Structural Fire Protection Research Articles

Numerical Analysis of Fire Resistance in Cross-Laminated Timber (CLT) Constructions Using CFD: Implications for Structural Integrity and Fire Protection

Fire represents a serious challenge to the safety and integrity of buildings, especially timber structures exposed to high temperatures and intense heat radiation. The combustibility of timber is one of the main reasons why regulations strictly limit timber as a building material, especially in multi-storey structures. This investigation seeks to assess the fire behaviour of cross-laminated timber (CLT) edifices and examine the ramifications for structural integrity and fire protection. Utilising computational fluid dynamics (CFD) simulations, critical variables including charring rate, heat emission, and smoke generation were analysed across two scenarios: one featuring exposed CLT and another incorporating protected CLT. The outcomes indicated that protective layers markedly diminish charring rates and heat emission, thereby augmenting fire resistance and constraining smoke dissemination. These revelations imply that CFD-based methodologies can proficiently inform fire protection design paradigms for CLT structures, presenting potential cost efficiencies by optimising material utilisation and minimising structural impairment.

Justification of the Efficiency of Application of Plaster for Fire Protection of Concrete Structures

The problem of using concrete for building structures is to ensure their stability and durability during operation within wide limits. Therefore, the object of research was the change in the properties of concrete during a fire and its protection when applying a heat-insulating layer of plaster, which is able to inhibit the temperature when the flame affects the coating. It has been proven that in the process of thermal action on fire-resistant plaster, the process of thermal insulation of concrete consists in the application of materials with low thermal conductivity as part of the plaster on the surface of the material. Similarly, under the influence of the burner flame, a temperature was created on the surface of the sample under the influence of the burner flame with a temperature of more than 800°С for 1800 s, the temperature on the surface of the concrete under the plaster coating did not exceed 120°С, which indicates the formation of a curtain for temperature. In this regard, experimental studies were conducted and it was established that the presence of aluminosilicate microspheres in the plaster leads to the formation of a thermally protective layer on the surface of concrete resistant to mechanical vibrations. According to experimental data, the coefficient of thermal conductivity and thermal conductivity of the plaster was calculated, which is 6.22·10–7 m2/s and 0.142 W/(m∙K), respectively, due to the addition of aluminosilicate microspheres. Thus, there are reasons to assert the possibility of targeted regulation of concrete fire protection processes by using fire-resistant plaster capable of forming a protective layer on the surface of the material, which slows down the rate of heat transfer.

Facile and effective construction of superhydrophobic, multi-functional and durable coatings on steel structure

Nowadays, steel is one of the most significant materials in industry and daily life. Unfortunately, the defects of steel structures such as collapse at high temperature, poor corrosion resistance, and bad surface functionality have severely restricted their further application. Applying functional coatings for steel structures is considered the effective strategy for settling theses disadvantages. Inspired by nature, eco-friendly, superhydrophobic, and multifunctional-integrated coatings were fabricated on steel via one-step spraying strategy in this paper. Along with silicon dioxide (SiO2) nanoparticles and epoxy resin/silicone resin (EP/SR), the coatings are jointly constituted by hydrophobic flame retardants (M-ALHP@ZIF-8) prepared via multi-stage modification. Due to the formation of micro/nano-scaled rough structure with low surface energy, the water contact angle (WCA) and water sliding angle (WSA) of as-prepared coatings can reach 162.4° ± 1.2° and 2.8° ± 0.4°. The water repellency with low water adhesion can endow the surface of steel with excellent self-cleaning, anti-fouling, and long-lasting anti-corrosion ability. Additionally, the superhydrophobic coatings have displayed good mechanical robustness, chemical stability and weather resistance, which can exhibit certain actual values. Accorded with Zn-catalyzed charring effect of flame retardants, as-prepared coatings have possessed outstanding fire protection capacity with the lowest backside temperature of 181 °C after 1 h fire impact tests. Consequently, this work has provided a facile and effective route for synchronously tackling the key challenges of poor fire protection and surface functionality for steel structures, which will be expected to pave the wide pathway for constructing multifunctional coatings in more fields.

