Standard Fire Conditions Research Articles

Experimental investigation into the effect of transparent fireproof coatings on charring behavior of glued laminated timber exposed to fire

As timber structures evolve towards greater heights and longer spans for buildings, there is a pressing need to enhance the fire resistance of timber structures. Considering the charring behavior of timber is crucial to the fire resistance of timber structures, it is a promising way to retard the charring behavior of timber and further enhance the fire resistance by applying transparent fireproof coatings. In this study, a series of fire tests were conducted to investigate the effect of transparent fireproof coatings on the charring behavior of Douglas fir glued laminated timber (Glulam) under small-scale ISO 834 standard fire conditions. Different coating types, coating quantities, exposed time to fire and member sizes were considered in the experiments. The experimental results including temperature profiles, maximum temperature, and charring rates for uncoated and coated Glulam specimens were carefully recorded and analyzed. Then, the effect of transparent fireproof coatings was quantified by the proposed ratio of delayed charring. The main mechanism of the delayed charring in fire was finally discussed. This study demonstrated that two transparent fireproof coatings can both effectively lower the temperature at different depths and delay the charring behavior of timber. The reduction in charring rates increased with the increase of coating quantity and decreased as the fire exposure time progressed. The ratio of delayed charring for two coatings can be over 30% in the initial stage of fire and over 20% for one-hour standard fire exposure. This study can provide technical support for enhancing the fire resistance of timber structures using transparent coatings.

Post-fire bond-slip performance of concrete-filled stainless steel tube columns

Concrete-filled stainless steel tube (CFSST) structures exhibit superior strength, durability, and fire resistance. These attributes, coupled with their aesthetic appeal and corrosion resistance, make them highly suitable for a broad range of civil engineering applications, ensuring long-term performance and safety across diverse environments. This study investigates the post-fire bond-slip performance of CFSST structures to facilitate the strengthening and retrofitting of fire-damaged CFSST structures. The paper reviews the bond-slip performance and fire resistance of CFSST. A series of fire tests and push-out tests were conducted on 99 circular CFSST stub columns, considering variables such as fire duration, wall thickness of the stainless steel tube, and concrete strength. The analysis covers the slip mechanism, load-slip relationship, sliding load, ultimate displacement, and ultimate bond strength of specimens post-fire. The bonding force between interfaces transitions from cementation to mechanical interlock and ultimately to friction, with some overlap among these mechanisms. A positive correlation exists between sliding load and wall thickness when fire duration is short. For shorter fire durations, fire exposure reduces the ultimate displacement while increasing bond-slip stiffness. Finally, a formula is proposed to predict the ultimate bond strength of CFSST stub columns following exposure to ISO 834 standard fire conditions.

FRP strip wraps for enhancing the fire resistance of RC beams strengthened with CFRP sheets bonded using the EBROG method: An experimental study

In recent decades, the application of fiber-reinforced polymers (FRP) composites in strengthening structural members has increased due to their low weight, high strength, and easy implementation. However, one of the main weaknesses of these materials is that as the temperature rises, the resin resistance and, consequently, the bond strength between the FRP and concrete member rapidly diminish. This causes the FRP to separate from the concrete substrate and prematurely fail the member. Therefore, previous studies have widely suggested fire protection materials to mitigate this weakness. However, it increases costs and exacerbates architectural problems. To eliminate the need for fire protection systems or reduce their thickness, this paper evaluates the combined effect of using FRP mechanical anchors and utilizing the EBROG Grooving method on reinforced concrete beams for flexural strengthening FRP. A total of six rectangular control beams were tested under flexural loads at ambient temperature, and four beams were examined under simultaneous flexural loading and fire conditions. The proposed anchorage system included two-layer wrapped CFRP strips along the beam axis at specified intervals and fan anchorage with holes with 120 mm spacing. To assess the effectiveness of the proposed anchorage systems and determine the maximum capacity of the beams, they were first examined at ambient temperatures. The results showed that under standard fire conditions, due to the formation of a tangential cable mechanism, RC beams strengthened with one and two layers of flexural CFRP and anchored with two-layer wrapped CFRP strips withstood constant loads of 7,85 KN and 9.8 KN for 77 and 66 min, respectively. Also, the RC beam resisted fire for up to 106 min under the applied load.

