1、 GUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK APRIL 2005 Guide to Color Coding Used in Online Version of the Guide The following summarizes the colors corresponding to Rule Changes, Corrigenda items and editorial changes in the Guide files which are available for download. Ru
2、le Changes: NOTICE NO. 1 July 2005 (effective 1 July 2005) NOTICE NO. 2 July 2007 (effective 1 July 2007) NOTICE NO. 3 November 2007 (effective 1 October 2007) NOTICE NO. 4 January 2008 (effective 1 January 2008) NOTICE NO. 5 July 2012 (effective 1 July 2012) NOTICE NO. 6 July 2015 (effective 1 July
3、 2015) Corrigenda: CORRIGENDA/EDITORIALS 30 January 2008 CORRIGENDA/EDITORIALS 31 March 2008 CORRIGENDA/EDITORIALS 1 July 2011 CORRIGENDA/EDITORIALS 5 March 2012 CORRIGENDA/EDITORIALS 1 February 2014 Editorials: Editorial Changes Guide for Vessels Intended to Carry Compressed Natural Gases in Bulk G
4、UIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK APRIL 2005 (Updated July 2015 see next page) American Bureau of Shipping Incorporated by Act of Legislature of the State of New York 1862 Copyright 2005 American Bureau of Shipping ABS Plaza 16855 Northchase Drive Houston, TX 77060
5、USA Updates July 2015 consolidation includes: February 2014 version plus Notice No. 6 February 2014 consolidation includes: July 2012 version plus Corrigenda/Editorials July 2012 consolidation includes: March 2012 version plus Notice No. 5 March 2012 consolidation includes: July 2011 version plus Co
6、rrigenda/Editorials July 2011 consolidation includes: March 2008 version plus Corrigenda/Editorials March 2008 consolidation includes: November 2007 version plus Notice No. 4, Corrigenda/Editorials November 2007 consolidation includes: July 2007 version plus Notice No. 3 July 2007 consolidation incl
7、udes: July 2005 Notice No. 1 July 2007 Notice No. 2 and added list of updates ABSGUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK .2005 iii Foreword Foreword 1 Introduction ABS has been requested by various designers to review their proposed design scenarios for the transportatio
8、n of compressed natural gas (CNG) by sea. The proposed CNG carrier designs considered thus far are considered somewhat novel in that they differ from any one of the vessels that are currently transporting methane by sea, not only in that the methane will not be transported as a cryogenic liquid, LNG
9、, but also in several key areas, including the following: Pressure and temperature of the cargo being carried Possible storage of cargo above the main deck Proposed method for loading and off-loading the cargo Proposed deviations from the IMO Gas Code factors of safety for hoop stress in independent
10、 Type B and C tanks. This Guide provides requirements for design, construction and periodic surveys required for maintenance of classification that would be applicable to CNG carriers, where it is intended to obtain ABS class for the vessels. These requirements may also serve to satisfy Port State a
11、nd Flag State Regulations as they develop. As these projects are still at the concept stage and various scenarios are being considered at this time, the objective will be to establish an overall philosophy or approach to provide a framework of reference material and cite precedence, where applicable
12、, as to what methodologies followed by designers in similar projects have proven successful in the past. While it is certainly not the intent of ABS to in any way prevent or stifle creative development of new ideas and concepts, ABS will point out where a proposal appears to go beyond the bounds of
13、what has been accepted practice in the past. In such cases, ABS will provide the designer with a list of steps considered necessary to establish that such a proposal, in fact, does not compromise the level of safety well established in the published Rules of the American Bureau of Shipping and those
14、 of applicable national and international Regulatory bodies. 2 Applicability of Existing ABS Rules and Regulatory Requirements for LNG Carriers to CNG Carriers It is recognized that the ABS “Rule Requirements for Vessels Intended to Carry Liquefied Gases in Bulk” (Part 5C, Chapter 8 of the ABS Rules
15、 for Building and Classing Steel Vessels), which is in full agreement with the IMO IGC Code, do not envisage the carriage of Compressed Natural Gas (CNG) as compared to LNG. However, it is considered that that these requirements are an excellent starting point for ABS as a Classification Society see
16、king to establish requirements for the safe transport of CNG by sea. Also, IMO Guidelines for Formal Safety Assessment (FSA) for use in the IMO Rule-Making Process, MSC/Circ. 1023, MEPC/Circ., should be used to qualify such a novel concept. Some of the hazards applicable to LNG carriers, such as met
17、hane vapor release, fire, explosion, toxicity, collision and grounding, would also be applicable to CNG carriers. However, there are a number of additional hazards or possible increased risk from the same hazards due to the differences identified in Paragraph 1 above. These would include the followi
18、ng; While there is no cryogenic liquid being transported or handled, the possibility of critical structure being exposed to low temperatures from impingement of auto-cooled escaping gas must be provided for in the design. While the existing requirements for LNG carriers establish hazardous areas aro
19、und potential sources of gas release, it will be required that a gas dispersion analysis be carried out to demonstrate that areas normally considered gas safe will not be engulfed during a venting or blow-down of high pressure gas or during an upset condition. Depending on the results of the gas dis
20、persion analysis, a vessel Emergency Shut-down system may be required to protect against the migration of methane gas into spaces normally containing a source of vapor ignition. iv ABSGUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK .2005 While a gas detection system in the cargo
21、 holds warns of a gas leak, since the gas is stored at high pressure in containers in cargo holds, a rapid gas release due to container or piping system failure could result in an overpressure condition in the cargo hold jeopardizing the integrity of the vessels hull. Accordingly, overpressure prote
22、ction for cargo hold spaces should be provided. The relief devices should have sufficient capacity to handle a rupture of the largest cargo tank, assuming rupture at any location. In addition to these relief devices, hatches shall be provided in each hold space cover. Discharge from the hold spaces
23、shall be routed to a safe location. While the IMO Gas Code includes requirements for active and passive fire protection systems applicable for liquid methane fires, it does not envisage a high pressure (jet) fire which could result from the ignition of a high pressure gas flow from a ruptured pipe.
