1、 Reference number ISO/TR 15656:2003(E) ISO 2003TECHNICAL REPORT ISO/TR 15656 First edition 2003-12-01 Fire resistance Guidelines for evaluating the predictive capability of calculation models for structural fire behaviour Rsistance au feu Lignes directrices pour valuer laptitude des modles mathmatiq
2、ues simuler le comportement des feux de structures ISO/TR 15656:2003(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 typefaces which are embedded are licensed to and inst
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7、656:2003(E) ISO 2003 All rights reserved iiiContents Page Foreword iv Introduction v 1 Scope 1 2 Normative references . 1 3 Terms and definitions. 1 4 Background information 2 4.1 General. 2 4.2 Potential users and their needs. 2 4.3 Predictive model capabilities, uncertainties of design component (
8、from ISO/TR 12471) 2 5 Outline of methodology 6 6 Definition and documentation of model and scenario 7 6.1 Types of models 7 6.2 Documentation 9 6.3 Deterministic versus probabilistic 10 7 Evaluation 10 7.1 Sources of errors in predictions . 10 7.2 Model application and use . 11 7.3 Model theoretica
9、l basis 12 7.4 Model solution. 12 7.5 Comparison of model results 14 7.6 Measurement uncertainty of data (from ISO/TR 13387-3) 17 7.7 Model sensitivity . 18 Bibliography . 22 ISO/TR 15656:2003(E) iv ISO 2003 All rights reservedForeword ISO (the International Organization for Standardization) is a wo
10、rldwide 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 has been established has the right to be represented o
11、n 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 standardization. International Standards are drafted
12、 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 bodies for voting. Publication as an International Standa
13、rd requires approval by at least 75 % of the member bodies casting a vote. In exceptional circumstances, when a technical committee has collected data of a different kind from that which is normally published as an International Standard (“state of the art”, for example), it may decide by a simple m
14、ajority vote of its participating members to publish a Technical Report. A Technical Report is entirely informative in nature and does not have to be reviewed until the data it provides are considered to be no longer valid or useful. Attention is drawn to the possibility that some of the elements of
15、 this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO/TR 15656 was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 2, Fire containment. ISO/TR 15656 is one of a series of documents developed by
16、 ISO/TC 92/SC 2 that provide guidance on important aspects of calculation methods for fire resistance of structures: ISO/TR 15655, Fire resistance Tests for thermo-physical and mechanical properties of structural materials at elevated temperatures for fire engineering design Others documents in this
17、 series are currently in preparation and include: ISO/TS 15657, Fire resistance Guidelines on computational structural fire design ISO/TS 15658, Fire resistance Guidelines for full scale structural fire tests Other related documents developed by ISO/TC 92/SC 2 that also provide data and information
18、for the determination of fire resistance include: ISO 834 (all parts), Fire-resistance tests Elements of building construction ISO/TR 10158, Principles and rationale underlying calculation methods in relation to fire resistance of structural elements ISO/TR 12470, Fire-resistance tests Guidance on t
19、he application and extension of results ISO/TR 12471 1) , Computational structural fire design State of the art and the need for further development of calculation models and for fire tests for determination of input material data required 1) In preparation. ISO/TR 15656:2003(E) ISO 2003 All rights
20、reserved vIntroduction Structural fire behaviour for a standard fire exposure has traditionally been experimentally determined by test methods described by International Standards such as ISO 834 (all parts). For a variety of reasons, calculation methods have been developed as alternative methodolog
21、ies for determining the fire endurance or fire resistance of structural members or assemblies. Since fire resistance is a critical component of fire safety regulations, it is essential that objective assessments of the accuracy and applicability of such calculation methods be conducted. In a review
22、of the state of the art of computational structural fire design, ISO/TR 12471, it was noted the “rapid progress in analytical and computer modelling of phenomena and processes of importance for a fire engineering design stresses the need for internationally standardized procedures for evaluating the
23、 predictive capabilities of the models and for documenting the computer software.” The development of this Technical Report is toward that end. TECHNICAL REPORT ISO/TR 15656:2003(E) ISO 2003 All rights reserved 1Fire resistance Guidelines for evaluating the predictive capability of calculation model
24、s for structural fire behaviour 1 Scope This Technical Report provides guidance for evaluating the predictive capability of calculation models for structural fire behaviour. It is specific to models that are intended to predict the fire resistance or fire endurance of structural members or assemblie
25、s. Such models include models simulating the thermal behaviour and mechanical behaviour of fire-exposed load-bearing and/or separating structures and structural elements. In this Technical Report, the term “model” includes all calculation procedures that are based on physical models. These mechanist
26、ic-based or physical models encompass all the physical, mathematical and numerical assumptions and approximations that are employed to describe the behaviour of structural members and assemblies when subjected to a fire. In general, such physical models are implemented as a computer code on a digita
27、l computer. The application and extension of results from calculation methods are generally limited to performance resulting from standard tests. Aspects of this Technical Report are applicable to calculation procedures not based on physical models. Mechanistic-based models can often be used to calc
28、ulate the behaviour of structures in non-standard fire exposures. The process of model evaluation is critical in establishing both the acceptable uses and limitations of fire models. It is not possible to evaluate a model in total; instead, this Technical Report is intended to provide methodologies
29、for evaluating the predictive capabilities for specific uses. Documentation of suitability for certain applications or scenarios does not imply validation for other scenarios. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated
30、references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 13943:2000, Fire safety Vocabulary 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 13943 apply.
