IBC code 1998

INTERNATIONAL CODE FOR THE: CONSTRUCTION AN·D EQUIPMENT OF SHIPS CARRYING DANGEROUS CHEMICALS IN BULK (IBC CODE) and Index of Dangerous Chemicals Carried in Bulk 1998 edition Foreword IBC Code first published in 1983 Second edition 1986 Third edition 1990 Fourth edition (included Index of Dangerous Chemicals Carried in Bulk) 1994 On 17 June 1983 the Maritime Safety Committee (MSC) adopted, by resolution MSC.4(48), the International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk (IBC Code) Under the provisions of chapter VII of the International Convention for the Safety of life at Sea, 1974 (SalAS 74), as amended in 1983, chemical tankers constructed on or after July 1986 must comply with the provisions Index of Dangerous Chemicals Carried in Bulk first published in 1985 Second edition 1987 Third edition 1990 fourth edition (included with IBC Code) 1994 Second combined edition of the Code 1998 by the INTERNATIONAL MARITIME ORGANIZATION Albert Embankment, London SE1 7SR Printed by the International Maritime Organization, London 10 ISBN 92-801-1456-5 On December 1985, by resolution MEPC.19(22), the IBC Code was extended by the Marine Environment Protection Committee (MEPC) to cover marine pollution aspects for the implementation of Annex II of the International Convention for the Prevention of Pollution from Ships, 1973, as modified by the Protocol of 1978 relating thereto (MARPOL 73/78) Under the provisions of regulation 13 of Annex II of MARPOl 73/78, chemical tankers constructed on or after July 1986 must comply wiJh the provisions of the Code The MSC then formally adopted the same amendments as those adopted by the MEPC by resolution MSC.10(54), under article VIII(b) of SalAS 74, so that the IBC Code remains identical for the purposes of both MARPOl 73/78 and SalAS IMO PUBLICATION Sales number: IMO-'OOE 74 The two Committees subsequently established appropriate procedures for amending the IBC Code (MEPC.25/20, annex 7) to ensure that the Code remains identical at all times under the mandatory requirements of the two Conventions Under MARPOl 73/78 chemical tankers must comply with the provisions of the Equipment of Ships Carrying Dangerous Under SalAS 74 the BCH Code remains Code is issued as a separate publication Copyright © IMO 1998 All rights reserved No part of this publication may, for sales purposes, be produced, stored in a retrieval system or transmitted in any form or by any means, electronic, electrostatic, magnetic tape, mechanical, photocopying or otherwise, without prior permission in writing from the International Maritime Organization constructed before July 1986 Code for the Construction and Chemicals in Bulk (BCH Code) as a recommendation The BCH The Index of Dangerous Chemicals Carried in Bulk - a supplement to the IBC and BCH Codes, contained an index of all chemicals referred to' in the BCH and IBC Codes which provided the various names known for a particular chemical This index has now been updated and incorporated into the present publication Previously, annexes II and III of MARPOl 73/78 contained lists of products which were reproduced in chapters, 17 a.nd 18 of the IBC Code as well as chapters VI and VII of pre-1993 editions of the BCH Code However, since 1993, the lists of products in chapters VI and VII of the BCH Code have been replaced by references to the IBC Code In addition, the lists of products in appendices II and III of annex II to the 1997 consolidated edition of MARPOl 73/78 have also been replaced by references to the IBC Code As a result, the IBC Code is now t"te definitive source of names for products subject to appendices \I and III of Annex II of MARPOl 73/78 Reference is also made to the MEPC.2/Circs, issued annually in December; these contain, inter alia, details of products that have been the subject of Tripartite Agreements and are, in effect, a supplement to the IBC Code Annex of these circulars includes products that are expected to become new or amended entries to the IBC Code A future am~ndfl'lent, shown in ~he circular, serves as prior notice of the carriage conditions which will only apply to that product wheo the next set of amendments enter into force A number of other documents closely related to the IBC Code are annexed to this publication The MSC and MEPC agreed that, at their spring 1990 sessions, they would adopt amendments to the BCH Code to introduce the harmonized system of survey and certification Under the provisions of these proposed amendments, they will enter into force when the 1988 SOlAS Protocol, which contains corresponding provisions, enters into force, at which time section 1.5 and the model form of the Certificate of Fitness will be replaced Contents Page International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk Preamble CHAPTER - GENERAL 1.1 Application 1.2 Hazards 1.3 Definitions 1.4 Equivalents 1.5 Surveys and certification CHAPTER - SHIP SURVIVAL CAPABILITY OF CARGO TANKS AND LOCATION 13 2.1 General 2.2 Freeboard and intact stability 2.3 Shipside discharges below the freeboard 2.4 Conditions 2.5 Damage assumptions 2.6 location 2.7 Flooding assumptions 2.8 Standard of damage 2.9 Survival requirements CHAPTER 14 14 deck 15 of loading 15 of cargo tanks 16 ~ 17 18 " " 19 - SHIP ARRANGEMENTS 3.1 Cargo segregation 3.2 Accommodation, service and machinery and control stations 20 spaces 20 3.3 Cargo pump-rooms 21 3.4 Access to spaces in t~e 22 3.5 Bilge and ballast arrangements cargo area 22 3.6 Pump and pipeline identification 3.7 Bow or stern loading and unloading arrangements 23 CHAPTER 10 - ELECTRICAL INSTAllATIONS 23 10.1 Ge~eral 10.2 Hazardous and wiring 10.3 Bonding 10.4 Electrical requirements CHAPTER - CARGO CONTAINMENT 4.1 Definitions 4.2 Tank type requirements 25 for individual product~ \ i \ 42 locations and types of equipment 43 45 for individual products 45 25 CHAPTER 11 - FIRE PROTECTION AND FIRE EXTINCTION CHAPTER - CARGO TRANSFER 5.1 Piping scantlings 5.2 Piping fabrication and joining 26 "28 details 5.3 Flange connections 5.4 Test requirements 5.5 Piping arrangements 5.6 Cargo-transfer 5.7 Ship's cargo hoses 28 for piping Application 11.2 Cargo pump-rooms 11.3 Cargo area 47 11.4 Special requirements 49 29 30 systems General 6.2 Special requirements 46 30 CHAPTER 12 - MECHANICAL VENTilATION 32 IN THE CARGO AREA Spaces normally entered during cargo-handling operations 50 12.2 Pump-rooms and other enclosed spaces normally entered 51 12.3 Spaces not normally 12.1 CHAPTER - MATERIALS OF CONSTRUCTION 6.1 46 29 control 11 entered 51 ' 32 for materials CHAPTER 13 - INSTRUMENTATION CHAPTER - CARGO TEMPERATURE CONTROL 7.1 General 7.2 Additional 34 , requirements 52 Vapour 52 detection CHAPTER 14 - PERSONNEL PROTECTION Application Protective 14.2 Safety equipment equipment 54 54 ' 36 venting 36 CHAPTER 15 - SPECIAL REQUIREMENTS 37 15.1 38 Acetone cyanohydrin and lactonitrile (80% or less) 38 15.2 Ammonium 15.3 Carbon disulphide 15.4 Diethyl ether 15.5 Hydrog~n 15.6 Motor fuel anti-knock compounds (containing lead alkyls) 63 Phosphorus, 64 Cargo-tank 8.3 Types of tank venting systems 8.4 Venting for individual requirements Cargo-tank 14.1 8.2 8.5 Gauging 13.2 35 CHAPTER - CARGO-TANK VENTING AND GAS-FREEING ARRANGEMENTS 8.1 13.1 products gas-freeing CHAPTER - ENVIRONMENTAL CONTROL 9.1 General 9.2 Environmental control requirements products 40 for individual 41 15.7 nitrate solution peroxide yellow solution 57 57 (93% or less) solutions or white ; 58 59 59 15.8 Propylene oxide and mixtures of ethylene oxide/ propylene oxide with an ethylene oxide content of not more than 30% by weight 65 15.9 Sodium chlorate 69 19.1 General 15.10 Sulphur (molten) 69 19.2 Ship survival capability 15.11 Acids 70 19.3 Ship arrangements 15.12 Toxic products 19.4 Cargo containment and incinerator 19.5 Cargo transfer 143 19.6 Materials 144 solution 15.14 15.15 (50% or less) 15 i3 Cargoes protected CHAPTER ' .' by additives , 71 71 Cargoes with a vapour pressure greater than 1.013 bar absolute at 37.8°C Cargoes' with low ignition temperature and wide flammability range [De/etedJ \ 72 "73 19 - REQUIREMENTS FOR SHIPS ENGAGED 11\1 THE INCINERATION AT SEA OF LIQUID CHEMICAL WASTE \ 141 and location of construction 19.7 Tank vent systems Cargo-tank Electrical installation control Cargo contamination 73 15.17 Increased ventilation requirements 74 19.10 Fire protection 74 19.11 Mechanical ventilation in the cargo area and in the incinerator location Special cargo pump-room 15.19 Overflow 15.20 Alkyl (CrC')) 15.21 Temperature CHAPTER 16.1 control nitrates, all isomers 75 75 Instrumentation 19.13 Personnel CHAPTER REQUIREMENTS 20 - TRANSPORT 20.1 Preamble 76 Definitions training 77 20.3 Applicability 78 20.4 Permitted 20.5 Documentation Cargo information Personnel quantity of cargo per tank of and entry into cargo tanks and overflow protection shipments Cargoes not to be exposed to excessive heat 78 20.6 Classification 79 20.7 Carriage and handling CHAPTER 16A ADDITIONAL MEASURES FOR THE PROTECTION OF THE MARINE ENVIRONMENT 16A.1 General 16A.2 Condition 16A.3 Procedures CHAPTER of carriage 17 - SUMMARY OF LIQUID 146 146 CHEMICAL WASTES 147 147 147 of liquid chemical 148 148 wastes of liquid chemical wastes 148 Manual Model form of International Certificate of Fitness for the Carriage of Dangerous Chemicals in Bulk OF MINIMUM 80 REQUIREMENTS 18 - LIST OF CHEMICALS TO WHICH DOES NOT APPLY 148 APPENDIX 80 Index of dangerous chemicals carried in bulk 81 Relevant decisions of the MSC and MEPC Criteria for hazard evaluation CHAPTER 80 and Arrangements 145 16.6 requirements 145 78 Dperational Stowage Df cargo samples Additional control 145 16.5 16.7 144 and fire extinguishing 19.12 20.2 16.3 Opening 74 76 allowable 16.2 16.4 sensors 16 - OPERATIONAL Maximum requirements 143 144 15.16 15.18 19.9 1-42 142 standards 19.8 environmental of cargo tanks THE CODE 129 of bulk chemicals Guidelines for the uniform application of the survival requirements of the Bulk Chemical Code and the Gas Carrier Code ';'.' 