The January 2001 edition of the Rules for Classification of Ships contains the following existing, new and renumbered rule chapters:

Pt.0 Ch.1 User Information, Amendments and Indexes
Pt.1 Ch.1 General Regulations
Pt.2 Ch.2 Metallic Materials
Pt.3 Ch.1 Hull Structural Design, Ships with Length 100 meters and above
Pt.3 Ch.2 Hull Structural Design, Ships with Length less than 100 meters
Pt.4 Ch.1 Machinery and Systems, General (new)
Pt.4 Ch.2 Rotating Machinery, General (new)
Pt.4 Ch.3 Rotating Machinery, Drivers (new)
Pt.4 Ch.4 Rotating Machinery, Power Transmissions (new)
Pt.4 Ch.5 Rotating Machinery, Driven Units (new)
Pt.4 Ch.6 Machinery Piping Systems (new)
Pt.4 Ch.7 Boilers, Pressure Vessels, Thermal-Oil Installations and Incinerators (renumbered)
Pt.4 Ch.8 Electrical Installations (renumbered)
Pt.4 Ch.9 Instrumentation and Automation (renumbered)
Pt.4 Ch.10 Fire Safety (renumbered)
Pt.4 Ch.11 Safety of Navigation (renumbered)
Pt.4 Ch.12 GMDSS and Internal Communication (renumbered)
Pt.5 Ch.1 Ships for Navigation in Ice
Pt.5 Ch.2 Passenger and Dry Cargo Ships
Pt.5 Ch.3 Oil Carriers
Pt.5 Ch.7 Tugs, Supply Vessels and other Offshore/Harbour Vessels
Pt.6 Ch.1 Miscellaneous Notations
Pt.6 Ch.4 Additional Fire Protection (F-AMC)
Pt.6 Ch.5 Integrated Computer Systems (ICS)
Pt.6 Ch.7 Dynamic Positioning Systems
Pt.6 Ch.8 Nautical Safety
Pt.6 Ch.13 Gas Fuelled Engine Installations (new)
Pt.7 Ch.1 General Requirements
Pt.7 Ch.2 Periodical Survey Requirements
Pt.7 Ch.4 Operational Requirements, Additional Class
Pt.7 Ch.8 Alternative Survey Arrangement for Propulsion Machinery

From January 2001 the following existing rule chapters from the Rules for Classification of Ships are withdrawn:

Pt.4 Ch.1 Machinery and Systems Design, General (renamed)
Pt.4 Ch.2 Propulsion and Auxiliary Machinery (renamed)
Pt.4 Ch.3 Boilers, Pressure Vessels, Thermal-Oil Installations and Incinerators
(renumbered)
Pt.4 Ch.4 Electrical Installations (renumbered)
Pt.4 Ch.5 Instrumentation and Automation (renumbered)
Pt.4 Ch.6 Fire Protection, Detection and Extinction (renamed and renumbered)
Pt.4 Ch.8 Safety of Navigation (renumbered)
Pt.4 Ch.9 GMDSS and Internal Communication (renumbered)
Pt.4 Ch.7 Arrangements for Coal Fired Boilers, Tentative Rules
Pt.5 Ch.9 Oil Production and Storage Vessels

In addition, some of the rule chapters have been subject to amendments, which have been inserted in Sec.3 of Pt.0 Ch.1. The changes come into force 1 July 2001.

Important rule changes
The rule changes covered by the revised chapters or Sec.3 of Pt.0 Ch.1 are as follows:

Pt.1 Ch.1 Sec.2 General Regulations - Scope of Rules and Class Notations
New class notations Standby Vessel and Supply Vessel Basic are added to the tables with notations in Pt.5 Ch.7. New class notation GAS FUELLED is added in accordance with the new Pt.6 Ch.13.

The previous class notations DYNPOS AUTS, DYNPOS AUT, DYNPOS AUTR and DYNPOS AUTRO have been renamed AUTS, AUT, AUTR and AUTRO in accordance with amendments in Pt.6 Ch.7. The class notation NAUT-C on bridge design, is deleted.

Pt.1 Ch.1 Sec.3 General Regulations - Classification Procedure
Under "Repairs" a reference has been made to a new Classification Note No. 72.1. The Classification Note is intended to provide a simple approach for deciding acceptable main hull scantlings at the time of the renewal survey for vessel not built to DNV class or where such scantlings were not decided at the newbuilding approval stage. The Classification Note is also intended to cover requirements for repair, repair yards and repair personnel.

The general description of the certification schemes and principles for certification of materials, components and systems have been made clearer, more complete and collected in one place. The use of the English language in specifications and drawings has been made a requirement. Conditions related to the use of digital drawings have also been addressed.

Pt.2 Ch.2 Sec.5 Metallic Materials - Steel Forgings
This section has been completely revised with respect to structure and content. The change of structure was motivated by general expectations from clients and surveyors to more user-friendly rules and a need for a generic structure that can serve as a template for coming revisions.

The changes in technical content were motivated by needs of clients and surveyors for consistency and predictability, especially on non-destructive testing. Furthermore a need for harmonisation with, or adoption of, existing industry standards where possible, notwithstanding the restrictions given in IACS unified requirements and implementation of recently developed IACS guidelines for non-destructive testing of steel forgings and castings. The table below illustrates the changes in structure.

Pt.2 Ch.2 Sec.7 Metallic Materials - Steel Castings
This section has been completely revised with respect to structure and content. The change of structure is motivated by general expectations from clients and surveyors to more user-friendly rules and a need for a generic structure that can serve as a template for coming revisions.

The changes in technical content were motivated by needs of clients and surveyors for consistency and predictability, especially on non-destructive testing. Furthermore a need for harmonisation with, or adoption of, existing industry standards where possible, notwithstanding the restrictions given in IACS unified requirements and implementation of recently developed IACS guidelines for non-destructive testing of steel forgings and castings. The table below illustrates the changes in structure.

Pt.2 Ch.2 Sec.9 Metallic Materials - Aluminium Alloys
This section has been completely revised with respect to title, structure and content. The change of title and structure will facilitate future inclusion of other aluminium products in the rules; e.g. castings and aluminium-steel transition inserts. The changes in technical content are motivated by a need for harmonisation with existing industry standards, where possible and implementation of IACS unified requirements W25 Aluminium Alloys for Hull Construction and Marine Structure.

Pt.2 Ch.2 Sec.10 Metallic Materials - Copper Alloy Castings
This section has been completely revised with respect to title, structure and content. The change of structure is motivated by a need for more ‘revision friendly’ rules. The existing rules for copper alloy tubes are moved from Sec.10 to Sec.11, see separate description of changes in Sec.11.

The changes in technical content are motivated by a need for harmonisation with existing industry standards, where possible, implementation of IACS unified requirements W24 Cast Copper Alloy Propellers.

