Fire Load Research Articles

Behavior of Zn5Al hot-dip galvanized steel members under fire exposure

PurposeBased on the known positive effects of conventional hot-dip galvanizing under fire exposure and indicative results on zinc–aluminum coatings from smallscale tests, a series of tests were conducted on zinc-5% aluminum galvanized test specimens under fire loads to verify the previous positive findings under largescale boundary conditions.Design/methodology/approachThe emissivity of zinc-5% aluminum galvanized surfaces applied to steel specimens was determined experimentally under real fire loads and laboratory thermal loads in accordance with the normative specifications of the standard fire curve. Both large and smallscale specimens were used in this study. The steel grade and surface conditions of the specimens were varied for both test scenarios.FindingsLargescale tests on specimens with typical steel construction dimensions under fire loads showed that the surface emissivity of zinc-5% aluminum galvanized steel was significantly lower than that of the conventionally galvanized steel. Only minor influences from the weathering of the specimens and steel chemistry were observed. These results agree well with those obtained from smallscale tests. The design values of zinc-5% aluminum melt (Zn5Al) required for the structural fire design were proposed based on the obtained results.Originality/valueThe novel tests presented in this study are the first ones to study the behavior of zinc-5% aluminum galvanized largescale steel construction components under the influence of real fire exposure and their positive effect on the emissivity of steel components galvanized by this method. The results provide valuable insights and information on the behavior in the case of fire and the associated savings potential for steel construction.

Structural fire investigation and analysis on rectangular shield tunnel assembled by composite segments

Rectangular shield tunnels have been extensively used in roads, railways, stations, etc. In this paper, the structural responses of rectangular shield tunnel assembled by composite segments under fire were investigated. The elaborate numerical model was established based on the real rectangular shield tunnel and relevant assumptions were proposed based on matters of fact to enhance the computational efficiency of the model. In both ambient and elevated temperature conditions, the reliability of the finite element model is validated by previous experimental results. Afterward, parametric studies were also performed by a series of numerical simulations by varying parameters such as fire curves, loading conditions, and material types. This involved calculating the temperature distribution and internal forces in steel plates and concrete, as well as examining lining deformation, joint opening, and vulnerability. According to the results, during the cooling stage of RABT curve, the joint opening can be reduced by more than 30% on average and up to 50%. Load conditions have a significant effect on the mechanical response of the tunnel structure, especially the deformation. In addition, under the effect of RWS fire curve, the structure of lower-degree concrete is unstable. The results contribute to the fire-resistant design of rectangular shield tunnels assembled with composite segments.

Regional High-Rise Building Fire Risk Assessment Based on the Spatial Markov Chain Model and an Indicator System

High-rise buildings (HRBs) are prone to high fire hazards due to their high occupant density, limited evacuation routes, and high fire load. The indicator system method, as a systematic evaluation method, is widely applied to assess HRB fire risk. However, the method is subjective because the determination of the indicator weights mainly relies on expert experience. In order to reduce the subjectivity of the indicator system method in assessing the fire risk of HRBs, this study proposes a new assessment method by combining the spatial Markov chain model and the indicator system method. In this new method, fire occurrence probability is calculated by the spatial Markov chain model using historical HRB fire accident data. An indicator system is built to characterize the fire consequence by the structure entropy weight method. Subsequently, HRBs in Beijing are used as a case to illustrate the practicality of this approach. Firstly, the spatial Markov chain model is trained and validated using the chi-square goodness-of-fit test based on fire accident data from 2018 to 2023 in Beijing. It was found that the best performance was achieved with the monthly period and the four-state. Then, the distribution of regional fire occurrence probability in April was predicted based on fire accident data in March 2023 in Beijing. It showed that areas with higher fire occurrence probability are mainly located in the central region, especially in the I District. Then, the indicator system was used to evaluate the HRB fire consequence in the I District. The assessment results showed that the areas with more severe fire consequences are mainly located in the II and IV Districts, due to the poor performance of the fire system or the absence of fire protection systems. Coupling the fire occurrence probability and its consequences shows that HRBs with higher fire risk are mainly located in area II and should be carefully supervised for fire management. This developed method can provide some insights into the fire safety management of HRBs and the layout of the fire stations.

