcontrolevenwithoutaloadon

thehookshouldbeavoidedbecausethesecouldbedangerousand

damagingtothestructureormachineryofthecrane.

12.2.21 Forcranesfittedwithlongjibs (andparticularlyextendedtelescopic

jibs)at largeradii, the influence on overturningmoment due to the

weight anddynamiceffects of the jib itself would be very large by

comparison with that due to the suspended load. Therefore, the

operational controls such as the jib derricking control should be

operatedsensitivelyandsmoothly.

12.2.22 Zoneofoperationforcranes:

(a) Cranes would usuallybe restrictedto different duties over the

front,rear-endorsidesofthecrane.Theliftingormovementof

loadsoverthefrontofthecranemayoverloadthefrontaxle(s)or

chassis frameowingto the weight distribution of the machine.

Thesafeworkingloadapplicabletothezoneofoperationshould

beobserved.


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(b) In some instances, operation of the hydraulic cranes with

telescopicjibsshouldberestrictedtotheblockedconditionwith

outriggerssetand free-on-wheelsduty may not bepermissible

(seesub-section6.2.5).

(c) Reference should be made to the manufacturer's manual for

detailsofrestrictions.

Fig.8Influenceofropestretchonboardoperation


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12.2.23 Whereameansforlockingoutor reducing thespringeffectof the

suspension is used during crane operations for truck crane, the

manufacturer'sinstructionsshouldbefollowedinrespectofitsuse.

12.3 Nearmaximumworkingloads

12.3.1 Whenhandlingloadwhichapproachesthemaximumworkingloadfor

anoperatingradius,cranemotionsshouldbeoperatedwithextreme

care. The load should initially be lifted just clearof the supporting

surfaceandbroughttorestinorderfortheslings,balanceoftheload,

etc.,arecheckedbeforeproceedingfurther. Proper care should be

exercisedbytheoperator,atalltimes,toavoidshockorsideloadingsonthejib. Careshouldalsobetakentoavoidthehookcontactingthe

jibheadstructure,either throughoverhoistingorwhenderrickingout

thejib.Inthelattercase,asthejibisderrickedoutthehookshould

beloweredoffinordertomaintainanadequateclearancebetweenthe

hookandjibheadstructure.

12.3.2 The safety precautions regarding the operations near maximum

workingloadsareasfollows:

(a) The weight of the load should be ascertained as reliable as

possible,forexample,bytheuseofaprovingringorothermeans

beforeliftingtheload.

(b) Atrialliftshouldthenbemadetochecktheoperationalstabilityby

raising the load just clear of the ground and at a radius

correspondingtothemaximumradiusatwhichtheloadistobe

handled.

(c) The load should then be placed on the ground to check if

adjustments to the outriggers, slinging and radius are required

priortothefinallift.

(d) Theoperatorshouldexercisepropercaretoavoidshockorside

loadingsbeingimposedonthejib.

(e) Any automatic safe load indicator fitted should not be solely

depended upon and only be used as a check that the load is

withinthecapacityofthecrane.


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12.4 Travellingwithsuspendedloads

12.4.1 Safeworkingloadsappropriatetofree-on-wheelsormobileoperation

shouldnotbeexceededwhentravellingwithsuspendedloads.

12.4.2 Anyspecialrestrictions imposedby themanufacturershouldalsobe

followed.

12.4.3 Thejibshouldbepositionedinthelineoftravelofthemachine.

12.4.4 Theloadshouldbecarriedforwardforthefullviewoftheoperator in

caseofcrawler-mountedorwheel-mountedcranes.

12.4.5 Theloadshouldbecarriedattherearofthetruckinthecaseoftruck-

mounted cranes (see sub-section 12.2.22). The crane operator

shouldremaininthecranecabintocontroltheloadandasecondman

should be used to drive thevehicle. Besides, a further competent

personshouldco-ordinatetheoperationandwarnofhazards.

12.4.6 In general, travelling acceleration and braking motions should beoperatedgentlytolimittheswingoftheload.

12.4.7 Steady linesshouldbeattached to theloadwhichin turnshouldbe

carriedasneartothegroundaspossibletopreventpendulummotion.

12.4.8 Groundpreparation:

12.4.8.1 Thegroundtobetraversedshouldbepreparedtoensureafirmand

levelaccessrouteforthecranewherenecessary.

12.4.8.2 Toprevent thecrane tilting laterallyor in thedirectionof travelling,

grounddepressionsorpot-holesifanyshouldbefilled.

12.4.8.3 Matsorothersuitabletravellingsurfacesshouldbelaidwheresinkage

ofthewheelsorcrawlerscouldoccurinsoftground.


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12.4.9 Slopes:

12.4.9.1 Mobilecranes travellingwithsuspendedloadsshouldbeavoidedto

travelonslopeswhereverpossible.