Pt.2 Ch.2 Sec.11 Metallic Materials - Non-Ferrous Tubes
This section has been completely revised with respect to title, structure and content. The content of the existing rules has been withdrawn and has been replaced with requirements for non-ferrous tubes. As a consequence, the existing rules for copper alloy tubes have been moved from Sec.10 to Sec.11. The changes in technical content for copper and copper alloy tubes are motivated by a need for harmonisation with existing industry standards, where possible. New requirements for titanium and titanium alloy tubes are also added.

Pt.3 Ch.1 Sec.1 Hull Structural Design, Ships with Length 100 Meters and above - General Requirements
The testing procedures for watertight compartments have been made clearer and the existing rules for tank testing have been generally updated according to IACS unified requirements (UR) S14 Testing procedures for watertight compartments. However, leak testing after the protective coating has been applied to the welds, provided that these welds were carefully inspected visually to the satisfaction of the surveyor is not accepted as it is in UR S14. It is considered incorrect that a visual inspection of welds can reveal leakage in the weld.

Furthermore the extent of structural testing of watertight hatch covers of tanks in combination carriers is different compared to UR S14. UR S14 requires every second hatch to be tested versus the amended rules that states all hatch covers. This enforcement is based on feedback and in service experience that clearly indicates individual differences between each hatch, hence every second hatch does not give an acceptable safety level.

All requirements for leak testing and structural testing for all ship types have been compiled into one new Table D1 in Pt.3 Ch.1 and Pt.3 Ch.2.

Pt.3 Ch.1 Sec.9 Hull Structural Design, Ships with Length 100 Meters and above - Bulkhead Structures
Requirements for testing of watertight bulkheads have been deleted here and have been transferred to Sec.1 (see above).

Pt.3 Ch.1 Sec.11 Hull Structural Design, Ships with Length 100 Meters and above - Openings and Closing Appliances
Requirements for testing of the following openings and closing appliances have been deleted here and have been transferred to Sec.1 (see above):

• inner and outer ports

• other watertight and weathertight closing appliances

• hatch covers

• access doors and hatches.

Pt.3 Ch.2 Sec.1 Hull Structural Design, Ships with Length less than 100 Meters - General Requirements
The testing procedures for watertight compartments have been made clearer and the existing rules for tank testing have been generally updated according to IACS unified requirements (UR) S14 Testing procedures for watertight compartments. However, leak testing after the protective coating has been applied to the welds, provided that these welds were carefully inspected visually to the satisfaction of the surveyor is not accepted as it is in UR S14. It is considered incorrect that a visual inspection of welds can reveal leakage in the weld.

Furthermore the extent of structural testing of watertight hatch covers of tanks in combination carriers is different compared to UR S14. UR S14 requires every second hatch to be tested versus the amended rules that states all hatch covers. This enforcement is based on feedback and in service experience that clearly indicates individual differences between each hatch, hence every second hatch does not give an acceptable safety level.

All requirements for leak testing and structural testing for all ship types have been compiled into one new Table D1 in Pt.3 Ch.1 and Pt.3 Ch.2.

Pt.3 Ch.2 Sec.8 Hull Structural Design, Ships with Length 100 Meters and above - Bulkhead Structures
Requirements for testing of watertight bulkheads have been deleted here and have been transferred to Sec.1 (see above).

Pt.3 Ch.2 Sec.11 Hull Structural Design, Ships with Length 100 Meters and above - Openings and Closing Appliances
Requirements for testing of the following openings and closing appliances have been deleted here and have been transferred to Sec.1 (see above):

• inner and outer ports

• other watertight and weathertight closing appliances

• hatch covers

• access doors and hatches.

Pt.3 Ch.3 Sec.2 Hull Equipment and Appendages - Sternframes, Rudders and Steering Gears
Requirements for testing of rudders have been deleted here and have been transferred to Ch.1 Sec.1 or Ch.2 Sec.1, as appropriate. (See above).

Pt.4 Ch.1 Machinery and Systems, General
Piping related requirements have been taken out of Pt.4 Ch.1 and have been moved to the new chapter (Pt.4 Ch.6 "Machinery Piping Systems"). The new Ch.6 is "self-contained" and the new general Pt.4 Ch.1 is a superior chapter for Pt.4 Ch.2 to Pt.4 Ch.12.

Pt.4 Ch.1 Sec.1 Machinery and Systems, General - General Requirements
Some of the definitions are deleted and some are moved to other relevant chapters. The explanation of the term Redundancy is expanded.

Pt.4 Ch.1 Sec.2 Machinery and Systems, General - Materials
Piping related material requirements have been moved to the new Ch.6.

Pt.4 Ch.1 Sec.3 Machinery and Systems, General - Design Principles
The requirements for redundancy on different levels are explained with requirements for minimum output power after single failure. The rule text is "tuned" to fit all types of machinery systems (also electrical). Example of the interpretation of the rule is given in a guidance note.

Guidance note on materials with high heat resistance is included.

Pt.4 Ch.1 Sec.4 Machinery and Systems, General - Spare Parts
New rule text on spare parts with guidance note is added.

Pt.4 Ch.2 to Ch.5 Rotating Machinery (new)
The main class rules for rotating machinery have been completely re-written and are now distributed in three chapters. The main reasons for the amendments are as follows:

The rules shall have a life cycle focus in the class involvement:

• The ship in operation phase should be as problem-free as possible.

• Requirements shall specified as early as possible to detect unacceptable designs or defects.

• It shall be a connection in the DNV involvement in the different phases (design, production, installation and operation).

• Built-in design safety shall not be reduced during production and installation.

The rules shall be customer or user friendly and transparent:

• Acceptance criteria have been used wherever possible to ensure that the customers know what DNV will accept, what DNV will reject and why.

• Important requirements that have been hidden in internal instructions should be included.

The 1A1 rules shall be improved based on experience and criticality of each component or system.

Pt.4 Ch.2 Rotating Machinery, General (new)
This is a new chapter. See general motives above. This chapter is a common denominator for the three following chapters. It contains important principles as well as explanations on how to fulfil certification requirements. The purpose is to give support on how to apply basic requirements in Pt.1 Ch.1 for rotating machinery. In every section in the following three chapters there are references to Ch.2. The sections are:

• Sec.1 Introduction

• Sec.2 Certification Principles

• Sec.3 Design and Documentation

• Sec.4 Material and Material Testing (Preliminarily. Will be replaced by revised Pt.2.)

• Sec.5 Special Materials and Processes (Preliminarily. Will be replaced by revised Pt.2.)

• Sec.6 Electric Power Generation

Special attention should be paid to Sec.2 stating that for small auxiliary machinery, the product certification may, upon special evaluation and acceptance, be waived for power ratings less than 200 kW and rated torque less than 5 kNm.