24、Accordingly, means to protect against such an occurrence will be required to be demonstrated for CNG carriers. Regarding the appropriate application of the requirements of Chapters 2 and 3 of the IGC Code to the damage assumptions and segregation of the cargo area, please note that in accordance wit
25、h Chapter 19 of the IGC Code, a vessel transporting methane is required to comply with the requirements for a type 2G ship, or 2PG if of 150 meters in length or less, as defined in 2.1.2 of the Code. Accordingly, ABS would consider the same to be applicable for the CNG carriers. 3 Flag State Require
26、ments ABS cannot speculate with regard to the requirements that would be applied to the proposed CNG carrier concept by an Administration. ABS can, however, offer the following insights based on the knowledge of past practices and the workings of the IMO Organization. i) Since the IMO IGC Code becam
27、e effective in 1975, it has been adopted and implemented by almost every maritime nation in the world and since that time virtually all of the LNG and LPG cargos that have been transported have been carried in vessels in full, or at least substantial, agreement with the Code. ii) While the transport
28、ation of natural gas in a gaseous state rather than a liquid state was never envisaged by the IMO IGC Code, it would be reasonable to assume that any Administration signatory to the IGC Code, such as the United States, would seek to establish some level of compliance with the Code, at least as a sta
29、rting point or frame of reference. iii) The LNG community is a relatively small community that meets in various forums such as SIGTTO (Society of Gas Tanker and Terminal Operators) and exchanges information readily. This community takes great pride in the fact that there has never been a major LNG i
30、ncident at sea. Owners and operators of gas carriers and terminals can influence their respective Flag States and they should be expected to rightfully demand that there be no reduction in overall safety as a result of this new means of transporting natural gas. iv) Reliability-based engineering and
31、 other methodologies have not been used heretofore to justify designs in the marine community, so many Administrations may not initially be prepared to consider designs that significantly differ from what has been done in the past on the basis of such studies. Administrations that are “Coastal State
32、s” for offshore activities may be more familiar with reliability-based engineering methods. v) Paragraph 1.4 of the IGC Code provides for Equivalents, which gives certain latitude toward the acceptance of alternative provisions, procedures or arrangements if such has been determined to be not less e
33、ffective. ABSGUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK .2005 v Table of Contents GUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK CONTENTS CHAPTER 1 Scope and Conditions of Classification (Supplement to the ABS Rules for Conditions of Classification) 1
34、See also separately published booklet ABS Rules for Conditions of Classification (Part 1) Section 1 Classification 4 Section 2 Classification Symbols and Notations 5 Section 3 Rules for Classification 6 Section 4 Submission of Data 7 Section 5 Hazards 9 Section 6 Conditions for Survey After Construc
35、tion. 10 Appendix 1 Definitions 11 Appendix 2 Abbreviations and References . 17 CHAPTER 2 Risk . 19 Section 1 General 20 Section 2 Requirements . 21 Section 3 Acceptance Criteria 28 Section 4 Limit State Design Interaction 29 CHAPTER 3 Ship Survival Capability and Location of Cargo Tanks 31 Section
36、1 General 33 Section 2 Freeboard and Intact Stability 34 Section 3 Shipside Discharges Below the Freeboard Deck 35 Section 4 Conditions of Loading 36 Section 5 Damage Assumptions for Stability Assessment 37 Section 6 Location of Cargo Tanks 39 Section 7 Flooding Assumptions 40 Section 8 Standard of