149 157 191 201 IBC Code Revised standards for the design, testing and locating of devices to 'prevent the passage of flame into cargo tanks in tankers 207 Revised factors to be taken into consideration when designing cargo tank venting and gas-freeing arrangements 222 Calculation of the capacity of foam systems for chemical tankers Procedures for inspection, cleaning, passivation and loading of tanks for the carriage of hydrogen peroxide solutions 8-60%, which have contained other cargoes, or for the carriage of other cargoes after the carriage of hydrogen peroxide 22:4 \ 22 Preamble The purpose of this Code is to provide an international standard for the safe carriage by sea in bulk of dangerous and noxious liquid chemicals listed in chapter 17 of the Code by prescribing the design and construction standards of ships, regardless of tonnage, involved in such carriage and the equipment they should carry so as to minimize the risk to the ship, to its crew and to the environment, having regard to the nature of the products involved The basic philosophy is to assign to each chemical tanker one of the ship types according to the degree of the hazards of the products carried by such ship Each of the products may have one or more hazard properties, which include flammability, toxicity, corrosivity and reactivity, as well as the hazard they may present to the environment if accidentally released Throughout the development of the Code it was recognized that it must be based upon sound naval architectural and engineering pr)nciples and the best understanding available as to the hazards of the various products covered; furthermore that chemical tanker design technology is not only a complex technology but is rapidly evolving C\ndthat the Code should not remain static Therefore the Organization will periodically review the Code, taking into account both experience and technical development Amendments to the Code involving requirements for new products and their conditions of carriage will be circulated as recommendations, on an interim basis, when adopted by the Maritime Safety Committee (MSe) and the Marine Environment Protection Committee (MEPe) of the Organization, in accordance with the provisions of article VIII of the International Convention for the Safety of Life at Sea, 1974 (SOLAS 74), and article 16 of the International Convention for the Prevention of Pollution from Ships, 1973, as modified by the Protocol relating thereto (MARPOL 73/78), respectively, pending the entry into force of these amendments The Code primarily deals with ship design and equipment In order to ensure the safe transport of the products, the total system rrlust, however, be appraised Other important facets of the safe transport of the products, such as training, operation, traffic control and handling in port, are being or will be examined further by the Organization The development of the Code has been greatly assisted by relevant work of the International Association of Classification Societies (lACS) and of the International Electrotechnical Commission (lEe) , Chapter 16 of the Code, dealing with operational requirements of chemical tankers, highlights the regulations in other chapters that are operational in nature and mentions those other important safety features that are peculiar to chemical tanker operation The layout of the Code is in line with the International Code for the Construction and Equipment of Ships Carrying liquefied Cases in Bulk (ICC Code), adopted by the Maritime Safety Committee at its forty-eighth session Cas carriers may also carry in bulk liquid chemicals covered by this Code, as Chapter prescribed in the ICC Code The 1998 edition of the Code is based on the original text as adopted by MSC resolution MSC.4(48) In response to resolution 15 of t~e International Conference on Marine Pollution, '19i3, the MEPC,\ at its twenty-second session, adopted, by resolution MEPC.19(22), the IBC Code extended to cover marine pollution prevention aspects for the implementation of Annex II to MARPOl 73/78 10 Subsequent to this, the 1998 edition of the amendments adopted by the following resolutions: Code includes • Resolution Adoption Deemed acceptance Entry into force MSC10(54) 29 April 1987 29 April 1988 30 October 1988 MSC14(57) MEPC32(27) 11 April 1989 17 March 1989 12 April 1990 12 April 1990 13 October 1990 13 October 1990 MSC28(61) MEPC55(33) 11 December 1992 30 October 1992 January 1994 January 1994 July 1994 July 1994 MSC50(66) MEPC69(38) June 1996 10 July 1996 January 1998 January 1998 July 1998 July 1998 MSC58(67) MEPC73(39) December 1996 10 March 1997 January 1998 10 January 1998 July 1998 10 July 1998* *Note: Parties invited to implement on July 1998 11 As from the date of entry into force of the 1983 amendments to SOlAS 74 (i.e July 1986) and the date of implementation of Annex II of MARPOl 73/78, this Code became subject to mandatory requirements under these Conventions Amendments to the Code, whether from the point of view of safety or of marine pollution, must therefore be adopted and brought into force in accordance with the procedures laid down in article VIII of SOlAS 74 and article 16 of MARPOl 73/78 respectively General 1.1 Application 1.1.1 The Code applies to ships regardless of size, including those of less than 500 tons gross tonnage, engaged in the carriage of bulk cargoes of dangerous or noxious liquid chemical substances, other than petroleum or similar flammable products as follows: ' products having significant fire hazards in excess of those of petroleum products and similar flammable products; products having significant hazards in addition to flammability Or other than Products that have been reviewed and determined not to present safety and pollution hazards to such an extent as to warrant the application of the Code are found in chapter 18 1.1.2 liquids covered by the Code are those having a vapour pressure not exceeding 2.8 bar absolute at a temperature of 37.8°C 1.1.2A For the purpose of the 1974 SOlAS Convention, the Code does not apply to ships which are engaged in the carriage of products included in chapter 17 solely on the basis of their pollution characteristics and identified as such by an entry of "P" only in column d 1.1.28 For the purposes of MARPOl 73/78, the Code applies only to chemical tankers, as defined in regulation 1(1) of Annex II thereof, which are engaged in the carriage of noxious liquid substances falling into category A, B or C and identified as such by an entry of "A", "B" or "C" in column c 1.1.3 For a product proposed for carriage in bulk, but not listed in chapter 17 or 18, the Administration and port Administrations involved in such carriage should prescribe the preliminary suitable conditions fo'r the carriage, having regard to the criteria for hazard evaluation of bulk chemicals The Organization should be notified of the conditions for consideration for inclusion of the product in the Code For the evaluation of the pollution hazard of such a product and assignment of its pollution category, the procedure specified in regulation 3(4) of Annex II of MARPOl 73/78 must be followed 1.1.4 Unless expressly provided otherwise, the Code applies to ships the keels of which are laid or which are at a stage at which: construction identifiable with the ship begins; and l ·2 assembly has commenced comprising at least 50 tonnes or 1% of 'the estimated mass of all structural material, whichever is less; 1.2.5 on or after July 1986 1.1.5 A ship, irrespective of the date of construction, which is converted to a chemical tanker on or after July 1986 should be treated as a chemical tanker constructed on the date on which such conversion commences This conversion provision does not apply to the modificatio'n of a ship referred to in regulation 1(12) of Annex II of MARPOL 73/78 1.1.6 Where reference is made in the Code to a paragraph, provisions of the subparagraphs of that designation should apply 1.2 1.2.6 " other products; or water; or the product itself (including polymerization) ' Marine pollution hazard, as defined by: bioaccumulation with attendant risk to aquatic life or human health or causing tainting to seafood; damage to living resources; hazard to human health; and reduction of amenities all the • Hazards Reactivity hazard, defined by reactivity with: Hazards of products covered by the Code include: 1.2.1 Fire hazard, defined by flash point, boiling point, flammability and autoignition temperature of the chemical 1.2.2 limits Health hazard, defined by: irritant or toxic effect on the skin or on the mucous membranes of the eyes, nose, throat and lungs in the gas or vapour state combined with vapour pressure; or irritational effects on the skin in the liquid state; or toxic effect, taking into account values of 1.3 Definitions The following definitions apply unless expressly provided (Additional definitions are given in individual chapters.) otherwise 1.3.1 Accommodation spaces are those spaces used for public spaces, corridors, lavatories, cabins, offices, hospitals, cinemas, games and hobbies rooms, barber shops, pantries containing no cooking appliances and similar spaces Public spaces are those portions of the accommodation spaces which are used for halls, dining rooms, lounges and similar permanently enclosed spaces LDso (oral): a dose which is lethal to 50% of the test subjects when administered orally; 1.3.2.1 Administration ship is entitled to fly LDso (skin): a dose which is lethal to 50% of the test subjects when administered to the skin; 1.3.2.2 Port administration means the appropriate authority of the country in the port of which the ship is loading or unloading LCso: the concentration test subjects which is lethal by inhalation to 50% of the 1.3.3 Boiling point is the temperature at which a product exhibits a vapour pressure equal to the atmospheric pressure 1.2.3 Water pollution hazard, defined by human toxicity, water solubility, volatility, odour or taste, and relative density 1.3.4 Breadth (B) means the maximum breadth of thE: ship, measured amidships to the moulded line of the frame in a ship with a metal shell and to the outer surface of the hull in a ship with a shell of any other material The breadth (B) should be measured in metres 1.2.4 Air pollution hazard, defined by: emergency exposure limit (E.E.L.) or LCso; vapour pressure; solubility in water; relative density of liquid; vapour density means the Government of the State whose flag the 1.3.5 Cargo area is that part of the ship that contains cargo tanks, slop tanks, cargo pump-rooms including pump-rooms, cofferdams, ballast or void spaces adjacent to cargo tanks or slop tanks and also deck areas throughout the entire length and breadth of the part of the ship over the above-mentioned spaces Where independent tanks are installed in hold spaces, cofferdams, ballast or void spaces at the after end of