Pt.4 Ch.3 Sec.1 Rotating Machinery, Drivers (new) - Diesel Engines
Turbocharger rules are revised and included in diesel engine section. Vibration requirements and methods for vibration calculation are included in the diesel engine section. Instrumentation requirements are increased to approximately E0 level. More focus is given on acceptance criteria and transparency on what DNV does. Involvement is based on criticality, life cycle focus and problem areas.

Pt.4 Ch.3 Sec.2 Rotating Machinery, Drivers (new) - Gas Turbines
The rules are more detailed than the previous edition, subsection A introduces the concept of system approval (as opposed to component approval) and presents a comprehensive list of documentation to be submitted. Particular attention is given to system integration.

The extensive design section comes as an answer to engine manufacturers as to better explain and present the approval exercise performed in DNV. While the New Machinery Project philosophy and methodology forms the basis for the revision, the main change is that a significantly more detailed and precise description of DNV requirements is provided.

The main improvements relate to the test requirements in general, and type testing in particular. Cycle-based testing represents the improvement in DNV's expertise towards gas turbine in-service operation. As modern ships, and in particular high speed ferries, use gas turbine propulsion with operating cycles including frequent start and stop sequences, it is necessary to introduce this aspect in the testing phase of new engines.

For inspection and testing, production verification process and extent of manufacturing survey arrangement are presented.

Following the same philosophy as type testing, cyclic loading is introduced in the certification test requirements for workshop testing. Less stringent than type testing, certification testing focuses on the operating profile each specific engine is intended for.

The extended list of control and alarms reflects the experience gathered in the past years on ships operating with gas turbine propulsion. Furthermore the concept of availability, in addition to safety, is highlighted and leads to changes in alarm logic. Specific fire safety requirements are introduced and strengthened, based on our acquired experience with fire incidents on gas turbine equipped vessels.

The requirements to arrangement have been clarified and made more precise based on accumulated experience. More precise requirements to gas turbine enclosures are provided.

The vibration subsection lists analysis and measurements to be performed with reference to the relevant rules sections. While the specific requirements are located elsewhere in the document this section functions as a look-up list for the relevant requirements.

Working as a checklist, the installation inspection subsection is intended to verify that the general arrangement of the gas turbine propulsion system onboard the ship is in compliance with rule requirements of other sections.

Shipboard testing cover both quay and sea trials. This subsection is designed to verify system integration and control system behaviour.

Pt.4 Ch.4 Sec.1 Rotating Machinery, Power Transmissions (new) - Shafting
A new basic method for calculation of shaft dimensions covering modern fatigue theory, design and production is described in a new Classification Note No. 41.4. Three new simplified methods replaces today’s method for quick, simple and safe assessment of shaft dimensioning. Involvement is based on criticality, life cycle focus and problem areas. Examples of application of the new basic method is presented in an Appendix to Classification Note 41.4

Pt.4 Ch.4 Sec.2 Rotating Machinery, Power Transmissions (new) - Gear Transmission
For welded gear wheel designs, either stress intensity limitation or specific stress levels combined with different weld qualities are included. Criteria against fretting are included. Criteria for elasto-plastic shrinking included. Inspection and testing updated are more in line with ISO 6336-5. Requirement for contact test in work shop testing of bevel gears (when necessary, under slow turning with full load applied) is included. Alarm and instrumentation requirements are updated to today’s standard. More focus on acceptance criteria and transparency on what DNV does. Involvement is based on criticality, life cycle focus and problem areas.

Pt.4 Ch.4 Sec.3 Rotating Machinery, Power Transmissions (new) - Clutches
The rules are updated to instruction to surveyor level. Monitoring updated to a reasonable minimum (already common practice in the industry).

Pt.4 Ch.4 Sec.4 Rotating Machinery, Power Transmissions (new) - Bending Compliant Couplings
Bending compliant couplings are separated from elastic couplings in a separate section. Type testing requirements are updated to today’s practice. Requirement for emergency claws is replaced by monitoring (twist alarm).

Pt.4 Ch.4 Sec.5 Rotating Machinery, Power Transmissions (new) - Torsionally Elastic Couplings
Type testing requirements are updated to today’s practice. Requirement for emergency claws is replaced by monitoring (twist alarm).

Pt.4 Ch.4 Sec.6 Rotating Machinery, Power Transmissions (new) - Elements of Composite Materials
Elements of composite materials will be considered on a case by case basis.

Pt.4 Ch.4 Sec.7 Rotating Machinery, Power Transmissions (new) - Jacking Machinery
Safety factors for storm holding loads are reduced. Provision for acceptance of approved full scale testing as a substitute and/or supplement to design calculations is included. Evaluation of brakes, connections and flexible mounting are included.

Pt.4 Ch.5 Sec.1 Rotating Machinery, Driven Units (new) - Propellers
The criteria for dimensioning of propeller blades are completely revised and made appropriate for modern propeller designs. The focus has moved from "required thickness" to stresses (relative allowable stresses). This will, for instance, simplify the approval process if approval is to be based on finite element calculations. In average, propeller blade scantlings will be about the same as previously.

Scantling criteria for propeller blades are taken out of the rules and are now given in a separate classification note 41.5 where:

• influence of profile thickness on fatigue properties is included

• material parameters are revised, reflecting more realistic values

• dynamic stress factor (mt) is revised according to existing experience

• influence of propellers skew on stresses is included

• influence of sectional profile on stresses is included

• centrifugal stresses are normally neglected

• requirement for tip-thickness is included

• additional low-cycle criteria is included for propellers with reversible direction of rotation
  more detailed description of how to handle propeller blades for tunnel thrusters is included.

Simple dimensioning criteria for pitch control mechanism are presented. These are mainly based on existing practise. The list of requested documentation is revised and given in a table. Table of required instrumentation and alarms are listed. For propellers with Baltic ice class, existing practice regarding reduction in ice torque for nozzle propellers has been included.

Pt.4 Ch.5 Sec.2 Rotating Machinery, Driven Units (new) - Water Jets
Requirements are included to secure that water jets do not experience loads for which they have n

In the installation phase: Focus on manufacturing of ducting as this greatly defines hydrodynamic operating conditions. In the operation phase: Control system indications and request for slow down when operating outside design assumptions.

Pt.4 Ch.5 Sec.3 Rotating Machinery, Driven Units (new) - Thrusters
Auxiliary thrusters of 300 kW or less no longer subject to design approval. Manufacturer shall submit information about any operational limitations, his design criteria and load assumptions. A guidance note indicating load cases and number of load cycles have been added. Strength and fatigue requirements for steering column have been added. Leakage detection for column seal at hull penetration has been added. Lifetime requirement for rolling bearings has been added. Minimum requirements for the lubrication system have been added. Exemption from certification granted for mass produced reduction gear boxes, which can easily be replaced. Applicable only for thrusters with two or more steering gear actuators and when the vessel is fully manoeuvrable with one thruster out of operation. Certification requirements for shafting have been harmonised in the different rule sections and the requirements are now given in Pt.4 Ch.4 Sec.1. Function testing is required for all hydraulic systems. Alarms and indications required are listed in a table. Azimuth thrusters shall be mounted in a watertight compartment if hull penetration is below deepest loaded waterline. Lower limit for application factor for propulsion plant is given.

