Standard Fire Tests Research Articles

Mechanical integrity of gas turbine enclosure doors under fire test conditions for A0 fire rating

PurposeAs fire doors are passive fire protection parts, the doors have to be certified through standard fire tests. It is usual practice to perform the standard fire testing on the components which require the fire certification. However, some gas turbine enclosure doors are too large to test at the test facility and hence the fire resistance test is practically not possible. The purpose of this paper is to develop a reliable finite element model, validate the model using the specimen door test results and extend the method to actual gas turbine enclosure doors to support the fire certification.Design/methodology/approachFirst, the standard fire testing on enclosure door test specimen was carried out. Second, the finite element analysis model was built and tuned to match the standard fire test deflections, and finally, the same modelling technique was extended to model the actual gas turbine enclosure door to verify the results for fire certification process.FindingsGap analysis, a method of post processing is suggested for result analysis. It was found suitable to verify the gap openings which are required for A0 rated fire certification according to fire test procedure code and also to check the mechanical integrity of the enclosure door frame assembly.Originality/valueThe method presented in this work could be used as support information along with the test specimen results for A0 class fire rating certification of the doors according to International Maritime Organization Resolution MSC.307 (88) Annexure 1: Part 3.

Influence of cavity insulation on the fire resistance of light gauge steel framed walls

Light gauge steel framed (LSF) walls are used in fire compartmentation to prevent the spread of fire, smoke and toxic gases. The fire behavioural characteristics of non-load bearing LSF walls are different from those of load bearing walls. In non-load bearing LSF walls, fire penetration to the ambient side is to be prevented for insulation and integrity criteria whereas in load bearing walls, steel studs need to be protected from heat for structural adequacy also. This paper investigates the fire resistance of non-load bearing and load bearing LSF walls with and without cavity insulation. It presents the details of a series of standard fire tests conducted to investigate the effect of cavity insulation in both load bearing and non-load bearing LSF walls. The use of cavity insulation increased the fire resistance level (FRL) of non-load bearing walls, while it significantly reduced the FRL of load bearing walls. A finite element parametric study was then conducted for LSF walls lined with both single and double layers of plasterboards. Both thermal and structural fire performance results of LSF walls from finite element analyses are presented and compared in this paper. These results showed that FRL of cavity insulated non-load bearing LSF walls increases by 10–20 min, while it is significantly reduced for load bearing LSF walls with load ratios below 0.7. This study highlights both the beneficial and detrimental effects of cavity insulated LSF walls exposed to fire.

Fire resistance and burnout resistance of reinforced concrete columns

This paper quantifies the resistance to complete burnout of reinforced concrete columns under fire exposure. It adopts a new metrics to complement the fire resistance rating that captures the specific effects of the cooling phase and characterizes explicitly the ability of a structural member to survive burnout. The analysis is performed on a dataset of 74 standard fire resistance tests on columns. Finite element modeling is applied first to reproduce the standard tests. The obtained ratio between the computed and experimental fire resistance has an average value of 0.95 with a standard deviation of 0.29. Then, finite element modeling is used to analyze the 74 columns under ‘standardized’ natural fire comprising a cooling phase. The effects of cooling are carefully incorporated in the materials laws including thorough consideration of irreversibility of properties and explicit modeling of transient creep. An iterative computational procedure is applied to subject each column to increasing durations of fire exposure until finding the shortest standardized fire that cannot be survived until burnout, from which the burnout resistance metrics is defined. The duration of this shortest fire increases approximately linearly with the fire resistance of the columns, but with a factor smaller than one, revealing an increased propensity to delayed failure in columns with longer fire resistance. Finally, a simple equation is formulated to estimate the burnout resistance from the fire resistance. Such equation can support design for complete burnout which has benefits for safety of fire brigades and first responders, as well as for property protection and resilience of the built environment.