Numerical analysis of fire-exposed reinforced concrete sections for assessing post-heating axial and flexural capacity

PurposeThis study investigates the impact of the fire decay phase on structural damage using the sectional analysis method. The primary objective of this work is to forecast the non-dimensional capacity parameters for the axial and flexural load-carrying capacity of reinforced concrete (RC) sections for heating and the subsequent post-heating phase (decay phase) of the fire.Design/methodology/approachThe sectional analysis method is used to determine the moment and axial capacities. The findings of sectional analysis and heat transfer for the heating stage are initially validated, and the analysis subsequently proceeds to determine the load capacity during the fire’s heating and decay phases by appropriately incorporating non-dimensional sectional and material parameters. The numerical analysis includes four fire curves with different cooling rates and steel percentages.FindingsThe study’s findings indicate that the rate at which the cooling process occurs after undergoing heating substantially impacts the axial and flexural capacity. The maximum degradation in axial and flexural capacity occurred in the range of 15–20% for cooling rates of 3 °C/min and 5 °C/min as compared to the capacity obtained at 120 min of heating for all steel percentages. As the fire cooling rate reduced to 1 °C/min, the highest deterioration in axial and flexural capacity reached 48–50% and 42–46%, respectively, in the post-heating stage.Research limitations/implicationsThe established non-dimensional parameters for axial and flexural capacity are limited to the analysed section in the study owing to the thermal profile, however, this can be modified depending on the section geometry and fire scenario.Practical implicationsThe study primarily focusses on the degradation of axial and flexural capacity at various time intervals during the entire fire exposure, including heating and cooling. The findings obtained showed that following the completion of the fire’s heating phase, the structural capacity continued to decrease over the subsequent post-heating period. It is recommended that structural members' fire resistance designs encompass both the heating and cooling phases of a fire. Since the capacity degradation varies with fire duration, the conventional method is inadequate to design the load capacity for appropriate fire safety. Therefore, it is essential to adopt a performance-based approach while designing structural elements' capacity for the desired fire resistance rating. The proposed technique of using non-dimensional parameters will effectively support predicting the load capacity for required fire resistance.Originality/valueThe fire-resistant requirements for reinforced concrete structures are generally established based on standard fire exposure conditions, which account for the fire growth phase. However, it is important to note that concrete structures can experience internal damage over time during the decay phase of fires, which can be quantitatively determined using the proposed non-dimensional parameter approach.

Fire Tests of Load-Bearing, Light-Steel-Framed Wall Systems Insulated with Polyurethane Foam

This paper presents the details of three fire tests conducted on light-steel-framed (LSF), load-bearing wall systems, which consist of polyurethane insulation injected into the cavities of the steel frame between two or three layers of gypsum fibreboard. To investigate the thermal and structural performance limits under standard fire conditions, observations were made during the tests, and temperatures and vertical displacements were recorded. Although combustible insulation was used, the results obtained are promising for the application of studied LSF wall systems in buildings, where fire resistance of more than 60 min is required.

Обоснование безопасного расстояния между размещенными в одной пожарной зоне кабелями каналов безопасности атомных электростанций с водо-водяными реакторами

Currently, there are no methods of mathematical modeling of the operability of power and signal cables used at the nuclear power plants in real and standard fire conditions, including the use of intumescent flame retardants. The purpose of the article is a theoretical assessment of the safe distance between the cables of the safety channels of nuclear power plants with pressurized water reactors located in the same fire zone. To achieve it, the time of occurrence of a short circuit in the cables of the channels of safety systems from the beginning of a real fire and depending on the distance between adjacent cable lines was estimated. An integral method of mathematical modeling of the development of a fire in a room is used. To determine the temperature distribution inside the cable insulation, the thermal conductivity equation is solved. The analysis of the obtained results is carried out. The calculation results made it possible to formulate the requirements for the swelling temperature of fire retardant compounds for treating the outer surfaces of SB cables: the above temperature should be no more than 150 °C for the flame retardant cables, and 180 °C for the non-flame retardant cables, as well as at distances between open cables of two safety systems smaller than 2, the outer surfaces of the safety cables must be treated with a fire retardant compound with a fire retardant efficiency of at least 120 minutes. The conducted theoretical assessment of the safe distance between the cables of the safety channels of nuclear power plants with pressurized water reactors located in the same fire zone, using the proposed mathematical model, showed that in a real fire, in order to prevent a short circuit in the cables of the safety systems, as well as ignition of the insulation of adjacent cables, it is required to justify safe distances between the adjacent cables of the safety system of nuclear power plants, taking into account the specific dimensions of the premises and the properties of the cable insulation material and the fire-retardant coatings used.

