Towards a Tailored Sensor Network for Fire Emergency Monitoring in Large buildings

Presentation by Dr. Rochan R. Upadhyay at IEEE-WRECOM on joint work carried out with Dr. Athanasia Tsertou.In this presentation, we describe some of the ongoing efforts in developing a wireless sensor network tailored specifically for fire emergency monitoring. Network simulations of a dense sensor network with a flat architecture and using off the shelf protocols such as Wi-fi and Zigbee reveals the serious performance degradtion due to power consumption and packet losses caused by simultaneous collisions. By performing computational simulations of several fire scenarios, we show that spatio-temporal collisions exist in the sensed data. These can be leveraged in communication protocols for more efficient transmissions. While we do not propose algorithms for achieving this, our study highlights the need to consider statistical properties of the fire data in the communication protocols

Smoke buildup and light scattering in a cylindrical cavity above a uniform flow

In this study, we use computational fluid dynamics (CFD) and aerosol dynamics modeling to investigate the buildup of smoke and light scattering in a cylindrical cavity geometry, considered to be an idealized representation of a photoelectric smoke detector. CFD coupled with the quadrature method of moments (QMOM) is used for simulation of aerosol dynamics. The Rayleigh-Debye-Gans/Polydisperse Fractal Aggregate (RDGPFA) theory is used for calculation of smoke extinction and angular light scattering. It is seen that the flow external to the cavity sets up a recirculating flow pattern within the cavity and that the flow processes determine the spatial distribution of smoke. Aerosol extinction and scattering calculations are performed to examine the time varying profiles of the intensity along a simulated LED light beam and the scattered intensity at different angles. The variation of the detector activation time with inlet velocity and smoke volume fraction is obtained from a calculation of the angular light scattering. The results are compared with calculations using an empirically determined detector response function and with a simpler model that assumes a uniform distribution of smoke inside the cavity. Results indicate that although the distribution of smoke inside the cavity is not uniformly mixed, the simple first order mixing model with appropriately chosen parameters is valid for predicting detector activation time

Towards a Tailored Sensor Network for Fire Emergency Monitoring in Large Buildings

Modern fire emergency systems are slowly moving from the traditional data-logging systems to a heterogeneous and dense network of wired/wireless sensors that can give a more complete view of the phenomenon. When the density of the sensors and/or the transmission rate start growing, standard and widely used communication protocols suffer from degradation in their performance, mostly due to the presence of simultaneous transmissions. Rather than proposing a new protocol that performs better than the standard ones in a set of network scenarios, this paper has a different aim. It attempts to draw conclusions from the nature of the sensed data itself, so that important spatial and/or temporal correlations can be revealed and, consequently, utilised for the future design of an indoor fire emergency-tailored protocol

Sensor-linked fire simulation using a Monte-Carlo approach

Peer-reviewed article published in the Proceedings of the 9th International Symposium on Fire Safety Science, Karlsruhe, 2008.This study is aimed at developing a predictive capability for uncontrolled compartment fires which can be “steered” by real-time measurements. This capability is an essential step towards facilitating emergency response via systems such as FireGrid, which seek to provide fire and rescue services with information on the possible evolution of fire incidents on the scene. The strategy proposed to achieve this is a novel coupled simulation tool, based on the Monte-Carlo-based fire model, CRISP, with scenario selection achieved via comparison with (pseudo) sensor inputs. Here, some key aspects of such a system are illustrated and discussed in the context of the detailed measurements obtained in the full-scale fire test undertaken in a furnished apartment at Dalmarnock. The capability of CRISP in reproducing the fire conditions – given knowledge of the approximate heat release rate in the fire – was first verified. It is then shown that continuous selection from amongst a multiplicity of scenarios generated in Monte-Carlo fashion can be achieved, so that the predictions evolve in a way that closely follows the real fire conditions. Whilst the benefits of sensor-steering are already clearly apparent, further improvements will be possible by establishing an appropriate feedback loop between the results assessment and the parametric space in which new fires are generated, perhaps using Bayesian methods. Nevertheless, true predictive capability remains crucially dependent on the sufficient representation in the model of the mechanisms of fire growth, and this must be the focus in achieving better forecasting ability