the aftermost hold space or at the forward end of the forwar~most hold space are excluded from the cargo area S 1.3.6 Cargo pump-room is a space containing pumps and their accessories for the handling of the products covered by the Code 1.3.7 Cargo service spaces are spaces within the cargo area used for workshops, lockers and store-rooms of more than m2 in area, ~sed for cargo-handling equipment 1.3.8 Cargo tank is the envelope designed to contain the cargo \ 1,3.9 Chemical tanker is a cargo ship constructed or adapted and used for the carriage in bulk of any liquid product listed in chapter 17 1.3.10 Cofferdam is the isolating space between two adjacent steel bulkheads or decks This space may be a void space or a ballast space 1.3.11 Control stations are those spaces in which ship's radio or" main navigating equipment or the emergency source of power is located or where the fire-recording or fire-control equipment is centralized This does not include special fire-control equipment which can be most practically located in the cargo area 1.3.12 Flammability limits are the conditions defining the state of fueloxidant mixture at which application of an adequately strong external ignition source is only just capable of producing flammability in a given test apparatus 1.3.13 Flashpoint is the temperature in degrees Celsius at which a product will give off enough flammable vapour to be ignited Values given in the Code are those of "closed-cup test" determined by an approved flashpoint apparatus 1.3.14 Hold space is the space enclosed by the ship's structure in which an independent cargo tank is situated 1.3.15 Independent means that a piping or venting system, for example, is in no way connected to another system and that there are no provisions available for the potential connection to other systems 1.3.16 Length (L) means 96% of the total length on a waterline at 85% of the least moulded depth measured from the top of the keel, or the length from the foreside of the stem to the axis of the rudder stock on that waterline, if that be greater In ships designed with a rake of keel, the waterline on which this length is measured should be parallel to the designed waterline The length (L) should be measured in metres 1.3.17 Machinery spaces of category spaces which contain: A are those spaces and trunks to such internal-combustion internal-combustion machinery used for purposes other than main propulsion where such machinery has in the aggregate a total power output of not less than 375 kW; or machinery used for main propulsion; or any oil-fired boiler or oil fuel unit 1.3.18 Machinery spaces are all machinery spaces of categor)fA and all other spaces cortaining propelling machinery, boilers, oil fuel units: steam and internal-combustion engines, generators and major electrical machinery, oil filling station, refrigerating, stabilizing, ventilation and air-conditioning machinery, and similar spaces, and trunks to such spaces 1.3.18A MARPOL 73/78 means the International Convention for the Prevention of Pollution from Ships, 1973, as modified by the Protocol of 1978 relating thereto 1.3.188 Noxious liquid substance means any substance designated in appendix II to Annex II of MARPOL 73/78 or provisionally assessed under the provisions of regulation 3(4) of that Annex as falling into category A, B, C or D 1.3.19 Oil fuel unit is the equipment used for the preparation of oil fuel for delivery to an oil-fired boiler, or equipment used for the preparation for delivery of heated oil to an internal-combustion engine, and includes any oil pressure pumps, filters and heaters dealing with oil at a pressure of more than 1.8 bar gauge 1.3.20 Organization is the International Maritime Organization (IMOj 1.3.21 Permeability of a space means the ratio of the volume wit'hin that space which is assumed to be occupied by water to the total volume of that space 1.3.22 Pump-room is a space, located in the cargo area, containing and their accessories for the handling of ballast and oil fuel pumps 1.3.22A Recognized standards are applicable international or national standards acceptable to the Administration or standards laid down and maintained by an organization which complies with the standards adopted by the Organization' and which is recognized by the Administration 1.3.23 Relative density of liquid is the ratio of the mass of a volume of a product to the mass of an equal volume of fresh water For a product of limited solubility, the relative density indicates whether it floats on water or sinks 1.3.24 Separate means that a cargo piping system or cargo vent' system, for example, is not connected to another cargo piping or cargo vent system This separation may be achieved by the use of design or operational methods Operational methods should not be used within a cargo tank 'and should consist of one of the following types: removing spool-pieces or valves and blanking the pipe ends; arrangement of two spectacle flanges in series, with p'rovisions for detecting leakage into the pipe between the two spectacle flanges • Refer to the Minimum standards for recognized organizations acting on behalf of the Administration, set out in appendix to the Guidelines for the authorization of organizations acting on behalf of the Administration adopted by the Organization by resolution A.T\9(18) 1.3.25 Service spaces are those spaces used for galleys, pantries containing cooking appliances, lockers, mail and specie rooms, store-rooms, workshops other than those forming part of the machinery spaces and similar spaces and trunks to such spaces circulate the same to other Contracting Governments to th~' 1~74 SOlAS Convention and Parties to MARPOl 73/78 for the information of their officers 1.3.26 1974 SOLAS Convention Safety of life at Sea, 1974 1.5 Surveys and certification 1.5.1 Survey procedure means the International Convention for the 1.3.27 1983 SOLAS amendments means the am~ndrf1ents to the 19i(4 SOlAS Convention adopted by the Maritime Safety Committee of the Organization at its forty-eigbth session on 17 June 1983 by resolution MSC.6(48) 1.3.27AStandards for Procedures and Arrangements means the Standards for Procedures and Arrangements for the Discharge of Noxious liquid Substances called for by Annex II of MAR POL 73/78 adopted by the Marine Environment Protection Committee at its twenty-second session by resolution MEPC.18(22) as may be amended by the Organization 1.3.28 Vapour density or the relative density of vapour is the ratio of the mass of a volume of vapour or gas (with no air present) to the mass of an equal volume of air at the same pressure and temperature Vapour density below or above indicates whether the vapour or gas is lighter or heavier than air 1.3.29 Vapour pressure is the equilibrium pressure of the saturated vapour above a liquid expressed in bars absolute at a specified temperature 1.3.30 Void space is an enclosed space in the cargo area external to a cargo tank, other than a hold space, ballast space, oil fuel tank, cargo pump-room, pump-room, or any space in normal use by personnel 1.4 Equivalents 1.4.1 Where the Code requires that a particular fitting, material, appliance, apparatus, item of equipment or type thereof should be fitted or carried in a ship, or that any particular provision should be made, or any procedure or arrangement should be complied with, the Administration may allow any other fitting, material, appliance, apparatus, item of equipment or type thereof to be fitted or carried, or any other provision, procedure or arrangement to be made in that ship, if it is satisfied by trial thereof or otherwise that such fitting, material, appliance, apparatus, item of equipment or type thereof or that any particular provision, procedure or arrangement is at least as effective as that required by the Code However, the Administration may not allow operational methods or procedures to be made an alternative to a particular fitting, material, appliance, apparatus, item of equipment, or type thereof, which are prescribed by the Code, unless such substitution is specifically allowed by the Code 1.4.2 When the Administration so allows any fitting, material, appliance, apparatus, item of equipment, or type thereof, or provision, procedure, or arrangement, or novel design or application to be substituted thereafter, it should commu.nicate to the Organization the particulars thereof, together with a report on the evidence submitted, so that the Organization may 8, 1.5.1.1 The survey of ships, so far as regards the enforcement of the provisions of the regulations and granting of exemptions therefrom, should be carried out by officers of the Administration The Administration may, however, entrust the surveys either to surveyors nominated for the purpose or to organizations recognized by it 1.5.1.2 The Administration nominating surveyors or recognizing organizations to conduct surveys should, as a minimum, empower any nominated surveyor or recognized organization to: require repairs to a ship; and carry out surveys if requested concerned by the port State authority' The Administration should notify the Organization of the specific responsibilities and conditions of the authority delegated to nominated surveyors or recognized organizations for circulation to the Contracting Governments 1.5.1.3 When a nominated surveyor or recognized organization determines that the condition of the ship or its equipment does not correspond substantially with the particulars of the certificate or is such that the ship is not fit to proceed to sea without danger to the ship or to persons on board, such surveyor or organization should immediately ensure that corrective action is taken and should in due course notify the Administration If such corrective action is not taken the relevant certificate should be withdrawn and the Administration should be notified immediately; and, if the ship is in a port of another Contracting Government, the port State authority concerned should also be notified immediately 1.5.1.4 In every case, the Administration should guarantee the completeness and efficiency of the survey, and should undertake to ens,ure the necessary arrangements to satisfy this obligation 1.5.2 Survey requirements 1.5.2.1 The structure, equipment, fittings, arrangements and material (other than items in respect of which a Cargo Ship Safety Construction Certificate, Cargo Ship Safety Equipment Certificate and Cargo Ship Safety