DNV GL rules for classification and offshore standards – July 2018 edition

The 2018 July edition of DNV GL rules for classification and offshore standards is now available.

1. General information

The July 2018 edition of the rules were formally approved on June 19th 2018 and includes both new and amended rules. 

Entry into force date is 1st of January 2019, except for Pt.2 Ch.4 relating to qualification of welders which enters into force from date of publication. 

The changes to the rules may be categorized as:

  • new and revised class notations 
  • implementation of external requirements (IACS unified requirements and relevant IMO codes)
  • general clarifications and corrections.

Additional to the updates to the rules for ships, rules for patrol boats have been clarified for high speed and light crafts (HSLC), naval vessels and yachts. 

For detailed list of changes, please see current changes in the relevant documents and/or contact your local DNV GL office for further information.

2. DNV GL rules for classification of ships

Below are highlights from the July 2018 edition of the DNV GL rules for classification of ships. 

2.1 New class notations

Ship type notations
  • DSV(Ready) / DSV(OCS) (DNVGL-RU-SHIP Pt.5 Ch.10 Sec.6) - diving support vessel
Additional class notations
  • RSCS+ (DNVGL-RU-SHIP Pt.6 Ch.4 Sec.10) - route specific container stowage
  • Cyber secure (DNVGL-RU-SHIP Pt.6 Ch.5 Sec.21) - cyber security
  • ER (DNVGL-RU-SHIP Pt.6 Ch.7 Sec.7) - emission reduction
  • UWILD (DNVGL-RU-SHIP Pt.6 Ch.9 Sec.8) - underwater inspection in lieu of dry docking.

2.2 Revised class notations

Ship type notations
  • Container ship (DNVGL-RU-SHIP Pt.5 Ch.2)
  • Passenger ship (DNVGL-RU-SHIP Pt.5 Ch.4)
  • Tanker for liquified gas (DNVGL-RU-SHIP Pt.5 Ch.7)
Additional class notations
  • Gas fuelled (DNVGL-RU-SHIP Pt.6 Ch.2 Sec.5) - gas as fuel
  • Ice (DNVGL-RU-SHIP Pt.6 Ch.6) - ice strengthening for the Northern Baltics.

2.3 Changes to material related topics (DNVGL-RU-SHIP Pt.2)

In DNVGL-RU-SHIP Pt.2 Ch.4 requirement to qualification of welders is reversed to January 2017 edition and requirements according to IACS UR W32 are removed. This enters into force from date of publication.

2.4 Changes to hull related topics (DNVGL-RU-SHIP Pt.3 and Pt.5)

For the July 2018 rules six (6) main topics are covered:

  • Special operations - load application
    • introduction of design load scenario for non-harbour and non-sailing operations
    • efficiency improved in design process.
  • Simplified scantling check for ships with length ≤ 90m 
    • simple rule check fit for hand calculations or spreadsheets
    • rule check analysis can be done without installation of rule check software
    • improved efficiency especially for small design offices not familiar with DNV GL software tools.
  • Waved induced loans
    • the load and acceleration formulas are improved based on parameter studies
    • beam sea pressure and longitudinal acceleration are tuned
    • more precise loads for non-conventional hull shapes/sizes.
  • Fillet welds
    • reduction of size of fillet welds mainly for tank and aft peak structures.
  • Tripping brackets / bow impact
    • more precise requirements lead to fewer tripping brackets and reduced cost.
  • Brittle crack arrest
    • introduction of new crack initiation avoidance solution utilizing enhanced NDT (Option B*)
    • increased flexibility for brittle crack arrest designs
    • the DNV GL developed option will provide a solution which is easy to apply and will avoid difficult designs like block shift without excessive material costs.

2.5 Changes to system related topics

Update of rules for torsional vibration and shafting to meet challenges with passing barred speed range (BSR) in an acceptable time. Failure to do so over time may result in fatigue problems with severe damage or total loss of propulsion. 

Rule references:
  • DNVGL-RU-SHIP Pt.4 Ch.2 Sec.2
  • DNVGL-RU-SHIP Pt.4 Ch.4 Sec.1

Clarification and definition of acceptable means to allow for no bypass option on selective catalytic reduction (SCR) installations. This to meet future challenges with possible poor fuel quality and to maintain an adequate level of safety for such installations.