Fire Resistance Performance of Constrained H-Shaped Steel Columns with Uneven Vertical Temperature Distributions

Steel columns, which are widely used in building frameworks and spatial structures, are susceptible to capacity degradation during fires, potentially leading to the overall collapse of buildings. Existing research on the fire resistance of steel columns assumes that the temperature loads encountered by steel columns are evenly distributed vertically. However, real-world fire scenarios often feature significant vertical temperature differences. Therefore, this study comprehensively investigated these variations to derive a temperature curve that accurately represents real fire conditions. Subsequently, the fire resistance limits of steel columns were studied using this temperature curve, leading to a revised calculation formula for the critical fire resistance temperatures of steel columns. The following conclusions were drawn: (1) Nonuniform longitudinal temperature distributions are influenced by parameters such as the fire source distance, the heights of ventilation openings, and the distance between a vent and the temperature measurement point. Among them, the fire source distance has the greatest impact, with the maximum longitudinal temperature difference reaching over 500 °C. (2) Variations in the load ratio and longitudinal temperature differences alter the failure positions of steel columns, reducing their critical temperatures by up to 200 °C. (3) The revised critical fire resistance temperature formula is more accurate and safer compared with that outlined in the “Technical Code for Fire Protection of Steel Structures” (GB51249-2017). These findings offer valuable insights for the fire designs of steel columns.

The Effect of Expanded Vermiculite on the Fire Resistance of Waterborne Acrylic Coatings.

Due to their ability to prevent or slow the spread of fires, fire-retardant coatings are utilized as the main means of fire protection for steel structures, combining easy application and high economic efficiency. This study investigates the effects of the particle size and dosage of expanded vermiculite (EV) on the fire resistance and application performance of coatings. Ammonium polyphosphate, melamine, and pentaerythritol were used as intumescent fire-retardant systems, along with waterborne hydroxyl-modified acrylic resins as the film-forming substances. The properties of fire resistance coatings were tested via scanning electron microscope (SEM), X-ray diffractometry (XRD), thermogravimetric analysis (TGA), limiting oxygen index (LOI), and cone calorimetry. The excellent fire performance of the coatings with 3 wt.% 300-mesh EV was proven, exhibiting a relative expansion of 30.43 times. Moreover, the surface structure of the charcoal layer was dense. The total smoke production (TSP) and smoke concentration (TSR) were only 0.18 m2 and 0.25 m2/m2.

ИОННОХРОМАТОГРАФИЧЕСКОЕ ИССЛЕДОВАНИЕ ОГНЕЗАЩИТНЫХ ВСПУЧИВАЮЩИХСЯ ПОКРЫТИЙ В ЭКСПЕРТИЗЕ ПОЖАРОВ

Fire protection of structures, as well as increasing the fire resistance of metal structures is an important task in reducing losses from fires. One common way to improve the fire resistance of a structure is to apply an intumescent flame retardant coating to the structure. Currently, expert practice has more often raised questions about establishing the presence or absence of fire protection on structures. The article considers the possibility of using the method of ion chromatography in order to determine the presence of fire-retardant components in the coating and determine the composition of the fire-retardant coating. The study was conducted on three flame retardant intumescent coatings with different binders. Two sample preparation methods were selected for the study: the study of directly aqueous solutions of intumescent coatings and the study of aqueous solutions of gases released during thermal destruction of coatings. Chromatograms of aqueous solutions of the tested coatings are given, indicating the presence of ions of fire-retardant components formed during hydrolysis. The results of the study showed that both methods have both advantages and disadvantages and can be used in preparation for analysis by ion chromatography to study flame retardant intumescent coatings.

