1、BRITISH STANDARDBS ISO 22538-1:2007Space systems Oxygen safety Part 1: Design of oxygen systems and components ICS 49.140g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g4
2、4g42g43g55g3g47g36g58BS ISO 22538-1:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2007 BSI 2007ISBN 978 0 580 53674 8National forewordThis British Standard is the UK implementation of ISO 22538-1:2007.The UK participation in
3、 its preparation was entrusted to Technical Committee ACE/68, Space systems and operations.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible
4、for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsReference numberISO 22538-1:2007(E)INTERNATIONAL STANDARD ISO22538-1First edition2007-09-01Space systems Oxygen safety Part 1: Design
5、of oxygen systems and components Systmes spatiaux Scurit des systmes doxygne Partie 1: Conception des systmes doxygne et leurs composants BS ISO 22538-1:2007ii iiiContents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Terms, definitions and abbreviated terms . 1 3.1 Terms and definitions
6、. 1 3.2 Abbreviated terms 2 4 Design approach. 2 4.1 General. 2 4.2 Design specifications. 2 4.3 Design reviews 2 4.4 Component and system testing 4 5 Design for high-pressure and high-temperature gaseous oxygen systems 4 5.1 Design features . 4 5.2 Materials guidelines 5 5.3 General design guidelin
7、es . 6 5.4 Specific system design guidelines . 7 6 Design for cryogenic oxygen systems.10 6.1 General. 10 6.2 Materials guidelines 11 6.3 General system installation guidelines 11 6.4 Design specifications. 11 6.5 Hazard considerations . 12 6.6 Component hardware and systems design considerations. 1
8、2 6.7 Electrical design guidelines 12 7 Standard practices 13 7.1 Liquid-oxygen vessels . 13 7.2 Piping systems 13 7.3 Liquid-oxygen piping systems 14 7.4 Gaseous oxygen piping systems 15 7.5 Systems connections and joints. 15 7.6 Components 16 Bibliography . 20 BS ISO 22538-1:2007iv Foreword ISO (t
9、he 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 subject for which a technical commit
10、tee 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 (IEC) on all matters of electrotech
11、nical 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 committees are circulated to the member
12、 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 held responsible for identifying
13、 any or all such patent rights. ISO 22538-1 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 14, Space systems and operations. ISO 22538 consists of the following parts, under the general title Space systems Oxygen safety: Part 1: Design of oxygen systems a
14、nd components Part 2: Selection of metallic materials for oxygen systems and components Part 3: Selection of non-metallic materials for oxygen systems and components Part 4: Hazards analyses for oxygen systems and components The following parts are under preparation: Part 5: Operational and emergenc
15、y procedures Part 6: Facility planning and implementation BS ISO 22538-1:20071Space systems Oxygen safety Part 1: Design of oxygen systems and components 1 Scope This part of ISO 22538 describes a process for the design of oxygen systems and their components. This part of ISO 22538 applies equally t
16、o ground support equipment, launch vehicles and spacecraft. 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 references, the latest edition of the referenced document (i
17、ncluding any amendments) applies. ISO 22538-2, Space systems Oxygen safety Part 2: Selection of metallic materials for oxygen systems and components ISO 22538-3, Space systems Oxygen safety Part 3: Selection of non-metallic materials for oxygen systems and components 3 Terms, definitions and abbrevi
18、ated terms 3.1 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1.1 direct oxygen service service in which materials and components are in direct contact with oxygen during normal operations 3.1.2 indirect oxygen service service in which materials
19、 and components are not normally in direct contact with oxygen but might be as a result of a malfunction, operator error or process disturbance 3.1.3 oxygen-enriched atmosphere mixture (gas or liquid) that contains more than 25 volume percent oxygen 3.1.4 qualified technical personnel persons such a
20、s engineers and chemists who, by virtue of education, training or experience, know how to apply physical and chemical principles involved in the reactions between oxygen and other materials BS ISO 22538-1:20072 3.2 Abbreviated terms CDR critical design review EPR emergency procedures review FMECA fa
21、ilure modes and effects criticality analysis GOX gaseous oxygen LOX liquid oxygen ORI operational readiness inspection PCTFE polychlorotrifluoroethylene PDR preliminary design review PTFE polytetrafluoroethylene SSA/SR system safety analysis/safety review TRR test readiness review 4 Design approach
22、4.1 General Oxygen is chemically stable and a strong oxidizer that supports combustion. It is not shock sensitive and is not flammable. Oxygen is reactive at ambient conditions and its reactivity increases with increasing pressure, temperature and concentration. Before embarking on a new task, it is
23、 important that designers, customers and operators understand the risks associated with oxygen systems. 4.2 Design specifications Each new design project begins with specifications for the requested item. It is important that these specifications do not create an unnecessary risk for personnel or eq
24、uipment. Most materials are flammable in high-pressure oxygen. An oxygen system designer shall understand that oxygen, fuel and a source of ignition are all that is necessary to start and propagate a fire. Many materials are combustible in oxygen-enriched environments and reactivity is generally inc
25、reased with increasing temperature and pressure; therefore, materials selection criteria are critical in achieving a successful final product. The designer shall attempt to avoid using flammable materials; however, many materials that are flammable at operating conditions can be safely used in some
26、applications by carefully avoiding ignition sources. The design shall never compromise safety to reduce costs. 4.3 Design reviews 4.3.1 General In addition to the standard practice of reviewing functional operation, component ignition and combustion in oxygen-enriched environments shall also be asse
27、ssed. The overall design process shall reduce hazards associated with component ignition and combustion. Before constructing oxygen facilities, equipment and systems, the design safety shall be approved by the designated installation safety authority or other approval points. The safety assessment p
