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Investigations take place in different locations and situations.

Qualifications and procedures for fire investigation

Some might say that investigating fire origin and cause is an “Art”, but it is actually a “Profession” and to be absolutely professional the investigator must act professionally and ethically. The best way to do this is to follow the “Standard” set by the National Fire Protection association (NFPA) – “NFPA 1033 Standard for Professional Qualifications of Fire Investigator”. This Standard sets out the ‘Job Performance Requirements’ (JPR’s) that are required to be followed to perform the task of fire investigator.

At subsection 1.2 – Purpose – The purpose of this standard shall be to specify the minimum job performance requirements for serving as a fire investigator in both the private and public sectors.

One of the most important aspects of the 1033 document is the fact that it stipulates (at 4.1.2) that the fire investigator shall employ [my emphasis] all elements of the “Scientific Method” as the operating analytical process throughout their investigation, and for the drawing of conclusions.

Some of the more important requirements in the document are designed to ensure the investigator maintains currency with modern and up-to-date techniques and developments by attending courses, workshops, seminars and by reading journals and publications. 4.1.4 – Maintain liaison with other interested professionals/entities. 4.1.5 – Adhere to all legal and regulatory requirements. And, have a basic knowledge (at least) of:

  • Fire science
  • Fire chemistry
  • Thermodynamics
  • Thermometry
  • Fire dynamics
  • Explosion dynamics
  • Computer fire modelling
  • Fire Investigation
  • Fire analysis
  • Fire investigation methodology
  • Fire investigation technology
  • Hazardous materials
  • Failure analysis and analytical tools
  • Fire protection systems
  • Evidence documentation, collection and preservation
  • Electricity and electrical systems.

NFPA 1033 is a “Standard” and therefore Shall be followed and complied with, according to the meaning of ‘Standard’.

The way to attain the JPR’s and comply with the requirements of 1033 is to follow the teachings and guidelines within “NFPA 921 – Guide for Fire and Explosion Investigation”.


The National Fire Protection Association publishes “NFPA 921 Guide to Fire and Explosion Investigation” which has been called by one court “the Bible for forensic fire scene investigation” and failure to follow it can mean the difference between winning and losing a case.


Investigation into a fire in a kitchen.

Investigation into a fire in a kitchen.

It’s universally utilized. It’s printed in English, French, Spanish, Korean, Chinese, Hebrew and Mandarin (Truly a “World Best Practice” document). In almost every case involved in litigation, an expert will say, “Yes, I did my investigation in accordance with NFPA 921.” More and more you’re seeing experts’ reports directly referencing NFPA 921. When someone is giving a deposition or testifying, you’re either going to be challenging the expert because he didn’t follow NFPA 921 or you’re supporting your own opinion because it’s consistent with NFPA 921. One court case referred to it as the “gold standard.”

NFPA 921 is a “Guide” and as such, Should be followed, not shall be, but it is recommended.

NFPA921 provides the educational knowledge required to be able to follow the procedures recommended to conduct a successful and legal fire origin and cause investigation. This is a very comprehensive document covering all aspects of fires and fire investigation, as well as explosions and explosion investigation. The main doctrine in NFPA 921 is that, to conduct a successful and legal investigation, the investigator must follow the basic methodology that is the “Scientific Method”.

3.3.139 – Scientific Method – The systematic pursuit of knowledge involving the recognition and formulation of a problem, the collection of data through observation and experiment, and the formulation and testing of a hypothesis.

Experiments can enhance your overall knowledge and expertise.

Experiments can enhance your overall knowledge and expertise.

There are pitfalls that can be encountered along the way and these can be overcome if the investigator is aware of what may happen; these are mindsets and can include, “Expectation Bias” and “Confirmation Bias” that can trip up the investigator, if not careful. Below is an example of another way an investigator can be caught out with their conclusion/s.


Simply put, negative corpus is the process of determining what caused a fire by eliminating each possible cause, one by one, until only one possible cause remains. The one remaining possibility is then concluded to be the cause of the fire, regardless of a complete lack of evidence to support that conclusion. In utilizing the negative corpus method, the most important factor in the final conclusion is not the ground truth but the order in which the investigator eliminates each possibility. Whichever cause is evaluated last is the winner.

The result of applying the negative corpus method is most commonly seen when a fire investigator finds no evidence of a competent ignition source that might be responsible for an accidental fire and uses the process of elimination alone to conclude, therefore, that the fire must have been started intentionally.

Recent editions of NFPA 921 have rejected negative corpus as a clear violation of the scientific method.

As a consequence of conducting an investigation one will eventually be called to deliver their findings in a court, to justify their conclusions (origin and cause hypothesis). After using the Scientific Method to reach a conclusion the investigator needs to present their evidence, following well-known rules (of the court) so that evidence is admissible. The investigator should be aware of the rules of evidence, and the rules of Expert Testimony, that apply in their own court jurisdiction. If not followed, their evidence may be ruled inadmissible, or their integrity and credibility may be called into question. In most texts pertaining to fire investigation there will be mention of court rules of evidence, the investigator should be aware of what the rules are that apply to them in their own jurisdiction or the jurisdiction where they are presenting evidence.

Documenting evidence at an investigation scene.

Documenting evidence at an investigation scene.

Daubert (USA) [USA Court precedent]

The Daubert v. Merrell Dow Pharmaceuticals decision was handed down in 1993, where the U.S. Supreme Court made judges the gatekeepers of expert testimony. The ruling said that judges have to determine if expert testimony is reliable, and that using a methodology that has been peer reviewed, published, and accepted was part of that reliability test. So in cases that included fire investigations, courts began gravitating towards NFPA 921, a consensus document from a group of leaders in the fire investigation community.

Makita (Australian court precedent)

Justice Heydon’s six expert opinion admissibility requirements summarized at [para 85]:

the opinion has to be on an area that the Court accepts is an area of specialised knowledge;

  • the witness must demonstrate that by reason of specified training, study or experience they are an expert in that area;
  • the opinion must be confined to matters within that area of expertise;
  • the expert must state, and the party calling the expert must prove, the facts on which the expert opinion is based;
  • if any facts relevant to the opinion are assumed they must be identified and proved in some other way; and
  • the expert must explain how the opinion expressed was reached.

** According to legal experts, it is the INTENT of the decision, not where it was made. ** Look at your own court-set precedent for admissibility of evidence.

** Both NFPA 1033/921 are dynamic documents that are revised on a 3/5 year cycle from public/private comments and from discussions between the individual committee members. **

For more information, go to www.nfpa.org


National Fire Protection Association – NFPA 1033 – “Standard for Professional Qualifications for Fire Investigator” (2014 Edition). NFPA USA.

National Fire Protection Association – NFPA 921 – “Guide for Fire and Explosion Investigation” (2014 Edition). NFPA USA.

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Ross joined the New South Wales Fire Brigades in 1970 and retired as an Inspector in 2003, spending sixteen years in the Fire Investigation Unit. He teaches Fire Investigation degree courses at Charles Sturt University, and has done since 2002. He is a member of the IAAI, ANZFSS, NFPA and has taught extensively throughout Australia, New Zealand and overseas.

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