Full-scale fire resistance tests of steel and plasterboard sheathed web-stiffened stud walls

Light gauge steel-framed (LSF) walls, commonly made with lipped channel studs and gypsum plasterboard sheathing, are increasingly being used in low to mid-rise buildings. Improvements have been made with respect to fire, wind/seismic and energy performance of LSF walls with the use of improved stud sections, wall configurations, different sheathing members, and insulation materials. Although the provision of sheet steel as sheathing has been found to improve the in-plane shear capacity of LSF walls, its effects on the fire performance of load bearing walls remain unknown. Three full-scale ISO 834 standard fire tests were conducted in this study to investigate the fire performance of axially loaded gypsum plasterboard and steel sheathed LSF walls made with web-stiffened studs. The results revealed that compared to the commonly used lipped channel stud, the web-stiffened stud is capable of withstanding a 57% greater axial compression load, yet yield the same fire resistance level (FRL), when sheathed only with two layers of gypsum plasterboard. Under the selected load ratio, the addition of steel sheathing caused only marginal improvements in the stud temperature development, resulting in minor improvements to the FRL of load bearing walls. However, the axial load bearing capacity improvement caused by the inclusion of steel sheathing allowed the web-stiffened stud to withstand a 10% greater axial compression load compared to the plasterboard only wall.

The fire performance of Cross Laminated Timber beams

Abstract The use of timber as a structural material in multi-storey buildings is often limited due to its combustible nature. The fire performance of the wooden members can be determined through the standard fire tests or, more often, using the calculation procedures recommended by the design codes. The fire resistance of a timber beam can be calculated based on the residual section without taking into account the charred area and the zero strength layer. However, the zero strength layer (d0) it is assumed to be a key parameter of the fire design of timber members. Recent studies show that the utilisation of d0 may be non-conservative in some applications and the simplified design approach method may not properly describe the complex behaviour of the timber members exposed to fire. The paper presents an experimental research on a loaded glulam beam (GL24H) exposed to the standard fire on three faces. Heat transfer and mechanical behaviour of the beam is estimated by simplified reduced cross-section method according to Eurocode 1995-1-2. The experimental charring rates are compared with theoretical and notional values.

NUMERICAL INVESTIGATION OF THE PERFORMANCE OF INSULATED FRP-STRENGTHENED REINFORCED CONCRETE BEAMS IN FIRE


 
 
 Fiber reinforced polymers (FRP) have been widely used in retrofitting and strengthening of deteriorated or deficient reinforced concrete (RC) elements. A major concern about those systems is their performance under elevated temperature which limits the application of FRP for strengthening requirements. Fire protection of the strengthening FRP system can be made by applying an external coating layer of a thermal resisting material. In order to predict the fire performance of such insulated FRP-strengthened members and their efficiency, experimental investigations are required to be carried out for such elements under realistic fire conditions, which requires time and cost.
 This paper presents numerical modelling of RC beams strengthened with externally bonded FRP and insulated by a fire protection layer under elevated temperature specified by standard fire tests. The nonlinear time domain transient thermal-stress finite element analysis is performed using the general purpose software ANSYS 12.1 in order to study the heat transfer mechanism and deformation within the beam for fire conditions initiating at the bottom side of the beam. The finite element model accounts for the variation in thermal and mechanical parameters of the constituent materials such as concrete, steel reinforcement bars, FRP and insulation material with temperature. Application is made on an FRP-strengthened and insulated RC T-beam which has been experimentally tested in the published literature in order to verify the adopted modelling procedure. The obtained numerical results are in good agreement with the experimental results regarding the temperature distribution across the beam and mid-span deflection. The presented procedure thus provides an economical and effective tool to investigate the effectiveness of fire insulation layers when subjected to high temperatures and to design thermal protection layers for FRP strengthening systems that satisfy fire resistance requirements specified in building codes and standards.
 
 

A Finite Element (FE) simulation of naked solid steel beam at elevated temperature

This paper presents the numerical analysis of temperature distribution of a simply supported naked solid steel beam under fire exposure. Prescriptive based approach particularly is the safest and easiest approach to determine the level of strength of structural member when expose to elevated temperature. However, this method assuming uniform fire exposure through the overall cross section of the structural member which may leads to over design. The outcome of the design may not reflect the real fire scenario. Performance based approach is a realistic approach which can predict the structural steel behavior. In this method, three main components were considered, namely fire exposure behavior, heat transfer analysis and mechanical reaction. Fire exposure behavior dealing with types or severity fire load exposed to structural member. There are few options available to determine the fire extent, namely nominal fire models, compartment fires, localized fires, zone models and computational fluid dynamics (CFD) models. Meanwhile, heat transfer analysis estimates the energy dissipation (initiate from fire) between structural elements due to temperature variation. Structural response incorporates finite element modeling that predicts the structural element behavior, namely stresses and deformation. This method considers the prime factors such as shadow effect, support condition, loading condition, boundary conditions and interaction properties between different structural elements which can optimize the structural behavior analysis. However, there are still lack of research that consider those factors that might jeopardize the behavior of steel beam. Owing to this, a performance based approach method was introduced in this research. Experimental investigation was retrieved from the readily available data of Compendium of UK Standard Fire Test Data. One sample of naked solid steel beam was selected from the wide range of naked solid beam available from the Compendium. Standard fire curve of ISO 834 was used during numerical simulation to correlate with the experimental investigation. From the results of the finite element simulation, the predicted member temperature agrees well with the experimental investigations. Hence, future works of cellular steel beam (CSB) with various web opening shapes can be initiate due to its limited researches related to CSB at elevated temperatures