28、rocess shall be integrated into the overall facility design review process. Each design review phase shall evaluate the safety aspects of the project according to its level of completion. BS ISO 22538-1:20073Reviews of the final drawings, designs, structures, and flow and containment systems shall i
29、nclude a safety assessment to identify potential system hazards and compliance with the proper regulatory organizations. The safety assessment shall also include the safety history of the system hardware. Such histories can identify equipment failures that may create hazardous conditions when the eq
30、uipment is integrated. All the procedures described in the following section refer to the design of both components and systems for oxygen use. The design reviews ultimately need to address all design aspects down to the individual part level because all parts pose potential hazards in oxygen servic
31、e. 4.3.2 Preliminary design review (PDR) A preliminary review shall be conducted on all materials and specifications. 4.3.3 Integrated failure modes and effects criticality analysis (FMECA) and hazard analysis FMECA reviews each hardware item and analyses it for each possible single-point failure mo
32、de and single-barrier failure and their worst-case effects on the entire system. A FMECA will also include the results of the oxygen hazards analysis. The interdependencies of all components shall be addressed and any single-point failures and the result of single-barrier failures shall be noted in
33、a summary list of action items for correction. Single-barrier failures are often overlooked, but the potential for component-part failures, such as diaphragm failures, can cause hazardous oxygen-enriched environments and may cause a substantially increased risk of ignition near electrical components
34、. Attempting to correct single-point failures simply through procedural actions is not a reliable method. In addition, the FMECA shall consider the effects of failures in both static and dynamic operating conditions. When performed early in the design phase, this analysis greatly assists the designe
35、r in ensuring reliable systems. The FMECA shall be performed before fabrication of the component or system. 4.3.4 Systems and subsystems hazards analysis The hazards analysis shall identify any conditions that could possibly cause death, injury or damage to the facility and surrounding property. It
36、shall also a) include the effects of component and assembly single-point failures, b) review all ignition modes for all components and assemblies, c) include hazards associated with contamination, d) review secondary hazards, such as leakage to electrical equipment, e) consider the effects of mainte
37、nance procedures on safety and performance, and f) review toxicity concerns, especially for breathing oxygen. 4.3.5 Critical design review (CDR) The final design review shall be held after all preliminary analyses have been completed and the action items from these analyses have been resolved. In th
38、is review, the final fabrication drawings and the supporting calculations are reviewed and all final action items resolved before authorizing fabrication and use. 4.3.6 System safety analysis/safety review (SSA/SR) All safety aspects, including oxygen hazards, shall be reviewed to ensure the integra
39、ted design solution does not present unacceptable risks to personnel and property. BS ISO 22538-1:20074 4.3.7 Other reviews In addition to the PDR, FMECA, CDR and SSA/SR, the reviews below may be conducted as needed. a) Test readiness review (TRR): Operational procedures, along with instrumentation
40、and control systems, shall be evaluated for their capacity to provide the required safety. Equipment performance shall be verified by analysis or by certification testing. It may be necessary to develop special procedures to counter hazardous conditions. b) Emergency procedures review (EPR): The saf
41、ety of personnel at or near oxygen systems shall be carefully reviewed together with emergency procedures in the earliest planning and design stages. Advanced planning for a variety of emergencies, such as fires and explosions, shall be undertaken so that the first priority is to reduce any risk to
42、life. c) Operational readiness inspection (ORI): An ORI may be required for any major facility change. Oxygen hazards shall be specifically reviewed for compliance with basic safety requirements. 4.4 Component and system testing 4.4.1 Intent/compliance The intent of component and system testing is t
43、o ensure the integrity of equipment for its intended use. A wide variety of tests may be required, depending upon the critical nature of the equipment and whether or not it is flight-rated hardware. Compliance with safety programmes for pressure vessels and pressurized systems is required. 4.4.2 Pro
44、totype development testing Initial testing is often best performed with inert fluids or gases; however, acceptance tests of the final hardware configuration shall be conducted with clean oxygen and parts cleaned for oxygen service. Testing with oxygen shall begin only after an oxygen hazards analysi
45、s has been performed on the specific test hardware. Engineering development testing is intended to verify safe and reliable operation over a realistic range of operating conditions. It includes pressure integrity tests, assembly leak tests and configurational tests. Consider worst-case operating tes
46、ts to re-evaluate limited design margins, single-point failures and any uncertainties in the design criteria. Life-cycle and flow tests are important in this phase of testing. Life-cycle tests shall be performed to determine the safety and longevity of systems components. The components shall be tes
47、ted in each operational mode with the number of cycles based on the anticipated end-use. These do not constitute qualification, life-cycle or pressure qualification (proof) tests. 4.4.3 Qualification and acceptance testing Test requirements will vary for each component or assembly to be tested. The
48、equipment supplier, test facility personnel and end-user shall develop a joint test programme to verify function and oxygen compatibility. 5 Design for high-pressure and high-temperature gaseous oxygen systems 5.1 Design features Design features, such as physical design of components and the compone
49、nt location in the system, shall be effectively coupled with proper materials selection to achieve safe operations. Evaluation of such design features shall begin with the preliminary design reviews. BS ISO 22538-1:200755.2 Materials guidelines 5.2.1 General Guidelines on materials compatibility with oxygen can be found in documents such as ASTM Manual Series MNL36 1. 5.2.2 Materials Designers of equipment for oxygen service shall thoroughly understand the reactivity of selected materials in oxygen-enriched environments. The designer shall usua