Resilience assessment of metro stations based on AHP-PSO fuzzy combined empowerment method with baggage impact perspective

Fire accidents are one of the serious security threats facing the metro, and the accurate determination of the index system and weights for fire assessment in underground stations is the key to conducting fire hazard assessment. Among them, the type and quantity of baggage, which varies with the number of passengers, is an important factor affecting the fire hazard assessment. This study is based on the combination of subjective and objective AHP (Analytic Hierarchy Process) with the available Particle Swarm Optimisation algorithm PSO (Particle Swarm Optimization) and the perfect CRITIC (Criteria Importance Through Intercriteria Correlation) empowered fuzzy evaluation method on the metro station fire hazard toughness indicator system and its weights were determined, and a fuzzy comprehensive evaluation model of metro station safety toughness under the influence of baggage was constructed. The practical application proves that the method provides a new perspective for the fire risk assessment of underground stations, and also provides a theoretical basis for the prevention and control of mobile fire load hazards in underground stations.

Характеристики тепловыделения при пламенном горении древесно-волокнистой плиты

Introduction. The beginning of the 21st century can be characterized by the rapid pace of development of modern construction of residential buildings. Various interior items are widely used in apartments, which are typical and intended to meet material needs. These items are the basis of the fire load. The term "fire load" is the amount of heat that can be released in a room during a fire. According to the amount of specific fire load, categorization of warehouse and industrial premises is made. However, categorization does not apply to residential premises, nevertheless, a study of fire load values is necessary due to the increase in fires in the residential sector. Goals and objectives. To determine the characteristics of heat release during combustion of MDF boards under the influence of a radiant heat flux of 40 kW/m2 with a local ignition source. The task is to estimate the contribution of flame and flameless combustion of the board to the total heat release, as well as to calculate the effective heat of combustion. Methods. To determine the parameters of heat release during combustion of medium-density fibreboard (MDF) boards, an installation operating on the thermocouple principle in accordance with state standard GOST R 57928-2017 was used. Results and discussion. The article presents experimentally obtained results of heat emission characteristics during combustion of MDF boards under the influence of a radiative heat flux of 40 kW/m2 with a local ignition source. The effective heat of combustion and contributions to it from flame and flameless (smoldering) combustion of the sample are determined. The influence of urea-formaldehyde adhesive in the composition of MDF boards on peak values of heat emission intensity is noted. Conclusion. The obtained results of heat emission characteristics during combustion of MDF boards allow their use for calculating the parameters of flammable load and in mathematical models of fire development. Simulating the most dangerous scenarios of fire development, which will allow determining the time of reaching the influence of hazardous factors on a person, ensuring the required fire resistance of the protected object, as well as conducting effective planning for calculating the volume of fire extinguishing agents and the method of extinguishing. Keywords: medium-density fibreboard (MDF); heat release; flame and flameless combustion; effective heat of combustion.