Computational analysis of thermal and structural failure criteria of a multi-storey steel frame exposed to fire

Structural fire design, until recently, has only assumed uniform fires inside the compartment, and the assessment of structural failure has been often based on a critical temperature criterion. While this criterion, to some extent, may be able to indicate the temperature at which the structural element is near to failure, it is based on standard fire tests and, therefore, its validity is limited to individual members exposed to uniform temperatures. It is unclear how representative a critical temperature criterion is of structural failure in the case of multi-story structures, particularly in the case of non-uniform fires such as travelling fires. Therefore, the aim of this study is to assess the validity of the critical temperature criterion for structures exposed to non-uniform fires and compare it to uniform fires. A generic 10-storey steel framed building is modelled using the finite element software LS-DYNA. In total, 117 different scenarios are investigated to cover a wide range of conditions of interest for design of modern steel buildings, varying the fire exposure (travelling fires, Eurocode parametric fires, ISO-834 standard fire, and SFPE standard), floor where the fire is burning, beam section size, and applied fire protection to the beams. For the different fire exposures considered, the analysis predicts structural failure at different times, in different locations and floors, and different failure mechanisms. Moreover, it is shown that there is no single worst case fire scenario: different fires can lead to failure in different structural ways. The comparison of the various structural and thermal failure criteria (ultimate strain, utilization, mid-span deflection, and critical temperature) show that there is no consistency between them, revealing a far more complex problem than reported in the literature. Lastly, this work has illustrated that the critical temperature criterion does not predict accurately the structural failure in time, space or failure mode of steel structures subjected to both uniform and non-uniform fires. Structural failure can only be predicted by advanced structural analysis, and, therefore, heat transfer analysis alone is not sufficient for design. Nevertheless, it was shown that the use of the critical temperature leads to conservative results for simple steel structures. For the sake of comprehensive design, a range of different fire scenarios, including both uniform and non-uniform, should be part of the analysis such that all likely structural responses and failure modes can be considered.

Experimental study on the onset of swelling for thin intumescent coatings

Intumescent coatings (also known as reactive coatings) are widely used to protect load-bearing steel structural elements during fire. Upon heating, these initially thin coatings swell to form a low density, highly insulating foamed char that insulates steel substrate. Within the context of modern fire safety engineering design of steel structural systems, thermal insulation during fire may be key for assuring that steel does not reach ‘critical’ temperatures that may yield local structural instability and/or progressive failure (i.e. global instability).Traditionally, the fire performance of intumescent coatings is typically based on compliance (and to some extent their performance) to the standard fire resistance test in furnace, where single coated elements are exposed to the standard temperature-time curve. Numerous research studies have emphasised the influence of heating conditions on the onset of swelling and the overall effectiveness of intumescence. Moreover, some studies have shown that slow growing fires or low heating regimes may cause an incomplete swelling of the intumescent coating, or even melting or delamination. Consequently, the onset of swelling of is key for assuring its effectiveness in providing thermal insulation to the steel substrate during fire. Past researchers have shown that the onset of swelling occurs for temperatures in the range of 200-300°C. There are limited research studies that have look at the effects of varied, non-standard heating regimes on the onset or effectiveness of swelling of thin intumescent coatings.The study presented herein investigates the onset of swelling for a commercially available thin intumescent coating exposed to a wide range of heating regimes. Experiments are performed by using radiant panels and controlling incident radiant heat flux at the exposed surface of coated steel samples. This allows for the direct and precise control of the thermal boundary conditions at the exposed surface of tested samples. The onset of swelling criteria were defined in two ways: (1) visual observation of swelling during heating or (2) time-history of the protected steel temperature.The outcomes of this work aim at yielding a sound understanding of the true effectiveness of thin intumescent coatings. Experimental results mainly show that onset of swelling is directly influenced by the heating regime and it occurs for test samples heated at constant incident radiant heat flux above 20 kW/m2. The onset of swelling for the tested thin intumescent coating occurs for steel temperatures between 150 and 300°C and ‘mean coating temperature’ between 350 and 450°C. However, the steel temperature at onset of swelling is inversely proportional to the amount of constant incident heat flux at the exposed surface of tested samples, while the ‘mean coating temperature’ is directly proportional. As a conclusion, the time-history of net heat flux at the exposed surface of tested samples is not the only parameter that governs the onset of swelling for thin intumescent coatings.

