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Copyright © 2013 ClassNK All rights reserved Introduction Amendments to MARPOL

Copyright © 2013 ClassNK All rights reserved Introduction Amendments to MARPOL Annex VI entered into force effective from 1 July 2010 concerning increasingly stringent requirements for nitrogen oxide (NOX) emissions from ships. Under these requirements, marine diesel engines have been subject to mandatory NOx Tier II requirements from 1 January 2011 that are about 15-22% lower than the NOx emission limits previously set under Tier I. Marine diesel engines also will be subject to NOx Tier III requirements from January 2016 in Emission Control Area(ECA), when engines will be required to satisfy a stricter limit that is about 80% lower than Tier I NOx emission limits. In addition, ships are now subject to a maximum limit on sulfur oxide (SOx) emissions of 3.5% m/m for fuel used from 1 January 2012 on the open sea. Moreover, ships have been subject to a maximum limit SOx emissions of 1.00% m/m from July 2010 when operating in an Emission Control Area (ECA). This limit is set to be further reduced to a maximum limit of just 0.1% m/m from January 2015. Amendments to MARPOL Annex VI adopted at IMO MEPC 62 dated in July 2011 also set forth new restrictions on carbon dioxide (CO2) emissions from ships that will become effective from 1 January 2013. As regulations curbing atmospheric pollution and greenhouse gas emissions grow ever stricter amid stronger calls for a greener shipping industry, attention is turning to the potential of natural gas as a cleaner alternative to liquid fuel oil. In theory, ships using the natural gas (LNG) methane with the same calorific power as diesel oil can reduce the amount of CO2 emissions by as much as 25%. In addition, the NOx emissions can be decreased about 80-90% through the use LNG instead of fuel heavy oil. Moreover, emissions of SOx and PM (particulate matter) are almost zero. For these reasons, LNG is known as a greener fuel of the future. Already, around 30 vessels, including many Norwegian ferries and offshore support ships operating in the North Sea, are powered by LNG, with use of the fuel expected to increase even further in the near future. Particular attention needs to be given to ensuring adequate safety precautions when using natural gas as fuel in order to decrease the potential of any explosive environment risk that may arise as a result of any gas leaks onboard the ship. International common safety requirements for natural gas fuelled ships were discussed at IMO MSC82 dated in June 2009, which resulted in the release of IMO Res.MSC285(86) INTERIM GUIDELINES ON SAFETY FOR NATURAL GAS-FUELLED ENGINE INSTALLATIONS IN SHIPS. Based on these interim guidelines, work has been preceding on the development of the INTERNATIONAL CODE OF SAFETY FOR SHIPS USING GASES OR OTHER LOW-FLASH POINT FUELS (IGF Code) for approval by the IMO scheduled by 2014 as new mandatory SOLAS requirements. Nippon Kaiji Kyokai (ClassNK) has developed guidelines entitled “Guidelines for Gas fuelled ships.” on design safety requirements for gas fuelled ships based on the current draft of the IGF Code. We hope these guidelines will provide practical guidance for shipyards, manufacturers, ship owners, managers, and operators looking to prepare their fleets for a safer, greener future. This edition of the Guidelines is simply for the purpose providing support in the design with respect to the current requirements, and will be amended periodically in accordance with any future changes in the IGF Code during future IMO discussions and rapid developments in the introduction of new technologies. Guidelines for Gas fuelled ships i Guidelines for Gas fuelled ships CONTENTS Chapter 1 Preamble ····························································································· 1 Chapter 2 General ······························································································· 2 2.1 Application ··································································································· 2 2.2 Definitions ··································································································· 2 2.3 Alternative design ··························································································· 4 Chapter 3 Function requirements ············································································ 5 3.1 Goal ··········································································································· 5 3.2 Functional requirements ···················································································· 5 Chapter 4 General requirement ··············································································· 7 4.1 Goal ··········································································································· 7 4.2 Risk Assessment ····························································································· 7 4.3 Limitation of explosion consequences ···································································· 7 Chapter 5 Ship design and arrangement ···································································· 8 5.1 Goal ··········································································································· 8 5.2 Functional requirements ···················································································· 8 5.3 General requirements ······················································································· 8 5.4 Machinery space concepts ················································································· 9 5.5 Requirements for gas safe machinery space ····························································· 9 5.6 Requirements for ESD-protected machinery spaces ···················································· 9 5.7 Requirements for location and protection of fuel piping ············································· 10 5.8 Requirements for machinery space design ····························································· 10 5.9 Requirements for bilge systems ········································································· 11 5.10 Requirements for drip trays ·············································································· 11 5.11 Requirements for arrangement of entrances and other openings ···································· 11 5.12 Requirements for air locks ··············································································· 11 Guidelines for Gas fuelled ships ii Chapter 6 Fuel Containment System ······································································ 13 6.1 Goal ········································································································· 13 6.2 Functional requirements ·················································································· 13 6.3 General requirements ····················································································· 13 6.4 Liquefied gas fuel containment ·········································································· 14 6.5 Portable tanks for liquefied gas fuel ···································································· 14 6.6 Compressed gas containment system ··································································· 14 6.7 Pressure relief system ····················································································· 15 6.8 Filling limit for liquefied gas fuel tanks ································································ 19 6.9 Maintaining fuel storage condition ······································································ 19 6.10 Atmospheric control within the fuel storage system ·················································· 20 6.11 Atmospheric control within hold spaces (Fuel containment systems other than type C independent tanks ························································································· 20 6.12 Environmental control of spaces surrounding type C independent tanks ·························· 21 6.13 Inerting ····································································································· 21 6.14 Inert gas production on board ············································································ 21 Chapter 7 General pipe design ·············································································· 22 7.1 Goal ········································································································· 22 7.2 Functional requirements ·················································································· 22 7.3 Requirements for general pipe design ·································································· 22 7.4 Requirements for materials ·············································································· 25 Chapter 8 Bunkering ·························································································· 26 8.1 Goal ········································································································· 26 8.2 Functional requirements ·················································································· 26 8.3 Requirements for bunkering station ····································································· 26 8.4 Requirements for manifold ··············································································· 26 8.5 Requirements for bunkering system ····································································· 26 Chapter 9 Fuel Supply to Consumers ······································································ 28 9.1 Goal ········································································································· 28 9.2 Functional requirements ·················································································· 28 9.3 Redundancy of fuel supply ··············································································· 28 9.4 Safety functions of gas supply system ·································································· 28 Guidelines for Gas fuelled ships iii 9.5 Requirements for fuel distribution outside of machinery space ····································· 32 9.6 Requirements for fuel supply to consumers in gas-safe machinery spaces ························ 32 9.7 Requirements for the design of ventilated duct, outer pipe against inner pipe gas leakage ······ 32 9.8 Requirements for gas compressors and pumps ························································ 33 Chapter 10 Power generation including propulsion and other energy converters ················· 34 10.1 Goal ········································································································· 34 10.2 Functional requirements ·················································································· 35 10.3 Requirements for internal combustion engines of Piston type ······································ 35 10.4 Requirements for boilers main and auxiliary ·························································· 35 10.5 Requirements for gas turbines ··········································································· 36 10.6 Requirements for fuel cells ··············································································· 36 Chapter 11 Fire Safety ·························································································· 37 11.1 Goal ········································································································· 37 11.2 Functional requirements ·················································································· 37 11.3 General ······································································································ 37 11.4 Fire protection ····························································································· 37 11.5 Fire main ··································································································· 37 11.6 Water spray system ························································································ 38 11.7 Dry chemical powder fire-extinguishing system ······················································ 38 11.8 Fire detection and alarm system ········································································· 38 Chapter 12 Explosion Protection ············································································· 39 12.1 Goal ········································································································· 39 12.2 Functional requirements ·················································································· 39 12.3 General requirements ····················································································· 39 12.4 Area classification ························································································· 39 12.5 Definition of hazardous area zones ····································································· 40 Chapter 13 Ventilation ·························································································· 41 13.1 Goal ········································································································· 41 13.2 Functional requirements ·················································································· 41 13.3 General requirements ····················································································· 41 13.4 Requirements for tank connection space ······························································· 42 13.5 Requirements for machinery spaces ···································································· 42 Guidelines for Gas fuelled ships iv 13.6 Requirements for fuel preparation room, pump and compressor rooms ··························· 43 13.7 Bunkering station ·························································································· 43 13.8 Ducts and double pipes ··················································································· 43 Chapter 14 Electrical installations ··········································································· 44 14.1 Goal ········································································································· 44 14.2 Functional requirements ·················································································· 44 14.3 General requirements ····················································································· 44 Chapter 15 Control, monitoring and safety systems ······················································ 45 15.1 Goal ········································································································· 45 15.2 Functional requirements ·················································································· 45 15.3 General requirements ····················································································· 45 15.4 Requirements for bunkering and gas tank monitoring················································ 45 15.5 Requirements for bunkering control ···································································· 46 15.6 Requirements for gas compressor monitoring ························································· 46 15.7 Requirements for gas engine monitoring ······························································· 46 15.8 Requirements for gas detection ·········································································· 47 15.9 Requirements for fire detection ·········································································· 47 15.10 Requirements for ventilation ············································································· 47 15.11 Safety functions of gas supply systems ································································· 48 Chapter16 Manufacture, workmanship and testing ····················································· 50 16.1 General requirements ····················································································· 50 16.2 Gas tanks ··································································································· 50 16.3 Gas piping systems ························································································ 51 16.4 Welding, post-weld heat treatment and non-destructive testing ····································· 52 16.5 Testing requirements ······················································································ 52 16.6 Other testing requirements ··············································································· 53 Guidelines for Gas fuelled ships - 1 - Chapter 1 Preamble These guidelines are based on IGF Code in the course of the development in IMO and provide criteria for the arrangement and installation of machinery, equipment and systems for ships operating with gas as fuel to minimize the risk to the ship, its crew and the environment, having regard to the nature of the fuels involved. Throughout the development of these guidelines it was recognized that it must be based upon sound naval architectural and engineering principles and the best understanding available of current operational experience, field data and research and development. Due to the rapidly evolving new fuels technology, the Society will periodically review these guidelines, taking into account both uploads/Industriel/ nkk-guide.pdf