Progressive Collapse Analysis of RC building due to Fire load

Fire hazard is perceived to be one of the most destructive hazards faced by mankind in any urban environment as a primary or a secondary consequential event. In recent decades there has been substantial increase in adaptation of RC buildings for residential, commercial & office purposes. Therefore, the building fire appears as a more frequent hazard in comparison with other natural or man-made events. The occurrence of fire is unpredictable and high frequent event, that has potential to create a disaster (resulting in huge loss of property and life). Therefore, there is an imminent need for its consideration during analysis, design of new buildings and in assessment of structural integrity for existing buildings. This aids in providing a safe and functional fire-resistant building during its design life. The recent incidents that have occurred in Hyderabad city (Deccan Mall & Swapnalok complex etc), Telangana state, India, in particular is an epitome of this disaster. However, the existing codes of practice for Indian code designed buildings (BIS) in particular do not address assessment of the building structural behaviour subjected to fire load. Moreover, progressive collapse mechanism of any building can initiate due to loss of critical structural components due to any unforeseen event like explosion, accident, etc. Further, there are more likelihood of triggering of a fire hazard, eventually resulting in cascading failure of a structure. Hence, an attempt has been made to assess the structural integrity of structure during initiation of progressive collapse subjected to fire load. The hypothetical G+3(ground + three floors) reinforced concrete building designed as per IS456:2000, modelled and analysed using the structural finite element software (SAP2000). Progressive collapse analysis of the building is performed as per the GSA guidelines and subjected to simultaneous application of fire load (as per ISO 834 standard fire curve as the input fire load) on all its structural components. Further the performance of the building under fire scenarios were assessed in terms of its resistance duration using the Structural fire software (SAFIR). The outcomes of the study clearly pronounce the structural vulnerability of the building components in resisting the fire exposure for certain duration of time, quantified in terms of response parameters (Bending moments, Shear forces, Demand Capacity Ratio (DCR), etc).

Проблема изложения требований норм в области пожарной безопасности в России

Purpose. The analysis of regulatory documents and scientific publications is presented, describing the discharge parameters of automatic fire extinguishing installations, as well as criteria for their design. The analysis is presented in chronological order of the documents' editions. In compliance with the requirements of regulatory documents in the field of fire safety, facilities under protection are provided with automatic fire extinguishing installations (AFEI). The currently valid regulatory documents do not specify the fire load, according to which groups of premises are classified and types and methods of fire extinguishing agents discharge are determined. The above mentioned makes it necessary to analyze the regulatory and scientific literature with the objective of further defining a unified methodology for designing automatic fire extinguishing installations. Methods. The authors have carried out a chronological analysis of special literature in order to identify the stages of AFEI discharge parameters development. All types of fire extinguishing installations, which are subject to the requirements of regulatory documents, have been studied. Findings. Based upon the outcomes of the study in question, it is possible to make a conclusion that at present the regulatory documents governing the requirements for automatic fire extinguishing installations lack current data on modern substances and materials, and therefore the methods described in this paper may be inaccurate and sometimes crucial when determining AFEI characteristics. Research application field. The outcomes of the given research may be used by: – scientific institutions within various structures and departments as the base for development of guideline values of fire load as well as requirements to AFEI working conditions; – educational institutions within various structures and departments in the course of teaching and learning activities; – manufacturers producing fire equipment intended to provide fire safety at the protected facilities of various purposes. Conclusions. The given problem may be solved be means of updating fire load parameters with the help of different software systems, as well as full-scale experiments. This will allow determining the actual fire load parameters and effective characteristics of automatic fire extinguishing installations for modern buildings and premises.

Analysis of the modern fire load of a car taking into account the use of new materials

The article analyzes modern requirements to different types of parking spaces, features of their organization. The multilevel variant of arrangement is considered separately, as well as the peculiarities of ensuring fire safety taking into account the fire resistance of structures, including the installation of automatic fire extinguishing system. Also as a result, a comparative analysis of polymers used in modern car construction as a source of specific fire load of parking lots is carried out. Keywords composites, fires, closed parking lot, automobile, fire load

Requirements for cables as categories of construction products and thermal resistance of power cables

