The NFPA 921, Guide for Fire and Explosion Investigations (2024 Edition) is the industry’s leading resource for fire investigation professionals, providing a scientific roadmap for determining the origin, cause, responsibility, and prevention of fires and explosions. Recognized by the Organization of Scientific Area Committees (OSAC) as the forensic science consensus guide, NFPA 921 is trusted by over 600 forensic science practitioners and experts to ensure accurate, fact-based fire investigations.

This latest 2024 edition introduces several key updates to enhance the investigative process. It includes guidance on an investigator’s potential confirmation bias, opinions, and expressions of certainty, ensuring that conclusions remain objective and scientifically valid. It also addresses the impact of suppression activities on fire ventilation and flow paths remote from the area of origin, which is critical for understanding fire behavior. Additionally, the latest edition has relocated all fire effects on electrical systems and components to Chapter 6, improving clarity and accessibility.

To further aid investigators, NFPA 921 now classifies fire causes into four general categories, providing a clearer framework for professionals and authorities having jurisdiction (AHJs). Expanded sections also offer guidance on fire investigator safety, health, and wellness, recognizing the physical and mental demands of the profession. The handbook also features updated content on hybrid electric vehicles (HEVs) and electric vehicles (EVs), as these types of fires require specialized investigative techniques. Furthermore, the revised chapter on wildfire investigations includes new terminology and unique indicators, helping professionals analyze and determine the causes of wildfires more effectively.