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1、 Reference number ISO 4126-9:2008(E) ISO 2008 INTERNATIONAL STANDARD ISO 4126-9 First edition 2008-04-15 Safety devices for protection against excessive pressure Part 9: Application and installation of safety devices excluding stand-alone bursting disc safety devices Dispositifs de scurit pour prote
2、ction contre les pressions excessives Partie 9: Application et installation des dispositifs de scurit autres que les dispositifs disque de rupture installs seuls Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resa
3、le, 07/25/2008 03:22:50 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 4126-9:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typeface
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8、.iso.org Published in Switzerland ii ISO 2008 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:22:50 MDTNo reproduction or networking permitted without license from IHS -,-,
9、- ISO 4126-9:2008(E) ISO 2008 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references. 1 3 Terms and definitions. 1 4 Risk consideration 3 5 Pressure limitation 4 5.1 General. 4 5.2 Setting of safety devices 5 6 Inlet line . 6 7 Outlet line 6 8 Installatio
10、n. 8 8.1 General. 8 8.2 Installation of safety valves or the main valve of a CSPRS or a POSV. 8 8.3 Installation of safety valves and bursting disc safety devices in series or parallel 9 8.4 Isolation of safety devices. 10 9 Lifting device. 11 Annex A (informative) Safety device applications 12 Anne
11、x B (informative) Sizing of multiple safety devices 15 Annex C (informative) Sizing of inlet lines. 17 Annex D (informative) Calculation of built-up back pressure 22 Annex E (informative) Calculation of reaction forces. 29 Annex F (informative) Calculation of noise level 30 Bibliography. 31 Copyrigh
12、t International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:22:50 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 4126-9:2008(E) iv ISO 2008 All rights reserved Foreword ISO (the Int
13、ernational 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 committee ha
14、s 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 electrotechnical
15、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 bodie
16、s 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 any o
17、r all such patent rights. ISO 4126-9 was prepared by Technical Committee ISO/TC 185, Safety devices for protection against excessive pressure. ISO 4126 consists of the following parts, under the general title Safety devices for protection against excessive pressure: Part 1: Safety valves Part 2: Bur
18、sting disc safety devices Part 3: Safety valves and bursting disc safety devices in combination Part 4: Pilot-operated safety valves Part 5: Controlled safety pressure relief systems (CSPRS) Part 6: Application, selection and installation of bursting disc safety devices Part 7: Common data Part 9: A
19、pplication and installation of safety devices excluding stand-alone bursting disc safety devices Part 10: Sizing of safety valves and connected inlet and outlet lines for gas/liquid two-phase flow Copyright International Organization for Standardization Provided by IHS under license with ISO License
20、e=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:22:50 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 4126-9:2008(E) ISO 2008 All rights reserved v Introduction A safety device or system is the final element to protect pressure equipment from exceeding its allowabl
21、e limits. Regulating and/or monitoring devices are not ultimate safety devices in the meaning of this International Standard. They become active in advance of an ultimate safety device (see Figure 1). It is important to consider not only the pressure-relieving device but also the whole of the equipm
22、ent protected, so as not to reduce the relieving capacity or adversely affect the proper operation of the pressure-relieving devices, in order to ensure that the relieving pressure is not exceeded. The value of the relieving pressure is 1,x times the maximum allowable pressure, PS, where x is define
23、d by a directive or national regulation. Operating problems can occur in pressure relief because of the selection of an inappropriate device or because a correctly selected device is adversely affected by improper handling, wrong installation or lack of maintenance. In some cases, it can be necessar
24、y to determine the basic details of the equipment protected so as to ensure that the maximum relieving pressure is not exceeded. NOTE 1 There can be requirements in a number of regulations to be respected and it is the responsibility of the user of this part of ISO 4126 to ensure compliance with the
25、se requirements. This part of ISO 4126 is also intended to draw attention to subjects that are not within its scope, but which are relevant to safety devices. NOTE 2 To cover the essential requirements of the various regulations, a safety device needs to incorporate a whole range of products. Many o
26、f these products are covered by International Standards, but there are others that will either never be standardized or that will not be standardized within the foreseeable future. Where standards have already been produced, where work is known to be proceeding or where there is the intention of pro
27、ducing an applicable standard, reference is made to the standard concerned. Where there is no standard to which to refer, this part of ISO 4126 merely specifies the essential requirements of the device. Copyright International Organization for Standardization Provided by IHS under license with ISO L
28、icensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:22:50 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 4126-9:2008(E) vi ISO 2008 All rights reserved Key X time Y pressure 1 reaction of regulating control system 2 reaction of monitoring system 3 reaction of sa
