Hookahs and smoldering hookah coals as an object of forensic fire and technical expertise

Udilov Timofei Vasil'evich ORCID: 0000-0001-9824-3032 PhD in Technical Science Deputy Head of the Institute; East Siberian Institute of the Ministry of Internal Affairs of the Russian Federation' 664074, Russia, Irkutsk region, Irkutsk, Lermontov str., 110 udilov_nauka@mail.ru Other publications by this author     Aleksandroi Vladimir Ivanovich Senior Lecturer at the Department of Technosphere Safety of the Northern Trans-Ural State Agricultural University 664074, Russia, Irkutsk, Lermontov str., 110 udilov_nauka@mail.ru Other publications by this author

Vavilov Aleksandr Mihailovich Senior lecturer; Department of Forensic Expertise; East Siberian Institute of the Ministry of Internal Affairs of the Russian Federation 664074, Russia, Irkutsk region, Irkutsk, Lermontov str., 110 saniok38@mail.ru

Currently, hookah smoking and hookah rooms in cultural and entertainment establishments and catering establishments have gained wide popularity. Smoking establishments are located in administrative buildings, as well as administrative premises of residential buildings: lounge bars, time bars, smoke bars and others. Such establishments are essentially smoking rooms or hookah halls.

It should be noted that one of the fire hazard factors of hookah rooms is the abundance of textiles, pillows, upholstered furniture, carpets and other combustible materials in the interior. At the same time, special solid fuel compositions are used for smoking hookahs – hookah coals that can smolder for a long time with the release of a large amount of heat.

Thus, there is a high probability of fire when smoldering hookah charcoal comes into direct contact with combustible materials.

Examples of such fires have been entering the information field throughout Russia every year for the last decade. At the same time, fires due to violations of safety rules when smoking hookah occur both in administrative and residential buildings, as well as other facilities where hookahs are used.

For example, on August 22, 2019, a fire broke out on the four-deck motor ship Pyotr Tchaikovsky, which was moored on Oktyabrskaya Embankment in St. Petersburg. At the time of the fire, there were people on the ship, more than 300 people were evacuated from the ship to the shore. The main version of the cause of the fire is hookah smoking in the cabin (The fire on the ship "Pyotr Tchaikovsky" in St. Petersburg occurred due to hookah smoking in the cabin - Ministry of Emergency Situations // Information and Analytical Agency "PortNews". [Electronic resource]: URL: https://portnews.ru/news/283079 / (date of access: 02/12/2024).

On March 26, 2021, a fire broke out in one of the apartments of a 23-storey residential building on Zemskaya Street in Chekhov, Moscow region, caused by a violation of safety rules when smoking hookah. According to eyewitnesses, the smoking device was accidentally overturned, burning coals poured out on the sofa, the flame began to spread rapidly across the living area (Hookah lovers started a fire in one of the skyscrapers of Chekhov near Moscow // Information and entertainment portal "Chekhov View" [Electronic resource]: URL: https://chehov-vid.ru/news/incidents/25048/lyubiteli-kalyana-ustroili-pozhar-v-odnoy-iz-vysotok-podmoskovnogo-chekhova / (date of access: 02/12/2024).

On August 16, 2021, a fire broke out in a detached building of the hookah bar "Mr.Smoke" in Vyazniki, Vladimir region. The fire area was 300 sq.m. (Employees of the Ministry of Emergency Situations of Russia liquidated a fire in the building of a hookah bar in the city of Vyazniki and prevented the spread of fire to the pharmacy building // The Main Directorate of the Ministry of Emergency Situations of Russia in the Vladimir region. [Electronic resource]: URL: https://33.mchs.gov.ru/deyatelnost/press-centr/novosti/4538417 (date of application: 02/12/2024).

On February 27, 2022, a fire broke out in one of the apartments of a 25-storey residential building on Avangardnaya Street in Krasnogorsk, Moscow region, caused by a violation of safety rules when smoking a hookah (In the Moscow region, an apartment burned down because of a hookah // Online publication radiokp.ru . [Electronic resource]: URL: https://radiokp.ru/proisshestviya/v-podmoskove-iz-za-kalyana-sgorela-kvartira_nid571281_au53651au (date of application: 02/12/2024).

On July 6, 2022, an administrative building on an area of 100 square meters was damaged by fire in Kineshma, Ivanovo region. There was a hookah bar in the building (26 people extinguished the fire in the hookah bar // Kineshma City News Resource 168 hours - WWW.168.RU " [Electronic resource]: URL: https://168.ru/news/gorod/pojar-v-kolyannoy-tushili-26-chelovek-37645 (date of application: 02/12/2024).

