NFPA 921 Update (2021) for Fire and Explosion Investigations
The National Fire Protection Agency (NFPA) publishes the NFPA 921 Guide for Fire and Explosion Investigations, which is the standard of care for all fire investigators to follow. Revisions to 921 are generally made every 3-4 years, with the last revision coming in 2017. The new 2021 revision of NFPA 921 has been released, which came into effect April 25, 2020, and supersedes all previous editions. It is not yet available electronically, but the paperbacks are available for order.
NFPA 921 is constantly being revised to stay current with the latest science on fire investigation. NFPA relies on the latest research, feedback and even scrutiny of the fire investigation community to ensure it stays up to date and as comprehensive as possible. As always, NFPA 921 relies on trained, certified investigators applying scientific principles and the scientific method to all fire and explosion investigations, and even goes as far as including an illustration of the scientific method on the front cover of the 2021 edition to emphasize the importance.
The 2021 revision is more robust than the previous 2017 version with a lot of changes and additions made. NFPA was wise to make the text changes within the guideline shaded in grey for easier recognition and comparison to the previous 2017 version.
One change which was noticed immediately in “Chapter 18 - Origin Determination” was the following:
Previously, in the 2017 edition, this section outlined four key elements to determine the origin of a fire. Without establishing an accurate area of fire origin, you cannot establish a reliable cause of the fire. In general, the four sources of data for consideration when determining the area of fire origin were witnesses, fire patterns, arc mapping and fire dynamics (NFPA 921- 18.1.2).
The revised 2021 changes to now use going forward has reduced the number of key elements from the previous four down to three. The three sources of data for consideration when determining the area of fire origin now are (NFPA 921 – 18.1.2):
Witness Information and/or Electronic Data. The analysis of observations reported by persons who witnessed the fire or were aware of conditions present at the time of the fire as well as the analysis of electronic data including but not limited to security camera footage, alarm system activation, or other such data recorded in and around the time of the fire event.
Fire Patterns. The analysis of effects and patterns left by the fire, which may include patterns involving electrical conductors.
Fire Dynamics. The analysis of the fire dynamics [i.e., the physics and chemistry of the fire initiation and growth and the interaction between the fire and the building’s systems].
Of note, the fourth previous key element outlined in the 2017 version was “Arc Mapping”, which was removed from the 2021 revision. Instead, “patterns involving electrical conductors” has now been included within “Fire Patterns” above. There has been a lot of debate and ongoing research involving the reliability of arc mapping when investigating fires, which has perhaps led NFPA to change the wordings within the 2021 guideline. This is something for fire investigators to be aware of. Arc mapping can still be a rather useful tool, if used appropriately, but also has certain limitations and misconceptions, which is beyond the scope of this article.
Many other revisions and additions are included in the new version of 921. Some interesting additions are found in “Chapter 11 – Fire Related Human Behaviour”, which added sections in “11.5 - Youth Fire-Setting Behaviour”; “11.5.1 - Developmental Stages” and “11.5.2 - Mental Health”. These sections outline children who may set fires, why they may set them, research on where fires may be set based on the developmental stages of children and other pertinent factors including mental health disorders such as attention deficit disorders (ADD/ADHD), conduct disorder and adjustment disorder, which may contribute.
It is important to carefully select a well-qualified and experienced fire investigator who is up to date on the latest developments and research within the field of fire and explosion investigation. Our firm has many fire investigators who have been qualified as experts to give you the peace of mind you are receiving sound, scientific answers and if litigation becomes reality. We are a team of highly educated and experienced engineers and fire investigators. Whether it is a fire in a building, vehicle, piece of equipment, appliance or electronic device, we are trained to investigate and handle the most complex of fire investigations and pride ourselves on our prompt service, report turnaround time and unmatched cost-effectiveness for our clients. We hope to see you on your next fire and appreciate the opportunity to serve you.