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 resistance of axially loaded semi-precast composite columns

Recently, semi-precast composite (SPC) columns have been newly developed using steel angles and internal molds. Although the manufacturability, constructability, and seismic performance of SPC columns have been proven to meet design requirements, their structural responses under fire conditions (or fire resistance) have not yet been reasonably examined. Thus, in the present study, an experimental study was conducted for five full-scale SPC columns under standard fire conditions. The test parameters included the joint detail, axial load ratio, thickness of the precast section, and slenderness ratio. The test results show that the fire resistance rating was relatively low due to the high moisture contents and relatively high axial load ratio, and concrete spalling controlled the fire resistance of the columns. The concrete spalling was affected by the concrete moisture contents and permeability, the consequent moisture clog phenomenon, the relatively high axial load ratio, and the longitudinal weak planes between the concrete cover and confined concrete created by longitudinal and transverse bars. Addressing these effects, a finite element analysis (FEA) model was developed for SPC columns using ABAQUS. Although there were some discrepancies between the test and analysis results, the FEA model gave a conservative prediction, which is reasonable for design purpose considering the complexity of nonlinear thermal-stress analysis.

Effect of Fireproof Coatings on the Post-Fire Behavior of CFRP Composite Sheets

This study examines the effect of two self-developed novel fireproof coatings on the fire resistance of carbon fiber-reinforced polymer (CFRP) composite sheets. The post-fire flexural properties were chosen as important indicators of fire resistance. This research involves two distinct fire conditions, the standard fire condition and the large-space fire condition, to simulate general interior fires and large-space fires. The post-fire flexural performance of CFRP sheets coated with two different self-developed fireproof coatings was evaluated through three-point bending tests after fire exposure. The experimental findings demonstrated a significant reduction of up to 80% in the post-fire flexural properties of CFRP sheets without fireproof coatings. However, CFRP sheets coated with fireproof coatings exhibited a substantial enhancement in their post-fire flexural properties. Under the large-space fire condition, the fire-resistance duration of CFRP sheets coated with fireproof coatings of at least 25 mm thickness exceeded 2 h, satisfying the requirements of GB50016-2014 fire-resistance class III (columns), class I (beams), and class I (floor slabs), respectively. Under the standard fire condition, CFRP sheets covered by fireproof coatings of 35 mm thickness exhibited a fire-resistance duration of 0.75 h, meeting the requirements of GB50016-2014 fire-resistance class IV (columns), class IV (beams), and class III (floor slabs), respectively.

Fire Performance of Steel-Timber Hybrid Beam Section

Slim-floor-type of steel-timber hybrid floor systems which use steel beams contained within the depth of the cross-laminated timber (CLT) floor slab offer many benefits, but there is still very little research available on the fire resistance performance of these systems. In the study presented in this paper two furnace tests and numerical simulations have been conducted to investigate the thermal profiles of the steel member and CLT slabs and to obtain information on the temperature development and charring of the hybrid beam section when it is exposed to standard fire conditions. Also, the effects of intumescent fire protection on temperatures and charring performance were investigated. Numerical 2D thermal simulations for unprotected and protected cases were conducted using SAFIR software, and the agreement between experiments and numerical-analysis predictions were in general very good. The results show that intumescent protection reduces the temperatures of the steel and CLT components as well as charring depth significantly, and the start of charring at CLT slab support may be delayed if intumescent paint protection thicker than that required for the load bearing steel member is used. The result also showed that CLT temperatures exceed 100°C already in the early stages of the fire which decrease the strength and stiffness properties of CLT much before the start of charring. Therefore, the fire design of the CLT slab support should not only consider the char depth and residual cross-section analysis but also the reduction in strength.