29、fety system 4 normal operating range PS maximum allowable pressure PS,accum maximum allowable accumulated pressure (PS 1,x) a No continuous operation in this zone. Figure 1 Diagram of typical system relationship Copyright International Organization for Standardization Provided by IHS under license w
30、ith ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:22:50 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 4126-9:2008(E) ISO 2008 All rights reserved 1 Safety devices for protection against excessive pressure Part 9: Application an
31、d installation of safety devices excluding stand- alone bursting disc safety devices 1 Scope This part of ISO 4126 covers the application and installations of safety devices such as safety valves, safety valves and bursting disc safety devices in combination, pilot-operated safety valves and control
32、led safety pressure-relief systems for the protection of pressure equipment. ISO 4126-6 covers the selection, application and installation of bursting disc safety devices. This part of ISO 4126 describes the normative requirements for applications and installations of safety devices to protect stati
33、c pressure equipment. The information contained in this part of ISO 4126 assumes single-phase flow of the fluid discharged from the safety device. ISO 4126-10 provides guidance specific to two-phase flow conditions. Equipment connected together in a system by piping of adequate capacity, which is fr
34、ee from potential blockages and does not contain any valve that can isolate any part, can be considered to be a safety system for the application of pressure relief. This part of ISO 4126 does not deal with other safety devices, such as safety related monitoring, control and regulation devices and o
35、ther limiting devices allowed by some national regulations. 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
36、ncluding any amendments) applies. ISO 4126-6, Safety devices for protection against excessive pressure Part 6: Application, selection and installation of bursting disc safety devices 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 safety devi
37、ce device that serves as the ultimate protection to ensure that the maximum allowable accumulated pressure is not exceeded EXAMPLE Safety valves, bursting disc safety devices, etc. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910
38、770001 Not for Resale, 07/25/2008 03:22:50 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 4126-9:2008(E) 2 ISO 2008 All rights reserved 3.2 safety system system including the safety devices and the interconnections between the equipment to be protected and any discharg
39、e connection to the nearest location of a safe disposal place NOTE This location can either be an atmospheric outlet or the connection into a safe collecting system or flare. 3.3 fail-safe status such that the pressure equipment remains in a safe condition in case of failure of any safety system com
40、ponent or energy source 3.4 self-diagnosis regular and automatic determination that all chosen components of a safety system are capable of functioning as required 3.5 redundancy provision of more than one device or system such that the necessary function will still be provided in case of failure of
41、 one or more of these devices 3.6 independence ability to function as required without interference from other equipment 3.7 hazard potential source of harm NOTE 1 The term “hazard” can be qualified in order to define its origin or the nature of the expected harm (see ISO/IEC Guide 51). NOTE 2 Harm
42、is the physical injury or damage to the health of people, or damage to property or to the environment. 3.8 risk combination of the probability of occurrence of harm and the severity of that harm NOTE See ISO/IEC Guide 51. 3.9 risk analysis use of available information to identify hazards and to esti
43、mate the risk NOTE See ISO/IEC Guide 51. 3.10 risk evaluation judgement on the basis of risk analysis as to whether a tolerable risk has been achieved NOTE See ISO/IEC Guide 51. 3.11 risk assessment overall process of risk analysis and risk evaluation NOTE See ISO/IEC Guide 51. Copyright Internation
44、al Organization for Standardization Provided by IHS under license with ISO Licensee=Boeing Co/5910770001 Not for Resale, 07/25/2008 03:22:50 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 4126-9:2008(E) ISO 2008 All rights reserved 3 3.12 reliability ability to perform
45、 a required function under specified conditions and for a given period of time without failing 3.13 pressure limiter device which ensures that the permitted maximum allowable pressure is not exceeded during continuous operation NOTE It activates the means for correction, or provides for shutdown or
46、shutdown and lockout. 3.14 safety freedom from unacceptable risk NOTE See ISO/IEC Guide 51. 3.15 maximum allowable pressure PS maximum pressure for which the equipment is designed, as specified by the manufacturer 3.16 maximum/minimum allowable temperature TS maximum/minimum temperatures for which t
47、he equipment is designed, as specified by the manufacturer 3.17 accumulated pressure pressure in the equipment to be protected which can exceed maximum allowable pressure for a short duration during the operation of safety devices 3.18 maximum allowable accumulated pressure PS,accum maximum allowabl
48、e value of the accumulated pressure in the equipment being protected which is fixed by national codes, regulations or directives 4 Risk consideration 4.1 All service conditions shall be considered when selecting the most appropriate safety concept, in order to ensure safe operation of the pressure equipment. This requires a realistic assessment of risk by means of risk analysis and risk evaluation. 4.2 Risk analysis involves, for example: a) determination