Light Gauge Steel Frame Walls Research Articles

Full-scale tests of load-bearing LSF walls made of built-up CFS channel sections under fire conditions

Built-up cold-formed steel (CFS) studs, such as back-to-back channels (BC) and nested channels (NC) are used in light gauge steel framed (LSF) wall systems instead of the conventional channel studs for improving their load-bearing capacity. However, the knowledge and understanding of their behaviour under fire conditions is limited. In this study, the behaviour of load-bearing LSF walls made of BC and NC studs under fire conditions was investigated using four full-scale standard fire tests. The obtained fire test results were evaluated in terms of both thermal and structural behavioural characteristics and fire resistance level (FRL), and were used in the comparison with those for conventional LSF walls made of single channel studs. The test results showed that (1) without cavity insulation, the thermal and structural behavioural characteristics of the LSF walls made of BC and NC studs are very similar to those of LSF walls made of channel studs, and their FRLs can be taken as the same for the same load ratio (2) LSF walls made of BC and NC studs with two layers of 16 mm thick gypsum plasterboards on each side and without cavity insulation have an FRL of 120 min for a load ratio of 0.4, and (3) the use of cavity insulation reduces the FRL of LSF walls made of NC studs. This paper presents the details of this research study and its outcomes.

Thermal performance and thermal transmittance prediction of novel light-gauge steel-framed straw walls

Thermal bridges in light-gauge steel-framed exterior walls lead to more winter heat loss, summer heat gain, and building pathologies generated by moisture condensation and mould growth, which are unfavorable for building energy efficiency and service life of sheathing panels. A novel light-gauge steel-framed straw wall with a nonmetallic broken bridge layer was proposed, which consists of two sheathing panels on both sides of the wall, two frames, a middle sandwich layer, and two kinds of fasteners. The environmentally friendly straw boards including paper straw board (PSB) and wheat straw strand board (WSSB) were used as middle sandwich layer and exterior panel respectively. This study focuses on the thermal performance and the prediction method of thermal transmittance (Um-value) for such walls. Tests using the temperature control box-heat flux meter method were carried out for three representative walls with different configurations. Based on analyses of the temperature and heat flux density distributions, it is found that the broken bridge layer and the airspaces between the sheathing panel and the track or the bracing can effectively reduce the thermal bridge effect, with the relative effects less than 5%. Based on the test results of the Um-values, different wall configurations were matched with the feasible climate zones on the basis of energy efficiency design. After the validation by comparing with the test results in terms of temperature, heat flux density, and Um-value, the numerical study was carried out to broaden the feasible climate zones, and walls with improved configurations were proposed and analyzed. The results show that, by replacing the unventilated airspaces with the expanded polystyrene (EPS) boards, a maximum improvement in thermal performance reaches 74.89%. Thus, the feasible climate zones of the walls have been extended to the severe cold zone. Finally, a thermal transmittance prediction methodology based on the calculation method specified in European Standard EN ISO 6946-2017 in conjunction with the modified method considering thermal bridge effect was used to predict the Um-‍values of the improved walls. This study provides a new design strategy with nonmetallic broken bridge layer to reduce the unfavorable influence of thermal bridges in light-gauge steel-framed walls. Such a design strategy contributes to less energy consumption in addition to making full use of agricultural waste straw, which plays a positive role in the development of green buildings.

Numerical thermal performance analysis of light steel insulated walls under fire

Light-gauge steel-framed (LSF) walls are being adopted by the Algerian construction industry as a new alternative to the traditional infilled frames due to the advantages they provide. The strength-to-weight ratio of Cold Formed Section (CFS) leads to lighter structures and a decrease in the building cost. However, in the case of fire, the high shape factor combined with the loss of material properties of the unprotected, slender CFS can result in structural failure. Because of their conductivity, elevated temperatures have an effect on the thermal performance of panels, necessitating the use of appropriate insulation. The purpose of this paper is to perform a numerical analysis of the thermal behavior of LSF walls protected by plasterboard or magnesium oxide board, as well as cavity insulations. Numerical models are developed, using ANSYS software to simulate the thermal performance of LSF walls under ISO 834 fire. Thermal simulations are done to predict temperature profiles, maximum temperatures, and the estimated fire resistance level (FRL). This research has produced results to better evaluate the influence of different systems of protection and insulation used for the CFS under fire.