Radio Certificate or Cargo Ship Safety Radiotelegraphy Certificate or' Cargo Ship Safety Radiotelephony Certificate are issued) of a chemical tanker should be subjected to the following surveys: • Port State authority has the meaning as presented in chapter I, regulation 19, of the 1978 Protocol to the 1974 SOlAS Convention 2.2 Each of the curves thus constructed relates to one position of assumed damage only arrd the caiculations should be repeated for each damage and lesser extent of damage to be assumed at any part of the ship 2.3 Where it can be determined by inspection that the effect of certain assumed damage will be less onerous than other assumed damage for which calculations are provided and curves prepared, then the investigation of such damage cases may be dispensed with 2.4 tanks in way" of the assumed damage filled with liquid at increments of about 25% between empty and the maximum weight of liquid, or liquids, intended to be carried in the particular tanks under consIderation; the distribution of liquids in the adjacent tanks concerned which will give the most severe result, taking into account trim; a number of draughts over the operating range, up to and including the Tropical Freeboard Mark The fresh water freeboards need not be considered; the effect of damage involving the machinery space and adjacent tanks containing liquids over a number of draughts as in 2.4.3; the ship in either the departure or the arrival condition, whichever will give the most severe result; the ship without trim and a sufficient number of trims covering the operating range, in order to permit interpolation Particulars concerning survival capability calculations 3.1 The calculations shDuld be based on moulded lines and include large appendages such as shaft bosses, skegs and bow thrusters 3.2 The metacentric heights (GM), stability levers (GZ) and centre of gravity positions (KG) for judging the final survival conditions should be calculated by the constant-displacement (lost-buoyancy) method 3.3 The calculations should be done for the ship freely trimming 3.4 Only computer calculations acceptable to the Administration be used should 3.5 Where the assumed damage causes the ship to trim by the stern, the ship in the intact condition should be assumed to have the largest allowable trim by the stern, consistent with operational requirements 3.6 Where the assumed damage causes the ship to trim by the bow, the ship in the intact condition should be assumed to have the largest allowable trim by the bow, consistent with operational requirements 202 account only where the maximum extent side cargo tanks, fuel be given attention: extent means the reduction of anyone of the" three maximum dimensions of damage singly or in combination and also the assessment of the effect of damage affecting any combination of compartments within the maximum extent of damage Where any damage involves the release of very heavy cargo liquid, then heel to the intact side of the ship may take place In such cases the effect of lesser vertical extent of damage above the level of the tank top may result in the larger angle of heel, since otherwise the effect of cargo loss may be compensated by flood water entering the double-bottom tanks on the damaged side The damage calculations should take account of:' 3.7 Lesser extent of damage should be taken into indicated by the presence of subdivision extending into of damage, e.g double-bottom tanks, side ballast tanks, tanks and void spaces However, the following should Lesser 3.8 The number of calculations required to show compliance with survival requirements should be that necessary to obtain sufficient data for the loading manual and should be such that all loading conditions indicated in paragraph can be covered, i.e no additional calculations should be necessary once the series of calculations has been executed 3.9 Calculations to determine the displacement, trim and the vertical position of the centre of gravity should be performed for each operational loading condition The vertical position of the centre of gravity should be corrected for free surface effects One method would be to construct graphs showing the free surface moments of the criterion angle for all filling levels at a specific gravity of one The free surface moments for all tanks can then be taken from the graphs and be multiplied by the cargo specific gravity 3.10 In calculating the effect of free surface of consumable liquids it is to be assumed that, for each type of liquid, at least one transverse pair or a single centreline tank has maximum free surface, and the tank or combination of tanks to be taken into account is to be that where the effect of free surfaces is the greatest; in each tank the centre of gravity of the contents is to be taken at the centre of volume of the tank The remaining tanks are to be assumed either completely empty or completely filled, and the distribution of consumable liquids among these tanks is to be such as to obtain the greatest possible height above the keel for the centre of gravity 3.11 To take account of the presence of structure within cargo compartments, a permeability of 0.95 should be assumed as stated in the Codes Where, in particular cases, such as the cargo tanks of gas carriers, this assumption would lead to a significant discrepancy in cargo-tank volume, it is preferable to calculate the permeability taking into account actual tank structure; the volume of tank insulation should then be calculated separately and an appropriate permeability applied 203 3.12 Attention should be paid to the possibility of progressive flooding through deck cargo pipes and common cargo-tank ventilation pipes if these are immersed at large angles of heel after damage The possibility of progressive flooding 'through ballast piping passing through the assumed extent of damage, where positive-action valves are not fitted to the ballast system at the open ends of the pipes in the tanks served, should be considered Where remote control systems are fitted to ballast valves and these controls pass through the assumed extent of damage, then the effect of damage to the system should be considered to ensure that the valves would remain closed in that event • 3.13 Where the ship· is required to be capable of sustaining bottom damage anywhere in its length (L), the following method should be used when damage is assumed to occur in the vicinity of the O.3L position from the forward perpendicular: When applying the longitudinal extent of bottom damage applicable to the foremost part of the ship, no part of the damage should be assumed to extend abaft the 0.3L position from the forward perpendicular .2 When applying the longitudinal extent of damage applicable to the rest of the ship's length, the damage should be assumed to extend to a foremost limit including a point at O.3L minus 5.0 m abaft the forward perpendicular 3.14 In ships carrying liquefied gases, large cargo tanks may be subdivided into sections by centreline and transverse bulkheads which are liquid-tight but which have openings near the top of the tank These openings would permit spillage of cargo from one section of the cargo tank to another when the ship is heeled where the tank is undamaged, or loss of cargo due to spillage from sections of a damaged cargo tank The effect of this spillage should be taken into account in calculations and also in any calculation of GM or KG for loading conditions where a "required GM" or "allowable KG" curve is to be used 3.15 In ships carrying liquefied gases, the ability of longitudinal bulkheads fitted within cargo tanks to withstand the unequal pressures due to flooding of one section of cargo tank should only be considered in the final stage of flooding 3.16 Where lubricating-oil drain tanks fitted below the main engine would be affected by the vertical extent of bottom damage, flooding of the engineroom by way of the drain tank and engine should be assumed to take place 3.17 In ships with machinery spaces aft, the machinery space and steeringgear compartment should be regarded as being common for damage purposes when any access is fitted in the after machinery-space bulkhead, unless a remotely operated sliding watertight door is fitted or the sill of the access openings fitted with hinged watertight doors which are to be kept closed at sea is at least 0.3 m above the damage waterline and will not be submerged within the minimum range bf residual stability 204 3.18 Where dry cargoes are carried at the same time as bulk liquid cargoes which require compliance with the requirements of the Codes then the permeability of the space carrying the dry cargo is to be ascertained 3.19 The harmonized regulations specify that no account should be taken of cross-flooding arrangements to attain stipulated limits of heel in the final state of equilibrium after damage However, compartments on the opposite side of a ship could be regarded as single compartments from the aspect of flooding if they were to be linked by openings or ducts of sufficiently large area In such cases consideration should be given to the adequacy of tank air flow and to the effect of free surface Stability information and Certificate of Fitness 4.1 With regard to loading conditions to be submitted to the Administration (exclusive of the loading condition contained in loading and stability manual), the principal objective, at the stage of design evaluation, is that the Administration can satisfy itself that the calculations presented will cover all conditions of full and partial loading, including variations of draught and trim To achieve this objective the Administration may either: require a complete analysis of survival requirements over the full range of probable loading conditions; or undertake approval on the basis of service conditions proposed by the builder or owner, in which case the Certificate of Fitness should be endorsed for the conditions accepted 4.2 Particular attention should be paid to the provision of adequate stability data to enable the master to take into account accurately the effect of liquid heeling moments of the contents of undamaged tanks These heeling moments vary with the specific gravity of the liquid and the percentage filling of the tanks and may change significantly in magnitude from condition to condition Adequate information would include curves showing the variation of liquid heeling moment with the contents