1、 Reference number ISO 24638:2008(E) ISO 2008INTERNATIONAL STANDARD ISO 24638 First edition 2008-11-15 Space systems Pressure components and pressure system integration Systmes spatiaux Intgration des composants sous pression et des systmes sous pression ISO 24638:2008(E) PDF disclaimer This PDF file
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5、008 All 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 co
6、untry of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2008 All rights reservedISO 24638:2008(E) ISO 2008 All rights reserved iii Contents Page Foreword iv Int
7、roduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Abbreviated terms 5 5 General requirements. 5 5.1 General. 5 5.2 Design requirements 5 5.3 Material requirements. 7 5.4 Fabrication and process requirements 7 5.5 Contamination control and cleanliness requirements 8 5.6
8、Quality assurance programme requirements 8 5.7 Qualification test requirements. 10 5.8 Operation and maintenance requirements 10 6 General pressurized-system requirements 12 6.1 System analysis requirements 12 6.2 Design features . 13 6.3 Component selection . 14 6.4 Design pressures 15 6.5 Mechanic
9、al-environment design . 16 6.6 Controls . 16 6.7 Protection 17 6.8 Electrical 17 6.9 Pressure relief . 17 6.10 Control devices . 19 6.11 Accumulators 19 6.12 Flexhose 20 7 Specific pressure system requirements.20 7.1 General. 20 7.2 Hydraulic systems 20 7.3 Pneumatic-system requirements 23 Annex A (
10、informative) Recommended minimum safety factors 24 Annex B (informative) Open line force calculation factors 25 ISO 24638:2008(E) iv ISO 2008 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies
11、). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and no
12、n-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Par
13、t 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting
14、 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 held responsible for identifying any or all such patent rights. ISO 24638 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcom
15、mittee SC 14, Space systems and operations. ISO 24638:2008(E) ISO 2008 All rights reserved v Introduction Space vehicles and their launch systems usually have a series of engines to use for both primary propulsion and secondary propulsion functions, such as attitude control and spin control. Differe
16、nt engines have different propellant feed systems; for example, the gas-pressure feed system is typically used for liquid propellant engines, and it consists of a high-pressure gas tank, a fuel tank and an oxidizer tank, valves and a pressure regulator. All these components are referred to as pressu
17、rized hardware. Due to their specific usage, the liquid propellant tanks and the high-pressure gas bottles are often referred to as pressure vessels, while valves, regulators and feed lines are usually called pressure components. ISO 14623 sets forth the standard requirements for pressure vessels in
18、 order to achieve safe operation and mission success. However, the requirements for pressure components are not covered in ISO 14623. Furthermore, the standard requirements for pressure system integration are lacking. Significant work has been done in the area of design, analysis and testing of pres
19、sure components for use in space systems. This International Standard establishes the preferred methods for these techniques and sets forth the requirements for assembly, installation, test, inspection, operation and maintenance of the pressure systems in spacecraft and launch vehicles. INTERNATIONA
20、L STANDARD ISO 24638:2008(E) ISO 2008 All rights reserved 1 Space systems Pressure components and pressure system integration 1 Scope This International Standard establishes the baseline requirements for the design, fabrication and testing of space flight pressure components. It also establishes the
21、 requirements for assembly, installation, test, inspection, operation and maintenance of the pressure systems in spacecraft and launch vehicles. These requirements, when implemented on a particular space system, ensure a high level of confidence in achieving safe and reliable operation. This Interna
22、tional Standard applies to all pressure components other than pressure vessels and pressurized structures in a pressure system. It covers lines, fittings, valves, bellows, hoses and other appropriate components that are integrated to form a pressure system. The requirements for pressure vessels and
23、pressurized structures are set forth in ISO 14623. This International Standard does not apply to engine components. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated refe
24、rences, the latest edition of the referenced document (including any amendments) applies. ISO 14623, Space systems Pressure vessels and pressurized structures Design and operation ISO 21347, Space systems Fracture and damage control 3 Terms and definitions For the purposes of this document, the foll
25、owing terms and definitions apply. 3.1 A-basis allowable mechanical strength value above which at least 99 % of the population of values is expected to fall, with a confidence level of 95 % NOTE See also B-basis allowable (3.3). 3.2 applied load applied stress actual load (stress) imposed on the har
26、dware in the service environment ISO 24638:2008(E) 2 ISO 2008 All rights reserved3.3 B-basis allowable mechanical strength value above which at least 90 % of the population of values is expected to fall, with a confidence level of 95 % NOTE See also A-basis allowable (3.1). 3.4 component functional
27、unit that is viewed as an entity for the purpose of analysis, manufacturing, maintenance, or record keeping 3.5 critical condition most severe environmental condition in terms of loads, pressures and temperatures, or combinations thereof, imposed on systems, subsystems, structures and components dur
28、ing service life 3.6 damage tolerance ability of a material or structure to resist failure due to the presence of flaws, cracks, delaminations, impact damage or other mechanical damage for a specified period of unrepaired usage 3.7 damage tolerance analysis safe-life analysis fracture mechanics-base
29、d analysis that predicts the flaw growth behaviour of a flawed hardware item which is under service load spectrum with a pre-specified scatter factor 3.8 design burst pressure burst pressure ultimate pressure differential pressure that pressurized hardware needs to withstand without burst in the app