Introduction. One of the main driving factors of the demand for cable and conductor products is the modern trend of urbanization, which leads to an increase in cities with significantly increased requirements for electrical networks of transportation and distribution of electrical energy. This requires the development of appropriate infrastructure with significant demand for electricity in the commercial, industrial and residential sectors. The construction industry uses a wide range of cables with an appropriate set of electrical and mechanical properties, resistance to the influence of external climatic factors, and, first of all, must meet fire safety requirements. Increasing construction activity is stimulating the market for fire-resistant cables in the construction industry. According to the Construction Products Regulation, power, telecommunication cables, data cables, control and management, fiber optic refer to construction products in the EU member states. These cables are intended for the supply of electrical energy and communication, which are permanently installed in buildings and other engineering structures. Power, telecommunications, data and control cables are considered construction products, and are the only electrical products classified as construction. Over the next 15 years, Eastern Europe is expected to see increased growth in the construction industry, as the end of the war in Ukraine requires nearly $1 trillion in reconstruction. A strategic task in the reconstruction of the country is the use of cable and conductor products with increased operational properties, including in the construction industry. Significant efforts and investments in innovation and certification of cable and conductor products require manufacturers to create construction products of the «Power, control and communication cables» category with a high level of fire safety in accordance with the Euroclassification of cables in terms of reaction to fire depending on the level of safety. Purpose. Analysis of fire safety requirements for cables as a category of construction products and determination of thermal resistance of power cables based on experimental thermal studies of modern electrical insulating compositions. Methodology. The thermal stability of power cables with a voltage of 0,66/1 kV was determined, depending on the design, based on the conducted experimental studies of the thermal stability of electrical insulation materials, between the core filling and the polymer sheath, removed from the cable samples. On the basis of the conducted correlation analysis between thermal resistance and fire load, which are important parameters for confirming the quality and safety of the entire cable, it has been proven that the efficiency of halogen-free compositions to meet fire safety requirements increases with the increase in the cross-section and number of cores in the cable. Practical value. Determining the heat load and fire resistance of cables of various designs and areas of application based on the obtained experimental data on the heat of combustion of polymer cable materials is necessary and justified at the stage of mastering and determining the prospects for the production of cables with modern halogen-free electrical insulation compositions in accordance with fire safety requirements.

Fragility curves derivation under fire actions for different types of bridges

The Italian infrastructure network of bridges is complex, due to the orography of the territory and the presence of different hazard sources. Furthermore, during their service life these infrastructures can be subjected also to extreme actions such as the fire. This paper presents a procedure for the fragility curves derivation under fire actions for different types of bridges. The novelty the work is to apply the fragility assessment also to the fire resistance aspects, especially related to the infrastructures. Two case study pilot R.C. and composite steel-R.C. bridges are modelled by assigning combined loads according to the fire load combination and deriving structural response under fire scenarios. By using the linear regression, the structural response parameters of the bridges are correlated with fire intensity, considering different performance levels. Finally, lognormal fragility curves are obtained, measuring the capacity of the case study bridges. The study also shows which of the fire scenario parameters can be better correlated to the structural response of the bridges.

Modelling of fire behavior of RC girders strengthened by external prestressing

Since the 1950s, external post-tensioning has been a powerful tool for retrofitting existing bridges. In unbonded prestressing, the post-tensioning tendons are positioned outside the concrete cross-section, and the prestressing forces are transferred to the girder through end anchorages, deviators, or saddles. This implies that these could be critical elements for the bridge performance against fire. This paper examines reinforced concrete bridges strengthened by external prestressing and subjected to fire, using a mixed experimental and analytical approach. Initially, load tests are conducted on a model of a bridge beam strengthened by external prestressing to assess the effectiveness of the intervention until failure. The ultimate limit state (ULS) capacity of the beam is then evaluated both before and after rehabilitation. Subsequently, the fire performance is investigated through different scenarios defined by the fire load curves of Eurocode, evaluating the cross-sectional temperatures resulting from fire, estimating the loss of external prestressing efficiency, and assessing the beam’s overall fire resistance. This methodology is then applied to a real girder bridge with adjacent beams of the same type, extending the approach used on the experimental scaled beam to an actual bridge deck. Results are presented in terms of performance levels for different traffic load values and residual capacity over time from fire ignition, providing a safety assessment of girder bridges under fire exposure. The procedure is straightforward and immediately applicable to many existing reinforced bridges. The findings demonstrate how quickly external prestressing degrades, leaving the beam unprotected, and highlight the fundamental importance of the protective sheath for external tendons in limiting this degradation. Evaluating load levels based on exposure time also allows engineers to estimate the service time before rescue arrives, given the expected traffic level.