of each individual tank 4.3 In addition to the usual loading information required under intact stability requirements, the master should be supplied with the following information pertaining to damage stability: data relative to loading and distribution of cargo and ballast necessary to ensure compliance with damage-survival requirements; data relative to the ship's survival capabilities; a damage-control drawing showing the position fittings and listing instructions for their control; data relating to the effect of free surface or liquid moments of cargo tanks at all stages of filling; of important heeling 205 ·5 4.4 example calculations calculations and standard blank forms to facilitate The following should be stated on the Certificate of Fitness: the deepest draught or least freeboard for those loading conditions which require greater freeboard than the International Load Line Certificate (1966); the range of specific gravities of cargoes which may be carried; this relates to all cargoes; , the particular cargo tanks in which certain ranges of specific gravities of cargoes may be carried, if relevant; details of fittings, valves etc., the control of which is essential for survival, together with instructions for control, operation and logging; and identification of required loading and stability manual Revised standards for the design, testing and locating of devices to prevent the passage of flame into cargo tanks in tankers (adopted by the MSC at its forty-ninth session, 1984, and amended at its fifty-fifth session, 1988*) INTRODUCTION 1.1 Purpose The 1981 and the 1983 amendments to the International Convention for the Safety of Life at Sea, 1974 (SOLAS 74), include revised requirements for fire safety measures for tankers Regulation 11-2/59 of these amendments contains provisions concerning venting, purging, gas-freeing and ventilation Regulation 11-2/59.1.5 states: "The venting system shall be provided with devices to prevent the passage of flame into the cargo tanks The design, testing and locating of these devices shall comply with the requirements established by the Administration which shall contain at least the Standards adopted by the Organization." 1.2 Application 1.2.1 These Standards are intended to cover the design, testing, locating and maintenance of "devices to prevent the passage of flame into cargo tanks" (hereafter called "devices") of tankers and combination carriers carrying crude oil and petroleum products having a flash point of 60°C (closed cup) or less and a Reid vapour pressure below atmospheric pressure, and other products having a similar fire hazard 1.2.2 Oil tankers and combination carriers fitted with an inert gas system in accordance with regulation 62 shall be fitted with devices which comply with these Standards, except that the tests specified in 3.2.3 and 3.3.3.2 are not required Such devices are only to be fitted at openings unless they are tested in accordance with 3.4 1.2.3 These Standards are intended for devices protecting cargo tanks containing crude oil, petroleum products and flammable chemicals In the case of the carriage of chemicals, the test media referred to in section can be used However, devices for chemical tankers dedicated to the carriage of products with MESGt less than 0.9 mm should be tested with appropriate media • The Standards were originally issued as the annex to MSC/Circ 373; these Revised Standards are in MSCjCirc 373/Rev t Refer to IEC Publication 79-1 206 207 1.2.4 Devices shall be tested and located Standards 1.2.5 in accordance these 1.3.5 High-velocity vent is a device to prevent the passage of flame, consisting of a mechanical valve which adjusts the opening available for flow in accordance with the pressure at the inlet of the valve in such a way that the efflux velocity cannot be less than 30 m/s caused by 1.3.6 Pressure/vacuum valve' is a device designed to maintain pressure and vacuum in a closed container within preset limits with Devices are installed to protect: openings designed to relieve pressure or vacuum thermal variations (regulation 11-2/59.1.2.1); ,openings designed to relieve pressure or vacuum during cargo loading, ballasting or during discharging (regulation 11-2/59.1.2.2); outlets designed for gas-freeing as described in the proposed regulation 1!-2/59.2.2.3 (appendix 1) 1.2.6 Devices shall not be capable of being bypassed or blocked open unless they are tested in the bypassed or blocked-open position in accordance with section 1.2.7 These Standards not include consideration of sources of ignition such as lighting discharges since insufficient information is available to formulate equipment recomm.endations All cargo-handling, tank-cleaning and ballasting operations shall be suspended on the approach of an electrical storm 1.2.8 These Standards are not intended to deal with the possibility of the passage of flame from one cargo tank to another on tankers with common venting systems 1.2.9 When outlet openings of gas-freeing systems on tankers not fitted with inert gas systems are required to be protected with devices, they shall comply with these Standards except that the tests specified in 3.2.3 and 3.3.3.2 are not required 1.2.10 Certain of the tests prescribed in section of these Standards are potentially hazardous, but no attempt is made in this circular to specify safety requirements for these tests 1.3 Definitions STANDARDS 2.1 Principles 2.1.1 Depending on their service and location, devices are required to protect against the propagation of: ~ moving flames; and/or stationary flames from pre-mixed gases; after ignition of gases resulting from any cause 2.1.2 When flammable situations may occur: 1.3.2 Flame screen is a device utilizing wire mesh to prevent the passage of unconfined flames, in accordance with a specified performance standard 1.3.3 Flame speed other system 1.3.4 is the speed at which a flame propagates along a pipe or Flashback is the transmission of a flame through a device outlets ignite, the follo~ing four At low gas velocities, the flame may: flash back; or stabilize itself as if the outlet were a burner At high velocities, the flame may: burn at a distance above the outlet; or be blown out 2.1.3 In order to prevent the passage of flame into a cargo tank, devices must be capable of performing one or more of the following functions: permitting the gas to pass through passages without flashback and without ignition of the gases on the protected side when the device is subjected to heating for a specified period; maintaining an efflux velocity in excess of the flame speed for the gas, irrespective of the geometric configuration of the device and without the ignition of gases on the protected side when the device is subjected to heating for a specified period; and preventing an influx of flame when conditions of vacuum occur within the cargo tanks For the purpose of these Standards, the following definitions are applicable 1.3.1 Flame arrester is a device to prevent the passage of flame in accordance with a specified performance standard Its flame-arresting element is based on the principle of quenching gases from • Pressure/Vacuum valves are devices to prevent the passage of flame when designed and tested in accordance with these Standards 2.2 MechanicaL design" standards 2.2.1 The casing or housing of devices shall meet similar standards of strength, heat resistance and corrosion resistance as the pipe to which they are attached 2.2.2 The design of devices shall allow for ease of inspection and removal of internal elements for replacement, cleaning or repair 2.2.3 All flat'joints of the hosing shall be machined true and shall provide for a joint having an adequ-ate metal-to-metal contact 2.2.4 Flame-arrester elements shall fit in the housing in such a way that flame cannot pass between the element and the housing 2.2.5 The clear area through flame arresters shall be at least 1.5 times the cross-sectional area of the vent line 2.2.6 Resilient seals may be installed only if their design is such that, if the seals are partially or completely damaged or burned, the device is still capable of effectively preventing the passage of flame 2.2.7 Devices shall allow for efficient drainage of moisture impairing their efficiency to prevent the passage of flame without 2.2.8 The casing and element and gasket materials shall be capable of withstanding the highest pressure and temperature to which the device may be exposed under both normal and specified fire test conditions 2.2.9 End-of-line devices shall be so constructed vertically upwards as to direct the efflux 2.2.10 Fastenings essential to the operation of the device (i.e screws, etc.) shall be protected against loosening 2.2.17 A flame-arrester element shall be designed to ensure quality control of manufacture to meet the characteristics of the prototype tested, in accordance with these Standards 2.3 Performance standards 2.3.1 Devices shall be tested in accordance with 3.5 and thereafter shown to meet the test requirements of 3.2 to 3.4, as appropriate 2.3.2 Performance characteristics, such as flow rates under both positive and negative pressure, operating sensitivity, flow resistance and velocity, shall be demonstrated by appropriate tests 2.3.3 Devices shall be designed and constructed to minimize the effect of fouling under normal operating conditions Instructions on how to determine when cleaning is required and the method of cleaning shall be provided for each device in the manufacturer's instruction manual 2.3.4 Devices shall be capable of operating in freezing conditions and, if any device is provided with heating arrangements so that its surface temperature exceeds 85°C, then it shall be tested at the highest operating temperature 2.3.5 Devices based upon maintaining a minimum velocity shall be capable of opening in such a way that a velocity of 30 m/s is immediately initiated, maintaining an efflux velocity of at least 30 m/s at all flow rates and, when the gas flow is interrupted, be capable of closing in such a way that this minimum velocity is maintained until the valve is fully closed 2.4 Flame screens 2.4.1 Flame screens shall be: 2.2.11 Means shall be provided to check that any valve lifts easily without remaining in the open positition .1 designed in such a manner improperly in the opening; 2.2.12 Devices in which the flame-arresting effect is achieved by the valve function and which are not equipped with the