Review of the charring rates of different timber species

AbstractDuring a fire, the load‐carrying cross section of timber members will reduce due to charring. This article summarizes experimental investigations into the charring rate of different timber species under standard fire conditions, identifies material properties that contribute to the variations of char rates across the different species, and evaluates the applicability of prescribed charring rates to solid timber, cross‐laminated timber (CLT), and glulam exposed to standard fires. Data from the literature showed that density had the greatest impact on charring rate. The charring rate of timber decreased with increasing density, particularly timber densities >700 kg/m3. Prescribed charring rates from current design standards provide reasonable estimates of the average charring rate of timber with densities <700 kg/m3 exposed to standard fire curves. A linear charring rate of 0.65 mm/min was found to be suitable for CLT and glulam exposed to a standard fire for up to 180 min if the CLT did not experience char fall‐off. The National Design Specification nonlinear charring model may underestimate the char depth of glulam exposed to standard fire curves for longer than 60 min; however, the percent underestimation was small and limited data was available. The review demonstrated the need for data on the char depths of glulam and CLT exposed to standard fire curves for longer than 60 min and particularly for longer than 120 min.

Numerical model of heat transfer for protected steel beam with cavity under ISO 834 standard fire

The temperature distribution of a member is an essential factor in determining the structural behavior at high temperatures. This paper presents a methodology for predicting the temperature distribution of a steel beam with a membrane enclosure type of protection under the ISO 834 standard fire conditions using an Abaqus finite element model. In this research, to enhance the reliability of the Abaqus simulation model, the Fire Dynamic Simulator (FDS) was used to simulate the convection process within the cavity between the protection cover and the steel beam. Thermal properties of steel and protection cover were adopted from Eurocode 3 and manufacturer's datasheets. The effects of damage to the fire protection cover on the beam at elevated temperatures were also discussed. It was found that using Abaqus in conjunction with FDS to consider the convective heat transfer within the cavity would predict the steel beam temperature more accurately than without considering the convective heat transfer.

The Behavior of Passive Fire Protection Materials Used for Fire Protection of Steel Structures in Standard, Hydrocarbon, and Jet Fire Exposure

Structural steel, when exposed to fire, loses its tensile strength and ability to resist deformation. Both organic and inorganic material-based passive fire protection systems, are being traditionally used to protect steel structures in such scenarios. This study focused on comparing the performance of the same organic and inorganic coatings in standard fire, hydrocarbon fire, and jet fire conditions. Standard, hydrocarbon fire, and jet fire experiments were carried out in full-scale fire resistance furnaces as per ASTM E-119, UL 1709, and ISO 22899-1 respectively. From the results, it was observed that both organic and inorganic materials tend to underperform in jet fire scenarios, when compared with standard and hydrocarbon fire due to the impingement/turbulence effect and the thermo-mechanical effect caused by the velocity of the gas.

Modelling charring of timber exposed to natural fire

Charring of timber structural elements in fire is one of the most fundamental phenomena that affect the fire resistance of these elements. For an accurate and safe design of structural fire resistance, it is important to consider charring of timber in natural fire exposures, since determining charring for standard fire exposure, which is a common practice, is outdated and in some cases unsafe, due to the fact that some natural fires can be much more severe. Currently, the prescriptive approach and simplified design methods fail to give information about charring of timber elements exposed to natural fire and thus, a performance-based design is needed. Therefore, this paper presents an upgrade and extension of a recently developed heat-mass-pyrolysis model named PYCIF. Originally, PYCIF model was developed only for standard fire conditions. In the present paper, several studies and analyses are performed to extend model application to natural fire conditions. Firstly, the sensitivity study is performed, where the impact of model parameters on the charring development is investigated. It is discovered, that the kinetic parameters for the reaction rate of the active cellulose production, namely activation energy E1 and pre-exponential factor A1, are the most influential. In the next analyses the model calibration for small-scale cone calorimeter tests and large-scale natural fire tests of cross-laminated timber (CLT) floor system is performed. A robust nature of the model is identified since minor parameter calibration is required for an accurate prediction of the charring depth and temperatures in timber elements exposed to various fire conditions. Furthermore, a strong connection between the heating rate of fire and kinetic parameters is discovered. In cases of faster heating rate, the kinetic parameters govern slower reaction rate of active cellulose.