Study on Fire Load and Duration of Fire in Logistics Facilities

Logistics facilities differ significantly from general buildings in terms of diffusion flame prevention technology, necessitating the application of fire diffusion prevention technology. The total fire load in a fire compartmentation was calculated according to the method presented in The NFPA (The National Fire Protection Association) Fire Protection Handbook, based on the results of a survey on the area, height, and rack dimensions of 29 logistics warehouses in Korea to improve the fire compartmentation standard. In addition, simulations were conducted using CFAST (Consolidated Fire and Smoke Transport) for the cross-validation of these methodologies. Through fire simulations, the temperature of the upper part of each fire compartment was derived, and the equivalent fire duration was calculated by converting it to an area based on the standard time-heating temperature curve of KSF 2257-1. The NFPA methodology and values calculated through fire simulations showed similar results. In addition, we analyzed the tendency of the equivalent fire duration according to the height of the fire compartmentation and confirmed that the higher the floor height, the higher the equivalent fire duration. The results of this study can be used as basic data for improving the fire prevention standards by calculating the equivalent fire duration according to the fire load of a logistics facility and for confirming the tendency of the equivalent fire duration according to the height of the fire compartment.

Assessment of structures repeatedly exposed to thermal loading and extinguishing water: a case study of a firefighting training facility

When designing a new structure or assessing an existing one, the risk of fire and its effect on the structure must be considered. Structures are usually assessed for fire resistance at the design stage – i.e. before the possible exposure to fire. If structure is exposed to fire during its service life, a post-fire assessment must be conducted in order to evaluate whether the structure is still safe and reliable for use. The post-fire assessment is conducted quite regularly; however, the assessment is usually conducted for structures exposed to fire only once. This paper presents an interesting and unique case study of a post-fire structural analysis of a firefighting training facility exposed to cyclic fire loading and the effect of extinguishing water. The main conclusion of the study is that though means of protection are recommended, the structure still has a sufficient load-bearing capacity and can continue being used as a firefighting training facility in the future. Aside from the specific conclusions for the investigated structure, this paper presents the best practices and methods for the post-fire assessment of structures exposed to repeated fire loading, and can thus be used as a guidance by other engineers and researchers interested in this topic.

Automatic Recognition of Indoor Fire and Combustible Material with Material-Auxiliary Fire Dataset

Early and timely fire detection within enclosed spaces notably diminishes the response time for emergency aid. Previous methods have mostly focused on singularly detecting either fire or combustible materials, rarely integrating both aspects, leading to a lack of a comprehensive understanding of indoor fire scenarios. Moreover, traditional fire load assessment methods such as empirical formula-based assessment are time-consuming and face challenges in diverse scenarios. In this paper, we collected a novel dataset of fire and materials, the Material-Auxiliary Fire Dataset (MAFD), and combined this dataset with deep learning to achieve both fire and material recognition and segmentation in the indoor scene. A sophisticated deep learning model, Dual Attention Network (DANet), was specifically designed for image semantic segmentation to recognize fire and combustible material. The experimental analysis of our MAFD database demonstrated that our approach achieved an accuracy of 84.26% and outperformed the prevalent methods (e.g., PSPNet, CCNet, FCN, ISANet, OCRNet), making a significant contribution to fire safety technology and enhancing the capacity to identify potential hazards indoors.

Life after a fiery death: Fire and plant biomass loading affect dissolved organic matter in experimental ponds.