flame-arrester elements (e.g high-velocity valves) must have a width of the contact area of the valve seat of at least mm .2 securely fitted in openings so that flames cannot circumvent the screen; and able to meet the requirements of these Standards, except that the test specified in 3.2.3 need not be complied with that they cannot be inserted 2.2.13 Devices shall be resistant to corrosion in accordance with 3.5.1 2.2.14 Elements, gaskets and seals shall be of material resistant to both seawater and the cargoes carried 2.2.15 The casing or housing shall be capable of passing a hydrostatic pressure test, as required in 3.5.2 2.2.16 In-line devices shall be able to withstand, without damage or permanent deformation, the internal pressure resulting from detonation when tested in accordance with section 3.4 2.5 Sizing, location and installation of devices 2.5.1 For determining the size of devices to avoid inadmissible pressure or vacuum in cargo tanks during loading or discharging, calculations of pressure losses shall be carried out The following parameters shall be taken into account: loading/discharge gas evolution; rates; .3 pressure loss across devices, taking into account the resistance coefficient; pressure loss in the vent piping system; pressure at which the vent opens if a high-velocity valve is used; and density of the saturated vapour/air 3.1.3 Tests described in this section using gasoline vapours (a non-leaded petroleum distillate consisting essentially of alphatic hydrocarbon compounds with a boiling range approximating 65°C/75°C), technical hexane vapours, or technical propane, as appropriate, and referred to in this section, are suitable for all devices protecting tanks containing a ftammable atmosphere of the cargoes referred to in 1.2.1 This does not preclude the use of gasoline vapours or technical hexane vapours for all tests referred to in this section mixture 2.5.2 Devices shall be located at the outlets to atmosphere unless tested and approved for in-line installation Devices for in-line installation may not be fitted at the outlets to atmosphere unless they have also been tested and approved for that position 2.5.3 Except as may be permitted in 1.2.2, flame screens referred to in 2.4 shall be fitted only at vacuum inlets through which vapours cannot be vented to atmosphere Flame screens shall be protected against mechanical damage 2.5.4 Where end-of-line devices are fitted with cowls, weather hoods and deflectors, etc., these attachments shall be fitted for the tests described in 3.2 3.2 Test procedures for flame arresters located at openings to the atmosphere 3.2.1 The test rig shall consist of an apparatus producing an explosive mixture, a small tank with a diaphragm, a flanged prototype of the flame arrester, a plastic bag' and a firing source in three positions (see appendix 2).t Other test rigs may be used, provided the tests referred to in this section are achieved to the satisfaction of the Administration 3.2.2 A flashback test shall be carried out as follows: 2.5.5 Where detonation flame arresters are installed, as in-line devices venting to atmosphere, they should be located at a sufficient distance from the open end of the pipeline so as to preclude the possibility of a stationary flame resting on the arrester ' 2.5.6 When venting to atmosphere is not performed through an end-of-line device according to 2.5.4, or a detonation flame arrester according to 2.5.5, the in-line device has to be specifically tested with the inclusion of all pipes, tees, bends, cowls, weather hoods, etc., which may be fitted between the device and atmosphere The testing shall consist of the flashback test of 3.2.2 and, if for the given installation it is possible for a stationary flame to rest on the device, the testing shall also include the endurance burning test of 3.2.3 2.5.7 Means shall be provided to enable personnel to reach devices situated more than m above deck to facilitate maintenance, repair and inspection ~ TYPE TEST PROCEDURES 3.1 Principles 3.1.1 Tests shall be conducted Administration by a laboratory acceptable to the 3.1.2 Only one device shall be submitted for each type test programme Such a device shall have the same dimensions and most unfavourable clearances expected in the production model If a flashback occurs, the tank diaphragm will burst and this will be audible and visible to the operator by the emission of a flame Flame, heat and pressure sensors may be used as an alternative to a bursting diaphragm 3.2.3 An endurance burning test shall be carried out, in addition to the flashback test, for flame arresters at outlets where flows of explosive vapour are foreseeable: The tank, flame arrester assembly and the plastic bag enveloping the prototype flame arrester shall be filled so that this volume contains the most easily ignitable propane/air mixturB.t The concentration of the mixture should be verified by appropriate testing of the gas composition in the plastic bag Where devices referred to in 2.5.6 are tested, the plastic bag shall be fitted at the outlet to atmosphere Three ignition sources shall be installed along the axis of the bag, one close to the flame arrester, another as far away as possible therefrom, and the third at the midpoint between these two These three sources shall be fired in succession, one during each of the three tests The test rig as referred to in 3.2.1 may be used, without the plastic bag The flame arrester shall be so installed that the mixture em.ission is vertical In this position the mixture shall be ignited , The dimensions of the plastic bag are dependent on those of the flame arrester, but for the flame arresters normally used on tankers, the plastic bag may have a circumference of m, a length of 2.5 m and a wall thickness of 0.05 m t In order to prevent remnants of the plastic bag from falling back on to the device being tested after ignition of the fuel/air mixture, it may be useful to mount a coarse wire frame across the device within the plastic bag The frame should be so constructed as not to interfere with the test result " Refer to IEC Publication 79-1 213 Where devices xeferred to in 2.5.6 are tested, the flame arrester shall b~ so installed as to reflect its final orientation .2 3.3 Endurance burning shall be achieved by using the most easily ignitable gasoline vapour/air mixture or the most easily ignitable technical hexane vapour/air mixture with the aid of a pilot flame or a spark igniter at the outlet By varying the proportions of the flammable mixture and the flow rate, the arrester shall be heated until the highest obtainable temperature on the car'go-tank side of , the arrester is reached The highest obtainable temperature may be considered to have been reached when the rate of rise of temperature does not exceed 0.5°e per minute over a 10 minute period This temperature shall be maintained for a period of 10 minutes, after which the flow shall be stopped and the conditions observed If difficulty arises in establishing thermal stability, the following criteria shall apply When the temperature has reached the apparent maximum, using the most severe conditions of flammable mixtures and flow rate, but increases at a rate in excess of 0.5°e per minute over a 10 minute period, endurance burning shall be continued for a period of two hours from the time the most severe apparent co.nditions have been established, after which the flow shall be stopped and the conditions observed Flashback shall not occur during this test Test procedures for high-velocity vents 3.3.1 The test rig shall be capable of producing the required volume flow rate In appendices and 4, drawings of suitable test rigs are shown Other test rigs may be used, provided the tests are achieved to the satisfaction of the Administration 3.3.2 A flow condition test shall be carried out with high-velocity vents using compressed air or gas at agreed flow rates The following shall be recorded: 214 The flow rate Where air or a gas other than vapours of cargoes with which the vent is to be used is employed in the test, the flow rates achieved shall be corrected to reflect the vapour density of such cargoes The pressure before the vent opens The pressure in the test tank on which the device is located shall not rise at a rate greater than 0.01 N/mm2/min .3 The pressure at which the vent opens .4 The pressure at which the vent closes .5 The efflux velocity at the outlet, which shall not be less than 30 m/s at any time when the valve is open 3.3.3 The following fire safety tests shall be conducted using a mixture of gasoline vapour and air or technical hexane vapour and air which produces the most easily ignitable mixture at the point of ignition This mixture shall be ignited with the aid of a permanent pilot flame or a spark igniter at the outlet: 3.4 Flashback tests, in which propane may be used instead of gasoline or hexane, shall be carried out with the vent in the upright position and then inclined at 10' from the vertical For some vent designs further tests with the vent inclined in more than one direction may be necessary In each of these tests the flow shall be reduced until the vent closes and the flame is extinguished, and each shall be carried out at least 50 times The vacuum side of combined valves shall be tested in accordance with 3.2.2 with the vacuum valve maintained in the open position for the duration of this test, in order to test the efficiency of the device which must be fitted ~ An endurance burning test, as described in 3.2.3, shall be carried out Following this test, the main flame shall be extinguished and then, with the pilot flame burning or the spark igniter discharging, small quantities of the most easily ignitable mixture shall be allowed to escape for a period of 10 minutes, during which time flashback shall not occur For the purposes of this test the soft seals or seats shall be removed Test rig and test procedures for detonation flame arresters located in-line 3.4.1 A flame arrester shall be installed at one end of a pipe of suitable length and of the same diameter as the flange of the flame arrester On the exposed flange, a plastic bag' shall be affixed The pipe shall be filled with the most easily ignitable mixture of propane and air, which shall then be ignited The velocity of the flame near the flame arrester shall be measured and shall have a value of that for stable detonations 3.4.2 Three detonation tests shall be conducted and