Experimental research on fire performance of U-shaped steel-concrete composite beam under uniformly distributed loading

Four U-shaped steel-concrete composite beams with channel connectors (CUSCBs) were designed and tested under the uniformly distributed vertical load and ISO-834 standard fire condition. The sectional temperature distribution, mid-span deformation development, fire resistance, and failure modes of each CUSCB under fire were investigated. The test results reveal the following facts: (1) All specimens fail flexurally; (2) The interface between the concrete flange and the U-shaped steel web remain intact and no local buckling occurs in U-shaped steel; (3) The concrete temperature decreases from the fired surface to the non-fired surface gradually; and (4) The temperature of the concrete at the corner between the lower flange and the web of U-shaped steel is higher than the concrete within the beam. Moreover, the fire resistance increases with the increase of fire protection layer thickness; and the bottom reinforcement in U-shaped steel can improve the fire resistance. The fire behavior of CUSCBs was also analyzed using the finite element program ABAQUS and the simulated temperature distributions and fire resistances were found to be in good agreement with the test results. Furthermore, the parametric analysis results show that the thickness of fire protection layer, the diameter of bottom reinforcement, the load ratio, and the thickness of U-shaped steel have significant impact on the fire resistance, while the section size and material strength have little impact. Lastly, design suggestions for the fire resistance design of CUSCBs are proposed.

Operability evaluation of electrical wires and cables subjected to simultaneous fire and current loadings

Introduction. Intumescent coatings are used as a means of protection from heat flows, and their mission is to preserve the operability of wires and cables under fire conditions coupled with simultaneous current loading. However, the effect of insulation destruction on the operability of cables has not been studied for the case of a real fire regime.Goals and objectives. The purpose of the article is to evaluate the experimental operability of electrical wires and cables subjected to simultaneous effects of fire and current loadings.To achieve this purpose, an experimental testing unit was applied to conduct the experimental testing of wires and cables manufactured by various producers. At the same time, the temperature effect of the heated environment on electrical parameters of wires and cables, such as resistivity, inductance and capacitance, was evaluated.Theoretical background. In real fire conditions, dependence of indoor temperature, affecting the heating of cable insulation, differs essentially from the same dependencies in cases of various standard fire conditions. Therefore, the insulation destruction process may occur before the coating intumescence starts.Results and discussion. An experimental testing unit has been developed. This unit allows for the gradual cable heating with a pre-set temperature measurement interval and cable electrical characteristics. Dependencies of resistivity, inductance and capacitance of standard electrical cables on the temperature of the air surrounding the cable are obtained. It’s been discovered that the gradual heating of an electrical conductor or cable eventually leads to a short circuit between its conductive cores and further electric current transmission in electrical wires and cables. It is shown that phases and amplitudes of an input electrical signal can drastically change before the short circuit.Сonclusions. The simultaneous effect of fire and current loadings on standard electrical wires and cables causes a short circuit in the temperature range, in which no intumescence of flame retardant coatings is initiated on the insulation surface. Therefore, these coatings can ineffectively maintain the operability of electrical wires and cables.

ОГНЕСТОЙКОСТЬ СТАЛЬНЫХ БАЛОК СТРОИТЕЛЬНОГО НАЗНАЧЕНИЯ

Приведены экспериментальные и численные исследования несущей способности стальных балок из сталей классов С255 и С355 при воздействии стандартного температурного режима пожара. Цель исследования - уточнение метода расчета предела огнестойкости изгибаемых стальных балок с учетом неравномерного распределения температуры в поперечном сечении, что позволит повысить точность расчетов и безопасность таких конструкций в практике строительства. The disadvantage of calculation and analytical methods for determining the fire resistance limits of building metal structures is the lack of practical information on the features of changes in the strength characteristics of the most common building steels at high exposure temperatures and the results of experimental studies to determine the bearing capacity of steel structures under fire exposure. For this purpose there were carried out studies of the strength characteristics of steels with rolled metal samples of C255 and C355 strength classes as well as empirical dependences of the change in the yield strength in the temperature range 20 °C < t < 700 °C were determined, which are necessary to calculate building metal structures for fire resistance. Experiments to determine the actual fire resistance of beams were carried out with class C255 rolled I-beams and class C355 welded I-beams. As controlled characteristic areas of steel temperature change there were taken the following items: the lower flange, the middle of the wall and the upper flange of the average I-section. Graphs of deformation (deflection) in the middle section of the beam under fire exposure are constructed. The calculation of fire resistance limit of bent steel beams was carried out taking into account the uneven distribution of temperature in the cross section. Comparison of experimental data and calculation results by means of the developed model, which takes into account the uneven heating of the section, showed their good agreement (up to 15 %) in terms of the loss of bearing capacity during three-sided heating under standard fire conditions.

