Fire Investigation (FIT) is one of many departments within the London Fire Brigade. The aim of Fire Investigation is to prevent future incidents and reduce injury or fatality from fire. This article will discuss the aspects and team that make Fire Investigation, with various skills sets and the scientific techniques used.
FIT will attend an incident when the predetermined attendance has been met or when requested by the incident commander. The role of the Fire Investigation Officer is to investigate the fire scene in order to determine the development, origin and cause of the fire and the behaviour of people involved. These findings are then communicated to various bodies in the form of written reports in accordance with procedure, under the guidance of the Station Commander and Group Commander. The team is made up of Fire Investigation Officers with various skill sets, including new roles of Cold Scene Examiners that have been introduced.
The team is made up of officers with various backgrounds and skill sets that include operational firefighters, fire-safety officers and academics. Skills sets include, but are not limited to, operational awareness of the fire ground, electricians, academic study in the sciences, experience and knowledge of fire safety, and research such as white goods. Every team member is required to undertake the Fire Investigation development process, which is aligned to the National Occupational Standards. Courses are provided and undertaken by the officers, and include theory and practical fire investigation and the legal processes. In 2019 the Fire Investigation team completed the recruitment of two Cold Scene Examiners in a drive to improve the communication link between Fire Safety and Fire Investigation teams.
The aim of the new role is to provide a link between the Fire Investigation Team and Fire Safety teams across London and improve feedback in regard to identified fire-safety failures/successes at incidents. Vincent Brown and I hold these roles and assist in conducting fire investigations in addition to liaising between the teams and carrying out research/thematic reviews on fire-safety issues.
Further advances in the team include officers undertaking degrees in science and fire-investigation-related subjects to further their knowledge and understanding of scientific principles required to undertake a fire investigation.
As scientific technologies and enhancement continue to progress in this field, like many others, it is important to have a thorough understanding. A team with the knowledge and experience and continuing development, both practical and academic, allows for efficient and effective fire investigations. Techniques are adopted and utilised as required. These include the use of a gas tec carried on each vehicle. This is a tool used to detect hydrocarbons on scene when an ignitable liquid is suspected to be present. This is backed up with the use of the fire-investigation dogs that have been trained to detect hydrocarbons. The dogs are deployed with the fire-investigation-dog handler to a scene when ignitable liquid is suspected to be present.
The team also make use of scientific advisers, an external company that are trained in the examination of materials, both on and off scene. For example, when it is hypothesised that an appliance is the cause of a fire and it requires a full examination, the item is then sampled, analysed and a report made.
Scientific method of fire investigation
Carrying out a fire investigation can be a long and complex process, and is often dynamic due to the nature of the role. To highlight this we are going to look at different aspects of fire investigation, to show how an investigation is managed and recorded for evidential purposes. A strategy used in fire investigation is that of the Scientific Method, which consists of seven steps. This is a systematic and logical approach that is used in the physical sciences and is to be followed by the investigation officer in order to correctly formulate, test and validate a hypothesis that is necessary for a successful fire investigation. The steps are as follows:
1. Recognise the need (identify the problem)
A fire has occurred and needs to be investigated. FIT considers scene protection and whether additional resources are required. The aim of fire investigation is to prevent future incidents and reduce injury or death from fire.
2. Define the problem
Define the manner in which to solve the problem by conducting an origin and cause investigation. The Fire Investigation Officer needs to ensure correct PPE and safe systems are in place. They may have to consult with structural engineers on scene before any scene examination can be carried out. Upon arrival they begin to develop and implement a plan for the investigation. Where it is suspected that a fire has been started deliberately, the Police will be informed and they will take primacy of the investigation. Often FIT will be asked to assist Police in that investigation. The scene needs to be secured, so that any possible evidence is not lost or destroyed. This is combined with other data-collection methods, such as interviewing witnesses.
