Objects of judicial fire technical expertise

The objects of judicial fire technical expertise are very diverse, these include:

- place of fire;

- charred and charred structural elements and parts of buildings (deformed and destroyed building structures made of metals, stone, reinforced concrete, wood and plastics), burnt interior items;

- damaged vehicles and other large items (including bulky technological and other equipment available there, the removal of which is not possible);

- mechanisms and equipment or their units and parts;

- burnt and unburned objects and their residues (including the alleged technical means of arson or objects with traces of flammable and combustible liquids);

- objects with localized traces of heat exposure (proplavami, burnout, etc.);

- fire debris (ash, ash, slag, coal, parts of burnt objects, substances and materials), traces of soot and burnout on objects, samples of material from areas under burnout;

- devices for igniting substances and materials;

- fire alarm devices, fire extinguishing equipment;

- electric heaters with cords;

- remnants of damaged light bulbs and lamps with signs of emergency operation;

- fragments of electrical wires and cables with traces of flashing (when laying in pipes and metal hoses together with pipes and metal hoses);

- electrical protection devices (fuses, circuit breakers, etc.), electrical switching devices with signs of emergency operation.

It should be emphasized that the place of fire is one of the most important and most informative objects of judicial fire-technical expertise. Unfortunately, parts of the fire and technical expertise in civil cases are appointed a few weeks, or even months after the fire, when all its traces have already been destroyed. Information remains recorded only in fairly superficial inspection protocols, several photographs (rarely video frames) and acts of fire. The mechanism of occurrence and development of fire, declared in the acts, rarely coincides with that established later in the production of judicial fire-technical expertise.

For example, when a fire broke out in the workshop of a garment factory, fragments of fused cables with aluminum conductors were found. On the basis of this, the fire report stated categorically that the fire had occurred "due to a short circuit in the wiring". However, examining the documentation by the expert in the production of fire-technical expertise showed that the power supply of the workshop was carried out using cables with copper conductors laid in steel metal hoses, and aluminum cables are remnants of the old power grid, which has not been used for more than five years but has not been dismantled. .

Thus, the most important step in the production of forensic fire and technical expertise is an expert inspection of the fire site. One of the main tasks of this inspection is to establish the focus of fire. Baseline information for establishing the focus and assessing the dynamics of a fire is obtained by comparative studies of the degree of thermal damage to building structures, equipment, communications, interior items, etc. For this purpose, a whole range of physical and physico-chemical methods is used, described in the literature. Their condition is described in detail in the research part of the expert's opinion and is recorded using schemes and photo tables and video filming. If there are several independent foci of fire, then their relationship is established.

If a fire lasts for a long time, the place of its occurrence may not have a pronounced set of so-called focal signs in the form of traces of local burning out, melting and deformation of objects and structures, etc. The determination of the source and mechanism of fire in the process of expert examination is preliminary; Finally, this issue is solved after laboratory research and documentation analysis.

During the inspection, they find out what combustible substances and materials were located on the object where they were located, what were the conditions for their storage or use. It is very important to establish the source of ignition, which can be an instrument of arson. Typical ignition sources include:

- open flame;

- heated surfaces (cases of equipment, devices and devices under normal and emergency operation modes);

- microbiological and chemical processes in substances and materials that occur with the release of heat;

- red-hot particles of a substance;

- sparks arising in electrical discharges, including atmospheric electricity.

It is necessary to take into account that far from each source this substance ignites. If, for example, a decay of cotton fabric can start from a burning cigarette, the synthetic fiber will only melt. Since the Bickford fuse cords, wicks, flammable and combustible liquids used for arson, smoldering tobacco products burn in the first place, it is almost impossible to detect their remains. However, an expert can judge about their use by indirect signs: the center of fire and the place of greatest burning out do not coincide; A lot of fires and the most intense burnout in certain places were found, cans or bottles from under flammable and combustible liquids were found. In any case, soil samples, burnt objects and substances, suspicious containers are removed from the intended fire for research in the laboratory. Preliminary analyzes of these substances for the presence of flammable and combustible liquids using indicators are carried out only with significant quantities of the substance.

If electrical wiring or electrical equipment with traces of flashing or thermal damage is detected in or near the fire center, they should be investigated to substantiate the assumption that a fire may occur as a result of an emergency mode in the electrical network. Moreover, the presence of flashings does not indicate that the emergency mode was the cause of the fire (for example, a short circuit), since it could also have arisen as a result of a fire. Electrical boards and electrical protection devices (electric tubes, automatic machines, etc.) must also be examined and investigated.