Pt.4 Ch.5 Sec.4 Rotating Machinery, Driven Units (new) - Compressors
This section has only been subject to minor changes.

Pt.4 Ch.6 Piping Systems (New)
Piping related requirements have been taken out of the existing Pt.4 Ch.1 and have been moved to this new chapter. The changes introduced in addition to the editorial amendments are as described in the following.

The definition of pipe class has been modified to reflect the latest changes in IACS unified requirements. Requirements for flame spread characteristics in line with IMO Res. A.653(16) have been added for plastic pipes. The requirements regarding drip trays and remote stop of pumps have been moved from fuel oil systems to a higher level, to make it clearer that these rules also are applicable to other flammable liquids. Requirements for lubrication oil separators have been added for vessels burning residual oils. Based on experience feedback, a requirement has been added for bypass arrangements where flow meters are installed in the fuel oil supply system. A further requirement has been added, stating that flexible hoses carrying flammable fluids shall be type approved. Acceptance of pipe couplings has been modified in line with IACS unified requirements. Sec.4 Ship Piping Systems on air pipes has been modified to reflect the latest SOLAS amendment to air pipes, from fuel oil service tanks. Requirements for hydraulic testing of fuel oil tanks have been deleted in Sec.5 Machinery Piping Systems and have been transferred to Pt.3 Ch.1 Sec.1 or Pt.3 Ch.2 Sec.1, as appropriate. Additionally, requirements for pneumatic and hydraulic equipment, currently included in existing Pt.4 Ch.5 Sec.5 D, are moved to the new Pt.4 Ch.6 Sec.5.

Pt.4 Ch.7 Sec.1 Boilers, Pressure Vessels, Thermal-Oil Installations and Incinerators - General Requirements
The requirements for documentation of thermal-oil installations are amended. In addition, an item "overpressure protection for condensers" is added in the section on documentation. Condensers, vacuum and atmospheric is clarified as being Class III pressure vessels.

Pt.4 Ch.7 Sec.3 Boilers, Pressure Vessels, Thermal-Oil Installations and Incinerators - Arrangement
It is now required that oil fired thermal-oil heaters not located in separate rooms are to be surrounded by coamings of height not less than 150 mm and with drainage to a closed tank.

The use of bellows or similar expansion elements in thermal-oil piping is not permitted within machinery spaces.

Clarification regarding the intended use of the exhaust bypass requirement for exhaust heated thermal-oil heaters is added.

A requirement for remote operation of the valve for fast gravity discharge of thermal-oil is introduced.

Pt.4 Ch.7 Sec.6 Boilers, Pressure Vessels, Thermal-Oil Installations and Incinerators - Mountings and Fittings
Specific requirements for acceptable means for protection of overpressure for vacuum condensers and atmospheric condensers are added.

Pt.4 Ch.8 Electrical Systems
This chapter is completely rewritten. The main changes are:

Restructuring

The main change to the rules is a restructuring:

• The Rules for Classification of Ships and the Rules for High Speed, Light Craft and Naval Surface Craft are co-ordinated into one unified set of requirements.

• Formal requirements related to the Society's work process form Sec.1, and are divided into three different tasks forming the complete verification scheme.

• Approval of the electrical system.

• Certification of the electrical equipment (Approval and product survey).

• Site survey.

• Technical requirements for electrical systems are separated from the requirements for equipment and components. This enables a clear set of requirements being imposed on the various stages of design and manufacturing.

Certification requirements

• General: Revised limits for when a product certificate is required.

• Medium range machines and transformers: A type approval certificate combined with works certificate may replace a NV product certificate.

• Electrical systems: Introduction of the possibility for type approval of electrical distribution systems.

Documentation

• New requirements for documentation are implemented. Focus is on information, no specific requirements for specific documents (or document names) are given. The tables are meant as a vehicle for information.
  

Technical requirements
Technical requirements have been updated where found necessary to keep abreast of the development in international standards. A change of technical requirements has not been the main issue of this revision. Some of the implemented changes are:

• Requirements for protection of emergency generator are added, as well as a requirement for an alarm when the emergency generator is disabled from starting.

• Updated terminology and clarified requirements for breaking capacity of circuit breakers.

• Acceptance of reduced distances for clearance and creepage when LV assemblies are type tested of partially type tested.

• Transformers with forced cooling are accepted.

• Requirements for class 5 conductors are added, in line with IEC.

• Today's prohibition against splicing of certain cables in junction boxes is deleted.

• Today's requirement about stripped back length of cable outer sheath is deleted.

• A new section for installations in hazardous areas in line with IEC, is added.

Pt.4 Ch.9 Sec.1 Instrumentation and Automation - General Requirements
The documentation requirements have been modified. The scope of documentation is about the same, but some document types have been deleted and their items have been combined with other document types.

Pt.4 Ch.9 Sec.5 Instrumentation and Automation - Component Design and Installation
A new location class for electromagnetic compatibility (emission) has been introduced into the rules. This is to take into account the different requirements for electromagnetic emission on the bridge or open deck and other locations.

Pt.4 Ch.10 Sec.1 Fire Safety - General Requirements
IMO MSC/Circ.847, Interpretations of vague expressions and other vague wording in SOLAS Chapter II-2 is to be regarded as part of the rules. Test requirements for fire divisions consisting of a non-combustible core and combustible veneers are added based on IACS unified interpretation SC125.

Pt.4 Ch.10 Sec.2 Fire Safety - Fire Pumps and Fire Main
In passenger ships of 1 000 gross tonnage and upwards, only one of the fire pumps required by SOLAS Reg. II-2/4.3.4 needs to be provided with automatic starting in accordance with IACS unified interpretation SC23.

For ships with class notation ICE- at least one of the fire pumps shall be connected to a sea chest, which is in compliance with Pt.5 Ch.1 Sec.2 C300 in accordance with IACS unified requirement F41 Sea intakes for fire pump on ships with ICE Class.

When calculating the number of hydrants as required by SOLAS Reg. II-2/4.5.1, the length of the water jet is to be ignored.

The required length of fire hoses has been adjusted in accordance with IMO MSC/Circ.847, Interpretations of vague expressions and other vague wording in SOLAS Chapter II-2.