On January 23, 2023, there was a fire in a hookah bar on Strastnoy Boulevard in Moscow (The fire in Elagin's mansion in Moscow occurred due to a fire in a hookah bar // The Internet portal of Rossiyskaya Gazeta. [Electronic resource]: URL: https://rg.ru/2023/01/23/pozhar-v-osobniake-elagina-v-moskve-proizoshel-iz-za-vozgoraniia-v-kaliannoj.html (date of application: 02/12/2024).

On July 2, 2023, a fire broke out in the hookah bar "Fog Hookah X GastroBar" on Bolshaya Moskovskaya Street in Vladimir (In Vladimir, on the night of July 2, 8 people were evacuated due to a fire in a hookah bar // Mass media network publication Tsargrad/Tsargrad. [Electronic resource]: URL: https://vladimir.tsargrad.tv/news/vo-vladimire-v-noch-na-2-ijulja-iz-za-pozhara-v-kaljannoj-jevakuirovali-8-chelovek_816860 (date of application: 02/12/2024).

On May 7, 2024, a fire broke out in a multi-storey residential building in Yekaterinburg, as a result of which a 30-year-old man died. The main version of the cause of the fire is a violation of safety rules when smoking a hookah (The apartment in the house on Soyuznaya in Yekaterinburg could catch fire due to smoking a hookah // Online publication "TagilCity". [Electronic resource]: URL: https://tagilcity.ru/news/2024-05-13/kvartira-v-dome-na-soyuznoy-v-ekaterinburge-mogla-zagoretsya-iz-za-kureniya-kalyana-5080293 (date of application: 02/12/2024).

Due to the significant number of fires in hookah smoking areas, conducting research to establish the involvement of tobacco smoking devices in the fire is an urgent task.

The fire danger of smoking rooms is traditionally associated with an ignition source and a high combustible load. A combustible load is combustible substances or materials located indoors or in open areas, and an ignition source is a means of energy action that initiates the occurrence of gorenje.

Smoldering coal, open fire and heated hookah surfaces can act as the main sources of ignition in hookah rooms. The most energy-intensive thermal ignition source, which is in a heated state for a long time, is smoldering hookah charcoal.

At various times, such authors as: M.K. Zaitsev, S.I. Zernov, N.A. Ilyin, A.P. Livchikov, B.V. Megorsky, G.P. Pavlov, G.V. Plotnikova, K.P. devoted their works to the theory and practice of forensic fire-technical expertise, in particular to the research of thermal ignition sources. Smirnov, S.I. Taubkin, L.N. Ulyanov, A.I. Fedotov, I.D. Cheshko, V.E. Chirko, S.O. Shulgin, etc. At the same time, in the scientific literature, when studying smoldering ignition sources and similar low-power ignition sources, the authors, as a rule, paid attention to smoldering tobacco products, smoldering particles, mechanical and welding sparks ^[1-5]. Currently, the issues affecting the peculiarities of the occurrence of combustion under the influence of smoldering hookah coals have not been reflected in the theoretical works of the above-mentioned authors. Gorenje

In expert practice, when investigating fires in hookah smoking areas, the most common question is: "Is it possible for certain objects to ignite from smoldering hookah charcoal?".

In order to assess the possibility of ignition of combustible materials from smoldering hookah charcoal, a number of experiments were planned and conducted.

Two types of hookah coals common on the domestic market were selected as objects of research: cubic natural charcoal for hookah "Ecocha" (Indonesia), fast-burning charcoal "Carbopol" (Poland).

Cotton fabric, cotton wool, paper, wood (pine), synthetic carpet with fine pile, synthetic carpet with large pile, decorative pillow with synthetic filling and pillowcase made of furniture fabric, PVC floor materials (linoleum, PVC tiles), floor panels, lined polymer films (laminate).

The methodology for conducting a study of the incendiary ability of hookah coals was as follows. Object No. 1 was heated in the flame of a gas burner for 60 seconds. In the study of object No. 2, heating was performed before the initiation composition began to burn. Gorenje Smoldering hookah charcoal was placed in the center of the surface of the investigated combustible material. With the help of a stopwatch, the time of events was recorded.

When conducting a study of the incendiary ability of hookah coals, it was found that when the combustible material comes into direct contact with smoldering hookah coal, charring occurs (wood, PVC floor materials, laminate), melting (synthetic carpet short-pile and long-pile, synthetic furniture filler), burning and ignition of combustible material (cotton fabric, cotton wool). Visual changes in the combustible material caused by exposure to smoldering hookah charcoal are observed from the first seconds of exposure.

Based on the results of an experimental study, it can be concluded that smoldering hookah charcoal can be considered as a possible source of ignition.

