|Review of Building Fire Performance Analysis by Robert W. Fitzgerald|
Viewpoint: Review of Building Fire Performance Analysis by Robert W. Fitzgerald
By M.C. Hui, MSFPE | Fire Protection Engineering
It has been said that about 70 percent of building regulations are related to fire safety. Yet national fire incident statistics show that fires still occur, with many fatalities and injuries as a result. The analytical framework and methodology in this recent publication by Robert W. Fitzgerald may be one of the means to determine how a building performs in a real fire and identify fire protection options that could improve the fire statistics.
This 515 page book is divided into 21 chapters with five appendices. Chapter 1 provides a general discussion on building codes and regulations, and various approval practices, and sets the tone for the rest of the book. Chapter 2 is a brief description of what are traditionally called active and passive fire protection measures. Chapter 3 discusses the basic concepts on fire development and the effects of fire on building structures as well as human beings. These two chapters, while being relatively short, prepare the readers for later chapters that could be considered to be the core of the book.
Chapter 4 is structured like a reconstruction of a multistory apartment building fire and illustrates how a fire could develop, spread and affect occupants under different circumstances. It also provides an abridged description of flame/heat movement analysis and finishes with a concise tabulated building performance-evaluation process.
Chapter 5 provides the food for thought on how building performance evaluations could be conducted, deterministically and probabilistically, on a timeline basis. A picture is worth more than a thousand words; this chapter contains various graphical representations to demonstrate how effective communication can be made with others, using the M curve (likelihood of manual fire department extinguishment) and the L curve (probability of fire damage to an extent) as examples. Three levels of evaluation are suggested, with Level 1 for gaining a basic understanding of performance, Level 2 for a better technical understanding and Level 3 for performance sensitivity.
Chapter 6 describes the architecture of Fitzgerald's method for analyzing building performance, which is a decision-tree-style network structure. It introduces two kinds of networks: A continuous-value network to portray performance (probability of success) on a continuous temporal sense, and a single-value network to take a snapshot of performance at a particular time.
Chapter 7 presents an overview of the entire performance evaluation process and provides a general discussion on various analyses as an introduction to subsequent chapters that are much more detailed on the same subject. Chapter 8 has a detailed treatment on design fires and provides a methodology to estimate the probabilities for the fire in the room of fire origin (RFO) to grow to particular stages. It is this chapter where the I-curve (self-termination of fire) is first mentioned. The three levels of evaluation are explained in more detail in this chapter. Chapter 9 is basically an extension of Chapter 8, but it considers fire spread beyond the RFO.
The next seven chapters are concentrated on performance of various fire-protection systems. Chapter 10 provides a comprehensive treatment on barrier performance and is the longest chapter in the entire book, which perhaps reflects Fitzgerald's civil engineering background and research interest. Chapter 11 is about evaluation of performance of fire detection and initial actions, not only on the hardware side but also on actions of occupants to detect fire and notify the fire department. Chapter 12 relates to manual fire suppression by the fire department and includes a detailed account on fire ground operation.
Chapter 13 is on automatic suppression by various types of sprinkler systems with their performance described by the A curve. While the discussion on sprinkler systems is fairly detailed, it would have been more complete if the issue about slow response of concealed-type sprinklers was also included. Chapter 1 describes the process of building the L-curve network based on the I-curve, A-curve and M-curve. Chapter 15 focuses on structural frame analysis (Fr curve), whereas Chapter 16 mainly deals with smoke hazard and tenability.
Chapter 17 is a summary of the building performance process and provides an example on how the process can be adapted to investigate alternative system components. Chapter 18 describes the framework and means to characterize risks for a building, in terms of human safety and property safety. Chapter 19 provides an introduction to the risk-management concept and process, but it has failed to mention two important elements of the process, i.e,. the establishment of risk-acceptance/tolerance criteria, and regular monitoring and review of the risk management system.
Chapter 20 covers all sorts of fire protection measures to prevent established burning and provides a framework on how the probabilities of their success can be estimated. Chapter 21 concludes the book with a brief discussion on decision-making and communication, followed by five appendices covering the basics of decision trees, rationale for using subjective probability in analyses, the role of judgment in engineering evaluations, inspection report forms and illustration of risk representation.
All in all, this book is about assessment of building fire performance using both deterministic and probabilistic techniques, which is also called fire risk assessment, and has got something for everyone. For practitioners who are not experienced in developing fire-safety strategies, they may find the first five chapters useful in terms of concepts on how fire safety can be achieved. For readers who wish to learn about decision trees and risk analyses, they may find Chapters 6 to 17 interesting. For practicing risk managers, they may treat the last four chapters as a refresher on risk management.
M.C. Hui is with Arup Fire, Ove Arup & Partners Hong Kong Ltd.