1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 12991:2012Liquefied natural gas (LNG) T a n k s f o r o n - b o a r d s t o r a g e a s a fuel for automotive vehiclesBS ISO 12991:2012 BRITISH STANDARDNational forewordTh
2、is British Standard is the UK implementation of ISO 12991:2012. The UK participation in its preparation was entrusted to T e c h n i c a l Committee PVE/18, Cryogenic vessels.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not p
3、urport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012. Published by BSI Standards Limited 2012.ISBN 978 0 580 65697 2 ICS 23.020.40; 75.200 Compliance with a British Standard cannot confer immunity from
4、 legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2012.Amendments issued since publicationDate T e x t a f f e c t e dBS ISO 12991:2012 ISO 2012Liquefied natural gas (LNG) Tanks for on-board storage as a fuel for
5、automotive vehiclesGaz naturel liqufi (GNL) Rservoirs pour le stockage bord comme carburant pour vhicules automobilesINTERNATIONAL STANDARDISO12991First edition2012-11-15Reference numberISO 12991:2012(E)BS ISO 12991:2012ISO 12991:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO
6、 2012All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the c
7、ountry of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 12991:2012ISO 12991:2012(E) ISO 2012 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope .12 N
8、ormative references 13 Terms and definitions .14 Requirements 34.1 General requirements . 34.2 Mechanical stresses 34.3 Thermal stresses . 44.4 Materials . 54.5 Design . 54.6 Insulation . General requirements . 64.7 Accessories . 64.8 Manufacturing and assembly 75 Type tests .75.1 Approval of new de
9、signs 75.2 Inner tank burst pressure test . 85.3 Holding time test . 85.4 Maximum fuelling level test . 85.5 Accessory type tests . 86 Routine tests and inspection 86.1 General . 86.2 Pressure test 96.3 Leak test 96.4 Verification of the dimensions . 96.5 Destructive and non-destructive tests of wel
10、ded joints 96.6 Visual inspection 107 Marking and labelling 107.1 Marking method . 107.2 Inner tank markings 107.3 Outer jacket markings 107.4 Temporary markings for first fuelling . 10Annex A (normative) Fuel tank type tests 12Annex B (normative) Accessory type tests 14Bibliography .16BS ISO 12991:
11、2012ISO 12991:2012(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a s
12、ubject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission
13、(IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical commit
14、tees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be
15、held responsible for identifying any or all such patent rights.ISO 12991 was prepared by Technical Committee ISO/TC 220, Cryogenic vessels.iv ISO 2012 All rights reservedBS ISO 12991:2012ISO 12991:2012(E)IntroductionThe fuel tanks described in this International Standard are intended to be used in c
16、onjunction with the fuelling system interface described in ISO 12617, which is under preparation. ISO 2012 All rights reserved vBS ISO 12991:2012BS ISO 12991:2012Liquefied natural gas (LNG) Tanks for on-board storage as a fuel for automotive vehicles1 ScopeThis International Standard specifies the c
17、onstruction requirements for refillable fuel tanks for liquefied natural gas (LNG) used in vehicles as well as the testing methods required to ensure that a reasonable level of protection from loss of life and property resulting from fire and explosion is provided.This International Standard is appl
18、icable to fuel tanks intended to be permanently attached to land vehicles but can be used as a guide for other mode of transport.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated refere
19、nces, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 1176, Road vehicles Masses vocabulary and codesISO 1431-1, Rubber, vulcanized or thermoplastic Resistance to ozone cracking Part 1: Static and dynamic st
20、rain testingISO 2768-1, General tolerances Part 1: Tolerances for linear and angular dimensions without individual tolerance indicationsISO 6957, Copper alloys Ammonia test for stress corrosion resistanceISO 9227, Corrosion tests in artificial atmospheres Salt spray testsISO 21013-3, Cryogenic vesse
21、ls Pressure-relief accessories for cryogenic service Part 3: Sizing and capacity determinationISO 21014, Cryogenic vessels Cryogenic insulation performanceISO 21028-1, Cryogenic vessels Toughness requirements for materials at cryogenic temperature Part 1: Temperatures below -80 degrees CISO 21029-1:
22、2004, Cryogenic vessels Transportable vacuum insulated vessels of not more than 1 000 litres volume Part 1: Design, fabrication, inspection and testsISO 23208, Cryogenic vessels Cleanliness for cryogenic service3 Terms and definitionsFor the purposes of this document, the following terms and definit
23、ions apply.3.1accessorydevice fixed directly to the inner tank or outer jacket of a fuel tank such as a pressure relief valve, shut-off valve, non-return valve or level gauge3.2boil-off management systemsystem that controls the boil-off of gas under normal conditionsINTERNATIONAL STANDARD ISO 12991:
24、2012(E) ISO 2012 All rights reserved 1BS ISO 12991:2012ISO 12991:2012(E)3.3burst pressurepressure that causes the rupture of a pressure vessel subjected to a constant increase of pressure during a destructive test3.4design temperaturetemperature of the inner tank, the outer jacket and all other acce
25、ssories to which fabrication drawings, inspections and physical measurements such as volume are referred3.5fuel tankvessel used for the storage of cryogenic liquefied natural gas (LNG) fuel3.7impermissible fault rangepressure range within which an unwanted event is to be expected3.8inner tankpart of
26、 the fuel tank that contains liquefied natural gas (LNG)3.9level gaugedevice that measures the level of liquefied natural gas (LNG) in the fuel tank3.10maximum allowable working pressureMAWPmaximum pressure to which a component is designed to be subjected to and which is the basis for determining th
27、e strength of the component under consideration3.11normal operating rangerange planned for the process valuesNOTE In the case of inner tanks, the normal operating range of the inner tank pressure is from 0 bar to the set pressure of the primary pressure relief valve, which is lower than or equal to
28、the maximum allowable working pressure (MAWP) of the inner tank.3.12outer jacketpart of the fuel tank that encases the inner tank(s) and its insulation system3.13outer pressurepressure acting on the outside of the inner tank or outer jacket3.14permissible fault rangerange between the normal operatin
29、g range and the impermissible fault range3.15pressurepressure for which the value is equal to the algebraic difference between the absolute pressure and the atmospheric pressureNOTE This is also known as gauge pressure.2 ISO 2012 All rights reservedBS ISO 12991:2012ISO 12991:2012(E)3.16holding timet
30、ime of the pressure increase in the inner tank measured from a starting pressure of 0 bar at the corresponding boiling point of liquefied natural gas (LNG) (164 C) up to the maximum allowable working pressure (MAWP) of the inner tankNOTE The holding time is a measure of the insulation performance of
31、 the fuel tank.3.17batch inner tank headsnumber (no more than 100) of tank heads produced by the same manufacturer, from the same material, and having the same dimensions3.18maximum massa maximum authorized total mass, as defined in ISO 11764 Requirements4.1 General requirementsThe fuel tank and its
32、 accessories shall function in a correct and safe way. It shall withstand and remain gas tight when subjected to the mechanical, thermal and chemical stresses specified in this International Standard.4.2 Mechanical stresses4.2.1 Inner/outer pressure4.2.1.1 Inner tankThe inner tank shall be designed
33、to resist the following inner test pressure:ptestMAWP=+13 1,( ) pMPatest=+13 01,( ,)()MAWP whereptestis the test pressure, expressed in bar MAWP is the maximum allowable working pressure of the inner tank, expressed in bar. The inner tank and its accessories shall be designed to resist an outer pres
34、sure of 1 bar.4.2.1.2 Outer jacketThe outer jacket shall be designed to resist an outer pressure of 1 bar (see 4.5.2).4.2.2 Accelerations4.2.2.1 GeneralThe fuel tank and its accessories shall be mounted and protected so that the accelerations shown in Table 1 can be absorbed without structural damag
35、e to the fuel tank and its accessories. No uncontrolled release of LNG is permitted. ISO 2012 All rights reserved 3BS ISO 12991:2012ISO 12991:2012(E)Table 1 AccelerationsVehicle categories AccelerationsVehicles of categories M1 and N1 20 g in the direction of travel8 g horizontally perpendicular to