Of particular practical interest are the results of a study of the flammable ability of hookah coals in contact with synthetic textile finishing materials of various densities, soft furniture elements and floor coverings, given in ^[6-9].

It was experimentally determined that the studied samples of floor coverings in contact with smoldering hookah coals of the Carbopol and Cocos brands experience thermal deformations and damage − the carpet melts, the surface of the laminate and parquet board is charred. The substrate under the laminate at the point of contact with the coal has also melted through. However, ignition and flame propagation over the surface of the studied floor coverings were not observed. According to the results of the experiments, it was concluded that the incendiary ability of hookah coals when interacting with floor coverings is determined by the properties of the latter, in particular by their chemical composition. Natural wood, if heated with smoldering hookah charcoal to 367 ° C, begins to smolder, which can eventually turn into flaming gorenje and fire.

When conducting experiments with synthetic upholstery furniture fabrics and upholstery fabrics of mixed composition, all the studied samples received thermal deformations and damage at the point of contact with smoldering hookah coals, ignition and flame propagation over the surface of the fabrics were not observed. The tissues at the point of contact with the embers melted and hardened.

In general, the experimental results confirmed the hypothesis ^[10] that in the case of a smoldering ignition source, self-sustaining smoldering of the material in contact with this ignition source is necessary for ignition to occur.

It should be noted that the interiors of public and residential premises are characterized by the presence of various combustible materials capable of supporting decay: elements of interior decoration, a combination of materials of furniture elements, textiles, clothing, etc. Therefore, smoldering hookah charcoal in prolonged contact with such combustible materials can cause flaming gorenje and fire.

Thus, during the production of fire-technical expertise of fires, the location of the smoldering hearth found on interior items (furniture, equipment, decorative elements, textiles, etc.) or building structures and finishing materials of the room (flooring) provides a basis for putting forward versions about the possible cause of the fire from a smoldering source.

It is obvious that a priori it is impossible to formulate a universal strictly specified algorithm for determining the involvement of tobacco smoking devices and hookah coals in the occurrence of a fire for all possible cases of fire. We have made an attempt to combine well-known information about the detection of signs of exposure to combustible materials from a relatively low-power ignition source with the results of experiments and studies of smoldering hookah coals.

In carrying out this study, a systematic approach was applied to the analysis of the situation of a fire-related incident, as well as general scientific empirical and theoretical research methods: observation, comparison, description, measurement, analysis and synthesis, deduction, generalization, analogy, etc.

When conducting a fire technical examination, one of the stages of work to establish the involvement of tobacco smoking devices and hookah coals in the occurrence of a fire is to investigate the circumstances of the incident. At the same time, the expert must consistently perform a set of the following measures ^[11]:

1. Inspection of the scene of an incident related to a fire.

2. Identification of the situation at the scene of the incident that preceded and (or) accompanied the fire.

3. Study of the case materials.

4. Making a decision on the need for additional expert research.

It is an undeniable fact that the definition of a fire source largely depends on the correctness of the establishment of the source of its occurrence. It is a mistake to believe that the case materials and witness statements can replace an inspection of the scene.

During the inspection of the scene of an incident related to a fire, the expert must:

1. Detect and fix the signs of a fire.

2. To detect, seize and ensure the safety of objects that may be material evidence.

3. Collect information and data reflecting the situation at the scene preceding and (or) accompanying the fire, including the location of interior items and furniture in the room, as well as information about the circumstances of fire detection and liquidation.

When constructing versions about the occurrence of a fire from a smoldering source, when examining the fire site, it is necessary to pay attention to the specific signs of non-flammable gorenje (smoldering).

Gorenje gorenje gorenje (smoldering) process differs from flaming combustion primarily by a lower temperature in the combustion zone, as well as a relatively low propagation velocity. Due to the physico-chemical features, the smoldering process proceeds more steadily, including under conditions of a limited amount of oxidizer (air oxygen).

Given the characteristic dynamics of the smoldering process, a weakly expressed convective flow and the almost complete absence of a radiant heat flux, local thermal damage to the combustible material will be observed directly in the smoldering zone and have clearly defined boundaries of deep burnout (charring). At the same time, closely located objects may have minimal signs of thermal damage or not at all.

When examining the fire site, it is advisable to pay attention to structural elements, interior elements of the room, furniture frame, areas of flooring with deep charring zones. Such zones will indicate places of longer thermal exposure to combustible materials, and, consequently, to foci of possible smoldering.

Relatively low temperatures in the smoldering hearth, the course of low-temperature pyrolysis reactions (thermal decomposition of combustible material with a limited amount of oxidizer) cause the formation of coal residues of combustible material of a characteristic type and density. For example, when wood is smoldering, a denser coal layer is formed without deep and large cracks. The physico-chemical properties of coal formed in the zone of low-temperature pyrolysis are the basis for the method of measuring the electrical resistance of coal samples, used in practice to calculate the temperature and duration of thermal exposure. The electrical resistance of the coal sample taken in the smoldering zone has higher values compared to the samples of coal formed in the flaming gorenje zones ^[10].