30、licable operational environment NOTE Design burst pressure is equal to the product of the maximum expected operating pressure or maximum design pressure and a design burst factor. 3.9 design safety factor design factor of safety factor of safety multiplying factor to be applied to limit loads and/or
31、 maximum expected operating pressure (or maximum design pressure) 3.10 detrimental deformation structural deformation, deflection or displacement that prevents any portion of the structure or other system from performing its intended function 3.11 fittings pressure components of a pressurized system
32、 used to connect lines, other pressure components and/or pressure vessels within the system 3.12 hazard existing or potential condition that can result in an accident ISO 24638:2008(E) ISO 2008 All rights reserved 3 3.13 hydrogen embrittlement mechanical-environmental failure process that results fr
33、om the initial presence or absorption of excessive amounts of hydrogen in metals, usually in combination with residual or applied tensile stresses 3.14 limit load highest predicted load or combination of loads that a structure can experience during its service life, in association with the applicabl
34、e operating environments NOTE The corresponding stress is called “limit stress”. 3.15 lines tubular pressure components of a pressurized system provided as a means for transferring fluids between components of the system NOTE Flexhoses are included. 3.16 loading spectrum representation of the cumula
35、tive loading anticipated for the structure under all expected operating environments NOTE Significant transportation and handling loads are included. 3.17 maximum allowed working pressure MAWP maximum differential pressure of a component designed to withstand safety and continue to operate normally
36、when installed in any pressure system 3.18 maximum design pressure MDP highest differential pressure defined by maximum relief pressure, maximum regulator pressure and/or maximum temperature, including transient pressures, at which a pressurized hardware item retains two-fault tolerance without fail
37、ure 3.19 maximum expected operating pressure MEOP highest differential pressure that a pressurized hardware item is expected to experience during its service life and yet retain its functionality, in association with its applicable operating environments NOTE In this International Standard, the use
38、of the term “maximum expected operating pressure (MEOP)” also signifies “maximum design pressure (MDP)”, “maximum operating pressure (MOP)” or “maximum allowed working pressure (MAWP)”, as appropriate, for a specific application or programme. 3.20 maximum operating pressure MOP maximum differential
39、pressure at which the component or the pressure system actually operates in an application NOTE MOP is synonymous with MEOP. ISO 24638:2008(E) 4 ISO 2008 All rights reserved3.21 pressure component component in a pressure system, other than a pressure vessel, or a pressurized structure that is design
40、ed largely by the internal pressure EXAMPLE Lines, fittings, pressure gauges, valves, bellows and hoses. 3.22 pressure vessel container designed primarily for the storage of pressurized fluids, which either contains gas/liquid with high energy level, or contains gas/liquid that will create a mishap
41、(accident) if released, or contains gas/liquid with high pressure level NOTE 1 This definition excludes pressurized structures and pressure components. NOTE 2 Energy and pressure levels are defined by each project and approved by the procuring authority (customer). If appropriate values are not defi
42、ned by the project, the following levels are used: stored energy is at least 19 310 J, based on adiabatic expansion of perfect gas; MEOP is at least 0,69 MPa. 3.23 pressurized structure structure designed to carry both internal pressure and vehicle structural loads EXAMPLE Launch vehicle main propel
43、lant tank, crew cabins, manned modules. 3.24 pressure system system that consists of pressure vessels or pressurized structures, or both, and other pressure components such as lines, fittings, and valves, which are exposed to, and structurally designed largely by, the acting pressure NOTE The term “
44、pressure system” does not include electrical or other control devices required for system operations. 3.25 proof factor multiplying factor applied to the limit load or MEOP (or MAWP, MDP and MOP) to obtain proof load or proof pressure for use in the acceptance testing 3.26 proof pressure product of
45、MEOP (or MAWP, MDP and MOP) and a proof factor NOTE The proof pressure is used to provide evidence of satisfactory workmanship and material quality and/or to establish maximum initial flaw sizes for damage tolerance life (safe-life) demonstration 3.27 scatter factor multiplying factor to be applied
46、to the number of load/pressure cycles, for the purpose of covering the scatters that potentially exist in the materials fatigue or crack growth data 3.28 service life period of time (or cycles) that starts with the manufacturing of the pressurized hardware and continues through all acceptance testin
47、g, handling, storage, transportation, launch operations, orbital operations, refurbishment, re-testing, re-entry or recovery from orbit, and reuse that can be required or specified for the item ISO 24638:2008(E) ISO 2008 All rights reserved 5 4 Abbreviated terms For the purposes of this document, th
48、e following abbreviated terms apply. COPV composite overwrapped pressure vessel MAWP maximum allowed working pressure MDP maximum design pressure MEOP maximum expected operating pressure MOP maximum operating pressure NDI non-destructive inspection QA quality assurance 5 General requirements 5.1 Gen
49、eral This clause presents the general requirements for pressure components in a pressure system regarding design and analysis, material selection and characterization, fabrication and process control, quality assurance (QA), operation and maintenance (including repair and refurbishment), and storage. The general pressure system requirements are presented in Clause 6. The integration requirements for specific pressure systems are presented in Clause 7. 5.2 Design requirements 5.2.1 Loads, pressures and environments The