12.4.9.2 If unavoidable, a competent person should be consulted for the

precautionsprior tothenegotiationand inattendancetoadviseon

the feasibility of the operation. The following points should be

particularlynoted:

(a) For safety sake, any crane used in the negotiation of slopes

shouldhaveagenerousmarginincapacityovertheloadstobe

lifted.

(b) Theloadshouldalwaysbecarriedontheuphillsideofthecrane,

irrespectiveofthetraveldirection.

(c) Theloadshouldalwaysbeplacedontheuphillsideofthecrane

and precautions takentoensure thatneither thejib nor crane

becomeunstableonreleaseoftheload.

(d) The load should always be carried as near to the groundas

possible.

(e) Theswingbrakeand/orslewinglockshouldbeengagedduring

thenegotiation.

(f) Noslewingshouldbeallowedexcepttomaintaintheloadinthe

uphilldirection.

(g) Before starting up a gradient by a crawler-mounted crane,

digginglocks,wherefitted,shouldbeengagedinthepositionto

prevent the crane from running backwards. The digging locks

shouldbeengagedagainwhenarrivingattheworkinglocationto

preventanymovementof thecrawlersbeforeshiftingtheclutch

fromtraveltoslew.

12.5 Carryingofpersonsbycrane

12.5.1 Acranecanonlybeusedtocarrypersonswheretheuseofabuilders

liftorasuspendedscaffoldisimpracticable. Thecarryingofpersons

byacraneissubjecttocertainstatutoryregulations. Requirementsinclude provisionofa properly designed safety chair,skip or cradle.


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Suitablemeasuresaretobetakentopreventsuchchair,skiporcradle

fromspinningortippinginamannerdangeroustoanyoccupant. Itis

recommendedthatpersonnelshouldnotbeloweredotherthanbyan

engine-power-controlled load-lowering mechanism. Theoccupantof

thechair,skiporcradleshouldwearasafetybeltsecuredtoasuitable

anchorage(Regulation18BoftheLALGR).

12.6 Communicationsystem

12.6.1 Intheinterestsofsafety,astandardsignallingcode(seeTable1)may

beadopted. Itisrecommendedthatcopiesofthesignalcodeshown

in Table 1 be issued to all crane operators, slingers and any otherpersonsconcerned.

12.6.2 In certain situations and where special lifts are involved, it may be

necessary to supplement the hand signals by other forms of

communicationsuchasradio,walkie-talkieortelephone.

12.6.3 Iftele-communicationequipmentsuchasradioorwalkie-talkieisused

in a multi-crane situation, suitable arrangement should be made toensurethattheradiofrequencyisnotinterruptedforwhateverreason

atanytimeduringthecraneoperationperiodandcorrectmessageis

receivedbypersonsusingsuchequipment.

12.7 Weather conditions

12.7.1 Cranesshallnotbeusedunderweatherconditionslikelytoendanger

itsstability.Beforeacraneistakenintouseafterexposuretoweather

conditionslikelytohaveaffectedthestabilityofthecrane,thecrane's

anchorageorballast,whereapplicable,shallbetestedbyacompetent

examiner(Regulation7GoftheLALGR).

12.7.2 Anyinstructionsissuedbythecranemanufacturersadvisingconditions

underwhichacraneshouldbetakenoutofserviceandrecommending

theconditionsinwhich itshouldbeplacedshouldbestrictly followed.

During adverse weather conditionssuch as rainstorm and lightning,


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adequate precautions should be taken to prevent personnel

associatedwiththeuseofthecranefrombeingendangered.

12.7.3 Cranes are generally designed to operate in conditions of normal

steadywindspeedandshouldnotbeoperatedinwindspeedsthatare

inexcessofthosespecifiedintheoperatinginstructionsforthecrane.

Gustywind conditions may haveanadverse effect onsafeworking

loadsandmachinestability. Eveninrelativelylightwindconditionsitis

prudent to avoid handling loads presenting large wind-catching

surfaces.Thelargesurfacesmightresultinlossofcontroloftheload

oroverturningofthecranedespitethedeadweightoftheloadbeing

withinthenormalworkingcapacityofthemachine.

12.7.4 Wherea load hasa largesurfacearea in relation to itsweight, for

examplealargetimbershutterorpanel,theactionofthewindorthe

load may give rise to unsafe working conditions in respect of the

strength or stability of the crane, or because the load cannot be

adequatelysecuredagainstswingingorspinning;withsomeloadsthis

canoccuratwindspeedsbelowthatspecifiedforin-serviceconditions.

Undersuchcircumstancesthesizeofthehookloadshouldbelimited

tothatwhichcanbesafelyhandledbythecraneandwhichwillnotcreateunsafeconditionsforoperatives.

12.7.5 Nameboardsorother itemspresentingawindcatchingareashould

notbefittedtothejibofamobilecranewithouttheexpressapprovalof

themanufacturer.

