Fire and Evacuation Modeling Technical Conference 2014

Dates: September 8-10, 2014  |  Location: Courtyard Gaithersburg Washingtonian Center in Gaithersburg, MD, USA

Overview

Thunderhead Engineering hosted the 2nd Fire and Evacuation Modeling Technical Conference (FEMTC) on September 8-10, 2014 in Gaithersburg, Maryland. There were two days of technical presentations on fire and evacuation modeling (September 8-9), with an optional third day of workshop classes on PyroSim and Pathfinder (September 10).

Key Speakers

List of Presentations

Please click on the title or the image below to access the full page for each presentation.

Improvements in FDS 6 and Development Update

The presentation will highlight various improvements in FDS, in particular those brought about in FDS version 6. The presentation will also describe current development efforts at NIST, VTT and elsewhere.

Automated Testing Process for FDS 6

This presentation gives an overview of the development of the automated testing process that was introduced in FDS 6, which allows for better collaboration between researchers, students, and the fire model development team. Statistical metrics are generated for the verification and validation cases so that practitioners can utilize the model uncertainty results in fire modeling analyses and probabilistic risk assessments.

Pyrolysis Parameterization and Validation for Polymeric Material

This work is focused on developing and applying a systematic methodology for the characterization of pyrolysis of polymeric materials based on milligram-scale and bench-scale tests to isolate a specific chemical and/or physical process in each scale level. The entire study is divided into two parts corresponding to two different scales of tests and analysis.

Influence of Input Parameters on the Fire Simulation

The use of computational fluid dynamics in fire safety engineering requires the applicability of the employed model according to a specific fire scenario. To be able to estimate how the simulation outcome is influenced by model assumptions and simplifications, the user has to evaluate the dominating physical processes and involved empirical parameter that has an essential influence on the specific fire scenario.

Interface Model to Fire-Thermo-Mechanical Performance-Based Analysis of Structures Under Fire Conditions

The use of computational fluid dynamics in fire safety engineering requires the applicability of the employed model according to a specific fire scenario. To be able to estimate how the simulation outcome is influenced by model assumptions and simplifications, the user has to evaluate the dominating physical processes and involved empirical parameter that has an essential influence on the specific fire scenario.

The Need for a Verification and Validation Protocol for Evacuation Models

To date, there is no standard Verification and Validation (V&V) protocol for the evaluation of evacuation model predictions. This paper is intended to open a discussion on the main issues associated with the definition of a standard procedure for the V&V of building fire evacuation models.

The User’s Guide to Evacuee Behavior

This presentation will briefly present a set of behavioral expectations related to evacuee performance that have been identified within the field. These expectations might then influence the model user’s attempts to develop egress scenarios, configure egress models in order to assess performance or interpret the results produced.

Lost in Abstraction: The complexity of Real Environments vs. the Assumptions of Models

Many if not most fire evacuation models are relatively insensitive to the complexity of human behaviour in the built environment. The complexity of human behaviour and the very long feedback loop on building disasters can lead to the approval of structures that have massive inherent vulnerabilities.

Fire and Evacuation Simulation in a Low Ceiling Sport Arena

In October 2014, Iceland will host the European TeamGym championships. The competition will be held in the Athletics and Exhibition Hall of the Laugardalshöll sports arena in Reykjavík. Verkís Consulting Engineers undertook a project concerning the safe evacuation of the public from the competition arena in case of fire. This is a major concern for the organizers and the local fire authority as the arena is primarily intended for athletics training or local competition without stands.

Developing a Swedish Best Practice Guideline for Proper Use of CFD Models when Performing ASET Analyses

The purpose of this paper is to spread the knowledge of the working process and to describe how different organisations within Sweden have collaborated to deal with issues concerning CFD-modelling. The paper also presents some of the technical aspects that the work generated to increase the knowledge concerning the use of FDS.

Study of the Dynamics of Fire and Smoke Control in Case of Evacuation in High Buildings, Based on Continuous Model FDS+EVAC

This article is a brief review of the methods of smoke control based on 3D simulation of the dynamics of fire with a case study applied to a 21 story building with an area of 2060m (Technological Department of Wuhan University of Technology, Hubei-China). In order to introduce the study based on continuous model FDS+Evac, some examples of simulation scenarios of fire in one of the building stairwells are presented. Also, natural ventilation, pressurization and dilution, are simulated as tested, with the aim of obtaining the optimal solution. Furthermore, the results are analysed and compared. Finally, it is also addressing continuation studies.

Evacuation Modeling in Road Tunnel Fire Events – CFD Influencing Evacuation Results

The purpose of this paper is to explore the factors that can be considered when employing pedestrian modeling techniques to analyze the evacuation time and tenability conditions during a fire incident using typical section of a bidirectional road tunnel as an example.

Impact of Soot Particle Size and Agglomeration on Soot Deposition

Soot deposition mechanisms have been added to FDS along with the ability to track specified particle size distributions. The impact of particle size assumptions and agglomeration on the predictions of soot deposition and visibility were investigated. Recommendations are made on additional research and data collection to support further improvements in soot modeling.

Performance Analysis and Shared Memory Parallelization of FDS

This article documents the efforts of providing an Open Multi-Processing (OpenMP) parallelised version of the Fire Dynamics Simulator (FDS), version 6, that also permits hybrid use with the Message Passing Interface (MPI).