Drier and hotter conditions linked with anthropogenic climate change can increase wildfire frequency and severity, influencing terrestrial and aquatic carbon cycles at broad spatial and temporal scales. The impacts of wildfire are complex and dependent on several factors that may increase terrestrial deposition and the influx of dissolved organic matter (DOM) from plants into nearby aquatic systems, resulting in the darkening of water color. We tested the effects of plant biomass quantity and its interaction with fire (burned vs. unburned plant biomass) on dissolved organic carbon (DOC) concentration and degradation (biological vs. photochemical) and DOM composition in 400 L freshwater ponds using a gradient experimental design. DOC concentration increased nonlinearly with plant biomass loading in both treatments, with overall higher concentrations (>56 mg/L) in the unburned treatment shortly after plant addition. We also observed nonlinear trends in fluorescence and UV-visibleabsorbance spectroscopic indices as a function of fire treatment and plant biomass, such as greater humification and specific UV absorbance at 254 nm (a proxy for aromatic DOM) over time. DOM humification occurred gradually over time with less humification in the burned treatment compared to the unburned treatment. Both burned and unburned biomass released noncolored, low molecular weight carbon compounds that were rapidly consumed by microbes. DOC decomposition exhibited a unimodal relationship with plant biomass, with microbes contributing more to DOC loss than photodegradation at intermediate biomass levels (100-300 g). Our findings demonstrate that the quantity of plant biomass leads to nonlinear responses in the dynamics and composition of DOM in experimental ponds that are altered by fire, indicating how disturbances interactively affect DOM processing and its role in aquatic environments.

Behavior of unbonded pre-stressing concrete beams with thermal insulation coating

ABSTRACT Pre-stressing concrete is commonly used in construction. One of the challenges that pre-stressing concrete (PC) faces is that fire exposure reduces the strength and serviceability of PC elements, which requires unique design considerations. The pre-stressing strands are more sensitive to high-temperature, deform larger than mild steel, and break quicker. This research investigates the thermal and structural response of totally unbonded pre-stressing T-beams subjected to increased temperatures and continuous service loads. Thermal coating was proposed to avoid damage and load carrying capacity reduction under fire loading. Seven medium-sized post-tensioned concrete beams were tested in a fire exposure (600°C for 3 h) in order to examine the effect of the following variables: presence of thermal coating, the use of different pre-stressing ratios, increasing the concrete cover, and studying the fire effect at the end anchor, which represents the weakest point at the unbonded system. The proposed insulating technique improved pre-stressing beam behavior during fire exposure by improving crack distribution and lowering strength loss. The thermally insulated beam with a high pre-stressing ratio attained 99.3% of the control specimen load carrying capacity, compared to 86% for the unprotected beam. The deflection of the thermally isolated beam was 7.8 mm, compared to 22.7 mm for the unprotected specimen after 180 min of fire exposure. The use of low pre-stressing ratio caused the insulated pre-stressing strands to rapidly deform with low increases in temperature, which caused rapid crack formation.

Numerical development of a thermo-mechanical prediction model at high temperature: case of rubber concretes

The constitutive models have an important role in understanding the thermo-mechanical behavior of concrete and predicting its durability under fire loading. In this paper, the authors have developed a new constitutive temperature-dependent model for rubber concrete based on several models, such as European and American models, to predict the mechanical behavior of rubber concrete subjected to fire loading. The thermal parameters such as thermal conductivity, heat capacity, and density are variables as a function of temperature. First, the temperature is computed using the finite difference method (FDM) using the implicit scheme. The mechanical parameters in the literature are computed and plotted, such as compressive strength, tensile strength, peak strain, and stress-strain relationship, and then the mean value is estimated to develop a new probabilistic model at elevated temperatures. To validate the developed model, we compare the behavior of rubber concrete with experimental measurements.