36、the direction of travelVehicles of categories M2 and N2 10 g in the direction of travel5 g horizontally perpendicular to the direction of travelVehicles of categories M3 and N3 6,6g in the direction of travel5 g horizontally perpendicular to the direction of travelThe vehicle categories include the
37、following: Category M1: Vehicles used for the transportation of passengers and comprising not more than eight seats in addition to the drivers seat. Category M2: Vehicles used for the transportation of passengers, comprising more than eight seats in addi-tion to the drivers seat, and having a maximu
38、m mass that does not exceed 5 000 kg. Category M3: Vehicles used for the transportation of passengers, comprising more than eight seats in addi-tion to the drivers seat, and having a maximum mass exceeding 5 000 kg. Category N1: Vehicles used for the transportation of goods and having a maximum mass
39、 that does not exceed 3 500 kg Category N2: Vehicles used for the transportation of goods and having a maximum mass exceeding 3 500 kg, but not exceeding 12 000 kg. Category N3: Vehicles used for the transportation of goods and having a maximum mass exceeding 12 000 kg.4.2.2.2 Inner and outer suppor
40、tWhen exposed to the accelerations described in Table 1, the stress in the support elements shall not exceed the minimum ultimate tensile strength of the material (Rm, calculated according with the linear stress model).The allowable stress in the support elements may not have to be calculated if it
41、can be demonstrated that the fuel tank supports the accelerations given in Table 1 without any structural damage to the inner tank or its supports.Acceptable calculation methods include finite element, finite difference, boundary element, and established calculation method.In these calculations stat
42、ic loads shall be substituted for static plus dynamic loads.4.3 Thermal stresses4.3.1 Design temperatureThe design temperature of the inner tank, the outer jacket and the accessories shall be 20C. In addition, the inner tank, the outer jacket and the accessories shall be designed to withstand a temp
43、erature range from the lowest to the highest possible operating temperatures that will be encountered in service.4 ISO 2012 All rights reservedBS ISO 12991:2012ISO 12991:2012(E)4.3.2 Ambient temperatureThe fuel tank shall be designed to withstand ambient temperatures ranging from 40C to 85C. If the
44、fuel tank is to be installed in areas of internal heat sources such as the internal combustion engine compartment of a vehicle, the fuel tank shall be designed for an ambient temperature of 120C, or a lower value if substantiated by calculations.4.3.3 Operating temperatureThe thermal stresses produc
45、ed by the operating conditions shall be considered. The inner vessel and the other components that may be in contact with LNG shall be designed to operate at 196 C.4.4 MaterialsThe materials of the fuel tank and its accessories shall be compatible, as applicable, witha) LNG, andb) other media and fl
46、uids found in a vehicle environment, such as coolants, brake fluid and battery acid.Materials used at low temperatures shall meet the toughness requirements of ISO 21028-1. For non-metallic materials, low temperature suitability shall be validated by an experimental method, taking into account the s
47、ervice conditions.The materials used for the outer jacket shall ensure the integrity of the insulation system and shall be made of austenitic stainless steelFor the inner vessel if materials other than austenitic stainless steels are used it shall be ensured that the materials will resist all the in
48、 service fatigue loadA corrosion allowance does not need to be added for the inner tank. A corrosion allowance does not need to be added on other surfaces, if they are protected against corrosion.For welded vessels, welds shall have properties equivalent to those specified for the parent material fo
49、r all temperatures that the material may encounter.4.5 Design4.5.1 Design validationEach type of vessel shall be validated in accordance with the design options specified in 10.1 of ISO 21029-1:2004 and in accordance with one of options given in 4.5.1.1 and 4.5.1.2.4.5.1.1 Validation by calculationThis option requires calculation in accordance with 10.3 of ISO 21029-1:2004. Additional calculations are required to validate the design for accelerations in 4.2.2.4.5.1.2 Validation by