Application of neural networks for light gauge steel fire walls

This research study evaluates the applicability of neural networks to determine the fire-resistance rating of Light gauge Steel Frame walls, made of cold-formed steel studs and lined with gypsum plasterboard.Many full-scale tests and numerical studies were conducted to determine the fire-performance of LSF walls, but these studies were expensive and time consuming. Therefore, an alternative option of using machine learning to predict the fire performance was proposed. The actual fire performance data from FEA and full-scale tests of previous research studies were used as inputs in the machine learning. Separate sets of training and test data were used; thus, test data is not used to calibrate the machine learning-based analysis. Here LSF walls made of different wall configurations and different steel profiles were considered. Training and testing of the artificial neural network are performed by combining different parameters such as loss function, keep probability factor, learning rate, the number of layers, and neurons to determine the optimal and accurate solution. The structural fire capacity of LSF walls obtained from machine learning was compared against the test data to evaluate its accuracy. Based on the findings, suitable neural network models with two hidden layers and suitable loss functions were recommended.

Design of sheathed built-up nested CFS channel studs in load-bearing LSF walls

Cold-formed steel built-up nested channel (NC) sections have been increasingly used to replace the commonly used lipped channel sections as the load-bearing studs of light gauge steel framed (LSF) walls with higher compression capacity. However, the related knowledge is limited and no research study has investigated such NC stud walls yet. In this study, an investigation was undertaken on the compression behaviour and capacity of LSF walls made of slender NC studs sheathed with gypsum plasterboards on both sides. Compression tests of sheathed NC studs were conducted first, which were then used in developing and validating suitable finite element models. The results obtained from tests and finite element models showed that plasterboards and stud-to-board screw connections had significant influence on the failure mode and compression capacity of sheathed NC studs, while the end fastener groups recommended in the current cold-formed steel design standards and the stud-to-stud screw connections had only marginal effects. Finally, a simple and conservative design method was proposed based on the Direct Strength Method equations in the current design standards. This paper presents the details of this research study, including the results, discussions and main findings.

Design of built-up back-to-back CFS channel compression members sheathed with gypsum plasterboards

Built-up back-to-back cold-formed steel channel (BC) members are increasingly used as studs for increasing the compression capacity of light gauge steel framed (LSF) walls, even though the knowledge of their behaviour is limited. In this study, the behaviour and capacities of LSF walls made of slender BC members sheathed with gypsum plasterboards on both sides were investigated using a series of compression tests and detailed finite element studies based on validated models. The numerical and experimental results showed that (1) screw connections of BC members had marginal effects on the compression capacities of the investigated sheathed BC members with non-staggered stud-to-board screw arrangement, and the capacities were mostly equal to twice the capacities of their individual members, (2) the restraints provided by the plasterboards and stud-to-board screw connections effectively prevented sheathed BC members from in-plane flexural buckling and considerably improved their compression capacities, and (3) the Direct Strength Method in the current design standards in combination with the guidelines and recommendations proposed in this study conservatively predicted the compression capacities of these members. Details of this research study, its results and findings are presented in this paper.