Pt.4 Ch.10 Sec.3 Fire Safety - Fixed Gas Fire Extinguishing System
The time delay unit required for the means provided for automatically giving audible warning of the release of fire-extinguishing medium into any space in which personnel normally work, as required by SOLAS Reg. II-2/5.1.6, shall be equipped with an override valve together with a signboard describing emergency operating instructions.

Storage rooms for fire-extinguishing medium for small local extinguishing systems need not be treated as control stations as required by SOLAS Reg. II-2/5.1.13.

CO2 bottles of sizes up to 53.3 kg (80 litre) may be approved case by case based on satisfactory handling arrangements. All bottles are to be of the same size.

Pt.4 Ch.10 Sec.4 Fire Safety - Fire Extinguishers
Each powder or carbon dioxide extinguisher should have a capacity of at least 5 kg, and each foam extinguisher a capacity of at least 9 litre in accordance with IMO MSC/Circ.847, Interpretations of vague expressions and other vague wording in SOLAS Chapter II-2.

Pt.4 Ch.10 Sec.5 Fire Safety - Fire Extinguishing Arrangements in Machinery Spaces
Machinery spaces of category A containing oil-fired boilers or oil fuel units may be provided with a type approved fixed fire-extinguishing systems complying with IMO MSC/Circ.848 or IMO MSC/Circ.668 in addition to those types mentioned in SOLAS Reg. II-2/7.1.1.

Pt.4 Ch.10 Sec.11 Fire Safety - Fireman's Outfit
Spare charges for the breathing apparatus required by SOLAS Reg. II-2/17.1 are to be stored in the same location as the breathing apparatus.

Pt.4 Ch.10 Sec.12 Fire Safety - Miscellaneous Items
Detailed guidance for a suitable fixed fire extinguishing system based on low expansion foam covering storage spaces for seismic cables containing flammable liquids are added.

Pt.4 Ch.10 Sec.13 Fire Safety - Arrangement for Helicopter Decks
It is no longer required that the fire-fighting equipment for helicopter decks is arranged in accordance with requirements from national authority.

Pt.4 Ch.10 Sec.15 Fire Safety - Fire Safety Measures for Cargo Ships
Watertight doors in fire resisting divisions are to be made from steel.

The regulations for paints, varnishes and other finishes used on exposed interior surfaces as required by SOLAS Reg. II-2/49.2, only apply to accommodation spaces, service spaces and control stations in accordance with IACS unified interpretation SC127.

Pt.4 Ch.10 Sec.15 Fire Safety - Fire Safety Measures for Cargo Ships less than 500 Gross Tonnage
A fixed fire extinguishing system may be provided for machinery spaces of category A, in lieu of the foam type extinguisher required for cargo ships above 150 but below 500 gross tonnage for unrestricted service.

Pt.5 Ch.1 Sec.3 Ships for Navigation in Ice - Ice Strengthening for the Northern Baltic
The Finnish Maritime Administration has, among others, in their Bulletin No.13/27.9.1999 informed DNV about the new requirements for the minimum engine output for their Ice Classes 1A and 1A Super, which are equivalent to DNV Ice Classes ICE-1A and ICE-1A*. The new requirements are valid from 1 January 2001.

Except for an amendment effecting vessels with nozzle propellers, only editorial amendments have been made. The amendment for nozzle propellers is intended to provide a practical approach for the calculation of increased thrust force at slow speed and the corresponding effect to the minimum required power.

Pt.5 Ch.2 Sec.5 Passenger and Dry Cargo Ships - Dry Bulk Cargo Carriers
Requirements for structural testing of hatch covers and ballast holds have been deleted here and have been transferred to Pt.3 Ch.1 Sec.1 or Pt.3 Ch.2 Sec.1, as appropriate.

Pt.5 Ch.3 Sec.1 Oil Carriers - General Requirements
Requirements for structural and leak testing of cargo tanks and watertight hatch covers in combination carriers have been deleted here and have been transferred to Pt.3 Ch.1 Sec.1 or Pt.3 Ch.2 Sec.1, as appropriate.

The definitions of Gas dangerous zones in the rules for oil carriers, chemical carriers, and liquefied gas carriers, include the distance of 4,5 m from ventilation outlets of cargo pump rooms (and compressor room).

This requirement is not based on international regulations, and it appears that other class societies apply 3 m in their similar definitions. Where sister ships are classed by both DNV and other societies, the difference of definitions has in some cases caused confusion.

No record of the background for DNV’s 4,5 m requirement has been found.

The only similar definition in an international instrument is found in the IGC Code, where a Gas dangerous space or zone is defined in 1.3.17.7 as:

"a zone on the open deck, or semi-enclosed space on the open deck, within 3 m of any cargo tank outlet, gas or vapour outlet, cargo pipe flange or cargo valve or of entrances and ventilation openings to cargo pump-rooms and cargo compressor rooms"

The same distance is used in the IGC Code 10.2.3.5 on description of hazardous zones.

On this basis the DNV requirement is harmonised with that of other class societies and the IGC Code.

Pt.5 Ch.3 Sec.3 Oil Carriers - Damage Stability and Ship Arrangement
The new requirements of MARPOL Annex I, 25 A enters into force for ships for which the building contract is placed on or after 1 February 1999, or having a keel laying date on or after 1 August 1999 or delivery on or after 1 February 2002. These are design requirements and are therefore included in Pt.5 Ch.3.

The requirement that the distance from the nearest tank hatch or cargo tank opening to windlass and chain pipe is not to be less than 6 m is deleted. The requirement was a special DNV requirement. The requirement was implemented prior to introduction of detailed definitions of gas dangerous zones and is now covered satisfactorily otherwise.

Pt.5 Ch.3 Sec.5 Oil Carriers - Gas-freeing and Venting of Cargo Tanks
Oil carriers of less than 20 000 dwt and chemical carriers are normally not fitted with inert gas plants. Instead, an arrangement with portable or permanently installed fans is provided for gas freeing. In case of permanently installed gas freeing fans, these are often located in gas safe spaces.

The rules address systems with permanently installed fans for ventilating and gas freeing of cargo tanks. Such systems will supply air to the cargo tanks through temporary connections to cargo piping or through tank hatches.

In the initial stage of gas freeing (down to 30% LEL), explosive mixtures of gas will (may) exist in the tanks. Depending on the means by which the tank gas mixture is vented, the gas freeing fans will operate against a certain back pressure from cargo tanks and associated piping. Should the fans stop during this operation, there is a risk of back flow of explosive gas mixtures through the air supply line. For gas freeing fans located in gas safe spaces, prevention of such back flow is considered to be of great importance.

The existing rule require a shut-off valve and a non-return valve in the air supply line. Various valve arrangements, with different level of safety against back flow, has been approved as compliant with this requirement.