Introduction to FireGrid

Chapter 1 in the book: The Dalmarnock Fire Tests: Experiments and Modelling, Edited by G. Rein, C. Abecassis Empis and R. Carvel, Published by the School of Engineering and Electronics, University of Edinburgh, 2007. ISBN 978-0-9557497-0-4FireGrid is an ambitious and innovative project, seeking to develop the technology to support a new way of managing emergency response in the modern built environment. Specific novel aspects include the integration of diverse modelling tools for fire, structural response and egress, data assimilation strategies for leveraging these model predictions via real-time feeds of sensor data, exploitation of robust self-organising wireless sensor networks, high-speed processing using grid/HPC infrastructures with ‘on-demand’ access of remote resources, and application of intelligent C&C algorithms. The Dalmarnock fire tests have provided a useful basis for the demonstration and discussion of these concepts and technologies, driving initial integration work and highlighting the potential benefits of such a system

An Architecture for an Integrated Fire Emergency Response System for the Built Environment

Peer-reviewed article published in the Proceedings of the 9th International Symposium on Fire Safety Science, Karlsruhe, 2008.FireGrid is a modern concept that aims to leverage a number of modern technologies to aid fire emergency response. In this paper we provide a brief introduction to the FireGrid project. A number of different technologies such as wireless sensor networks, grid-enabled High Performance Computing (HPC) implementation of fire models, and artificial intelligence tools need to be integrated to build up a modern fire emergency response system. We propose a system architecture that provides the framework for integration of the various technologies. We describe the components of the generic FireGrid system architecture in detail. Finally we present a small-scale demonstration experiment which has been completed to highlight the concept and application of the FireGrid system to an actual fire. Although our proposed system architecture provides a versatile framework for integration, a number of new and interesting research problems need to be solved before actual deployment of the system. We outline some of the challenges involved which require significant interdisciplinary collaborations

Simulation of population balance equations using quadrature based moment methods

Population Balance Equations (PBE) are used for modeling a variety of particulate processes as well as various stochastic phenomena in science and engineering. However PBEs are difficult to solve because they describe the evolution of a probability density function (PDF) in high dimensional spaces. Due to their unique mathematical structure and properties, these equations require special solution techniques. Moment methods are a class of solution techniques that evolve only a few moments of the PDF. While moment methods are simpler, they are known to have closure problems, i.e. a finite set of moment equations do not fully describe the PDF or its evolution. The purpose of this dissertation is to investigate a closure scheme for the moment equations that is based on Gaussian quadrature. This approach, known as the Quadrature Method of Moments (QMOM), is very general as it does not require any a priori assumptions on the form of the PDF. In this study, I first evaluate the accuracy of the moment closure by applying QMOM to solve some well known problems in aerosol science, such as particle nucleation and growth in well stirred reactors and size dependent transport of aerosol particles. I find that results obtained using QMOM compare favorably with results obtained using more expensive techniques. Moment methods are particularly suited for implementation in CFD codes. As an example of a model for smoke detectors, I use QMOM to simulate smoke entry and light scattering in a cylindrical cavity above a uniform flow. As further examples, I describe the use of QMOM in applications such as statistical uncertainty propagation and simulation of turbulent mixing and chemical reaction using the PDF transport equation. While moment methods are widely applicable, they have some limitations. I find that the solutions depend on the choice of moments and that there may not be a globally optimal set of moments. This becomes more problematic for solutions of multivariate PBEs using an extension called the Direct Quadrature Method of Moments (DQMOM). The insights from this work can lead to a greater appreciation of the benefits and limitations of moment methods for solving PBEs.Mechanical Engineerin

Intercalibration Results. Description and Results of a Predictive Model for Pyrolysis

We consider a model for in-depth pyrolysis using a continuum theory of mixtures. The material is assumed to be composed of a number of distinct solid and gas phases. The pyrolysis process is modeled as an inter-conversion of different constituent phases. The gas transport is assumed to be instantaneous and therefore gas momentum equation is not solved. We use data provided for Carbon Phenolic. Results show good (but not exact) agreement with FIAT results. Differences could be attributed to different treatment of the transport properties of the solid mixture and the integration of pyrolysis kinetics