Numerical modelling of LSF walls under combined compression and bending actions and fire conditions

Numerical modelling of cold-formed steel walls used in determining the ambient temperature ultimate capacities has evolved from the use of idealised stud-only models to advanced models by employing sheathing and connection characteristics. Due to the convergence issues associated with elevated temperature structural models, attempts to incorporate sheathing are scarcely seen in the literature. In this study, the behaviour of light gauge steel framed (LSF) walls under combined axial and lateral loads and fire exposure was investigated by using stud-only and advanced structural finite element (FE) models. The advanced model is an improved single stud model which included gypsum plasterboard sheathing while also making models computationally less demanding. It incorporated material and geometric non-linearities, contact interactions, idealised in-plane restraints and explicit modelling of gypsum plasterboard sheathing, and was validated using full-scale fire test results. The predicted fire resistance levels (FRLs), failure modes, axial shortening and lateral deflection plots showed good agreement with fire test results. Furthermore, thermal FE models were also developed and validated against fire test results. They will be extended to obtain the time–temperature profiles of cavity insulated and non-insulated single and double plasterboard sheathed LSF walls exposed to fire for use in structural parametric studies. This paper summarises the findings of this study and proposes suitable recommendations for FE modelling of LSF walls under combined compression and bending actions and fire conditions.

Fire resistance of external light gauge steel framed walls with brick veneer cladding

This paper presents the details of an experimental study to evaluate the fire resistance of external light-gauge steel-framed (LSF) walls with brick veneer cladding. Brick veneer is one of the most opted external cladding in Australian low to mid-rise construction for their aesthetic appeal with load bearing light-gauge steel framing or timber framing as the structural backing. However, no experimental data is available on the fire resistance of brick veneer walls with LSF backing. This experimental study included five small-scale non-load bearing fire tests of LSF walls with brick veneer cladding exposed to the standard fire. Two test walls with brick veneer constructed using normal and high temperature mortars were tested with fire from the external side (brick veneer exposed to fire), and the third wall constructed using normal mortar was tested with fire from the internal side (plasterboard exposed to fire). The first two test walls were also exposed to a second fire exposure. This study also included detailed elevated temperature thermal property tests of brick and the two types of mortar used in the fire tests. Brick veneer cladding provided very good protection to the thin-walled steel studs. No failure was observed in all the five fire tests giving fire resistance level of more than 240 min. Structural failure times of load bearing walls were also estimated to be more than 240 min for fire on the external side under load ratios of up to 0.4 while it was 30 min for fire on the internal side.

DSM design of LSF walls subject to distortional buckling

With the new advancements in constructions technologies, the use of cold-formed steel (CFS) construction is becoming popular due to its inherent advantages over conventional construction materials. These high performing CFS sections, such as the web stiffened lipped channel studs, are more likely to be subjected to distortional buckling under compression load. Although many numerical and experimental studies have been undertaken on unsheathed CFS columns subjected to distortional buckling, there is limited research on light gauge steel framed (LSF) walls subject to distortional buckling. The behaviour of sheathed wall studs is significantly different to that of columns due to the complicated boundary conditions provided by the stud-to-sheathing contact interactions and screw connections. Although CFS design standards recognize the sheathing boards as a means of providing lateral and rotational restraints, they do not provide any information on their effects on studs subject to distortional buckling. In this study, the suitability of currently available numerical modelling techniques on predicting the distortional buckling behaviour of LSF walls was investigated. It was identified that the distortional buckling capacity is highly sensitive to the in-plane restraints provided by screw connections. The effects of stud geometry, stiffness of screw connections and stud length on the distortional buckling capacity were investigated in a detailed numerical parametric study involving more than 3500 finite element analyses. Finally, the accuracy of the current direct strength method was investigated and suitable modifications are proposed. Moreover, alternative simplified design methods and their accuracy are also discussed.

Fire performance analyses of modular wall panel designs with loadbearing SHS columns