High-Throughput Fire Tests and Weathering-Induced Degradation Behaviour of Intumescent Coatings

In this work, the weathering-induced degradation of intumescent coatings was investigated by a systematic and comprehensive approach. A mechanism is revealed that is proposed to be responsible for the loss of function of intumescent coatings induced by weathering.First, the thermal decomposition of artificially weathered intumescent coatings was examined. To get a better understanding of the weathering and ageing phenomena, the degradation behaviour of the single ingredients during the weathering process was investigated, as well as their chemical and physical interactions. For the systematic approach, the materials that are essential for intumescence (ammonium polyphosphate, pentaerythritol, titanium dioxide, melamine and the binder) are treated with moisture, elevated temperature and UV radiation.Thermogravimetry (TG) and IR spectroscopy were used to compare the initial samples with their different grades of weathering. We demonstrate that ammonium polyphosphate, melamine and the binder are mainly responsible for the ageing process. Further, it was demonstrated that TG and IR spectroscopy are suitable measuring methods to detect the effects of weathering on intumescent coatings.Finally, a small-scale fire test procedure is introduced. Based on the reduction of the sample size, up to 50 samples can be tested in a single fire test. The results of this fire test have the same quality as the results from standard intermediate fire tests corresponding to DIN 4102-8.

REVIEW ON COLUMN FIRE RESISTANCE DESIGN FOR CONCRETE FILLED STEEL TUBE

The use of concrete filled steel tube (CFST) columns offers an alternative for providing the required fire resistance and load bearing capacity, making its use in medium and high rise structures are highly popular. This paper aims to review the previous studies on CFST column under fire. The standards or codes of practice used in fire resistance designs have been highlighted. The design of the CFST column is summarised with previous investigations on experiments and numerical modelling at ambient temperature and elevated temperature. Different conclusions were drawn depending on the material’s properties, considered parameters and the method used for the investigations. Outer diameter or width of the steel tube, steel tube thickness, concrete grade, column length, and eccentricity of loadings are among the parameters that affects the structural behaviour of CFST columns under fire. Several numerical analyses software were adequately used for simulating the behaviour of CFST columns at elevated temperatures, and validated using experimental results. Furthermore, the advantages of using the fire resistance design approaches on CFST columns filled with lightweight foamed concrete is highlighted. In conclusion, there is the need for more studies on standard fire tests of CFST column filled with light weight foamed concrete which is not covered in the current design guide.

Post-fire damage assessment of Korean bridges using thermal–structure interaction fire analysis

To evaluate fire-induced damage to bridge structures, the thermal–structure interaction (TSI) fire analysis method is proposed, verified and applied to examine the behaviour of bridge superstructures with steel–concrete composite sections and prestressed concrete (PSC) exposed to fire loading. The proposed TSI fire analysis consists of two different modelling parts: thermal transfer analysis and thermodynamic structural analysis. The body temperature inside the structure is first calculated using fire curve boundary conditions in an overall non-linear transient thermal transfer analysis. Thermodynamic structural analysis is then performed based on the entire temperature and heat distribution in the structure. To validate the proposed method, comparisons are made with standard fire test results: the temperature distribution and the deflection of the steel–concrete composite superstructure agreed closely with the results of the standard fire test. The proposed fire analysis method is finally applied to two bridges with different superstructures (steel–concrete composite and PSC) damaged by recent fire events in Korea.