FEATURES OF FIRE PROTECTION TREATMENT OF LOAD-BEARING BUILDING STRUCTURES

The article emphasizes that wood is a flammable material, flames spread quickly, which poses a threat to building structures. Therefore, it must be protected by effective means of fire protection. Regulatory and technical documentation is presented, which establishes requirements for the quality of fire protection of wooden structures. Using the example of state reserve enterprises, it is shown that there are many methods of fire-resistant treatment of wooden structures with flame retardants. Among them are the impregnation of wood with inorganic salts and the application of coatings on an organic basis. These include impregnation of wood with inorganic salts and application of coatings on an organic basis. It is shown that the specified methods of processing have disadvantages during application and operation, which include the moistening of wood under the influence of external natural factors, which leads to the dissolution and leaching of salts, increased smoke formation, and the formation of toxic combustion products. The constituent parts of the intumescent coating are proposed and their effectiveness in relation to fire protection of wood is determined. Depending on the content of PVA-dispersion, a change in the coefficient of swelling was determined, which is in the range from 14.3 to 25.1. Thus, it was determined that when mineral fillers are added to the composition of the organo-mineral composition in the amount of 10%, it helps to increase the coefficient of swelling from 30 to 36.7, which is 1.5...1.84 times greater than the value of the coefficient of swelling of the optimal composition of the organo-mineral composition without fillers. The article presents research on the creation of fire-resistant intumescent coatings capable of providing a wide range of fire-resistant and operational properties. After testing samples treated with an intumescent coating, under the action of a burner flame, a sample weight loss of no more than 6% was obtained, and the temperature of flue gases did not exceed 184ºС, which refers the treated wood to the group of non-combustible materials. Thus, the intumescent coating provides the first group of fire protection efficiency. Keywords: building structures, fire-resistant treatment, state reserve enterprises, intumescent coatings, fire-resistant properties, efficiency.

Воздействие криогенных сред и струйного горения на эпоксидные интумесцентные композиции, предназначенные для защиты оборудования и строительных конструкций нефтегазового комплекса

The article discusses the studies of epoxy intumescent fire-protective coating of steel structures impacted by cryogenic media and jet fire, in accordance with the requirements of the methodology developed at the Orenburg branch of the Federal State Autonomous Educational Institution of Higher Education VNIIPO EMERCOM of Russia, and harmonized with the international standards ISO 22899-1:2021, ISO 20088-1:2016, and ISO 20088-3. The tests have been conducted with the epoxy fire- and cryogenic-protective intumescent composition «Plamkor-5» (produced by JSC Scientific and Production Holding «VMP», Yekaterinburg, Russia). According to the results of the test for resistance of a square-shaped sample with internal dimensions 1500×1500×500 mm and a central shelf made of 10 mm thick carbon steel coated with the fire-retardant composition «Plamkor-5» to cryogenic fluid spill, it has been established that the sample does not reach the critical temperature of minus 49 °C with an actual 22.37 mm dry layer thickness. The average sample temperature at the 60th minute of the test was minus 32.09 °C. The results of the test of a similar sample in order to determine the resistance of the fire-protective composition «Plamkor-5» to a jet fire with an actual 10,89 mm thickness of the protective dry layer have shown that the sample does not reach the critical temperature of 500 °С during 60-minute fire exposure, whereas the average temperature of the sample was only 37 % (184.84 ºС) of the temperature limit value. According to the results of the test for resistance of a steel column shape sample of I-section 25K2 coated with the fire-retardant composition «Plamkor-5» to spill under the pressure of the cryogenic liquid, it has been established that the sample does not reach the critical temperature of minus –49 °С with an actual 23.78 mm dry layer thickness, whereas the average temperature of the sample at the 60th minute of test was minus 48.38 °С. The obtained results are comparable with the effect of the best import analogs; therefore, «Plamkor-5»-based fire-protective coatings can be used for the design and development of fire protection of building structures, at the facilities of the oil and gas industry, in tunnel structures, and civil engineering.

Recent Progress in Two-Dimensional Nanomaterials for Flame Retardance and Fire-Warning Applications.

Graphene-like 2D nanomaterials, such as graphene, MXene, molybdenum disulfide, and boron nitride, present a promising avenue for eco-friendly flame retardants. Their inherent characteristics, including metal-like conductivity, high specific surface area, electron transport capacity, and solution processability, make them highly suitable for applications in both structural fire protection and fire alarm systems. This review offers an up-to-date exploration of advancements in flame retardant composites, utilizing pristine graphene-like nanosheets, versatile graphene-like nanosheets with multiple functions, and collaborative systems based on these nanomaterials. Moreover, graphene-like 2D nanomaterials exhibit considerable potential in the development of early fire alarm systems, enabling timely warnings. This review provides an overview of flame-retarding and fire-warning mechanisms, diverse multifunctional nanocomposites, and the evolving trends in the development of fire alarm systems anchored in graphene-like 2D nanomaterials and their derivatives. Ultimately, the existing challenges and prospective directions for the utilization of graphene-like 2D nanomaterials in flame retardant and fire-warning applications are put forward.

