ISO/TC 92/SC 4/WG 7 - Verification and validation of calculation methods

This document describes a protocol for the verification and validation of building fire evacuation models. This document mostly addresses evacuation model components as they are in microscopic (agent-based) models. Nevertheless, it can be adopted (entirely or partially) for macroscopic models if the model is able to represent the components under consideration. The area of application of the evacuation models discussed in this document includes performance-based design of buildings and the review of the effectiveness of evacuation planning and procedures. The evacuation process is represented with evacuation models in which people's movement and their interaction with the environment make use of human behaviour in fire theories and empirical observations[5]. The simulation of evacuation is represented using mathematical models and/or agent‑to‑agent and agent-to-environment rules. The area of application of this document relates to buildings. This document is not intended to cover aspects of transportation systems in motion (e.g. trains, ships) since specific ad-hoc additional tests may be required for addressing the simulation of human behaviour during evacuation in these types of systems[6]. This document includes a list of components for verification and validation testing as well as a methodology for the analysis and assessment of accuracy associated with evacuation models. The procedure for the analysis of acceptance criteria is also included. A comprehensive list of components for testing is presented in this document, since the scope of the testing has not been artificially restricted to a set of straightforward applications. Nevertheless, the application of evacuation models as a design tool can be affected by the numbers of variables affecting human behaviour under consideration. A high number of influences can hamper the acceptance of the results obtained given the level of complexity associated with the results. Simpler calculation methods, such as macroscopic models, capacity analyses or flow calculations, are affected to a lower extent by the need to aim at high fidelity modelling. In contrast, more sophisticated calculation methods (i.e. agent-based models) rely more on the ability to demonstrate that the simulation is able to represent different emergent behaviours. For this reason, the components for testing are divided into different categories, enabling the evacuation model tester to test an evacuation model both in relation to the degree of sophistication embedded in the model as well as the specific scope of the model application. In Annex A, a reporting template is provided to provide guidance to users regarding a format for presenting test results and exemplary application of verification and validation tests are presented in Annex B.

ISO 16730-1:2015 establishes a framework for the verification and validation of all types of calculation methods used as tools for fire safety engineering by specifying specific procedures and requirements for the purpose. It does not address specific fire models, but it is applicable to analytical models, algebraic correlations and complex numerical models, which are addressed as calculation methods in the context of this International Standard. This International Standard includes - a process to determine that the relevant equations and calculation methods are implemented correctly (verification) and that the calculation method being considered is an accurate representation of the real world (validation), - requirements for documentation to demonstrate the adequacy of the scientific and technical basis of a calculation method, - requirements for data against which a calculation method's predicted results are checked, and - guidance on use of this International Standard by developers and/or users of calculation methods, and by those assessing the results obtained by using calculation methods.

ISO 16730‑1 describes what the contents of a technical documentation and of a user's manual should be for an assessment, if the application of a calculation method as engineering tool to predict real-world scenarios leads to validated results. The purpose of ISO/TR 16730-3:2013 is to show how ISO 16730‑1 is applied to a calculation method, for a specific example. It demonstrates how technical and users' aspects of the method are properly described in order to enable the assessment of the method in view of verification and validation. The example in ISO/TR 16730-3:2013 describes the application of procedures given in ISO 16730‑1 for a computational fluid dynamics (CFD) model (ISIS). The main objective of the specific model treated in ISO/TR 16730-3:2013 is the simulation of a fire in an open environment or confined compartments with natural or forced ventilation system.

ISO 16730‑1 describes what the contents of a technical documentation and of a user's manual should be for an assessment, if the application of a calculation method as engineering tool to predict real-world scenarios leads to validate results. The purpose of ISO 16730-5:2013 is to show how ISO 16730‑1 is applied to a calculation method, for a specific example. It demonstrates how technical and users' aspects of the method are properly described in order to enable the assessment of the method in view of verification and validation. The example in ISO 16730-5:2013 describes the application of procedures given in ISO 16730‑1 for an evacuation model (EXIT89). The main objective of the specific model treated in ISO 16730-5:2013 is the simulation of the evacuation of a high-rise building with a large occupant population.

ISO 16730-4:2013 shows how ISO 16730‑1 is applied to a calculation method for a specific example. It demonstrates how technical and users' aspects of the method are properly described in order to enable the assessment of the method in view of verification and validation. The example it gives describes the application of procedures given in ISO 16730‑1 for a structural fire resistance model. The main objective of the specific model treated here is the simulation of the heat transfer and structural responses of wall assemblies.

ISO/TR 16730-2:2013 shows how ISO 16730‑1 is applied to a calculation method for a specific example. It demonstrates how technical and users' aspects of the method are properly described in order to enable the assessment of the method in view of verification and validation. ISO/TR 16730-2:2013 describes the application of procedures given in ISO 16730‑1 for a fire zone model (CFAST). The main objective of the specific model treated here is the simulation of a fire in an open environment or in confined compartments with a natural or forced ventilation system.

ISO/TS 13477:2013 provides guidance for assessing the use of fire zone models for calculating gas temperature and concentrations and smoke layer position due to fire within an enclosure. It contains general guidance to be read in conjunction with specific model documentation provided by the model developers. It is not a basis for justifying the use of any particular model. It is important that users of fire zone models understand the theoretical basis of a model and are capable of assessing the accuracy and validity of the results. Zone models can also include additional sub-models for predicting related phenomena such as sprinkler, thermal or smoke detector activation, mechanical ventilation, glass fracture or flame spread. ISO/TS 13477:2013 is not intended as a basis for regulation.

ISO 16730:2008 provides a framework for assessment, verification and validation of all types of calculation methods used as tools for fire safety engineering. It does not address specific fire models, but is intended to be applicable to both analytical models and complex numerical models that are addressed as calculation methods in the context of this International Standard. It is not a step-by-step procedure, but does describe techniques for detecting errors and finding limitations in a calculation method. ISO 16730:2008 includes the following: a process to ensure that the equations and calculation methods are implemented correctly (verification) and that the calculation method being considered is solving the appropriate problem (validation); requirements for documentation to demonstrate the adequacy of the scientific and technical basis of a calculation method; requirements for data against which a calculation method's predicted results shall be checked; guidance on use of this ISO 16730:2008 by developers and/or users of calculation methods, and by those assessing the results obtained by using calculation methods.