NONLINEAR FINITE ELEMENT ANALYSIS OF INSULATED FRP STRENGTHENED REINFORCED CONCRETE COLUMNS SUBJECTED TO FIRE

In recent decades, Fiber Reinforced Polymers (FRP) have shown tremendous potential for retrofitting or repairing existing deficient or damaged concrete structural elements due to their superior properties such as high strength, corrosion resistance and ease of application. However, concern arises about the vulnerability of FRP material to combustion under fire condition, since they are usually applied to the exterior surface of structural members. Damage of the FRP strengthening layer due to high temperature is likely to decrease the load carrying capacity of the columns and threaten the safety of the structure. This paper presents numerical investigation of the behaviour of reinforced concrete (RC) columns strengthened with FRP sheets and insulated by a thermal resisting coating under service load and fire conditions. The finite element numerical modelling and nonlinear analysis are made using the nonlinear finite element analysis software ANSYS 12.1 [1]. The numerical model is verified for several FRP confined and insulated RC columns that have been experimentally tested under service load and standard fire tests in the published literature. The obtained numerical results are in good agreement with the experimental ones regarding the temperature distribution and axial deformation response. Consequently, the presented modelling gives an economic tool to investigate the behaviour of loaded FRP strengthened RC columns under high temperatures occurring in case of fire, if the modelling is verified against experimental works. Furthermore, the model can be used to design thermal protection layers for FRP strengthened RC columns to fulfill fire resistance requirements specified in building codes and standards.

Design of a continuous concrete filled steel tubular column in fire

Concrete filled steel tubular (CFST) columns used in multi-storey buildings are generally designed as continuous members. The fire behaviour is predicted based on the results of experimental standard fire testing of CFST members where the same temperature is applied to the column over the full column height. Over the past 36 years, 238 experimental tests have been reported in the literature on CFST columns; different types of concrete infill have been considered: plain, steel fibre and bar reinforced concrete. In these tests, the columns were loaded axially under either concentric or eccentric load, and subjected to the standard ISO 834 fire or its equivalent in a furnace. This paper has focused on the in-depth analysis of behaviour of a continuous CFST columns in fire and provided a simple design procedure to calculate the axial capacity of the CFST columns at elevated temperature. The examples given in the later section gives a step by step design procedure for practicing engineers to calculate the axial capacity of both concentrically and eccentrically loaded CFST columns in fire.

Fire performance of load bearing LSF wall systems made of low strength steel studs

Light gauge steel frame (LSF) walls are commonly used in single and two storey residential and commercial buildings and modular based mid-rise building construction. They are lined with single or two layers of gypsum plasterboards and used with or without cavity insulation or noggings. This paper presents the details of a series of standard fire tests of load bearing LSF walls used in low-rise building construction to investigate the effects of using low strength steel studs, noggings and cavity insulation. The presence of cavity insulation significantly reduced the fire resistance level (FRL) of load bearing walls while the use of noggings increased the FRL, and these findings are considered valid for both low and high strength steel stud walls. Structural finite element models of fire tested walls were then developed using appropriate elevated temperature mechanical properties, validated using the fire test results and used in a parametric study of LSF walls made of both low and high strength steel studs. The results showed that FRL of low strength steel stud walls is reduced by about 25% in the common load ratio range in comparison with high strength steel stud walls, while their critical hot flange temperatures are reduced. These differences are due to the variations in their elevated temperature mechanical properties caused by the material composition. Reliable fire performance results of both low and high strength steel stud walls from finite element analyses and fire tests are presented and compared in this paper. This study has highlighted the importance of using accurate elevated temperature mechanical property reduction factors in numerical analyses and design of LSF walls.

Framework for a performance-based analysis of fires following earthquakes

Most current structural fire codes focus on achieving prescribed fire ratings, which are based on standard fire tests with minor relevance to what is required for fire safety. These prescriptive design approaches do not provide sufficient information regarding the performance of structural members or systems under elevated temperatures. Furthermore, the limited structural design provisions provide no indication of the level of reliability of structures since comprehensive treatment of the uncertainties associated with the hazard is not considered. It is therefore imperative to move towards performance-based engineering not only to quantify structural reliability for given performance objectives but also to ensure more economic and safe design. This paper provides details on the development of a new analysis framework for probabilistic performance-based analysis of a fire following an earthquake. The framework is then utilized to develop fragilities of steel structural members and systems subjected to cascading hazards of earthquake and fire while considering buckling of columns as the damage limit state. Uncertainties associated with fire hazard, passive fire protection, gravity load, and earthquake intensity are accounted for in the framework. The proposed performance-based approach for the analysis of a fire following an earthquake can be considered an extension of the Pacific Earthquake Engineering Research (PEER) performance-based earthquake engineering framework and used by engineers to assess structural performance under the multiple hazards.

