A fire scene looks like a puzzle, but it’s a puzzle where the pieces melt, burn, and get hauled away before anyone can measure them. On the 25th anniversary of 9/11, I sit down with Professor Vincent Brannigan to ask a questions - does a fire investigation truly use the scientific method, or are we doing something else and calling it science?

Vincent brings a rare mix of experience as a fire protection engineer, a lawyer who has seen cases up close, and a historian of science who cares deeply about how we justify knowledge in court. We talk about the World Trade Center collapse, what made investigation so difficult, and how code and design assumptions (like fireproofing priorities and sprinklers) shape outcomes long before any investigator arrives. From there, we get precise about language: what a hypothesis is, what makes a scientific hypothesis testable, why a theory is not a casual idea, and why “proof” is the wrong word in most scientific and forensic contexts.

Then we take the discussion into the context of NFPA 921 directly. We explore why much of forensic fire reasoning is abductive inference (the Sherlock Holmes style of “best explanation”), why that can be useful, and why it becomes dangerous when it’s presented as if it carries the repeatability of lab science. We dig into witness statements, models and simulations, experiments that actually help, and the uncomfortable gap between “possible,” “probable,” and “true” when the courtroom demands answers.

If you care about fire investigation, forensic fire science, expert testimony, and how fire engineering knowledge becomes evidence or a foundation of new code recommendations, this conversation will sharpen how you think and how you write.

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The Fire Science Show is produced by the Fire Science Media in collaboration with OFR Consultants. Thank you to the podcast sponsor for their continuous support towards our mission.