6 Edition Vs. 7 Edition - Seatrax.co.uk

Introduction to APISpecification 2C6th Edition vs. 7th Edition

Goals of API Spec 2C 7th Edition Address gross overload/supply boat entanglement issue Incorporate all types of offshore cranes, including:––––––ConstructionDerrick BargesPipe Lay VesselsSupport VesselsShipboard CranesKnuckle Boom Cranes Provide design requirements for new crane uses withoutsignificantly affecting cranes currently covered by previous editions Differentiate between crane designs based on intensity or frequencyof use

Significant Changes from 6th Edition Gross overload / supply boat entanglement Duty cycle consideration (frequency / intensity of use) Wire rope design factors Structural design factors

Background API Spec 2C 6th Edition and European standard EN 13852-1 and -2both published 2004 addressing offshore crane sizing and safetyrequirements API Spec 2C 6th Edition– Focused on cranes for oil production and drilling facilities– Safety based on structural design and integrity– Increased safety factors are emphasized above instrumentation /gadgets as a means of providing safe cranes EN 13852– Covers cranes for all offshore applications– Safety focused on instrumentation / gadgets instead of increased safetyfactors– Main requirement is an Automatic Overload Protection System (AOPS)that takes control away from the operator and releases the brakes whileover the supply boat

Background API Spec 2C 7th Edition drafted to incorporate additionalcrane uses, expanding on previous versions andmaintaining safe operations as governing theme– Designed as a superior international standard for offshorecranes based on more realistic criteria and more definitiveguidance

Gross Overload Conditions /Failure Mode AssessmentAPI 6th Edition Did not specifically addressGross overload conditionsFailure mode calculations onlyrequired upon request ofpurchaserAPI 7th Edition Addresses gross overloadusing failure mode assessmentRequires failure mode resultsto be provided to the customerProtects the crane operator inthe event of an unboundedgross overload (supply boatentanglement)If failure mode cannot be met,gross overload protectionsystem (GOPS) required toassure that structure holdingthe operator does not fail in theevent of a gross overloadNo AOPS required

Supply Boat EntanglementCausing Gross Overload Not to be confused with exceeding the SWL of thecrane

Gross Overload Conditions(From Supply Boat Entanglement)API 7th EditionEN 13852 Seems to consider supply boatentanglement to be a common eventDamage to equipment unacceptable incatastrophic eventsAccomplished through AutomaticOverload Protection System (AOPS)which senses an overload andreleases the loadAOPS creates increased risk ofmalfunction and dropped loads Considers supply boat entanglementan extremely rare but serious eventwith special attention requiredEquipment damage consideredacceptable in this rare catastrophiceventAccomplished through failure modeassessment showing structure holdingoperator’s cabin will not be first to failin any conditionConsiders hazards created by AOPSto be worse than the potential benefits

Pitfalls of AOPS AOPS requirements over emphasize protection ofreplaceable components/machinery to the extent ofcreating additional hazards to personnel. Examples of additional personnel hazards– Holds loads over supply boat personnel with brakes intentionallydisabled– Loads supported only by retention or containment of hydraulic oilpressure– Can and have inadvertently dropped loads on supply boat– Complexity of components adds to number of parts that must bemaintained, inspected, and tested– Numerous components increase likelihood of failure– Creates a false sense of security

Example of Failure Assessment(From Supply Boat Entanglement)800,000PedestalSuspensionBoomMain RopeGantry700,000Failure Load 07090Working Radius (ft)110130150

Example of Failure Assessment(From Supply Boat Entanglement)800,000700,000PedestalMinimum FailureOffboard SWLFailure Load 07090Working Radius (ft)110130150

Example of Supply Boat Entanglement Crane on semi-submersible subjected toevent while handling anchorsInstantaneous overload in excess of 200%SWLWire rope pulled off the hoist drum,hydraulic motor destroyed due tooverspeedNo personnel injuriesCrane returned to service followingreplacement of wire rope and hydraulicmotorOutcome acceptable under API 7th Editionbut not EN 13852

Structural FatigueAPI 6th Edition Structural fatigue requirement is25,000 cycles at 133% of maxSWLCrane structures expected to last30-40 yearsAPI 7th Edition *EN 13852 and ISO assumemachinery and structures havesame useful life Structural fatigue requirement is1,000,000 cycles at 50% onboardSWLEquivalent fatigue damage of 6thEditionDifferentiates between structuresand machinery*Crane structures expected to lastat least 30-40 years

Machinery and Wire Rope Duty CycleAPI 6th Edition Did not address duty cycle, onlystructural fatigueAPI 7th Edition * EN 13852 and ISO assumemachinery and structureshave same useful life Differentiates between structuresand machinery*Machinery expected to last 5years before major overhaul /replacementAPI machinery is replaced oroverhauled multiple times beforecrane structure is retiredDuty classifications based onactual historical crane usage data

Duty Classifications ExamplesProduction DutyConstruction DutyIntermediate DutyDrilling Duty

Crane Duty ClassificationsCrane Duty CycleClassificationTypical AnnualOperating HoursTypical ApplicationsProduction Duty200Offshore cranes on fixed production platformsConstruction Duty1000Offshore cranes on barges or vessels, heavy liftcranesIntermediate Duty2,000Offshore cranes on fixed or floating platforms withtemporary rigs or intermittent periods of intensiveuseDrilling Duty5,000Offshore cranes on MODUs or floating productionfacilities with full-time, heavy-use drillingoperationsNote: Where possible, purchaser specified data used in place of duty classifications