Study on the influence of slope on smoke overflow and temperature characteristics of carriages with lateral openings in subway fires

This research explores the impact of slope on fire hazards in train carriages with multiple lateral openings in underground tunnel fires. Utilizing FDS software, a comprehensive full-scale fire scenario is simulated to study smoke overflow and temperature distribution in inclined tunnels with slopes ranging from 0 % to 4 % and Heat Release Rates (1 MW–10 MW) under natural ventilation. The study reveals that smoke mainly originates from the upstream end door and the door near the fire source, with smoke overflow from the upstream end door increasing significantly with the slope. Fire power has minimal impact on smoke overflow. When fire power is large, the longitudinal temperature distribution inside the carriage exhibits an overall increasing trend with increasing slope. The maximum carriage temperature decreases steadily with the slope for Q˙ ≤ 5 MW, while the slope has less influence on temperature variation for Q˙ > 5 MW. A modified prediction model is proposed to forecast maximum ceiling temperature during fire scenarios, providing valuable insights for structural fire protection, fire detection, and smoke control in metro areas. This study enhances understanding of smoke movement and temperature distribution in train carriage fires in inclined tunnels, contributing to engineering practices.

PROBLEMATIC ASPECTS OF DETERMINING FIRE PROTECTION OF WOOD

Annually, fires inflict huge losses to both business entities of various forms of ownership and the state overall. According to analytical data for nine months of 2023, 2212 fires occurred in Ukraine at objects of different forms of ownership subject to state supervision (control) in technogenic and fire safety. Many researchers confirm that fire protection of wood is an effective prophylactic measure. However, there are significant factors influencing the reduction of its efficiency directly and also factors that do not affect the efficiency of fire protection directly but provide an objective determination of the quality of fire protection. One of the factors in objectively determining the quality of fire protection is verifying the fire protection compliance. This study aims to determine the causes and patterns of improper fire protection of wooden building structures with fire-retardant solutions (lower than stated in the manufacturer’s regulations). The analysis of recent research and publications shows that the issue of verifying the compliance of fire protection of wooden structures directly after the works in Ukraine has not been studied. Many modern fire protection solutions on the Ukrainian market require improved quality control methods. The existent system of verification of the compliance of fire protection has substantial defects and does not give a possibility to define objectively the quality of fire protection. Precise terminology is absent in normative acts, the methods described for verifying fire protection are not up-to-date, and the regulatory documents for fireproof solutions, in most cases, do not contain the necessary information for quality control. Improvement of verification of the compliance of fire protection of the exploited wood is a necessity at all stages, beginning from determining correct terminology and actualisation of the Rules of fire protection to developing effective methods of verification taking into account the features of modern fireproof solutions. Keywords: fire protection of wood, fire protection compliance verification, fire protection rules, wood impregnation.

Development of test methods for fire-retardant coatings of steel engineering structures during operation