Standard fire testing of chimney linings from composite materials

Improper construction on of chimneys can lead to dwelling-house fires, smoke poisoning or death [1]. Due to the constantly increasing demands, new and more advanced chimney linings are being produced and used. In the case of reinforced concrete and brick chimneys, modern chimney technology applies linings. It is well known that the stainless steel and aluminum linings already in use can eventually become victim to corrosion.Due to the emerging corrosion defects, the development of a newer, more advanced material providing the same level of air tightness in the long term, has been proposed. The new composite lining material is expected to withstand aggressive corrosive substances produced in the chimney shaft and to meet the flammability requirements specified in the regulations. It is well-known, however, that high temperatures or fire are generally unfavorable for plastics.In our experiments, a newly developed composite material was tested according to the standards (non-flammability A1, A2, flame spread) for chimney linings. In addition to the relevant standard requirements, a more rigorous flammability test was performed, i.e. the flammability of the composite material was tested with different oxygen contents, which in our opinion perfectly and realistically reveals the flammability of a material and also replaces other traditional tests.The main goal of our experiments was to observe the built-in sizes not the standard ones and to classify accordingly. This is not only the direction of safety, but also gives a more realistic approach to the behavior of composite inline exposed to heat and fire.Fire classification and requirements do not keep up with the development of plastics and composites, so we make a proposal for a realistic classification. Accompanied by the results of the oxygen index test, we have given the parameter that expresses the best the non-flammability of composites. Incineration in an oxygen-rich environment reveals potentially hidden flammability characteristics, which standard tests cannot detect. The requirements of fire standards mandatory for building materials [2] do not change even if the composites are tested in their actual size.

Full-Scale Standard Fire Experiment and Numerical Modelling Behaviour of Non-Load Bearing Calcium Silicate Partition Drywall

The study uses the non-load bearing calcium silicate partition drywall as the test specimen, with full-scale standard fire test and the CFD finite element numerical modelling simulation on 300 cm × 300 cm area specimen. The whole process of experiment fire test and the numerical modelling simulation result is highly correlated. This numerical modelling simulation can be applied to other researches on the other wall systems. This is an innovative and valuable research. Since they are highly correlated, the CFD finite element numerical modelling can be processed to work out the predicted results before the test, which can greatly save the cost of test. When the predicted results is satisfying, the standard fire test can be processed to verify the results.

Thermal analysis of polymer ignition

SummaryGas phase criteria for the onset of flaming combustion of solids in fires are used to locate a critical temperature Tcr in a nonisothermal analysis (TA) experiment that corresponds to the surface temperature of the solid at ignition in a fire test, Tign. This critical TA temperature occurs at low conversion of solid to gaseous fuel so it is independent of the heating rate in the test or the thermal decomposition reaction model. However, Tcr depends on the thermal properties of the polymer and the conditions of the fire test in which the gas phase criteria were measured. Nonisothermal analysis data in nitrogen and air were obtained for 20 polymers by thermogravimetric analysis and microscale combustion calorimetry. The critical temperatures Tcrs obtained from TA experiments compared favorably with analytic results for a simple polymer ignition model and finite element simulations and were in qualitative agreement with ignition temperatures measured in standardized fire tests.

Experimental investigation on temperature distribution of foamed concrete filled steel tube column under standard fire

Standard fire test was carried out on 3 hollow steel tube and 6 foamed concrete filled steel tube columns. Temperature distribution on the columns was investigated. 1500 kg/m3 and 1800 kg/m3 foamed concrete density at 15%, 20% and 25% load level are the parameters considered. The columns investigated were 2400 mm long, 139.7 mm outer diameter and 6 mm steel tube thickness. The result shows that foamed concrete filled steel tube columns has the highest fire resistance of 43 minutes at 15% load level and low critical temperature of 671 ºC at 25% load level using 1500 kg/m3 foamed concrete density. Fire resistance of foamed concrete filled column increases with lower foamed concrete strength. Foamed concrete can be used to provide more fire resistance to hollow steel column or to replace normal weight concrete in concrete filled columns. Since filling hollow steel with foamed concrete produce column with high fire resistance than unfilled hollow steel column. Therefore normal weight concrete can be substituted with foamed concrete in concrete filled column, it will reduces the self-weight of the structure because of its light weight at the same time providing the desired fire resistance.