Historical Crane Usage Data2006Usage (Hours)Drilling Contractor Data: (based on logs & engine hours)2340Average of Jackups-Primary Crane6552Max of Jackups-Primary Crane19No. of Primary CranesAverage of Semi/DrillShips-Primary CraneMax of Semi/DrillShips-Primary CraneNo. of Primary 084868102325441611Production Platform Data #1: (based on Engine Hours)Average of Platform Cranes w/o DrillingMax of Platform Cranes w/o DrillingNo. of Cranes4631233Production Platform Data #2: (based on Hoist Hour Meters)Average of Platform Cranes w/o DrillingMax of Platform Cranes w/o DrillingNo. of Cranes46408164Floating Production / Drilling Systems:Spars/TLP with Drilling Rig (4)Spars/TLP w/o Rig (1)Ave / Max 2315 / 5000 engine hr/yr650 engine hr/yr

Wire Rope Design FactorsAPI 6th Edition *API 7th EditionFixed design factor of 5 forrunning rigging without reevingefficiencyFixed design factor of 4 forstanding riggingImpractical for larger cranes, suchas construction cranes and derrickbarges Certifying authorities for largercranes use design factor of 3for lifts over 160 tons andaccount for reeving efficiency Little to no effect on cranescovered by API 6th EditionSliding factor based on SWL thatallows larger cranes lower factorsin line with industry practice*Reeving efficiency nowconsidered due to high number ofparts of line required for largerconstruction cranesHigher capacity cranes, such asderrick barges, have similarfactors to current certifyingauthorities

Wire Rope Design Factors6API 6th EditionDesign Factor5Note: API 7th Edition, EN 138521, DNV and Lloyds curves areall overlapping4API 7th EditionAPI 6th EditionEN 13852-1DNVLloyds32050,000100,000150,000200,000SWL (lb)250,000300,000350,000400,000

Structural Design FactorsAPI 7th EditionEN 13852 Uses same factor of safety forpedestal / slew bearing as the restof the crane structureNo additional factor on thepedestal / slew bearing Uses higher factor of safety forpedestal / slew bearing comparedto the rest of the crane structureSignificant additional factor ofsafety applied to the pedestal /slew bearing to help ensure thatthe main crane structure andoperator remain attached to theplatform in a catastrophic event

Structural Design FactorsAPI 6th Edition *Minimum onboard dynamic coefficient(Cv) of 1.33Additional Pedestal factor of 1.5Impractical for large constructioncranes, derrick barges or shipboardcranes in calm watersCertifying authorities useapproximately 1.1 for Cv for liftsover 160 tons and many do not usea pedestal factorAPI 7th Edition Little to no effect on cranes currentlycovered by API 6th EditionSliding minimum onboard dynamiccoefficient from 1.33 to 1.1 based onSWLAdditional sliding pedestal factor from1.5 to 1.2 based on SWLOffboard dynamic coefficients fortypical oil production cranes have notchangedHigher capacity cranes, such asderrick barges, have similar factors tocurrent certifying authorities

API 7th Edition Structural Design Factors1.601.50Onboard CvPedestal 000200,000SWL (lb)250,000300,000350,000400,000

Minimum Hook VelocityAPI 6th Edition Calculations given but was notmandatoryMinimum hook velocity of 20 ft/min at0 ft significant wave heightAPI 7th Edition Mandatory for all offboard ratingsIf not met, load chart cannot beprovided for the specific conditionsMinimum hook velocity of 2 ft/min at 0ft significant wave heightAbove 6 ft significant wave heightminimum hook velocity is the same asthe 6th Edition

Minimum Hook Velocity100Hook Velocity (ft/min)7550API 6thAPI 7thEN 13852250036Significant Wave Height (ft)912

Other Changes Cylinder design factors updated to include dynamic load factor Cv Hoist section updated to require separate dynamic and static brakes Load/moment indicators required on intermediate, drilling, andconstruction duty cranes Personnel capacity increased to 50% of SWL as opposed to 33% ofSWL to more adequately align with OSHA and other standards andsimplify ratings Align noise requirements with OSHA

Other Changes Material requirements clarified and aligned throughout the standard Minimum toughness (Charpy) requirements provided instead ofrelying on crane manufacturer to determine ductility requirements Example calculations updated to reflect changes Default Dynamic Method (fixed Cv of 2.0) renamed Legacy DynamicMethod to discourage use Drastically reduced number of references to external standards forease of use internationally

Summary API 7th Edition is a viable international standard incorporating alloffshore crane applications Failure mode calculations/GOPS ensure operator safety withoutincreasing the risk of dropping the load In the rare event of supply boat entanglement, injury to personnel isprevented Cranes covered by the 6th Edition essentially unchanged whilehigher capacity cranes use similar to factors used by certifyingauthorities Entire standard reviewed and updated to match current technologyand practice

Summary API 7th Edition provides definitive technicalguidance and unambiguous design rules toensure cranes are designed to safely operate inthe challenging offshore environment Cranes designed to API 2C 7th Edition provide asuperior balance of safety and simplicity

Design Factor API 7th Edition API 6th Edition EN 13852-1 DNV Lloyds Note: API 7th Edition, EN 13852-1, DNV and Lloyds curves are all overlapping API 6th Edition. Structural Design Factors EN 13852 Uses same factor of safety for pedestal / slew bearing as the rest of the crane structure No additional factor on the pedestal / slew bearing API 7th Edition Uses higher factor of safety .