Buckling failure analysis of storage tanks under the synergistic effects of fire and wind loads

Fire-induced domino effect is one of the main threats to hazardous material storage tanks, and many attempts have been conducted to assess the vulnerability of storage tanks exposed to fire to evaluate domino effect risk. However, past research ignored the influence of wind load on the thermal buckling behavior of storage tanks exposed to fire, which may underestimate the risk of exposed tanks. This paper thus conducts a numerical simulation of the thermal buckling behavior of steel vertical dome storage tanks under the synergistic effect of static wind loads and thermal effects. The effects of wind parameters and heat radiation parameters on the thermal post-buckling behavior and the time to failure (ttf) of storage tanks are investigated to analyze the synergistic effects of fire and wind loads. By comparing the circumferential and meridional stresses before and after the thermal post-buckling stage, it is found that under the disturbing effect of the positive wind pressure load, the thermal post-buckling of the tanks on downwind occurs earlier and more severe. Besides, the effects of wind angle, fire location height, and diameter on buckling damage were investigated. The comparative analysis of different scenarios shows that the tanks in the windy scenario are more prone to thermal post-buckling, and the deformation is intensified, with an increased likelihood of failure.

TG-FTIR-MS and Py-GC/MS study on the pyrolysis characteristics and gas evolution behavior of forest duff

Temperate and boreal duff layers are well-distributed in forests and swamps across North America, Europe, and Asia. Despite its abundance, forest duff remains predominantly a fire load or forest redundancy rather than being developed as a biofuel. This study analyzed the pyrolysis characteristics and gas evolution behavior of forest duff at different heating rates and pyrolysis temperatures by coupling technique TG-FTIR-MS and Py-GC/MS. The pyrolysis behavior of forest duff was modeled by a parallel reaction scheme encompassing water evaporation and hemicellulose, cellulose, and lignin degradation. The calculated decomposition temperature ranges of hemicellulose, cellulose, and lignin were 180–400 °C, 220–540 °C, and 200–800 °C, respectively. The temperature zones for the primary mass conversion were 200–500 °C, from which the main functional groups and volatile products were C-O-C, CO, -CnH2n+1, -OH, and non-condensable gases (CO2, CO, and CH4). The carbohydrate and ketone yields peaked at 288 °C, whereas the maximum acid and ester yields were at 320 °C. The yields of furans, phenols, and aromatics increased with pyrolysis temperature, peaking at 622 °C. This study elucidates the influence of the heating rate and pyrolysis temperature on the selectivity of bioenergy and value-added chemicals from forest duff pyrolysis.

Determination of heat transfer process in vertical cable tunnels of nuclear power plants under real fire conditions

The object of the study was heat and mass transfer processes occurring in vertical cable tunnels. The problem to be solved was the definition of process mechanisms in the inner space of the tunnel. For this, field tests were conducted, mathematical models were created, and computational experiments were conducted to establish specific parameters that affect the temperature regime of a fire in a vertical cable tunnel of a nuclear power plant. The dynamics of temperature changes with known geometric parameters and fire load were determined, and the adequacy of mathematical models built in the Fire Dynamics Simulator software was investigated and computational experiments were carried out. It has been proven that they consist in determining the temperature regime in a vertical cable tunnel of a nuclear power plant with known technical and geometric parameters. Such studies have practical applications in the field of safety of nuclear power plants and the development of new technologies in this field. An important conclusion of these studies is the possibility of determining the fire resistance of building structures of vertical cable tunnels of nuclear power plants with the selection of the most severe temperature regime, according to the conducted field test. This means that research results can be used in practice in designing and evaluating the safety of such objects. The conducted research established that the temperature in the inner space of the tunnel can reach values from 1200 to 1400 ℃. The following factors influence the maximum temperature value and the maximum time to reach the maximum temperature in the fire cell: fire load, height and area of the tunnel. With a lower fire load, the maximum temperature in the vertical cable tunnel of the nuclear power plant was 75 % lower. Therefore, the results of these studies have a direct practical application in the field of safety of nuclear power plants and can be used to improve and develop new technologies in this field