With the aim of a more uniform level of safety in these systems, the revised rule is more specific, by requiring one automatically operated shut-off valve and one non-return valve in series. The location of the valves is also specified, by requiring both to be located close to the boundary of the gas safe space with at least the non-return valve on the outside. Further, the control of the automatic valve is specified by requiring that the valve is to open after the fans are started and is to close automatically when the fans stop.

Pt.5 Ch.4 Sec.1 Chemical Carriers - General Requirements
The definitions of Gas dangerous zones in the rules for chemical carriers and liquefied gas carriers is amended as described under Pt.5 Ch.3 Sec.1 Oil Carriers - General Requirements.

Pt.5 Ch.4 Sec.5 Chemical Carriers - Scantlings and Testing of Cargo Tanks
Requirements for structural testing cargo tanks have been deleted here and have been transferred to Pt.3 Ch.1 Sec.1 or Pt.3 Ch.2 Sec.1, as appropriate.

Pt.5 Ch.4 Sec.9 Chemical Carriers - Gas-freeing and Venting of Cargo Tanks
Oil carriers of less than 20 000 dwt and chemical carriers are normally not fitted with inert gas plants. Instead, an arrangement with portable or permanently installed fans is provided for gas freeing. In case of permanently installed gas freeing fans, these are often located in gas safe spaces.

The same changes as described under Pt.5 Ch.3 Sec.5 Oil Carriers - Gas-freeing and Venting of Cargo Tanks apply to chemical carriers.

Pt.5 Ch.5 Sec.1 Liquefied Gas Carriers - General Requirements
The definitions of Gas dangerous zones in the rules for chemical carriers and liquefied gas carriers is amended as described under Pt.5 Ch.3 Sec.1 Oil Carriers - General Requirements.

Pt.5 Ch.7 Sec.3 Tugs, Supply Vessels and other Offshore/Harbour Vessels - Supply Vessels
The present rules for the class notation Supply Vessel are basically the same as at the time of their original development in the mid 70’s.

Since then the size and type of offshore support vessels have changed significantly. Originally the rules were developed and aimed at those vessels intended for operation in the North Sea. Later, there was a demand for offshore support vessels, in other offshore fields, with less severe environmental conditions. In these new areas other class societies have achieved more success than DNV, due mainly to the less severe requirements for vessels operating in these areas.

As a result of this, it has been found necessary to review the rules and, in response to market demand, to create an alternative set of rules for vessels primarily engaged in offshore operations outside of the North Sea area. Bearing in mind that these types of offshore support vessel may occasionally operate in the North Sea.

The amended rules keep the original class notation Supply Vessel, with stricter requirements primarily intended for vessels operating in the North Sea. A new class notation Supply Vessel Basic is added. This new class notation is DNV's response to the market demand and targets vessels operating mostly, in less severe offshore fields, e.g. South East Asia, Africa, Brazil, etc.

Based on approval experience, amendments to existing requirements have also been made to give clearer and more detailed text.

Pt.5 Ch.7 Sec.18 Tugs, Supply Vessels and other Offshore/Harbour Vessels - Standby Vessels (New)
In the past DNV has been contacted about the possibility of a specific class notation for vessels employed on standby service, especially in the North Sea. In fact several offshore support vessels, with rescue facilities, have been built to DNV class without class involvement, in regard to the standby service and rescue function. Additionally, standby vessels have been built for operation in other parts of the world with no specific requirements being enforced by the local authorities. It is therefore defined a minimum set of requirements for the safety equipment, rescue facilities and survivors, be covered by a class notation for standby vessels. It covers requirements for hull strength, towing equipment, rescue facilities, safety equipment and stability, amongst others.

The draft text has been developed using the following as a basis:

• In-service experience with DNV classed vessels being employed on standby service.

• Regulations from USCG and NMD.

• Guidelines from UKOOA (UK Offshore Operators Association).

Pt.6 Ch.1 Sec. 4 Miscellaneous Notations - Diving Systems
The Rules for Certification of Diving Systems, 1988 does not require the certification of hyperbaric lifeboats for the certification of diving systems. Since 1988, IMO has issued Guidance for Hyperbaric Evacuation, which is referred to in the Code of Safety for Diving Systems. This code was issued in its latest revision in 1995. The text of the IMO guidelines requiring hyperbaric evacuation has been included in the rules.

Furthermore essential services, emergency services and non-essential services are defined for power supplies together with the corresponding time limit of availability.

Changes in the industry, including the shift in the UK from DoE to HSE, necessitate a change of references in the text. The rules now refer to class notation DYNPOS AUTR, with a secondary reference to IMO rather than to DoE and NPD.

Pt.6 Ch.4 Sec.1 Additional Fire Protection (F-AMC) - General Requirements
The rules for additional fire protection are completely re-written and the philosophy is described below. Sec.1 is streamlined to include only items that apply for all class notations. Previous requirements now included in SOLAS for all ships are removed.

Pt.6 Ch.4 Sec.2 Additional Fire Protection (F-AMC) - Accommodation
For the accommodation, focus is on cost-efficient requirements for fire detection in cabins, escape ways and restrictions on the use of combustible materials.

Pt.6 Ch.4 Sec.3 Additional Fire Protection (F-AMC) - Machinery Spaces
In line with recommendations from a report on engine room fires, focus has been put on the following areas:

• Prevent fires by updating requirements for the oil systems (SOLAS Reg. II-2/15.2.9 to II-2/15.2.11 implemented in 1998 reduce the need for additional fuel system requirements).
  

• Prevent fires by introducing requirements for thermoscanning of engines, exhaust ducts, steam ducts (if any) and similar equipment where hot surfaces above 220 ° C may be expected.

• Rapid detection by enhancing requirements for smoke, heat and flame detectors.

• Rapid confirmation of fire by introducing requirements for TV monitoring of the engine room.

• Rapid release of water based local fire fighting system (similar to the present rules for F-M).

• Improved reliability of main fire extinguishing system.

• Improved manual fire fighting equipment (portable extinguishers and lightweight fireman’s equipment).

• Requirements for main and local extinguishing systems are updated with minor changes. For instance, only stainless steel or brass is accepted for CO2 valves, whereas only systems tested according to IMO MSC/Circ.913 is accepted for local systems.

• A new requirement for corrosion resistant closing appliances is introduced, as this is an identified trouble area.

Pt.6 Ch.4 Sec.4 Additional Fire Protection (F-AMC) - Deck and Cargo Area
The requirement for additional quantity of extinguishing agent to cover simultaneous fires in different compartments (engine room and pump rooms) is deleted as such fires is not considered a probable scenario.

Pt.6 Ch.5 Integrated Computer Systems (ICS)
The current rules for integrated computer systems went through a major revision before they were released in January 99. Based upon input from users, some minor changes are introduced in order to meet the user's needs and increase the market acceptance of the rules.

The new rules cover the present and future technologies for computer based systems. It mainly focuses on arrangement and extended testing at the manufacturer's works and at the yard. It also provides the tools necessary for maintenance of the integrated computer systems during the whole lifecycle of the systems in the operational phase.