Introduction. Prediction of the durability of flame-retardant coatings of steel engineering structures and preservation of their performance during operation remain important research directions. There is a lack of normative documents in the field of fire protection, regulating the process of testing of flame-retardant coatings during operation, as well as determination of their durability (service life).Aim. To develop test methods for determining the resistance of flame-retardant coatings of steel engineering structures exposed to climatic factors, preservation of their fireproof and anti-corrosion properties during operation.Materials and methods. Test specimens included 600 x 600 x 5 mm plates made of 08kp and 08ps sheet steel according to State Standard 16523-97 and State Standard 9045-93 with a flame-retardant agent applied on the front side.Results. Methods for testing thin-layer intumescent and structural flame-retardant coatings during operation are proposed. The methodology of accelerated climatic testing of specimens coated with thin-layer intumescent flame-retardant coatings (flame-retardant paints) corresponds to State Standard 9.401-2018. These coatings are inherently high-solid paint materials. A new methodology, sequence, and modes of testing are developed for structural flame-retardant coatings. The subsequent assessment of fireproof properties of coatings and their preservation is carried out by the methods of fire protection efficiency according to State Standard R 53295-99 and the methods of thermal analysis. These methods imply comparison of the characteristics of the initial flame-retardant coating and those obtained after sample aging. The preservation of fireproof properties by thin-layer intumescent and structural coatings is additionally evaluated by the intumescence coefficient and the change in thermal conductivity, respectively.Conclusions. Test methods for flame-retardant coatings of steel engineering structures during operation are developed. Threshold levels of changes in their properties are established. After accelerated climatic tests, fire protection efficiency should not decrease by no more than 20 %. For structural fire protection, an increase in thermal conductivity by no more than 5 % is permitted. For thin-layer coatings, the arithmetic mean value of the intumescence coefficient should not decrease by no more than 30 % of the initial value.Implications. The developed methods were used in the preparation of a draft national standard of the Russian Federation “Steel engineering structures with fireproof coatings. Test methods for anticorrosion properties and resistance to climatic factors during operation” to ensure regulatory fire safety requirements for these structures.

Fire Protection of Steel Structures of Oil and Gas Facilities: Multilayer, Removable, Non-Combustible Covers

Fire protection is required to protect metal structures of oil and gas facilities from fires. Such fire protection should provide high fire resistance limits: 60, 90, 120 and more minutes. Specialists of LLC “RPC PROMIZOL ” developed a multilayer, removable type of fire protection made of superfine basalt fibre and ceramic materials for operation in Arctic conditions. Five experimental studies were carried out in standard and hydrocarbon fire regimes. The fire protection effectiveness of the products for I20 beams without load was obtained: a 50 mm thick coating provided 130 min of a standard fire regime; a 15 mm thick coating provided 60 min. The 15 mm thick coating provided 30 min of a hydrocarbon fire regime and the 50 mm thick coating provided 93 min of a hydrocarbon fire regime. The I40 beam under a load of 19.9 tf showed an R243 for the standard fire regime. The coefficients of effective thermal conductivity and specific heat capacity of fire-retardant compositions were determined by solving the inverse heat conduction problem. The problem was solved by modelling using the QuickField 7.0 software package, which implements FEM. Modelling showed that for obtaining the fire resistance limit R120 under the standard fire regime for the sample steel structure from an I40 beam, it is enough to apply fire protection with a thickness of 25 mm instead of 50 mm, which agrees with the experimental data. For the hydrocarbon regime, it is predicted that R120 can be obtained at a thickness of 45 mm instead of 50 mm.

ДОСЛІДЖЕННЯ ВОГНЕСТІЙКОСТІ ПОКРИТТЯ РЕАКТИВНОГО ТИПУ В УМОВАХ ВУГЛЕВОДНЕВОЇ ПОЖЕЖІ

The purpose of the study is to compare the efficiency of reactive fire protection coatings in modelling scenarios of standard and hydrocarbon fires. Methodology. Fire tests were carried out in a small-scale furnace, as regulated by DSTU EN 16623:2015. The linear coefficient of swelling K was determined in accordance with DSTU-N P B V.1.1-29:2010, and the strength of the char layer was measured using a ST-2 structurometer. The chemical structure of the thermolysis products of the fireproof coatings was studied by IR spectroscopy. Results. The study proposes an experimental protocol for assessing the strength of swollen coatings on steel plates under the influence of a standard and hydrocarbon fire. The evaluation method is based on monitoring the physical integrity and mechanical stability of the char-insulating layer formed from the reactive coating under high temperatures. It has been found that the reactive-type coating under the influence of a standard and hydrocarbon fire forms heat-protective char layers, the degree of swelling, mechanical strength and adhesion of which to the metal plate are proportional and differ on average by up to 10 %. It has been concluded that the studied coating Ammokote MW-120 can be used for fire protection of steel structures operated under potential conditions of hydrocarbon fire. Scientific novelty. The study proposes a simple and reliable method for assessing the possibility of using reactive-type coatings for fire protection of metal structures intended for use and certified for standard fire conditions in hydrocarbon fires. Pactical significance is to expand the scope of application of Ammokote MW-120 coating for fire protection of steel structures under the influence of standard and hydrocarbon fires. Keywords: fire protection of steel structures, hydrocarbon fire, intumescent coating, swelling coefficient.