The results of our experimental studies of hookah coals confirm the hypothesis of the formation of deep charring zones in the places of contact of hookah coal with combustible materials (wood, laminated floor coverings).

As a rule, the location of the smoldering hearth found on interior items (furniture, equipment, decorative elements, textiles, etc.) or building structures and finishing materials of the room (flooring) provides a basis for putting forward versions about the possible cause of the fire from a smoldering source.

It is advisable to start analyzing the version about the possible involvement of smoldering hookah charcoal or heated surfaces of a tobacco smoking device by excluding other versions of the occurrence of a fire. This approach is due to a number of factors, one of which is the lack of the possibility of removing hookah coal as a physical object as material evidence at the scene of an incident related to a fire.

When putting forward versions, the presence (absence) of the following factors at the scene of the fire incident is analyzed:

1. The presence of a set of conditions necessary and sufficient for the occurrence of combustion from smoldering hookah charcoal or the heated surface of a tobacco smoking device. Gorenje

2. The presence of signs of the dynamics of gorenje propagation, characteristic of low-power ignition sources.

3. The presence of signs of prolonged decay on interior items, surrounding structures, and furniture structural elements.

Considering the first factor, it is necessary to take into account the physico-chemical features of the occurrence and development of gorenje. Thus, it is most likely that only solid combustible materials capable of self-sustaining smoldering combustion, with a certain degree of probability, under prolonged exposure to a low-power ignition source, heat up to a state where no third-party energy source is required for the process of self-smoldering.Gorenje.

At the same time, the probability of burning from smoldering hookah coal increases in cases where conditions are created for the smoldering process to proceed with minimal heat loss, the possibility of heat accumulation and the presence of an oxidizer (air oxygen) in sufficient quantities. Gorenje

So, for example, the most "favorable" place for the occurrence of burning from smoldering hookah charcoal may be the space between a decorative pillow and a seat or back, the space between a decorative blanket and a seat of upholstered furniture, the space between cushions of upholstered furniture, the space between textile interior elements, elements of outerwear and structural elements of upholstered furniture.Gorenjesus, the space between pillows of upholstered furniture, the space between textile interior elements, elements of outerwear and structural elements of upholstered furniture.

Considering the above, when constructing versions about the occurrence of a fire from smoldering hookah charcoal, it is necessary to take into account the above factors: the most likely place where smoldering hookah charcoal enters, the presence of conditions for heat accumulation, the presence of air exchange, air inflow into the smoldering zone.

The second factor that must be taken into account when putting forward versions is the presence of signs of gorenje propagation dynamics characteristic of low-power ignition sources.

According to the results of laboratory studies ^[6-9], the smoldering of hookah charcoal with dimensions of 25x25x25 mm in calm air can last for 60 minutes. At the same time, the smoldering temperature of hookah charcoal can reach values of 500 ⁰ C, which in many ways exceeds the temperature of smoldering (295 ⁰ C), ignition (255 ⁰ C) and self-ignition of wood (399 ⁰ C) ^[12].

Situations with ignition sources of this kind are characterized by a long duration of the smoldering stage (the so-called "induction period") during which heat accumulates and the process of thermal destruction of the combustible material develops, then, if appropriate factors are present, the smoldering passes into the stage of flame combustion. Gorenje

Fires that develop rapidly and dynamically at the initial stage are not typical for ignition sources of this kind. The presence of an induction period is a qualifying sign of fires caused by a low-power ignition source ^[10], or a smoldering ignition source.

The third factor that must be taken into account when putting forward versions is the presence of signs of prolonged decay on interior items, surrounding structures, and furniture structural elements.

As noted earlier, the smoldering process occurs locally, at the site of the initiator, in a small area, and if it continues for a long time, as in the case of the smoldering of hookah coal, then significant (deep) thermal damage to the combustible material occurs. At the same time, the thermal effect on structures and objects located outside the smoldering zone is minimal.

Thus, the conducted experimental studies of hookah coals confirm the hypothesis of the formation of deep charring zones in the places of contact of hookah coal with combustible materials (wood, laminated floor coverings). Based on the results of experimental studies, an algorithm for constructing versions about the occurrence of a fire from smoldering hookah coal is formulated, including the expert's attention to the need to take into account such factors as the most likely place of ingress of smoldering hookah coal, the presence of conditions for heat accumulation, the presence of air exchange, the presence of air inflow into the smoldering zone.