Pt.6 Ch.7 Dynamic Positioning Systems
The rules for dynamic positioning systems were revised in 1990 and it has been found necessary to make changes, mainly due to the technical development and the IMO MSC/Circ.645 "Guidelines for vessels with dynamic positioning systems". The changes are minor and are described as follows:

• the general layout is changed to make the rules easier to access

• the additional class notation T has been deleted

• FMEA required for all projects with class notations AUTR and AUTRO

• redundancy test required for all projects with class notations AUTR and AUTRO

• three gyrocompasses required for class notation AUTR as per MSC/Circ.645

• separation requirements for class notation AUTRO are specified

• location of DP-control centre and equipment arrangement are specified

Pt.6 Ch.8 Nautical Safety
The existing rules date from July 1991. Over the past 10 years IMO has caught up with many of the technical specifications in the rules that address different navigational equipment, and DNV has gained experience from discussing and applying these rules. The rules are re-written and have been structured differently, in order to separate technical and operational requirements.

Pt.6 Ch.8 Sec.1 Nautical Safety - General
Some definitions have been reworded, new definitions have been added. The class notations have been re-organised to better serve the needs of the shipyards and individual shipowners, and to ensure that the ship has a valid certificate after re-sale of the ship.

Class notation NAUT-C covering bridge design, which is included in W1-OC, has been removed from the rules.

The remaining notations W1-OC and W1 now cover the technical part of the rules only. Compliance with this part is the responsibility of the shipyard and allows the yard to produce a clean certificate without compliance with operational part (Sec.9), which is the responsibility of the shipowners (together with the captain during the operation).

The class notation assigned the ship will be extended with a suffix Q when Sec.9 is complied with, making the notation W1-OC Q and W1 Q respectively. A separate audit will take place before approving the class notation to be extended with suffix Q.

The requirements for documentation to be submitted have been revised. Each requirement specifies the total documentation required for approval of a certain area within the rules.

Pt.6 Ch.8 Sec.2 Nautical Safety - Design of Workplace
The content on bridge and workstation arrangement has been re-structured and also includes the requirements for location of equipment. In addition, a summary of the requirements only applicable for W1 is given in a separate sub-section. Requirements regarding height of lower edge of bridge windows for W1-OC ships have been modified. The use of approved technical means for compliance with the required view astern outside the sector for bridge visibility related to collision avoidance is indicated.

Pt.6 Ch.8 Sec.4 Nautical Safety - Carriage Requirements for Navigational Systems and Equipment
The manufacturer or supplier of a grounding avoidance system is required to provide a course of competence in compliance with the knowledge requirements in Sec.9. Relevant equipment is grouped under collision avoidance system, grounding avoidance system and heavy weather avoidance system. The last group is prepared with the aim to take advantage of new technology by revising the requirements in accordance with the availability of upcoming systems within weather information systems to aid avoidance of heavy weather situations and hull monitoring systems to aid avoidance of structural damage.

Pt.6 Ch.8 Sec.5 Nautical Safety - General Bridge Equipment Requirements
Environmental requirements, which are addressed in the rules for main class are deleted. Power supply requirements are elaborated as found necessary based on experience gained.

Pt.6 Ch.8 Sec.6 Nautical Safety - Specific Requirements for Different Types of Bridge Equipment
Specific requirements, which now are covered by new IMO performance standards, as for example electronic chart systems (ECDIS), have been replaced by a reference to the IMO standard. Requirements specific for W1 are added for each type of equipment when applicable. Requirements for grounding avoidance system (GAS) are replacing the former automatic navigation and track-keeping system (ANTS). Detailed functional requirements have been established to govern the manufacturer's development. The sub-section for internal communication is harmonised with new IMO and classification requirements.

Pt.6 Ch.8 Sec.7 Nautical Safety - Man and Machine Interface
This section is rationalised, taking into consideration transfer of previous requirements to main class. Relevant main requirements are maintained for rule consistency.

Pt.6 Ch.8 Sec.8 Nautical Safety - Ship Manoeuvring Information
This section is harmonised with IMO requirements.

Pt.6 Ch.8 Sec.9 Nautical Safety - Qualifications and Operational Procedures
This section is rationalised by only maintaining requirements addressing the competence required for mastering the grounding avoidance system installed, when applicable, and procedures required for bridge operations under different operating conditions. Non-compliance does not affect the assignment of the basic class notations W1-OC and W1. Compliance extends the basic class notations with the suffix Q.

RP-28-00 * Gas fuelled engine installations

Pt.6 Ch.13 Gas Fuelled Engine Installations (New)
In the past only two ship types have been fitted with gas engine installations. These were liquefied natural gas (LNG) tankers and floating production and storage (FPSO) vessels. The first gas fuelled ship, other than a LNG or FPSO, was a car ferry, which was classed by DNV and delivered in January 2000. The existing classification standards were used as the basis for classifying this vessel, but additional criteria had to be developed to fully cover the installation. For instance, the storage of gas onboard vessels that were not gas carriers, is not covered in the current rules. New projects are expected to materialise very soon, therefore, a classification standard for such gas installations is urgently needed.

In the current rules the safety concept is based on one option, in that, gas piping in engine rooms onboard ships has to be fully enclosed in an outer pipe. The space between the gas pipe and the outer pipe is required to be ventilated and equipped with a gas detection facility. If gas is detected in the double pipe then the gas supply is automatically shut down. Any subsequent gas leakage in the inner pipe will not lead to leakage into the machinery space, and the engine room is considered to be gas safe.

The new rules introduce a second option, which is a new concept in regard to gas fuel in machinery spaces. This is called the ESD "emergency shutdown protected machinery space". In this option the gas pipes are not fully enclosed in double pipes, in the engine room. A condition for accepting ESD protected machinery spaces is that the gas engines are located in at least two separate engine rooms. The ESD protected engine room is considered gas safe under normal conditions. Ventilation and gas detection is required. If a gas concentration of 20% of the lower explosion limit (LEL) is detected on two of the detectors in the room, then all of the electrical equipment, not explosion proof, is to be automatically disconnected, in addition to the initiation of a gas supply emergency shut-down. In this way potential fire risks are removed. The lighting and ventilation fans are required to be of explosion proof type. The ESD protected machinery space is the concept utilised in the gas ferry.

Another new introduction into the rules is the requirement for excess flow shut down. This requirement is based on the possibility than an unexpected event causes a full rupture of the pipe. In this case an orifice senses the sudden pressure jump due to the excess flow, and the gas supply is shut down automatically. The shut down should be time delayed to prevent unwanted shutdown due to transient load variations.