Fire protection of steel structures

Fire protection of steel structures

Reliability-based Fire Protection of Structural Cables due to Deck Fires on Cable Supported Bridges

Cable supported bridges are typically part of community-critical infrastructure and therefore the consequences arising from extensive structural damage due to a fire and the subsequent operational discontinuity could be significant beyond the damage to the bridge itself and the cost of repairs. Bridge design standards generally do not provide guidance and hence fire resistance requirements are often informed by first principles assessments of the thermal and structural response of the structure to proposed fire scenarios. A deterministic assessment can provide a reasonable worst-case scenario but it does not allow bridge stakeholders to make informed decisions with regards to uncertainty and the low likelihood of fires occurring to identify the benefits of investments in structural fire protection. This is because the target reliability required for each bridge may be different depending on its characteristics, and the expected fire severity has a probabilistic nature. This research aims to fill this gap by undertaking a reliability-based analysis to assess the probability of structural failure by considering the probability of a fire of a given size occurring and the uncertainty in the incident location and wind. The methodology is demonstrated through the case study of an operational 450 m long cable supported bridge section and a fire scenario based on a liquid fuel tanker. Liquid tankers can result into two type of fire scenario: first, a fire being contained within the tanker; and secondly, a fire due to a pool on the deck. Both fire scenarios have been characterised and it was determined that the contained tanker scenario presents a more onerous design case owing to its more prolonged duration. A Monte Carlo analysis was undertaken for a total of 10,000 independent trials of the combination of the location of the fire and the wind direction. The frequency of the fire was also examined to establish the probability of structural failure of a cable. It was established that the inclusion of wind can sometimes reduce the estimated height at which cables may experience temperatures with the potential to cause cable failure. However, for a number of the cases, the estimated height can remain broadly similar (i.e. within a couple metres difference) to the worst-case calculated value. Based on this analysis, the influence of the required level of reliability as well the fire protection duration specification agreed with bridge stakeholders can be used to determine the height at which cable fire protection is necessary to reduce the probability of structural failure to a level acceptable to the stakeholders. This approach allows bridge designers and stakeholders to make informed decisions with regards to provision and extent of fire preventive/protective measures for cable supported bridges.

THERMAL DECOMPOSITION OF MONO- AND DIETHANOLAMINEBORATE MODIFIED WOOD IN AIR ATMOSPHERE

"For cellulosic materials used in various branches of the economy, the issue of increasing thermal stability is still relevant today. Especially acute is the problem of fire resistance for wood materials used in building structures. In our work, we investigated the effect of mono- and diethanolamine borates on the thermal decomposition of wood in an air atmosphere. It has been previously found that mono- and diethanolaminoborates, when used as surface modifiers, provide 100% biostability to plant raw materials. In this regard, the purpose of the study was to identify the flame retardant effect of the described modifiers. In the course of the study, it was found that the developed compositions, the main components of which are boron-nitrogen compounds, effectively reduce the combustibility of wood materials, suppress smoldering, and reduce the burning rate of wood. Since it is the smoldering of wood after the liquidation of the fire that is the main cause of structural collapse, which prevents evacuation during the fire, the use of the developed compositions for fire protection of wooden structures is extremely appropriate. A regression model of the dependence of activation energy on conversion has been obtained and substantiated on the basis of correlation and regression analysis. The presented semi-logarithmic model can be further applied to predict the dependence of the activation energy value of the thermal decomposition process of modified wood on the degree of conversion."

