Ministry of the
Solicitor General

OFM - 04-52-03

Fire Investigation Practices

Public Fire Safety Guidelines

Subject Coding

PFSG 04-52-03


Fire Prevention and Public Education


March 2001


Fire Investigation Practices


Under Review


To describe essential components to enhance competence of fire department personnel in fire origin and cause determination and the investigation of fires.


Every fire should be investigated in accordance with the OFM protocol. Generally, the Office of the Fire Marshal only investigates fires where there is a provincial interest. The fire services have the responsibility to investigate all other fire occurrences within their jurisdiction. To clarify the roles and relationship between the OFM and the fire service, the following criteria have been developed by the Office of the Fire Marshal.

OFM Criteria

  • All fatal fires or critical injuries*
  • Explosions*
  • Incendiary fires
  • Large loss fires exceeding $ 500,000
  • Fire of unusual origin or circumstance, e.g. unusual fire/smoke spread, or involves circumstances that may result in widespread public concern, i.e. environmental hazards.
  • Multi-unit residential occupancies where fire spread is beyond unit of origin.

*The OFM investigates ALL reported fatal fires or critical injuries and explosions. The remaining categories may or may not be investigated all of the time depending on the nature of the incident and/or the availability of OFM fire investigators.

There is a joint responsibility to investigate fires.

FPPA Subsection 14(1) The Fire Marshal or fire chief may, without a warrant, enter on land or premises if,

  1. a fire has occurred on the land or premises; or
  2. he or she has reason to believe that a substance or device that is likely to cause a fire may be situated on the land or premises.

FPPA Subsection 14(2) authorizes the securing of premises, the examination and/or removal of any article or materials and the recording of the same. This section also authorizes the investigator to make inquiries of any person, orally or in writing.

Determining cause and origin:

The key function of a fire investigator is to adequately determine the cause and origin of fires. To do this adequately basic training in arson detection would be required, followed by advanced training in arson investigation.

Assessing code compliance:

During the course of an investigation, the trained investigator must be able to recognize building code and/or fire code violations. Code compliance must be assessed in order to ensure continued public safety. An assessment of the performance of the building and the reaction of the occupants must also be made. Where necessary, action must be taken to ensure that improvements are made.

Assessing fire suppression effectiveness:

After each structure fire or other significant incident, a de-briefing should be held to identify the strengths and weaknesses of the fire suppression operations used. A summary of the assessment should be documented and utilized to improve performance. This process contributes to continuous improvement.

Determining Effectiveness Of Built-In Suppression Features:

When a built-in suppression feature is encountered during the course of an investigation the following points must be considered:

  • did the system activate and function as intended? If not, why not?
  • did it malfunction through accident or fail by design?
  • was the installed system adequate for the intended occupancy?

Interaction With OFM Investigator:

Training and partnerships will serve to create and strengthen the relationship between the fire service investigator and the OFM investigator. Over time, and with continued guidance, a more confident and capable fire investigator will emerge.

Supporting criminal prosecutions:

The capability and the confidence instilled in the fire service investigator through interaction with the OFM investigator will provide the police with a competent and reliable witness when criminal prosecutions are undertaken.

Consulting with police and other agencies:

Through the course of investigation training, fire personnel must be made aware of the agencies available for consultation and assistance, what assistance they can provide, as well as when and how the assistance of those agencies can be secured.

Forensic services:

The fire service investigator must be trained in the proper collection, preservation, and maintenance of continuity of evidence so that the submitted exhibits can be analyzed by the Centre of Forensic Sciences or other agencies i.e. OFM engineer, Canadian Standards Association, etc. and its results be made admissible in court.


Through training, the fire service investigator will be made aware of the need for continuous documentation of the incident from his/her first involvement through to a successful completion.

The fire service investigator must learn that the accepted methods of gathering and recording information must be adhered to in order to be admissible in court proceedings.

The content of the fire service investigator’s personal notebook becomes the basis for the information needed to complete a confidential brief to crown counsel. All information gathered during the course of the investigation becomes part of the permanent record and is therefore subject to disclosure.

The fire service investigator must not only be professional in knowledge and attitude, but also in appearance and decorum, affording the respect that is due the court being addressed. A judge and/or jury may well decide the credibility of the investigator’s testimony depending upon their first impression and their qualifications.

Codes, Standards, and Best Practices:

Codes, Standards and Best Practices resources available to assist in establishing local policy on this assessment are listed below. All are available at . Please feel free to copy and distribute this document. We ask that the document not be altered in any way, that the Office of the Fire Marshal be credited and that the documents be used for non-commercial purposes only.

See also;
PFSG 04-52-12 Fire Investigation practices
NFPA 921
NFPA 1033