Modular Building Systems (MBS) are still in the phase of developing its popularity in the industry, with emerging novel designs. Initially, MBS walls and floors had been highly influenced by the Light-gauge Steel Frame (LSF) designs made of Cold-Formed (CF) steel studs, either as loadbearing or non-loadbearing types which have been extensively researched all over the world. However, recently the MBS practice in the industry tends to incorporate Square Hollow Section (SHS) steel columns for their improved structural performance and convenience at the manufacturing stage despite of the limited research knowledge in terms of the Fire Resistance Level (FRL). Moreover, catastrophic failures and fatal accidents are common with steel-based structures in case of a fire. Hence, the fire performance of loadbearing modular walls with SHS columns have been identified as a critical research gap. Firstly, Finite Element Models (FEM) were developed for the original modular wall, a Light-weight Timber Frame (LTF) wall and some LSF walls. The FEM analyses results very well matched with the full-scale experimental results so that the FEM techniques were confidently used to study the effect of variables chosen based on material availability options, cost reduction and construction practice. Structural and Insulation FRLs have been evaluated for the chosen parametric walls, where the produced graphs of structural and insulation FRLs can be referred to determine the adequate thickness of column sheathing and the Insulation Ratio (IR) respectively. The choice of non-loadbearing stud type can be evaluated against other limitations related to energy, cost and construction practice.

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.

Experimental investigation and design of sheathed LSF wall panels under eccentric axial compression

Sheathing is an important component in cold-formed Light gauge Steel Framed (LSF) walls and floors. LSF wall studs with one- or two-sided sheathing have been shown to have an increased ultimate compression capacity since the sheathing is capable of restraining global buckling modes. Although sheathing’s contribution has been ignored in the past, current design standards include provisions for the consideration of sheathing in the design of LSF walls. Australian cold-formed steel standard allows the designers to consider sheathing’s lateral and rotational restraints to studs, but it does not quantify the restraint values to be used. A recent report of American Iron and Steel Institute (AISI RP 13-1) provides suitable design guidelines for LSF walls with single sheathing, non-identical sheathing and different fastener spacings subject to axial compression, however, they have not been validated for LSF walls under combined compression and bending actions. An experimental investigation on LSF wall panels subject to combined actions due to eccentric loading was conducted in this research to understand the effects of loading eccentricity on sheathed LSF wall panels. Fifteen single stud wall panels of 1.5 m and 3.0 m height made of lipped channel studs were tested under concentric and major axis eccentric compression loading. Effects of sheathing and loading eccentricity on the failure modes and ultimate capacities were evaluated, and importantly, the suitability of the sheathing braced design guidelines in AISI RP 13-1 was investigated. The results showed that the use of the spring-based restraints recommended in AISI RP 13-1 with the linear interaction equation provides improvements in predicting the capacity of sheathed walls subject to eccentric compression.

Advanced numerical modelling of light-gauge steel framed walls subject to eccentric compression

The current numerical studies and design of light-gauge steel framed (LSF) wall and floor systems are largely confined to individual members with idealised boundary conditions. Idealised single stud models of LSF walls that have been extensively used in the past are unable to capture the complex behaviour associated with stud-to-sheathing and stud-to-track connections. The ultimate capacities and failure modes predicted by these models may not always be accurate because of which designers have to resort to expensive and time-consuming full-scale testing. Advanced numerical models that explicitly model all LSF wall components are available in recent literature. However, they are limited to LSF walls under axial compression. In this study, the behaviour of LSF walls made of lipped channel studs under eccentric axial compression was investigated by developing a sheathed stud model simulating the sheathing material, tracks and connections using ABAQUS. This advanced model incorporated material and geometrical non-linearities, contact interactions, non-linear behaviour of stud-to-sheathing connections and explicit modelling of gypsum plasterboard sheathing, and was validated using experimental results. The failure modes, ultimate capacities and load versus axial shortening and lateral deflection curves predicted by the advanced model were compared with those predicted by the simple single stud models and suitable recommendations were proposed for finite element modelling of LSF walls under combined loading actions. This paper presents the details of the development of advanced models of LSF walls subject to compression and bending actions and its findings.

