By John R. Hall, Jr. | Fire Protection Engineering
The field of fire risk assessment has been growing by leaps and bounds in the past few years. Every major international standards-developing organization has a new guide on the subject, as do many nations.
Fire risk assessment has taken three principal forms. The oldest is the risk index method, primarily associated with the insurance industry. These can be thought of as checklists on steroids: not strong on explicit empirical parameters or fundamental physics, but arguably quite useful and successful over their century-plus existence. Next oldest is the classic risk analysis model (e.g., a fault tree or event tree) converted to fire safety, a mostly or wholly probabilistic approach. And the newest is probability-weighted hazard analysis, in which the probabilities are reserved for ignition and reliability, while physics models are used for everything else.
The first of the globally publicized probability-weighted hazard analysis models came from a collaboration between Canada and Australia. The latter effort, centered at Victoria University of Technology under the direction of co-author Beck, led to CESARE Risk.
Oddly, given this history, the book does not focus on probability-weighted hazard analyses but favors stochastic modeling for most modeling components as its approach to fire risk analysis (not fire risk assessment because there is also no discussion of evaluation). Buyer beware: This is an original and useful book, but readers will be disappointed if they are looking for something different than what the authors have chosen to address.
Chapter 2 is a conceptual overview of fire and building safety from fire. Chapter 3 covers the basics of probability theory. The latter is a bit more detailed than the corresponding chapter in the SFPE Handbook but stops well short of a full course. The reader will probably find it more useful as a refresher than as a tutorial.
Chapter 4 is a short chapter on the Beta reliability index, which can be associated with Hkan Frantzich of Lund University. This is the first published treatment of this increasingly popular index in a book for the general reader. Chapter 5 covers the basics of Monte Carlo simulation. It would have been preferable if the authors included a warning that Monte Carlo is not a substitute for empirical information on probabilities but rather a practical method for working with probabilities with limited information or common assumptions.
Chapter 6 introduces event and fault trees. The oddly titled Chapter 7 on performance-based optimal design is in a location where one would expect a transitional chapter and overview of fire risk analysis, but the chapter does not provide a general conceptual model, settling for a few paragraphs on criteria, uncertainty and some other topics not covered elsewhere. The book would have benefited from a stronger transitional chapter and some integrative concepts for the chapters to follow.
Chapter 8 begins a string of chapters on the modeling of particular phenomena, in this case fire initiation. With Chapter 9 (on "personal factors"), these play to the strengths of national fire incident databases and discuss them at some length. Chapter 10 is on barrier resistance. It was a little surprising that this chapter did not reference the work of Teresa Ling and Brady Williamson. Chapter 11 is about fire growth and the CESARE Risk one-zone model. Chapter 12 is on smoke spread and combines deterministic and stochastic simulation. Chapter 13 is on human behavior as handled by a submodel of CESARE Risk. Chapter 14 is on performance assessment of (active) fire safety systems, using empirically based probability measures. Chapter 15 is on fire brigade response, which has historically been the most undertreated component of these models; the authors' full chapter is most welcome.
Chapters 16-17 complete the book with two case studies. Like most well-done, well-chosen case studies, these are very helpful, though there will be a temptation to use them as a shortcut guide on how to use the general methods in all situations.
Putting it all together, this is a useful book that will fill an important gap on the engineer's bookshelf, but it is not a definitive tome for the ages. This book is recommended for those involved in fire risk assessment and those who would like to consider using these methods in such assessments, but there is a more comprehensive and ambitious book still to be written on this subject.
John Hall is with the National Fire Protection Association.