12.7.6 Before a lifting operation is started, information on wind conditions

shouldbeobtainedthroughtheweatherforecasttoensurethewind

speedlimitspecifiedbythemanufacturerisnotexceeded.

12.7.7 Anyliftingoperationshouldbestoppedandthemobilecraneshouldbe

securedinanappropriateout-of-serviceconditionwheneverthewind

speedlimitspecifiedbythemanufacturerisexceeded.

12.8 Mobilecranesforotherduties

12.8.1 General


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12.8.1.1 Mobilecranesshouldnotbeusedforgrabbing,magnetordemolition

ballservice,tandemlifting,pilingoperationsoranyotherdutieswhich

mightimposeexcessiveand/orindeterminateloadingsontothecrane

structureunlesspriorapprovalforsuchspecificoperationhasbeen

obtainedfromthemanufacturer.

12.8.1.2 Workingloadsareoftenrequiredtobereducedinaccordancewith

thedutyconditionsapplyingforamobilecranetobeusedforother

duties such as magnet or grabbing crane service. Manufacturer's

recommendationsshouldbestrictlyfollowedforeachspecificusage.

12.8.2 Demolitionballservice

12.8.2.1 Inthisservicearoundorpear-shapedweight,knownasademolition

ball,issuspendedfromthehoistropeofacraneandcausedtomove

tostrikethebuilding, structureorotherobject tobedemolishedso

thattheimpactcausescollapse.

12.8.2.2 Bythenatureofdemolitionballservice,dynamicloadingsareimposed

onthejibstructureandotherpartsofthecranebythemovementandimpact of the ball. In rating a machine for this service, special

attention should bepaid to the facts that the magnitude of these

dynamicloadingswillvarywidelyaccordingtothemethodofusingthe

demolitionball,theskilloftheoperatoratcontrollingtheballandthe

impact resistanceof the building being demolished. Lesserloads

and/or shorter jibs should therefore beadopted by the demolition

contractor.

12.8.3 PilingService

12.8.3.1 Piles are usually driven into the ground by meansof an impact or

reciprocating hammer. Bored-pile techniques, with or without

casings,mayalsobeusedwherebythepileiscastinitslocationby

pouringconcreteintoaholedrivenorboredintotheground. Piling

operations,onoccasions,aretowithdraworextractthepile(orpile

casing)oncetheirusefulpurposehasbeenserved.


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12.8.3.2 Pilingservicenecessitatestheuseofspecialequipment. Depending

onthetypeorsophisticationofpiling,thisequipmentmayeitherbein

thesimpleformofatemporaryattachmenttoacraneor,attheother

extreme, may form a permanent special-purpose installation on a

machine.

12.8.3.3 Forpile extraction,an extractor, which is usuallyofreciprocatingor

vibratorytype(andmaybeusedeitherfordriving-inorpulling-outpiles)

strikesthepileupwardsandloosensitsadhesionintheground. The

actualpulltowithdrawthepileisdonebythehoistlinefromwhichthe

extractorissuspended. Extractionshouldbeeffectedbyasmooth

pullonthe hoist lineand undernocircumstancesshould the hoist

ropebejerkedorthemachinetippedtoachievefasterresults.

12.8.3.4 Inassessingtherequiredcapacityofacraneforpileextractionduty,

inadditiontotheweightoftheextractorandpile,accountshouldbe

takenof the frictionalforcesoccurringbetweenthegroundand the

pileduringextraction. Inthecaseofsheetpileextractionafurther

allowanceisnecessaryforthefrictionbetweentheclutchesofthepile

beingextractedandtheadjacentpileremainingintheground.Asthe

frictional effects are largely unknown factors, until extractioncommences, the largestcraneonsite with amplesafetyallowance

availablewillalwaysgivethesafestandquickestresultsprovidingthe

pulldoesnotexceedtheextractorrating.

12.8.4 Grabbingandmagnetcraneservice

12.8.4.1 When usingcranes for specialduties such as grabbing or magnet

craneservice,allowanceshouldbemadenotonlyfortheweightof

thegrab,magnetorotherattachments,togetherwithload,butalso

for additional loadings imposed on the crane resulting from fast

slewing,grabsuctioneffects,impacts,etc. Ingeneral,forgrabbing

ormagnetcraneservicetheweightofthegrab andcontents,or the

weight of the magnet and loadwillbeless than the corresponding

safeworkingloadsforcraneservice. Referenceshouldbemadeto

themanufacturer'sspecificationfordetailsofspecialdutyratingsfor

anymachine.


