Tasks of the judicial fire technical expertise

The main tasks of the judicial fire technical expertise are:

- determination of the place and time of the initial burning (the fire, the direction of propagation of combustion, features of the fire);

- the establishment of the mechanism for the emergence and development of combustion;

- identification of circumstances contributing to the emergence and development of fire.

As a rule, questions of a diagnostic nature are submitted to the resolution of judicial fire-technical expertise, which can be divided into several groups in accordance with the tasks to be solved. Consider these aspects in more detail.

A. Establishment of the source of fire, diagnosis of the dynamics of fire in space and in time. The following questions can be resolved in this task group:

- where was the seat of fire?

- is this place (part of the room, part of the area, installation, etc.) the place of the initial occurrence of burning?

- what signs indicate the location of the fire in this place?

- What is the mechanism of formation of focal signs; Are there in this case several independent fires, and if so, what is their relationship?

- What explains the local damage (deformation, burnout, charring, etc.) of this object, structure?

- What is the highest temperature reached and fire conditions in this place (in this area)?

- Are there any signs that characterize burning in case of fire in the presence of flammable liquids?

- what substances, materials were burning, judging by the recorded data on the color and density of smoke, the color of the flame?

- Is the temperature developed during the fire enough to melt these objects and materials, to destroy building structures, etc.?

- What is the linear (mass) rate of burnout of a substance, material?

- What is the rate of propagation of fiery burning (flameless burning or smoldering) to the fed material?

- what substances, materials from those located in the fire center (room) could be preserved in case of fire (to what extent)?

- How much time is needed for the transition of the smoldering material of this material into a fiery burning under specific conditions?

- What are the ways of spreading fire from the fire; what was the rate of development of combustion, the growth of the fire area; in what direction did the fire spread in this area (door, wall, etc.)?

- what is the position of the door (sash, etc.) during a fire; What are the patterns of development of a fire in an open (closed) room at the location of the fire in this place?

- what is the duration of the fire; what time did the burning happen? how much time did it take to get fire and smoke out of the building?

How long does it take to burn a layer of material of a certain thickness during a fire impact (when contacting an object heated to a given temperature)?

- How much time is needed for complete combustion of these materials, objects under the specified conditions?

B. Diagnostics of the fire mechanism includes the following questions:

- what happened earlier: fire or explosion?

- What is the mechanism of occurrence of burning in the fire in the case under consideration?

Here we should highlight issues related to the diagnosis of features of the interaction of the ignition source with a flammable substance, spontaneous combustion of substances and materials:

- at what duration of exposure of a given ignition source can ignition of these substances, materials, products and structures occur?

- Is the occurrence of burning of these substances, materials, products under specific conditions possible?

- Is spontaneous combustion (thermal, chemical, microbiological) of these substances and materials possible under these conditions?

- Are there signs indicating the occurrence of combustion in the fire site due to spontaneous combustion?

- is there enough heat released during the interaction of these substances for the occurrence of combustion under these conditions?

- Are there any traces of flammable liquids, fuels and lubricants on the presented objects, and if so, which ones? (It is solved by a complex judicial fire-technical examination and forensic examination of substances and materials.) Is there a connection between their presence at the fire site and its occurrence and development?

Another group of questions concerns the diagnosis of the possibility of fire from sources of ignition of electrical nature: highly heated current-carrying elements, places of poor-quality contact connections, short circuits, burning insulation, small-sized particles of red-hot metal, spark discharges, etc .:

- Was the electrical installation of the burned object energized under fire conditions?

- Are there any evidence of flushes, current overload, short circuit, etc. on the evidence presented?

- what caused the change in material properties and the formation of defects (flushes, burn-throughs, section changes) on material evidence: by thermal effects of fire or emergency conditions in electrical circuits?

- What is the mechanism for the emergence and development of emergency operation of electrical installations; When did the emergency mode arise: before the fire or during the development of the fire?

- What is the causal link emergency mode in the electrical installation and the occurrence of fire?

- whether the electrical protection device has been activated during the emergency mode of the electrical installation, and if it did not work, then what caused it; Are there any signs of changes, alterations in the nodes and details of the electrical protection device, and if so, how did it affect its characteristics?

- are these items remnants of an electrical appliance (electrical protection device, switching apparatus, etc.), and if so, which specific (type, brand)?

- what caused the destruction of the fuse-link fuse: emergency mode in the mains or fire?

When establishing the possibility of a fire from emergency operation of technological equipment, devices and devices for industrial and domestic purposes, issues are resolved:

- what temperature developed on the surface of the operating device?

- Is this temperature sufficient for the occurrence of combustion of these materials?

- what fire hazard manifestations accompany this emergency operation of the equipment?

- Is it possible to ignite a given substance, material under the action of a source of thermal radiation of a given type under the specified conditions?

- what is the fireproof distance to such a source; Is it possible to ignite a substance, a material when it comes into contact with the heated surface of the device, or a device under specified conditions?

- what is the heating period before signs of burning appear?

- can the indicated malfunctions of equipment, instruments, devices cause a fire under these conditions?

Questions asked by experts about the possibility of a fire from an open flame (which can accompany the operation of heating stoves, cooking stoves, gas water heaters, etc.) can be summarized to the following list:

- Is it possible to ignite the object, the material when it is in contact with an open flame (matches, fire flame, gas burner, etc.)?

- after what time when a flame is exposed to a flame, does the material ignite?

- under what conditions (mutual spatial arrangement of the flame and flammable material, the method of their contact, etc.) the material burning can occur?

Often a fire arises from small sources of ignition (particles of a burning or hot substance generated during operation of furnaces, vehicle engines and heating systems, from fires and other open sources of combustion; during electric and gas welding; short circuits; mechanical processing of solid materials, impacts, etc. ). In these cases it is recommended to ask questions:

- Is it possible to ignite the substance, material in contact with red-hot or burning particles?

- whether a fire from this source?

Since it is not possible to exclude arson as a cause of burning in civil cases on fires in courts of general jurisdiction and arbitration courts, let us point out the questions that in this case are put to the resolution of fire and technical expertise:

- Are there any signs of fire due to arson?

- Could the objects found at the scene of the fire and submitted for examination, make up a device, a device to commit arson?

- is this device incendiary and what is its principle of operation?

- Will the device ensure ignition of the substance, material, or object under the indicated conditions?

- Do the results of the research of the presented objects indicate a certain method of arson?