Charring performance of timber structures protected by traditional lime-based plasters

There are limited performance data available on the fire resistance of lime-based plasters as a fire protection system for timber structures; no design values are given in the current fire part of Eurocode 5. This complicates the design and assessment of such (historic) building structures, as the contribution of lime plasters in case of fire is not clear. This paper aims to provide relevant data and assessment tools for the fire safety design and evaluation of the protection ability of lime-based plasters in combination with timber structures under standard fire exposure conditions. An overview of experimental studies in small and model-scale to determine the protection effect of various lime plaster systems is presented. The investigation is carried out in view of the design concept given in the European fire design standard with respect to the start time of charring of timber and the charring rate of timber behind the plaster system. Results present new knowledge and fire-related performance data of selected lime-based plasters regarding their protection ability under different heat exposure conditions and scales. References are made to the commonly used gypsum plasterboards and previous studies by the authors for an extended evaluation of test results. Obtained results demonstrate that thicker plaster coats are able to provide similar initial protection compared to the gypsum plasterboards for the start time of charring and the charring rate of protected timber until its fall-off.

Autonomous detection of concrete damage under fire conditions

The rapid advancement in computer vision has facilitated new means for the automatic assessment of structural damages. This study aims to develop a deep learning-based autonomous damage detection framework for concrete structures under fire conditions. A hybrid deep learning network comprising of Convolution Neural Network (CNN) and Long Short Term Memory (LSTM) network is proposed herein. Initially, the CNN is applied in the feature extraction phase, and the LSTM is used for damage detection and classification. The proposed hybrid network is then deployed to evaluate the structural damage of three types of self-compacting concrete (SCC) specimens exposed to standard fire conditions. A series of systematic studies are performed to optimize the network architecture and hyper-parameters. The effectiveness of the proposed hybrid method is contrasted with existing CNN methods against real datasets. Our analysis shows that the proposed framework delivers a robust and improved performance against traditional deep learning methods. Overall, the proposed framework opens the door for adopting autonomous damage detection systems for post-fire conditions.

Fire performance of lightweight concrete-filled LSF wall panels

Light Gauge Steel Frame (LSF) wall panels with cold-formed thin-walled steel-Lipped Channel Sections (LCS) and plasterboard linings are increasingly used in the construction industry due to their lightweight and constructability characteristics. However, due to the high thermal conductivity of the LCS, rapid heat transfer is observed in LSF walls, causing negative impacts to the fire performance of the LSF wall elements. Cavity insulation is one of the practical solutions used in the industry to improve the fire performance of LSF walls. Insulation materials such as rockwool, glass fibre, cellulose fibre, ceramic fibre are commonly used as cavity insulation materials in LSF walls. A novel approach in LSF walls is the introduction of lightweight concrete filling as a cavity filler. The effect of lightweight concrete filling on the fire performance of LSF walls was analysed with the numerical investigation in this study. Fire performance of conventional LSF walls with 12.5 mm and 15 mm single and double plasterboard with Autoclaved Aerated Concrete (AAC) with 600 kg/m3 density, Foam Concrete (FC) with 650 kg/m3 density and FC with 1000 kg/m3 density lightweight concrete fillings were compared with LSF walls without cavity insulation and rockwool insulation under standard and hydrocarbon fire conditions. It was observed promising improvement in insulation and load-bearing fire ratings in LSF walls with lightweight concrete filling. Among lightweight concrete materials considered, FC with 1000 kg/m3 density has exhibited the best fire performance. LSF walls performance could be enhanced with lightweight concrete fillings depending on the application with improved fire performance.