It should be especially emphasized that if an expert is presented with fragments of electrical wiring, seized at the site of a fire, together with them should be presented the power grid layout with the linking of these fragments to specific parts of this circuit. Otherwise, the study does not make sense, since the melting points cannot be tied to the fire center and it is not possible to resolve the issue of a causal link between the emergency mode of electrical installations and the occurrence of a fire. The electrical circuit of the object, which in this case should be attached to the inspection protocol, indicates the withdrawn fragments of electrical wiring, electrical equipment and electrical protection devices.

A thorough inspection should be subjected to stoves, chimneys, welding sites. Fire debris is disassembled and inspected, and if necessary, sifted. It can sometimes detect parts of the devices used for arson. Research of garbage allows to establish what exactly burned down and in what quantity.

In a completely burnt-out room or car, a concentric or frontal inspection is carried out with successive movement in a spiral or radius and gradual advancement to the place of the intended source. Fire trash carry a shovel or shovel to free space and carefully inspect, removing what may be relevant to the cause of the fire. Since the fire develops predominantly in the upstream direction, when searching for a fire, it is necessary to detect the lowest level where there are burns, burnouts, etc. To do this, it is required to clear the fire debris by removing and sifting it, as well as to flush the floor, which will make it possible to most clearly identify areas with signs of thermal damage. The floor is usually damaged to a lesser extent than the walls and ceiling. In the absence of flammable liquid, the floorboards do not light up from the upper plane, but from the edges, which heat up faster from external thermal effects. Under furniture on low legs, the floor usually remains intact, it preserves parquet, carpet or linoleum flooring.

If the object is completely destroyed by fire, careful layering dismantling of fire debris and residues of structures is carried out, trying to avoid confusion with the belonging of the detected objects to one or another aggregate, etc. Unsystematic disassembly and cleaning after a strong fire, as a rule, does not make sense. The expert needs to analyze the information already available and determine the place where the fire may be located in order to start clearing from this particular area1.

Its specificity has an expert inspection of forest and bush fires. Finding a fire in the place of such a fire is difficult because of the large area. Therefore, for the preliminary orientation and determination of the boundaries of the inspection zone, the experts use the results of daily fire monitoring observations, weather reports and information about the situation on board the aircraft with reference to geographical landmarks.

As mentioned above, the objects of fire and technical expertise are very diverse. Since, in addition, in the civil and arbitration process objects for fire and technical expertise are presented by the parties, it is necessary to dwell on some of the requirements for these objects. Substances, materials, objects and their fragments should be packed and marked. We emphasize that the packaging must comply with the nature and properties of the object, to preserve the evidential information it contains. Seizures are noted on the burned object plan. We illustrate the importance of this thesis by example.

The permission of the judicial fire-technical expertise, appointed upon the fire at the dacha, was asked whether the fire had arisen as a result of arson using gasoline. Experts were provided with firefighting garbage, seized during the inspection of the fire site and packed in newsprint. Since the fire occurred seven months before the appointment of the examination, and the packaging was not sealed at all, it was not possible to conclude that traces of a flammable (volatile) liquid — gasoline — were present in the firefighter.

Samples of combustible substances and materials, electrical wires and cables (if necessary, protection devices and other equipment), other samples for the production of comparative studies and model expert experiments are presented as comparative samples when appointing judicial fire-technical examinations.

In the production of forensic fire and technical expertise, as well as some other engineering and technical examinations, there is a need to analyze the technical documentation of the burned object and its equipment, to summarize information about the circumstances of the occurrence, detection and development of a fire until it is eliminated, to carry out modeling of the processes that occurred during the fire. The effectiveness of the examination is largely determined by the quality and completeness of the materials submitted to the expert, which include:

- protocols of inspections of the fire site, illustrated in detail by photo tables, drawings, diagrams;

- information on the date of the fire, the place and time of its detection, weather conditions;

- characteristics of the burned object, data on materials and fire resistance of structures;

- Types of combustible loading on site, its localization and methods of placement;

- Detailed external electrical circuits (from a transformer substation) and internal power supply of the object (indicating the location of the seized electrical conductors and electrical appliances and installations), reflecting the positions of the electric shunt switches;

- types, number and locations of lighting and household appliances, power electrical equipment; marks and lengths of sections of wires and cables, methods of installation (open, in pipes, etc.);

- characteristics of heating, fire extinguishing, electrical protection devices;

- information about the events that preceded the fire and were in causal connection with its occurrence;

- signs on which the fire was discovered, and the conditions for its detection, features of the development and extinguishing of the fire, its overall duration, consequences.