3. Collect data
The investigator documents the incident by observation, examination, experiment and other direct-data-gathering means, including heat and smoke patterns, fuel loading and layering of debris, photographs and drawings made on scene and the collection of evidence. (This is where items involved in the fire may be sampled for testing by the investigator.) Tests and experiments may be conducted and sometimes these are field based or may be conducted away from the scene. It is not limited to the area of origin, information can come from a variety of sources, such as historical data and lifestyle. Witness information will be recorded contemporaneously to gather relevant details around the possible origin, cause and fire development.
4. Analyse the data
This step requires all of the data to be analysed, formulating hypotheses based on observations made. The investigator relies on their knowledge, training and experience to evaluate the data. Predictions should be tested against established scientific knowledge of fire dynamics, fire-testing experience and experimental data. The types of data evaluated can be the patterns of fire damage, how fire-safety systems behaved during a fire and the analysis of electrical items/installations. It is important not to rely on one piece of data; the more information collected the greater the weight of the hypothesis and scientific certainty. The hypothesis made is based on the understanding of the data and on the evidence. It is a necessity to keep an open mind and remain completely impartial, avoiding cognitive bias.
5. Develop a hypothesis (inductive reasoning)
This is where the investigator develops a tentative working hypothesis as to the origin, cause and development of the fire, based on the data analysis formed solely from the data collected and which is consistent with the on-scene observations made, physical evidence gathered and information obtained from witnesses. Information considered may be the fuel loading observed, room dimensions and whether fire doors or windows were open or closed. There are many other factors, and these are just a few examples of information that may assist in developing a working hypothesis.
6. Test the hypothesis (deductive reasoning)
The investigator will test all the information gathered against other known facts based on experience/training and recognised published data and analysis. The hypothesis is not valid unless it can stand a careful and serious challenge. This process is used to eliminate other potential causes. This may involve seeking further information from witnesses or gathering additional data to test the existing hypothesis. This is a cyclical process and steps 4, 5 and 6 should be repeated until there are no discrepancies with the working hypothesis. Alternative explanations can be created to test the original hypothesis and may also identify issues that need to be considered. The hypothesis needs to be consistent with the facts and the principles of science. Any hypothesis that does not withstand examination by deductive reasoning will be deemed undetermined.
7. Select final hypothesis
Having considered all the information and data gathered, the investigator will then make an authoritative conclusion as to the origin and cause of the fire. This involves the identification of competent ignition sources and should establish a level of confidence as to the selection of the final hypothesis, based on deductive reasoning, evidence and research obtained. The investigator has applied scientific knowledge to recreate the path and spread of the fire, traced it back to its origin and established its cause. The opinions of the investigator are expressed to a reasonable degree of scientific certainty.
No two fires are the same, so it is important to follow the procedures and scientific methodologies carefully and call upon others of experience and knowledge. In addition to working with internal departments, such as Fire Safety and Fire Engineering, the London Fire Brigade Fire Investigation Team often work with other agencies that include, but are not limited to, the Police, HSE and Bureau Veritas Scientific Advisers. Whenever conducting a fire investigation either alone or with others, it is important to consider the intricacies of a full-scene examination, for example by delayering debris using trowel work and sifting magnets. The scene is fully examined to answer four main questions: what was the item first ignited, what was the ignition source, was it sufficient to ignite that fuel and how did the item first ignited come into contact with the ignition source? The Fire Investigator should ask themselves: has everything been considered, will the determination stand up to scrutiny? The team will hold peer reviews and challenge hypotheses from an investigation. Many reports are submitted following an investigation depending on the circumstances of the incident, and the origin and cause will be included if known. Sometimes a cause is not known. For example, if there is more than one hypothesis and there is not enough evidence/ data to prove the hypothesis and there is no probable cause, then it is deemed undetermined.
The purpose of this article is to give readers a short introduction and an insight into the world of Fire Investigation. It is not exhaustive or limited and requires a great interest and commitment for those that wish to pursue a career in this field.
For more information, go to www.london-fire.gov.uk