31、NOTE In discussions of models, the terms “evaluation”, “verification” and “validation” have taken on specific but different meanings. There is no consensus on the requirements for an evaluation to be considered verification or validation. The dictionary definition of “evaluate” is “to examine and ju
32、dge.” “Verify” is defined as “to establish the truth, accuracy, or reality of.” The definition of “validation” includes “the process of determining the degree of validity of a measuring device.” “Valid” is considered to “imply being supported by objective truth or generally accepted authority.” For
33、the purposes of this Technical Report, no judgement is made as to what is required for a model to be “verified” or “validated.” The intent is to review methodologies that are available to evaluate fire models for purposes of gaining verification or validation of such fire models for their defined ap
34、plications. The term “evaluation” is used in all cases. “For clarity it would be better for the word (i.e. validation) not to be used at all but for people to say explicitly what they mean.” 1ISO/TR 15656:2003(E) 2 ISO 2003 All rights reserved4 Background information 4.1 General Structural fire beha
35、viour for a standard fire exposure has traditionally been experimentally determined by test methods described by standards such as ISO 834. For a variety of reasons, calculation methods have been developed as alternative methodologies for determining the fire endurance or fire resistance of structur
36、al members or assemblies. Since fire resistance is a critical component of fire safety regulations, it is essential that objective assessments of the accuracy and applicability of such calculation methods be conducted. In a review of the state of the art of computational structural fire design (ISO/
37、TR 12471), it was noted that “rapid progress in analytical and computer modelling of phenomena and processes of importance for a fire engineering design stresses the need of internationally standardized procedures for evaluating the predictive capabilities of the models and for documenting the compu
38、ter software.” In an earlier review of fire-dedicated thermal and structural computer programs, it was noted that programs are commonly only validated against specific and limited test data. Little work had been presented by way of general validation of these methods. ASTM has developed ASTM E 1355,
39、 Standard guide for evaluating the predictive capability of fire models. This was used to develop the initial draft of this document. ISO/TC 92/SC 4 is developing guidelines, ISO/TR 13389, Fire engineering Assessment and verification of mathematical fire models. These documents provide guidance that
40、 are applicable to any fire model but their primary intended applications are to models that predict fire growth in compartments. A number of papers have been published on the evaluation of a fire model 2-10. . Some of these documents will be reviewed in ISO/TR 13389. A 1993 review of seven thermal
41、analysis programs and fourteen structural analysis was dedicated to fire endurance analysis 2 . An assessment of fire models based on a matrix of criteria and weighting factors has been presented 10 . Criteria include field of application (4 points), scientific verification (6 points), precision of
42、method (2 points), physical background (1 point), completeness (2 points), input existent (2 points), user friendliness (1 point) and approval/standard or experience (2 points). The sum of the weighting factors is 20 points. The system was applied to existing simplified methods for concrete, structu
43、ral steel and timber. 4.2 Potential users and their needs This Technical Report is intended to meet the needs of users of fire models. Users of models need to assure themselves that they are using an appropriate model for an application and that it provides adequate accuracy. Developers of performan
44、ce-based code provisions and other approving officials need to ensure that the results of calculations using mathematical models show clearly that the model is used within its applicable limits and has an acceptable level of accuracy. The methodologies discussed in this Technical Report will assist
45、model developers and marketers in developing the documentation of predictive capabilities for specific applications that should be available on their calculation methods. Part of model development includes the identification and documentation of precision and limits of applicability, and independent
46、 testing. Educators can use the methods to demonstrate the application and acceptability of calculation methods being taught. This Technical Report should also be useful for educators of future model developers so future models of greater complexity and availability are used within their limitations
47、 of application and precision. 4.3 Predictive model capabilities, uncertainties of design component (from ISO/TR 12471) Few systematic studies of the predictive capabilities of models and related computer software, used for describing the simulated fire exposure and the thermal and mechanical behavi
48、our of fire exposed structures, have appeared in the literature. Recent studies seem to indicate that the situation now is improved. Such studies include compartment fire modelling 1,11,12and modelling of the thermal and mechanical behaviour of structures 2,13 . General categories have been identifi
49、ed regarding possible sources of error in using a computer model to predict the value of a state-variable such as temperature or heat flux 1,11 . The categories specified are a) unreality of the theoretical and numerical assumptions in the model, b) errors in the numerical solution techniques, c) software errors, ISO/TR 15656:2003(E) ISO 2003 All rights reserved 3d) hardware faults, and e) application errors. For 10 zone models and 3 field models for the compartment fire, the Loss Prevention Council p