Numerical Insights into the Parallel Solution of the FDS Pressure Equation: Scalability and Accuracy

As an alternative approach the solver package Scalable Recursive Clustering (ScaRC) is under development consisting of a selection of different iterative solution techniques of domain decomposition and multi-grid type which belong to the most efficient and robust solvers for huge systems of equations. Based on elaborated numerical combinations of local and global mechanisms for capturing the overall physical effects, ScaRC has already proven considerably enhanced scalability and accuracy properties for a variety of different test and verification cases. This article is intended to give an overview of the underlying concepts as well as the current state of development accompanied by some illustrative numerical test examples and comparisons with the current FFTsolver.

Defining a Crowd Safety Factor for the Designs of Assemblies

This paper promotes the discussion on how to minimize escape times considering the Relative Distance Between Exits (RDBE) as a “Crowd Factor” for the designs of assemblies. This study suggests that the exits’ locations have an important impact for highly dense places.

Use of Pathfinder in the Study of Occupant Movement in Stairwells

The goal of this paper is to compare empirical egress data to data produced by computer egress models. The empirical egress data presently considered consists of video recordings of unannounced fire drills conducted in several high-rise office buildings. The computer egress modeling data consists of a series of model runs to assess merging for a simple building configuration with one stairwell using the Pathfinder egress modeling software.

Egress from a Hospital Ward: A Case Study

There are many issues in a hospital evacuation, related both to patients conditions and to building complexity. Moreover, as consequences of the fire, there may be delays in surgeries and in medical diagnoses or interruption of treatment for both inpatients and outpatients. This work identifies and assesses problems that arise in the egress from the ward located at third floor of the University Hospital Campus Bio-Medico of Rome, using Pathfinder and its powerful tools.

Effects of Exit Discharge Congestion on the Effective Evacuation Time in a Typical Underground Metro Station Design

The focus of this study is on the modeling of the effect of congestions in the exits discharge area on the effective evacuation time in a typical underground metro station fire. The results suggest that the projected maximum occupancy levels of an open space close to the exit discharge correlates with the movement capabilities of the evacuates at the corridors, stairs, escalators, and other facilities.This work identifies and assesses problems that arise in the egress from the ward located at third floor of the University Hospital Campus Bio-Medico of Rome, using Pathfinder and its powerful tools.

Pathfinder Verification and Validation Tests

This presentation provides an overview of the verification and validation process for Pathfinder, and how it relates to the software development and automated quality testing process.

Industry Accepted Design: A Case Study on Prescriptive vs. Performance-Based Design Criteria

A prescriptive and performance based analysis has been conducted on a College Campus Building in Southern California. The building is proposed to be the center of operations as well as having administration facilities for the College. It will house an administrative office, production and support facilities. Based upon the performance-based analyses that were conducted for the building, it was evident that the performance-based design criteria applied to the analyses were more stringent than those inherent in the prescriptive design requirements. This paper will address the differences in industry-accepted design criteria for both prescriptive- and performance-based design solutions. Options for rectifying the difference in these criteria will also be presented.

Modeling of Carbon Monoxide Dispersion from Vehicle Exhaust in a Partially-Enclosed Roadway Using FDS

The design for a partially enclosed roadway raised concerns regarding the potential for development of hazardous carbon monoxide (CO) concentrations. The proposed roadway section is covered by buildings on three sides with one side open to a river. There were concerns that wind conditions may cause vehicle exhaust to become trapped in the roadway during stalled traffic conditions. Based on the FDS model results it was found that the critical limit for 15-minute average CO concentration of 120 ppm was never exceeded at any point. This analysis showed that the natural ventilation of the partially enclosed roadway was sufficient and no additional mechanical exhaust systems were required.

Approach to Define the Aerodynamic Free Area for Natural Smoke Vents in a CFD Simulation Environment

Provided naturally or mechanically, smoke and heat exhaust from buildings is one of the key application fields of CFD simulations. In an FDS/PyroSim environment, natural smoke vents may be modelled by simple openings called “Hole” elements, whose sizes are essential in the findings of simulation. In our paper, we propose a method to model natural flat roof ventilators in CFD simulation using a proper size.

A Partially-Stirred Batch Reactor Model for Under-Ventilated Fire Dynamics

As a step toward improved prediction of CO concentrations in under-ventilated compartment fires (which are low-Mach turbulent reacting flows), this talk presents a framework for transport, mixing, and reaction of chemical species in large-eddy simulation (LES). A partially-stirred batch reactor (PaSR) is adopted as a simple yet flexible model to treat a spectrum of complexity in the chemical reaction network, from mixture-fraction-based state relations to detailed chemical kinetics. Each computational cell is modeled as a PaSR. The PaSR model is implemented in a low-Mach LES solver called the Fire Dynamics Simulator (FDS). Verification and validation of this model within FDS will also be presented.

Optimization of Smoke Ventilation Strategy in a Typical Underground Metro Station Fire

Compartment fire is an unwanted event that needs to be accessed carefully in order to ensure the safety of occupants and structures. This study emphasizes on fire and smoke spreads in a typical underground metro station.

Integral Methodology for Fire Sprinkler System Design Following the Performance-Based Design Method

This paper proposes a methodology for a thorough specification of sprinkler systems following the performance based method, by providing a theoretical approach into meeting the scenario’s phenomenological fire behavior with the system’s design features seeking to obtain personnel protection and fire suppression as design objectives.

FDS Simulation of the Combined Use of Sprinklers and Water Mist Fire Extinguishing Systems

The purpose of this study is to investigate the effect of sprinkler water droplets with relatively large diameter on the movement of several orders of magnitude smaller water mist particles. The aim of the simulation is to analyze the flow field under a 1m x 1m shelf element with installation height of 1.5 m in the middle of the room, with and without n-heptane tray fire, using combined sprinklers and water mist extinguishing systems.