Assessment of compatibility of metal fire-proof compositions with primer coatings to maximize effectiveness of flame retardants

Introduction. The present paper considers the issues of work planning for fire protection of steel structures, including the correct selection of primer coating in order to avoid potential problems, to save time and budget, as well as to ensure long-term durability of the structures due to the applied fire protection coating. The compatibility of materials appears to be essential when creating projects and coating technology to maximize the effectiveness of fire-proof materials.Aim. To establish the relevant requirements for the scope and sequence of work in assessing the compatibility of fire-proof compositions with the applied primer of steel structures.Materials and methods. The compatibility of flame retardants with primers was assessed using certified and verified laboratory equipment. The paper describes a modern laboratory facility for testing.Results. The results of testing compatibility of flame retardants with primers are presented. The coating system should be evaluated for the defects, its criticality in the subsequent operation, the degree of coating interlayer adhesion, and the ability of the coating to resist adverse environmental effects. Following the obtained information, recommendations are given on the compatibility of certain coating materials.Conclusion. The study demonstrated the significance of material compatibility when creating projects and coating application technology to ensure maximum effectiveness of flame retardants and to tackle the crucial task — providing long-term fire resistance of structures.

Application of hybrid cement in passive fire protection of steel structures

PurposeThe aim of this paper is to determine the thermal conductivity of a protective layer of alkali-activated cement and the possibility of performing fire protection with fireclay sand and Lightweight mortar. Unprotected steel structures have generally low fire resistance and require surface protection. The design of passive protection of a steel element must consider the service life of the structure and the possible need to replace the fire protection layer. Currently, conventional passive protection options include intumescent coatings, which are subject to frequent inspection and renewal, gypsum and cement-based fire coatings and gypsum and cement board fire protection.Design/methodology/approachAlkali-activated cements provide an alternative to traditional Portland clinker-based materials for specific areas. This paper presents the properties of hybrid cement, its manufacturability for conventional mortars and the development of passive fire protection. Fire experiments were conducted with mortar with alkali-activated and fireclay sand and lightweight mortar with alkali-activated cement and expanded perlite. Fire experiment FE modelling.FindingsThe temperatures of the protected steel and the formation of cracks in the protective layer were investigated. Based on the experiments, the thermal conductivities of the two protective layers were determined. Conclusions are presented on the applicability of alkaline-activated cement mortars and the possibilities of applicability for the protection of steel structures. The functionality of the passive fire layer was confirmed and the strengths of the mortar used were determined. The use of alkali-activated cements was shown to be a suitable option for sustainable passive fire protection of steel structures.Originality/valueEco-friendly fire protection based on hybrid alkali-activated cement of steel members.

Специфика пассивной противопожарной защиты для атомных электрических станций

Passive fire protection systems (elements) are the most preferred for use to ensure nuclear and radiation safety of the nuclear power plants in case of internal and external fires. The main passive fire protection systems (elements) of the nuclear power plants include: fire-resistant structures (walls, ceilings, columns, screens, etc.); fire-resistant sealing of penetrations (technological, electrical, ventilation, etc.); fire-resistant filling of openings in fire barriers (doors, gates, dampers, airlocks, etc.); structural fire protection; fire-resistant coatings; devices for emergency draining and self-extinguishing of flammable liquids. Among them, it is possible to distinguish both systems (elements) that perform the function only of fire protection (for example, fire-resistant coatings, fire dampers for ventilation systems), and the systems (elements) that perform other basic functions that also require fire protection (for example, building structures, sealed doors). Passive systems (elements) may simultaneously be subject to the requirements for protection against fire, other internal and external influences (flooding, flying objects, explosions, etc.), as well as the operational requirements specific to the nuclear power plants (resistance to radiation-ionizing radiation, decontaminating compositions, vibrations, high temperatures, etc.). Due to the complex nature of the requirements, a certain imperfection of the regulatory framework and processes for organizing design and construction in the nuclear industry, there is a certain shortage of products for the implementation of passive fire protection solutions that meet the necessary requirements. To solve the above problems in the field of passive fire protection of the nuclear power plants, it seems appropriate to organize work in the following areas: conducting research based on the Russian and international experience; development of the regulatory framework; improvement of the design and construction processes. The work in these areas could contribute to the early saturation of the Russian market with domestic products of passive fire protection, as a result, increase the level of safety and economic efficiency of the nuclear power plants.