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12.8.5 TandemLiftingbymobilecranes

12.8.5.1 Liftinga load with two cranes isa potentially dangerous operation

which should be avoided except where the physical dimensions,

characteristicsorweightoftheloadpreventthisbeinghandledbya

singlecrane. Therearestatutoryrequirementsgoverningthe lifting

operationinwhichmorethanonecraneisused(Regulation7Iofthe

LALGR). Tandemliftingrequiresextremelycarefulplanningandan

accurateassessmentoftheshareoftheloadwhichistobecarriedby

eachcrane. Thereshouldbeafullappreciationofhowandtowhat

extentthiscanvaryshouldtheloadcomeoutoflevelorshouldoneor

bothcraneshavetoderrick,travelorslew,resultinginthehoistropes

comingoutofplumb.

12.8.5.2 Ifanyofthesecircumstancesoccuranadditionalloadcanbethrown

oneitherorbothcraneswhichmayaffectcranestabilityorcausea

structuralcollapse.

12.8.5.3 Special lifting tackles may be also necessary to suit the maximum

variation in load distribution and direction of application which can

occurduringtandemlifting.

12.8.5.4 Alltandemliftingoperationsshouldbethoroughlyplannedinadvance

bya competentperson. Where possible cranes ofequal capacity

andsimilar characteristics should be used. The cranes and lifting

tackle to be used should be selected to have a capacity margin

greaterthanthatneededfortheproportionedloadwhenhandledas

asinglelift.

12.8.5.5 Acompetentpersonshouldbespeciallyappointedtosupervise the

operation,andthesignalstoeachcraneoperatorshouldbeclearand

wellrehearsed.


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12.8.6 Otherspecialusesofhydraulicallydrivenmobilecranes

12.8.6.1 InHongKong,hydraulicallydrivenmobilecraneswhichareoperated

withhydraulicpumpsandmotorsaresometimesusedindrivingother

machineries in foundation work. Beside lifting work, these cranes

candelivertheirpressurizedfluidtodriveotherhydraulicmachineries

suchasoscillatorsanddrillingmachines.Forthesafeoperationof

hydraulicallydrivenmobilecraneswhendrivingothermachineries,the

followinghazardsshouldbeobserved:

(a) burstingofhydraulichosesofmachinerycausing interruptionof

supplyoffluidtothecrane;

(b) decrease in stability of crane when attached with thesemachineries;

(c) increaseinbackpressurewhichmayaffectthesafetyofcrane;

and

(d) overheatingofhydraulicfluidduetoextraloading.


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13.Maintenance

13.1 Statutory requirements

13.1.1 Cranesshouldbeproperlymaintained(Regulation4(b)oftheLALGR).

Table2givesthelegalrequirementsundertheLALGRforthetesting

andexaminationofcranesaftersubstantialrepair.

13.2 Plannedmaintenance

13.2.1 Inorder that mobile cranes may operate safely and efficiently, it is

essentialtocarryoutpreventivemaintenanceworksothattheriskof

accidents and stoppages owing to breakdowns are reduced to a

minimum.Manufacturersinstructionmanualsrecommendthatspecific

tasksbecarriedoutatstatedintervalsandtheseshould befollowed.

Anyrepairsorreplacementcomponentsshouldbeinaccordancewith

the manufacturer's recommendations or specifications. To avoid

excessivedown-time,expendableitemssuchasropes,frictionlinings,

etc.,shouldbekeptinstock.

13.2.2 Inadditiontoanystatutoryregulations,arecordorlogshouldbekept

for all cranes, giving information such as diameter, length and

construction details of ropes, hours worked, adjustments, insulation

checks,renewalofparts,thoroughexaminationsandrepairs.Basedon

this record a programme of planned maintenance and repair work

should be introduced to contribute towards trouble free and safe

operation.

13.3 Competenceofmaintenancepersonnel

13.3.1 Allmaintenancestaffshouldbefullyaware ofthehazardsinvolvedin

working on cranes. Maintenance staff should have an adequate

workingknowledgeofthemachinerytheyarerequiredtomaintainand

haveaccesstothemanufacturer'srelevantliterature.


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13.3.2 The maintenance foreman should be responsible for instructing the

staffinallaspectsofsafeworking.Wherespecialmachineryisinvolved,

personnel should be properly instructed, such as by attending

maintenance,serviceandoperatingcoursesgivenbythemanufacturer

oftheequipment.


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14.Inspection,Examinationand Test ing

14.1 Therearestatutoryrequirementsgoverningthetesting,examinationand

inspectionofmobilecranes(Regulations5,7A,7B,7Eand7Gofthe

LALGR). Daily inspectionshall be carriedoutbya competentperson

whilsttestandexaminationshallbecarriedoutbyacompetentexaminer.

Reference can be made to Table 2 which is a summary of the legal

requirementsoftesting,thoroughexaminationandinspectionsofmobile

cranes. Testingof mobile cranes should conform toBritishStandard

7121orequivalentstandards. Referenceshould alsobemade tothe

G

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