Fires are very complex. In addition, the longer they burn the more difficult they can become to determine the cause and origin as evidence can be burned up in the fire. Over the next few weeks or months I will be discussing a number of fire investigation aspects. I will turn to the National Fire Protection Association (NFPA) 921 Guide for Fire and Explosion Investigators as a primary reference in many cases. NFPA 921 was first issued in 1992 and is the work of numerous people active in fire investigation. The document has a wealth of information and contains 30 chapters.

My initial focus will be examining the content of several key chapters in NFPA 921 that include

  • Chapter 4 Basic Methodology
  • Chapter 5 Basic Fire Science
  • Chapter 6 Fire Patterns
  • Chapter 7 Building Systems
  • Chapter 8 Fire Protection Systems
  • Chapter 9 Electricity and Fire
  • Chapter 10 Building Fuel Gas Systems

These chapters, as the titles suggest, contain a lot of valuable information with respect to fire investigations. Background will be given as it relates to carrying out a fire investigation, the basics of the fire itself, the types of things one will see when they are at a fire scene, and what types of systems one could run across in a building that could be involved in the fire.

It is important to note that NFPA 921 is a GUIDE and NOT a standard. The scope of the document as defined by NFPA

“This document is designed to assist individuals who are charged with the responsibility of investigating and analyzing fire and explosion incidents and rendering opinions as to the origin, cause, responsibility, or prevention of such incidents, and the damage and injuries which arise from such incidents.”
Upcoming Series – Fire Investigations

Randy Clarksean


Randy is a Ph.D., P.E., CFEI, CFII Mechanical Engineer with over 30 years of experience in failure analysis, fires, and forensic engineering. In addition he has expertise in areas of technical due diligence consulting, heat transfer, thermal systems, management, and general technical consulting services.


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