Rule reference:
  • DNVGL-RU-SHIP Pt.4 Ch.6 Sec.8

3. Comments to class notations

3.1 New class notations

Ship type notations
DSV / DSV(Ready) / DSV(OCS) - diving support vessel (DNVGL-RU-SHIP Pt.5 Ch.10 Sec.6) 
  • DNV GL is re-introducing DSV as the ship type notation name - following market request for the notation and name as a reference standard and trade brand
  • appreciating that diving systems today are separately classed, we are introducing a class notation showing a vessel capability to take a diving system onboard - DSV(Ready) 
  • following the above, we are also introducing a class notation to recognize a DNV GL classed vessel with a diving system classed by another society - DSV(OCS).  
Additional class notations
RSCS+ - route specific container stowage (DNVGL-RU-SHIP Pt.6 Ch.4 Sec.10) 
  • RSCS+ is replacing RSCS 
  • meeting market requests for a class notation covering short voyages with partial loading and increased metacentric height
  • also offering the option to apply weather dependent accelerations - giving increased stowage flexibility. 
  • individual route reduction factors calculations offered in application on the Veracity platform.
Cyber secure - cyber security (DNVGL-RU-SHIP Pt.6 Ch.5 Sec.21) 
  • introducing a class notation for handling of cyber risks 
  • the rules aim to ensure that sufficient and correctly performed cyber security barriers are established to prevent, mitigate and respond to cyber-attacks. The barriers are a combination of technical, organizational and behavioural measures implemented on board the vessel.
ER - emission reduction - (DNVGL-RU-SHIP Pt.6 Ch.7 Sec.7) 
  • introducing a class notation to support the installation and use of exhaust gas cleaning systems on board vessels
  • the notation provides criteria for the safe and environmentally friendly arrangement and installation of machinery for NOx and SOx exhaust gas emission reduction.
UWILD - underwater inspection in lieu of dry docking - (DNVGL-RU-SHIP Pt.6 Ch.9 Sec.8) 
  • introducing a class notation for accepting that vessels staying in one location may be subjected to alternative survey methods to replace renewal survey in dry dock 
  • the rules give requirements to design solutions on the vessel, as well as procedural requirements and limitations.

3.2 Revised class notations

Ship type notations
Container ship (DNVGL-RU-SHIP Pt.5 Ch.2) 
  • alternative brittle crack arrest solution 
  • scantling of centreline girder.
Passenger ship (DNVGL-RU-SHIP Pt.5 Ch.4) 
  • improvements and clarifications with respect to global FE loading conditions, load application methods, response combinations and target values 
  • clarifications for monolithic and laminated glass railings related to test requirements and stanchion distances.
Tanker for liquified gas (DNVGL-RU-SHIP Pt.5 Ch.7) 
  • clearly separated IGC Code and DNV GL requirements by introducing quote and interpretation elements in the rules. 
Additional class notations
Gas fuelled (DNVGL-RU-SHIP Pt.6 Ch.2 Sec.5) 
  • clarification of closing time for tank valves 
  • rule alignment with IGF Code.
Ice - ice strengthening for the Northern Baltics (DNVGL-RU-SHIP Pt.6 Ch.6) 
  • the notation has been updated to meet the latest requirements from the Finnish Transport Safety Agency (TraFi) 
  • mainly covering new requirements for structural loads on azimuthing propulsors and related load calculations to be carried out.

4. Offshore class rules and standards, July 2018 edition

Below is given a general overview of the main changes related to the offshore class document portfolio.

4.1 New class rules for modular drilling and well systems 

A new set of class rules DNVGL-RU-OU-0294 has been issued introducing a classification service for modular drilling and well systems. These may be granted class notations Modular drilling system or Modular well system

The new notations are accompanied by optional qualifiers N, US and UKVS covering additional shelf state requirements. 

Depending on location of the systems when in operation, application notations MODU, Offshore, Ship or Land will be assigned. 

4.2 Updated offshore standards

DNVGL-OS-B101 Metallic materials  
  • The contents have been updated and aligned with DNVGL-RU-SHIP Pt.2 Ch.1 and Ch.2.
DNVGL-OS-C101 Design of offshore steel structures, general
  • The sections on design fatigue factors (DFF) and soil safety factors have been updated. 
DNVGL-OS-C102 Structural design of offshore ship-shaped units
  • the document has been re-formatted and technically updated to be aligned with DNVGL-RU-SHIP Pt.3 
  • the contents of the enhanced fatigue notation FMS have been updated and included in the document. This was previously found in a separate DNVGL-RP-C206, which will be deleted.
  • new class notation FAB has been introduced to cover extended NDT scope for FSO/FPSOs operating in harsh locations 
  • material and welding requirements have been aligned with the ship rules 
DNVGL-OS-E201 Oil and gas processing systems
  • barrier management principles have been introduced and process systems barriers defined
  • the document has been alignment with latest industry practice and scope of work for class has been clarified. 
DNVGL-OS-E-301 Position mooring
  • the results from the NORMOOR JIP have been implemented with new safety factors for ULS and ALS conditions 
  • a new class notation qualifier HC has been introduced for units with heading control. 
DNVGL-OS-E302 Offshore mooring chain
  • a new chain high strength material grade R6 has been introduced
  • the document has been aligned with new IACS UR W22.

4.3 Class notations for dynamic positioning - new qualifiers for close bus-tie operation of mobile offshore units 

Two new qualifiers providing rig owners a possibility to qualify their DP3 systems for closed bus-tie operation has been introduced in DNVGL-RU-OU-0101 Offshore drilling and support units.   

The qualifiers CB and CBT may be given to units with DPS(3) or DYNPOS(AUTRO) notations. The qualifiers specify different extent of test requirements.

  • CB: closed bus-tie integrity documented through FMEA, computer simulations and inspections. Complies with DNVGL-RU-SHIP PT.6 Ch.3 Sec.1 App.A Technical system configurations based on closed bus-ties, except for the requirements for live earth fault and short circuit testing.
  • CBT: closed bus-tie integrity documented through FMEA, computer simulations, inspections, survey and testing. DNVGL-RU-SHIP Pt.6 Ch.3 Sec.1 App.A.

Oslo, Norway, 2018-07-03
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