no flashback shall occur through the device and no part of the flame arrester shall be damaged or show permanent deformation 3.4.3 Other test rigs may be used provided the tests are achieved to the satisfaction of the Administration A drawing of the test rig is shown in appendix 3.5 Operational test procedures 3.5.1 A corrosion test shall be carried out In this test a complete device, including a section of the pipe to which it is fitted, shall be exposed to a 20'Yo sodium chloride solution spray at a temperature of 25°C for a period of 240 hours and allowed to dry for 48 hours An equivalent test may be used to the , The dimensions shall be at least m circumference, m length and a material wall thickness of 0.05 mm 215 satisfaction of the Administration Following this test, all movable parts shall operate properly and there shall be 1:10 corrosion deposits which cannot be washed off • 3.5.2 A hydraulic pressure test shall be carried out in the casing or housing of a simple device, in accordance with 2.2.1 MISCELLANEOUS 4.1 Marking of deyice 4.3 Manufacturer's manual 4.3.1 The manufacturer shall supply a copy of the instruction which shall kept on board the tanker and which shall include: manual, installation instructions; operating instructions; maintenance requirements, including cleaning (see 2.3.3); copy of the laboratory report referred to in 4.2; and flow test data, including flow rates under both positive and negative pressures, operating sensitivity, flow resistance and velocity Each device shall be permanently marked, or have a permanently fixed tag made of stainless steel or other corrosion-resistant material, to indicate: Appendix manufacturer's name or trade mark; style, type, model or other manufacturer's device; size of the outlet for which the device is approved; approved location for installation, including maximum or minimum length of pipe, if any, between the device and the atmosphere; Arrangements for purging and/or gas-freeing shall be such as to minimize the hazards due to the dispersal of flammable vapours in the atmosphere aQd to flammable mixtures in a cargo tank Accordingly: direction of flow through the device; indication of the fest laboratory and report number; and compliance with the requirements of MSC/Circ 373/Rev 4.2 Laboratory report 4.2.1 The laboratory report shall include: 216 instruction designation for the detailed drawings of the device; types of tests, conducted Where in-line devices are tested, this inforr}lation should include the maximum pressures and velocities observed in the test; specific advice on approved attachments; types of cargo for which the device is approved; drawings of the test rig; in the case of a high-velocity vent, the pressures at which the device opens and closes in the efflux velocity; and all the information marked on the device in 4.1 Proposed amendments to regulation 11-2/59 [see Note below] Cargo tank purging and/or gas-freeing* When the ship is provided with an inert gas system, the cargo tanks shall first be purged in accordance with the provisions of regulation 62.13 until the concentration of hydrocarbon vapours in the cargo tanks has been reduced to less than 2% by volume Thereafter, gas-freeing may take place at the cargo tank deck level .2 When the ship is not provided with an inert gas system, the operation shall be such that the flammable vapour is discharged initially: 2.1 through the vent outlets as specified in paragraph 1.9; or 2.2 through outlets at least m above the cargo tank deck level with a vertical efflux velocity of at least 30 m/s maintained during the gas-freeing operation; or 2.3 through outlets at least m above the cargo tank deck level with a vertical efflux velocity of at least 20 m/s and which are protected by suitable devices to prevent the passage of flame When the flammable vapour concentration at the outlet has been reduced to 30% of the lower flammable limit, gas-freeing may thereafter be continued at cargo tank deck level • Refer to the Revised standards for the design, testing and locating of devices to prevent the passage of flame into cargo tanks in tankers (MSC/Circ 373/Rev 1) and to Revised factors to be taken into consideration when designing cargo tank venting and gas-freeing arrangements (MSC/Circ 450/Rev 1) Note: This amended text was adopted by resolution MSC.13(57) on 11 April 1989 217 · having regard to the types of cargo intended to be carried and their temperature, is to be considered Revised factors to be taken into consideration when designing cargo tank venting and gas-freeing arrangements Design to prevent liquid overfill: where overflow control systems are fitted, consideration is to be given to the dynamic condition during loading .8 Location of vent outlets: horizontal and vertical distances of the vent outlets are to be in accordance with regulation 11-2/59 The amendments to the International Convention for the Safety of Life at Sea, 1974 (SOLAS 1974), include requirements for fire safety measures for tankers in 'regulations 11-2/59 and 62, and the IBC and ICC Codes These amendments contain arrangements for venting, inerting, purging, gas-freeing an~ ventilation .9 Types of venting systems: due regard is to be given to cargo The Sub-Committee on Fire Protection has considered problems associated with the design of cargo tank venting and gas-freeing arrangements and the Maritime Safety Committee has approved the main factors to be considered for the design of the arrangements in above as follows: Maximum loading/discharge rate: the venting system should be designed to take into consideration the maximum permissible loading/discharge rate for each cargo tank and in the case of a combined venting system, for each group of tanks These loading and discharge rates should also be used for the design of the inert gas system, regulation 11-2/62.3.1 Gas evolution: regulation 11-2/59.1.9.5 requires at least 25% to be added to the maximum loading rate to account for the increased volume due to gas evolution from the cargo A higher gas evolution factor may be considered for highly volatile cargoes Pressure loss across devices: data relating to pressure loss across devices to prevent the passage of flame, approved in accordance with MSC/Circ 373 and referred to in regulation 11-2/59.1.5, are to be considered in the design of the venting system Fouling of devices should be taken into account Pressure loss in the venting system: pressure loss calculations of systems incluping pipes, valves, bends, fittings, etc., should be madE; to ensure that the pressure inside the cargo tanks does not exceed the pressure these tanks are designed to withstand, taking into consideration and above In the case where a combined venting system is used in association with loading of cargo tanks simultaneously, the combined effect of vapour pressure generated in the tanks and venting system should be considered 222 Pressure at which the vents open: the initial opening pressure of the vent valves should be considered in selecting the appropriate valves for the venting system .6 Density of the gaseous mixture: the maximum density of the gaseous mixtures likely to be encountered in the cargo tanks, segregation when considering a venting system or inert gas system common to more than one tank Where the inert gas main is designed for venting of cargo tanks, additional means for venting of these tanks are to be in accordance with regulation 112/62.11.3 • 10 Vent draining arrangements: the draining arrangements for venting systems are to be designed in accordance with regulation 11-2/59.1.4 .11 Gas-freeing: in designing a gas-freeing system in conformity with proposed regulation 11-2/59.2.2.2 and 59.2.2.3 (see annex') in order to achieve the required exit velocities, the following should be considered: ' the flow characteristics of the fans to be used; the pressure losses created by the design of a particular tank's inlets and outlets; the pressure achievable in the fan driving medium (e.g water or compressed air); the densities of the cargo vapour/air mixtures for the range of cargoes to be carried Repairs and renewal of the venting system should conform to the original design parameters Factors in the above paragraphs are to be taken into consideration when modifications are carried out to the venting system The master is to be provided with a manual containing information relating to the maximum loading and unloading rates for each tank or group of tanks established during the design of the venting system, as per paragraph above Data referred to in paragraph 4.3 of MSC/Circ 373/Rev should be taken into consideration when renewing devices referred to in the above circular * The annex has not been included Its text is identical with appendix of MSC/Circ 373/ Rev (see page 217) 223 Calculations · Calculation of the capacity of foam systems for chemical tankers* Determination of foam supply rate: 11.3.5 The largest of: 11.3.5.1 - the foam supply rate based upon the entire cargo deck area l/m2/min In section 11.3 of the IBC Code concerning 'fire-extinguishing arrangements for cargo tank areas the foam supply has to be determined in accordance with paragraphs 11.3.5 to 11.3.7 In order to provide for a correct interpretation of the requirements the Sub-Committee on Fire Protection agreed on the following example for a calculation of foam system for a chemical tanker of 10,000 tonnes deadweight The Maritime Safety Committee at its forty-fourth session agreed that this example be followed when calculating the capacity of foam systems for chemical tankers Example of foam system calculation for chemical tanker of 10,000 dwt Ship particulars 11.3.5.2 = 14.5 m Length of cargo area = 56 m Length of largest cargo tank =9 m Cargo deck area = 14.5 m x 56 m = 812 m Horizontal sectional area of single largest tank = 14.5 m x m = 130.5 m2 11.3.5.3 = 130.5 m2 - Area protected by largest monitor = m m x 14.5 m x 130.5 m2 = 2,610 I/min the foam supply rate based upon the area protected by the largest monitor 10 l/m2/min x 130.5 m2 = *1,305 I/min (*Shall not be less than 1,250 I/min) • The foam supply rate is therefore 2,610 I/min, which is the largest of the three above calculated rates Determination - 11.3.7 - of the required quantity of foam concentrate: 2,610 I/min is the foam supply rate from regulation 3.14.5 This flow rate for thirty minutes will require 30 x 2,610 I/min = 78,300 litres of foam-water solution If a 5% foam concentrate is used, then 5% of the 78,300 litres must be foam concentrate, or 0.05 x 78,300 = 3,915 litres Determination Note: For the purpose of this illustration, a single tank encompasses the entire beam of the ship) Proposed monitor spacing the foam supply rate based upon the horizontal sectional area of the single largest tank 20 l/m2/min 11.3.6 Beam - x 812 m2 = 1,624 I/min of the minimum monitor capacity: Each monitor must supply at least: (a) 50% of the required foam rate; or (b) 10 l/m2/min for the area it protects; or (c) 1,250 I/min, whichever is greater 50% of the foam supply rate = 2,610 I/min x 0.5 = 1,305 I/min 10 l/m2/min times the area the monitor protects = 130.5 m2 x 10 l/m2/min = 1,305 I/min The minimum monitor capacity is therefore 1,305 I/min Designer wishes to increase monitor spacing to 15 metres between monitors Recalculate required foam supply: 11.3.5.1 - same as before - 1,624 I/min 11.3.5.2 - same as before - 2,610 I/min 11.3.5.3 - larger area covered by monitor is 15 m x 14.5 m = 217.5 m2 10 l/m2/min x 21 7.5 m2 = 2,175 //min The required foam rate therefore remains 2,610 litres per minute 225 Recalculate required foam concentrate supply: 11.3.6 The minimum" foam supply rate has not changed; therefore 3,915 litres of foam concentrate are still required Recalculate minimum monitor capacity: 11.3.7 10 !