Experience with the first gas ferry has been the basis for this new rule chapter. Moreover, the chapter also covers other ship types and types of installation. Additionally, the information formerly given in Class Note 42.1 "Dual Fuel Arrangements for Diesel Engines with High Pressure Gas Injection" and Certification Note 2.11 "Standard for Certification of Gas Burning Internal Combustion Engine Installations" has been included. All in all this new rule chapter covers the entire gas installation including gas containment, piping arrangements and gas engine design, and both dual fuel and gas only engine installations.

Pt.7 Ch.1 Sec.1 General Requirements - Application of the Rules
The new Classification Note No. 72.1 is intended to provide a simple approach for deciding acceptable main hull scantlings at the time of the renewal survey for vessel not built to DNV class or where such scantlings were not decided at the newbuilding approval stage.

Pt.7 Ch.1 Sec.3 General Requirements - Retroactive Rule Requirements
The Finnish Maritime Administration has, among others, in their Bulletin No.13/27.9.1999 informed DNV about the new requirements for the minimum engine output for their Ice Classes 1A and 1A Super, which are equivalent to DNV Ice Classes ICE-1A and ICE-1A*. The new requirements are valid from 1 January 2001. These requirements will also effect the existing vessels that were built before 2001-01-01.

Except for an amendment effecting vessels with nozzle propellers, only editorial amendments have been made. The amendment for nozzle propellers is intended to provide a practical approach for the calculation of increased thrust force at slow speed and the corresponding effect to the minimum required power.

Pt.7 Ch.2 Sec.1 Periodical Survey Requirements - General Requirements
Vessels with more than 3 years since last tailshaft withdrawal will have to carry out a complete tailshaft survey in connection with the implementation survey to obtain tailshaft monitoring (TMON) unless the condition of the shaft and bearing can be properly documented. Formerly there was no such time limit for when, in the survey cycle, a vessel could obtain TMON. The 15 year interval between complete surveys has been removed for vessels obtaining TMON based on the new machinery rules (see changes described under Pt.4). The scope for TMON has been extended to include arrangements where roller bearings are applied to support the shafting, such as podded propulsors and thrusters. The requirements for retention of TMON are specified in the rules and not only in the record on board, which has been the practice until now.

The requirements for planned maintenance systems (PMS) have been adapted to the new planned maintenance systems with their functions and possibilities. It is noted that stricter requirements from IMO for continuous improvement of the maintenance are given. The new rules for PMS survey arrangements are the first step in a total upgrading project for the PMS survey arrangement.

Based on the amended IACS unified requirement Z17 Procedural Requirements for Service Suppliers that covers approval of firms engaged in the examination of Ro-Ro ships’ bow, stern, side and inner doors, DNV may now recognise inspections carried out by an approved service supplier, as part of the annual surveys.

New IACS unified requirements (UR) have been implemented as described below.

Z6 Continuous system for hull special survey

According to IACS UR, continuous hull surveys may be applied for ships other than Oil Tankers, Combination Carriers, Bulk Carriers and Chemical Tankers (i.e. not for ships subject to ESP requirements). DNV Rules, however, restrict the application of continuous hull surveys to specific ship types; passenger ships, container ships, ro-ro ships and liquefied gas carriers, a restriction that mainly has impact for general cargo ships. The DNV Rules are not amended in accordance with this IACS UR.

Pt.7 Ch.2 Sec.2 Periodical Survey Requirements - Survey Extent - Main Class
Bunker tanks, tanks for consumables etc. onboard a ship can be of integral type (e.g. a double bottom fuel tank or a lubrication oil sump tank) or of independent type (e.g. a fuel oil daily service tank or a cylinder lubrication oil tank). Depending on the ship's the age, the number of fuel or diesel oil and lubrication oil tanks that are to be internally inspected are given in the rules. It is generally understood that the oil tanks chosen for internal inspection should be of the integral type. This is however not specified in the rules and from time to time independent tanks have been inspected at hull renewal survey. It should also be avoided that the same tanks are inspected at each renewal survey. The level of precision of the requirements for inspection of fuel and lubrication oil tanks is therefor increased.

New IACS unified requirements (UR) have been implemented as described below.

Z7 Hull classification surveys

Examination of anchors and chain cables and chain lockers and all cofferdams at first renewal survey. Particular emphasise is given on examination of engine room structures (mainly as outcome of discussions with OCIMF and INTERTANKO). Waiver regarding application of soft coatings in 'small' tanks i included.

Pt.7 Ch.2 Sec.3 Periodical Survey Requirements - Survey Extent - Additional Class. Special Service and Type Notations
New IACS unified requirements (UR) have been implemented as described below.

Z10.1 Hull surveys of Oil Tankers

Enhancement of requirements related to examination and operational testing of piping systems, in particular ballast pipes in cargo tanks and cargo pipes in ballast tanks and void spaces including owner's obligation to advise on all occasions when this piping is open during repair periods. Survey planning meeting prior to commencing the renewal survey with participation of the thickness measurement company. Extent of thickness measurements for areas with substantial corrosion as given, is maintained as 'guidance' and not as mandatory requirements as given in the IACS UR Z10.1.

Z10.2 Hull surveys of Bulk Carriers

Examination of all piping and penetrations in cargo holds at annual surveys for ships over 15 years of age. Survey planning meeting prior to commencing the renewal survey with participation of the thickness measurement company. Minimum extent of close-up examination at renewal survey including specific note related to transverse bulkheads requiring close-up at four levels. Extent of thickness measurements for areas with 'substantial corrosion' as given, is maintained as 'guidance' and not as mandatory requirements as given in IACS UR Z10.2. For ore carriers, the rules stipulate that extent of examination of wing tanks (i.e. ballast tanks) is to be as given for oil tankers at intermediate and renewal survey. This will in general require an extended scope for close-up examination that is recommended maintained based on previous experience with corrosion in such tanks. Revision of IACS UR in this respect is currently being discussed.

Z10.3 Hull surveys of Chemical Tankers

See comments for oil tankers, in general.

Pt.7 Ch.2 Sec.4 Periodical Survey Requirements - Survey Extent, Additional Class. Special Equipment and Systems Notations
The survey requirements for integrated computer systems have been revised.

Survey requirements for the class notation Q for nautical safety have been added.

Pt.7 Ch.4 Sec.3 Operational Requirements, Additional Class - Tankers for Oil
The current IACS unified requirement L3 has been redefined as an IACS recommendation, hence the content of the current Pt.7 Ch.4 Sec.3 and App. B is removed.

Pt.7 Ch.8 Alternative Survey Arrangement for Propulsion Machinery
Since the class notation NAUTICUS(Propulsion) was first introduced in January 1999, the market has clearly expressed expectations of a notation that is covering the whole machinery onboard the vessel and not just the main propulsion line. With the amendments introduced, DNV is taking one further step in fulfilling these expectations by adding electrical power generation and engine room auxiliaries to the scope.