Finite element analysis of lightweight concrete-filled LSF walls exposed to realistic design fire

PurposeLight-Gauge Steel Frame (LSF) structures are popular in building construction due to their lightweight, easy erecting and constructability characteristics. However, due to steel lipped channel sections negative fire performance, cavity insulation materials are utilized in the LSF configuration to enhance its fire performance. The applicability of lightweight concrete filling as cavity insulation in LSF and its effect on the fire performance of LSF are investigated under realistic design fire exposure, and results are compared with standard fire exposure.Design/methodology/approachA Finite Element model (FEM) was developed to simulate the fire performance of Light Gauge Steel Frame (LSF) walls exposed to realistic design fires. The model was developed utilising Abaqus subroutine to incorporate temperature-dependent properties of the material based on the heating and cooling phases of the realistic design fire temperature. The developed model was validated with the available experimental results and incorporated into a parametric study to evaluate the fire performance of conventional LSF walls compared to LSF walls with lightweight concrete filling under standard and realistic fire exposures.FindingsNovel FEM was developed incorporating temperature and phase (heating and cooling) dependent material properties in simulating the fire performance of structures exposed to realistic design fires. The validated FEM was utilised in the parametric study, and results exhibited that the LSF walls with lightweight concrete have shown better fire performance under insulation and load-bearing criteria in Eurocode parametric fire exposure. Foamed Concrete (FC) of 1,000 kg/m3 density showed best fire performance among lightweight concrete filling, followed by FC of 650 kg/m3 and Autoclaved Aerated Concrete (AAC) 600 kg/m3.Research limitations/implicationsThe developed FEM is capable of investigating the insulation and load-bearing fire ratings of LSF walls. However, with the availability of the elevated temperature mechanical properties of the LSF wall, materials developed model could be further extended to simulate the complete fire behaviour.Practical implicationsLSF structures are popular in building construction due to their lightweight, easy erecting and constructability characteristics. However, due to steel-lipped channel sections negative fire performance, cavity insulation materials are utilised in the LSF configuration to enhance its fire performance. The lightweight concrete filling in LSF is a novel idea that could be practically implemented in the construction, which would enhance both fire performance and the mechanical performance of LSF walls.Originality/valueLimited studies have investigated the fire performance of structural elements exposed to realistic design fires. Numerical models developed in those studies have considered a similar approach as models developed to simulate standard fire exposure. However, due to the heating phase and the cooling phase of the realistic design fires, the numerical model should incorporate both temperature and phase (heating and cooling phase) dependent properties, which was incorporated in this study and validated with the experimental results. Further lightweight concrete filling in LSF is a novel technique in which fire performance was investigated in this study.

Experimental and numerical investigations of LSF walls subject to distortional buckling

Light gauge Steel Frame (LSF) wall systems are increasingly replacing the conventional concrete and heavy steel structural systems due to the many advantages they offer. Web stiffeners are often included in the wall stud sections to improve their local buckling capacities and thus most of these studs are prone to buckle distortionally. Unlike for other buckling modes, the composite behaviour of wall studs sheathed with gypsum plasterboard is complicated for distortional buckling. This paper presents the details and results of experimental and numerical investigations into the structural behaviour of LSF walls subject to distortional buckling. Eight LSF wall assemblies were tested with varying parameters such as stud geometry, plasterboard thickness, number of plasterboard layers, sheathing arrangements and screw spacing. A high-fidelity finite element model capable of simulating the behaviour of LSF walls was developed and validated using the experimental results. The developed numerical models included geometric and material nonlinearities, initial geometric imperfections, contact interactions between stud, track and plasterboard sheathing, and most importantly the non-linear in-plane and pull-through screw connection behaviour. The validated numerical model was also used to further investigate the distortional buckling behaviour of LSF walls and the effects of some of the key modelling parameters. The analyses showed that stud-to-sheathing screw connections have a significant effect on the load-bearing capacity of LSF walls subject to distortional buckling, which can be enhanced by reducing the screw spacing and increasing the sheathing thickness and the number of sheathing layers.

