"The issue of intent is not, per se, a fire science issue. Science cannot yet prove whether an action was deliberate or intentional - there's no meter or detector yet developed to "prove" intent. Intent is, however, an issue for fire investigation...or at least for fire analysis as defined in 921. That definition includes determining responsibility for a fire and "responsibility" can include intent (was it willful, deliberate, unintended, foreseeable, etc.) Chapter 12 is full of "intent" assessment issues - "Negligence ...a person has not behaved in a manner of a reasonable prudent person..." Chapter 20 discusses the issue of responsibility in more detail, but "responsibility" is, per 20.5.1 "in the form of an act or omission." The inference in an "Act" is that there was some intent to commit the act and omissions may be willful or deliberate based on intent to not act. And, in 20.5.3 "it is the responsibility of the person who performs the analysis to identify responsibility..." So, intent still underlies many sections in the 2021 edition."

Intent can be inferred from indirect evidence in some, but maybe not all, incidents.

"But, more to what I believe is the issue... how does a fire investigator classify a fire now that the old Chapter 21 Classification has been removed; does 921 allow classification - 921 is not completely mute on classification. Chapter 19, 19.8 Incident Classification "...if an incident requires classification, the investigator should refer to the appropriate classification system." It then refers to examples of classification systems that the investigator may use. The comments presented by the Technical Committee on the 2nd draft of the 2021 edition of 921 states " Since incident classification is addressed in other standards and is dependent on jurisdiction/organization use, providing specific definitions for incident classifications in NFPA 921 is not necessary.” By placing the classification issue in the hands of jurisdictions, I am aware of numerous jurisdictions who have created policies establishing their classification standards. The Technical Committee chose to provide less guidance on classification instead of addressing some of the issues in classification. Thus, leaving the classification up to local jurisdictions and fire investigation agencies to provide their own defined classifications."

The same question holds, how does someone, outside of the Incendiary Fire chapter in 921, reliably determine an incendiary fire. By moving this determination downstream of the fire investigation, how does this change the requirements for evidence?

"The core concern seems to be "what methodology is applied to assess "intent" in a fire investigation?" I suggest that there is a methodology but I'll hold that for another day. The simple answer is - there is no "scientifically reproducible" method. Establishing intent is not part of "science" (It can be assessed by using a method that could be described as similar to the scientific method.) This is an area where fire investigation slides more into its "legal" persona and less in its "science" (My contention is that fire investigation lives in a world where science and "law" overlap and that some things, like determining responsibility edge more toward the law side of the scale.)"

One can use surrogate or indirect evidence using the SM to reach a reliable determination in some, but perhaps, not all incidents.

"A complex issue for sure."

I still do not understand how these changes in NFPA 921 has provided more value added in reaching a reliable determination. Any problems with the previous methodology seem to have been kicked down the path to some other entity and methodology that is not clear.

Douglas J. Carpenter, MScFPE, CFEI, PE, FSFPE
Vice President & Principal Engineer
Combustion Science & Engineering, Inc.
8940 Old Annapolis Road, Suite L
Columbia, MD 21045
(410) 884-3266
(410) 884-3267 (fax)
www.csefire.com