/m2/min - 50% of foam supply rate 2,610 !/min x 0.5 = 1,305 !/min of area protected by monitor = 10 !/m /minx217.5 m2 = 2,175 !/min Procedures for inspection, cleaning, passivation and loading of tanks for the carriage of hydrogen peroxide solutions 8-60%, which have contained other cargoes, or for the carriage of other cargoes after the carriage of hydrogen peroxide* The new minimum monitor capacity is therefore 2,175 !/min Tanks having contained cargoes other than hydrogen peroxide should be inspected, cleaned and passivated before re-use for the transport of hydrogen peroxide solutions The procedures for inspection and cleaning, as given in paragraphs 1.1 to 1.7 below, apply to both stainless steel and pure aluminium tanks (see paragraph 4.20.16 of the BCH Code and paragraph 15.5.15 of the IBC Code) Procedures for passivation are given in paragraph 1.8 for stainless steel and 1.9 for aluminium Unless otherwise specified, all steps apply to the tanks and to all associated equipment having been in contact with the other cargo 1.1 After unloading the previous cargo the tank should be rendered safe and inspected for any residues, scale and rust 1.2 Tanks and associated equipment should be washed with clean filtered water The water to be used should at least have the quality of potable water with a low chlorine content 1.3 Trace residues and vapours of the previous cargo should be removed by steaming of tank and equipment 1.4 Tank and equipment are washed again with clean water (quality as above) and dried, using filtered, oil-free air 1.5 The atmosphere in the tank should be sampled and investigated for the presence of organic vapours and oxygen concentration 1.6 The tank should be checked again by visual inspection for residues of the previous cargo, scale and rust as well as for any smell of the previous cargo 1.7 If inspection or measurements indicate the presence of residues of the previous cargo or its vapours, steps 1.2 to 1.4 should be repeated 1.8 Tank and equipment made from stainless steel which have contained other cargoes than hydrogen peroxide or which have been under repair should be cleaned and passivated, regardless of any previous passivation, according to the following procedure: * These procedures were originally published as the annex to MSCjCirc 394 226 227 .1 New welds and other repaired parts should be cleaned and finished using stainless steer wire brush, chisel, sandpaper or buff Rough su'rfaces should be given a smooth finish A final polishing is necessary .2 Fatty and oily residues should be removed by the use of appropriate organic solvents or detergent solutions in water The use of chlorine-containing compounds should be avoided as they can seriously interfere with passivation .3 The residues of the degreasing agent followed by a washing with water In the next step, scale and rust should be removed by the application of"acid (e.g a mixture of nitric and hydrofluoric acids), followed again by a washing with clean water .5 All the metal surfaces which can come into contact with hydrogen peroxide should be passivated by the application of nitric acid of a concentration between 10 and 35% by weight The nitric acid must be free from heavy metals, other oxidizing agents or hydrogen fluoride The passivation process should continue for to 24 hours, depending upon the concentration of acid, the ambient temperature and other factors During this time a continuous contact between the surfaces to be passivated and the nitric acid should be ensured In the case of large surfaces this may be achieved by recirculating the acid Hydrogen gas may be evolved in the passivation process, leading to the presence of an explosive atmosphere in the tanks Therefore, appropriate measures must be taken to avoid the build-up or the ignition of such an atmosphere .6 should The tank should be washed with a solution of a sulphonated detergent in hot water, followed by a washing with water .2 The surface should then be treated for 15 to 20 minutes with a solution of sodium hydroxide of a concentration of 7% by weight or treated for a longer period with a less concentrated solution (e.g for 12 hours with 0.4 to 0.5% sodium hydroxide) To prevent excessive corrosion at the bottom of the tank when treating with more concentrated solutions of sodium hydroxide, water should be added continuously to dilute the sodium hydroxide solution which collects there The tank should be thoroughly washed with clean, filtered water As soon as possible after washing, the surface should be passivated by the application of nitric acid of a concentration between 30 and 35% by weight The passivation process should continue for 16 to 24 hours During this time a continous contact between the surfaces to be passivated and the nitric acid should be ensured .4 After passivation the surfaces should be thoroughly washed with clean, filtered water The washing process should be repeated until the effluent water has the same pH value as the incoming water .5 A visual inspection should be made to ensure that all surfaces have been treated It is recommended that an additional flushing is carried out for a minimum of 24 hours with dilute hydrogen peroxide solution of a concentraction approximately 3% by weight be removed, After passivation the surfaces should be thoroughly washed with clean filtered water The washing process should be repeated until the effluent 'water has the same pH value as the incoming water Surfaces treated according to the above steps may cause some decomposition when coming into contact with hydrogen peroxide for the first time This decomposition will cease after a short -time (usually within two or three days) Therefore an additional flushing with hydrogen peroxide for a period of at least two days is recommended Only degreasing agents and acid cleaning agents which have been recommended for this purpose by the manufacturer of the hydrogen peroxide should be used in the process 1.9 Tanks and equipment made from aluminium and which have contained cargoes other than hydrogen peroxide, or which have been under repair, should be cleaned and passivated The following is an example of a recommended procedure: 228 1.10 The concentraction and stability of the hydrogen peroxide solution to be loaded should be determined 1.11 The hydrogen peroxide is loaded under intermittent visual supervision of the interior of the tank from an appropriate opening 1.12 If substantial bubbling is observed which does not disappear within 15 minutes after the completion of loading, the contents of the tank should be unloaded and disposed of in an environmetally safe manner The tank and equipment should then be repassivated as described above 1.13 The concentration and stability of the hydrogen peroxide solution should be determined again If the same values are obtained within the limits of error as in step 1.9, the tank is considered to be properly passivated and the cargo ready for shipment 1.14 Steps 1.1 to 1.7 should be carried out under the supervision of the master or shipper Steps 1.8 to 1.12 should be carried out under the on-site supervision and responsibility of a respresentative of the hydrogen peroxide manufacturer or under supervision and responsibility of another person familiar with the safety-relevant properties of hydrogen peroxide 229 The following procedure should be applied when tanks having contained hydrogen peroxide solution are to be used for other products (unless otherwise specified, all steps apply to the tanks and to all associated equipment having been in contact with hydrogen peroxide): Hydrogen peroxide cargo residue should be drained as completely as possible from tanks and equipment .2 Tanks and equipment should be rinsed with clean water, and subsequently thoroughly washed with clean water .3 The interior of the tank should be dried and inspected for any residues Steps 2.1 to 2.3 should be carried out under the supervision of the master or the shipper Step 2.3 should be carried out by a person familier with the safetyrelevant properties of the chemical to be transported and of hydrogen peroxide SPECIAL CAUTIONS: Hydrogen peroxide decomposition may enrich the atmosphere with oxygen and appropriate precautions should be observed Hydrogen gas may be evolved in the passivation processes described in paragraphs 1.8.5, 1.9.2 and 1.9.4, leading to the presence of an explosive atmosphere in the tank Therefore, appropriate measures must be taken to avoid the build-up or the ignition of such an atmosphere 230 ... January 1998 January 1998 July 1998 July 1998 MSC58(67) MEPC73(39) December 1996 10 March 1997 January 1998 10 January 1998 July 1998 10 July 1998* *Note: Parties invited to implement on July 1998. .. tanks THE CODE 129 of bulk chemicals Guidelines for the uniform application of the survival requirements of the Bulk Chemical Code and the Gas Carrier Code ';'.' 149 157 191 201 IBC Code Revised... 17 a.nd 18 of the IBC Code as well as chapters VI and VII of pre-1993 editions of the BCH Code However, since 1993, the lists of products in chapters VI and VII of the BCH Code have been replaced