37、Damage 43 Section 9 Survival Requirements . 44 Appendix 1 Onboard Computers for Stability Calculations . 45 vi ABSGUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK .2005 CHAPTER 4 Ship Arrangements 52 Section 1 Segregation of the Cargo Area 53 Section 2 Accommodations, Service and
38、 Machinery Spaces and Control Stations . 55 Section 3 Cargo Pump Room and Cargo Compressor Rooms . 57 Section 4 Cargo Control Rooms 58 Section 5 Access to Spaces in the Cargo Area . 59 Section 6 Air-locks . 62 Section 7 Bilge, Ballast and Fuel Oil Arrangements 63 Section 8 Athwartships, Bow, Stern a
39、nd Turret (Internal/External) Loading and Unloading Arrangements 64 Section 9 Hull Structure . 66 Section 10 Access 67 Section 11 Emergency Escape and Safe Refuge 68 CHAPTER 5 Cargo Containment 69 Section 1 General 72 Section 2 Definitions 73 Section 3 Design Loads . 76 Section 4 Structural Analyses
40、 79 Section 5 Allowable Stresses and Corrosion Allowances . 82 Section 6 Installation of Cargo Tanks and Supports 83 Section 7 Thermal Protection . 84 Section 8 Insulation 85 Section 9 Insulation Materials 87 Section 10 Cargo Tank Fabrication and Testing . 88 Section 11 Stress Relieving for Cargo Ta
41、nks 94 Section 12 Guidance Formulae for Acceleration Components 95 Section 13 Stress Categories 97 Appendix 1 Probabilistic Limit State Design Approach . 99 CHAPTER 6 Process Pressure Vessels and Liquid, Vapor and Pressure Piping Systems . 111 Section 1 General 112 Section 2 Cargo and Process Piping
42、 . 113 Section 3 Piping Fabrication and Joining Details . 116 Section 4 Testing of Piping 117 Section 5 Cargo System Valving Requirements 118 Section 6 Ships Cargo Hoses . 119 ABSGUIDE FOR VESSELS INTENDED TO CARRY COMPRESSED NATURAL GASES IN BULK .2005 vii CHAPTER 7 Materials of Construction 120 Se
43、ction 1 General Material Requirements . 122 Section 2 Special Processing and Testing Requirements . 127 Section 3 Tests and Test Data . 131 Section 4 General Requirements on Testing and Inspection 134 Section 5 Qualification and Production Weld Testing 140 CHAPTER 8 Cargo Pressure/Temperature Contro
44、l 143 Section 1 General 144 Section 2 Refrigeration Systems 145 CHAPTER 9 Cargo Tank, Cargo Handling, Cargo Process and Piping Overprotection and Vent System 146 Section 1 General 147 Section 2 Pressure Relief Systems 149 Section 3 Pressure/Vacuum Protection for Cargo Hold 151 Section 4 Size of Valv
45、es 152 CHAPTER 10 Environmental Control . 153 Section 1 Environmental Control within Cargo Tanks and Cargo Piping Systems 154 Section 2 Environmental Control within the Hold Spaces for Cargo Tanks . 155 Section 3 Inerting . 156 Section 4 Inert Gas Production Onboard . 157 CHAPTER 11 Electrical Insta
46、llations . 158 Section 1 General 159 Section 2 Types of Equipment . 160 CHAPTER 12 Fire Protection and Fire Extinction . 162 Section 1 Fire Safety Requirements 163 Section 2 Fire Water Main Equipment . 164 Section 3 Water Spray System 165 Section 4 Dry Chemical Powder Fire-extinguishing Systems 167
47、Section 5 Cargo Handling System and Equipment 169 Section 6 Firemens Outfits 170 CHAPTER 13 Mechancial Ventilation in the Cargo Area 171 Section 1 Spaces Required to be Entered During Normal Cargo Handling Operations 172 Section 2 Spaces not Normally Entered 175 viii ABSGUIDE FOR VESSELS INTENDED TO
48、 CARRY COMPRESSED NATURAL GASES IN BULK .2005 CHAPTER 14 Instrumentation (Gauging, Gas Detection and Cargo Handling Controls) . 176 Section 1 General 177 Section 2 Level Indicators for Cargo Tanks (If Applicable) 178 Section 3 Overflow Control (If Applicable) . 179 Section 4 Pressure Gauges . 180 Se
49、ction 5 Temperature-indicating Devices 181 Section 6 Gas Detection Requirements . 182 CHAPTER 15 Use of Cargo as Fuel 185 Section 1 General 186 CHAPTER 16 Operating Requirements 187 Section 1 Cargo Information 188 Section 2 Personnel Training . 189 Section 3 Entry into Spaces . 190 Section 4 Carriage of Cargo at Low Temperature . 191 Section 5 Protective Equipment . 192 Section 6 Systems and Controls 193 Section 7 Cargo Transfer Operations 194 CHAPTER 17 Surveys . 195 Section 1 Surveys During Construction . 197 Section