Thermal and structural behavior of cold-formed steel frame wall under fire condition

Light gauge Steel Frame (LSF) system, are extensively used in residential, commercial and industrial buildings. Its growing popularity in building construction industry is due to several advantages over other construction materials such as light weight, high strength and stiffness, uniform quality, ease of prefabrication and mass production, economy in transportation and handling. Fire safety of cold-formed steel structures has become more important since cold-formed thin-walled steel sections heat up quickly under fire condition (high section factor and high thermal conductivity) and present low fire resistance. LSF wall systems are used as primary load bearing structural members providing strength and stability in multi-story LSF buildings. Therefore a better understanding of the fire performance of LSF wall systems is required. The structural behavior of the LSF walls at high temperatures depends on the temperature distribution at the wall component and the mechanical property of cold-formed steel and other materials used in LSF walls at elevated temperatures. Also, the thermal performance of the LSF wall is influenced by its components, including the stud cross-section, stud size, sheathing, and insulation types and their thicknesses, and thermal properties of them. In this paper, a numerical study was undertaken using the finite element program ABAQUS. The structural finite element analysis were conducted under transient state condition using the time–temperature profiles of wall components obtained from the thermal analysis. The finite element thermal and structural models were first validated by comparing their results with the previous test results and then a parametric study was conducted with considering the effect of various parameters such as type of sheathing and its arrangement, stud web depth, stud flange width, and stud cross-section shape. The temperature distribution and time–temperature profile of the wall component and Fire-Resistance Rating (FRR) of the wall have been calculated. The results showed that sheathing is one of the most critical factors in fire resistance of walls and has a significant influence on the FRR of walls and increasing the stud depth affects the thermal and structural behavior of the LSF wall and leads to an increase in the FRR of the wall against fire. Also, increasing the stud flange width of LSF wall does not affect the thermal behavior and temperature distribution of the wall, but leads to an increase in the FRR of the wall against fire. The stud cross-section shape does not affect the temperature distribution in the cross-section but can affect the wall’s behavior under fire conditions.

Novel conventional and modular LSF wall panels with improved fire performance

Fire performance of Light-gauge Steel Frame (LSF) constructions is being extensively investigated recently, due to the critical behaviour of cold-formed steel structures at elevated temperatures. Among the many design parameters involved with LSF constructions, the effect of cavity insulation inside LSF walls at different ratios on the Fire Resistance Level (FRL) has not been addressed yet. Hence, Finite Element Models (FEMs) were developed for the LSF walls to simulate the full-scale fire tests conducted applying the standard fire temperatures, where the Finite Element Analyses (FEA) results were very well agreeing with the experimental results. Thereafter, the validated FEMs were extended to study the fire performance of the conventional and modular LSF wall systems with different cavity insulation ratios, where 0.4 cavity insulation ratio was found to be most efficient when structural FRL is of concern while producing satisfactory energy performance at reduced material costs. To calculate the structural FRLs of conventional and modular, single and double plasterboard layers sheathed LSF walls, 4 empirical models have been proposed where more than 97% accuracy was achieved. Moreover, incorporating back blocking panels and discontinuous insulation options, several novel conventional and modular LSF walls have been proposed with up-to 70% improvement in structural FRL.

Fire resistance of external LSF walls with corrugated steel cladding

This paper presents the details of full-scale standard fire tests of external light-gauge steel-framed (LSF) walls with corrugated steel cladding exposed to fire on the external side. Corrugated steel cladding of 0.42mm thickness is generally used in roof and wall systems of buildings. In this study, it is used as the wall cladding of external LSF walls and as a lightweight cladding replacement to the combustible aluminium composite panels. A detailed investigation was undertaken to evaluate and understand the fire and energy performance of corrugated steel clad external LSF walls, which included (a) thermal property tests of two different types of Earthwool insulation (glass fibre insulation) used in wall systems, (b) full-scale (3m×3m) load bearing standard fire tests of two external LSF wall systems – first with cavity insulation and the second with external insulation and (c) THERM modelling of the tested walls. Steel cladding prevented direct exposure of fire on plasterboards and hence delayed the temperature rise and increased the failure time. Overlaps along the vertical edges of steel cladding played a critical role as gaps formed during the tests. The two external LSF wall systems achieved fire resistance levels (FRLs) in excess of two hours (122min and 158min) with improvements greater than 40% due to the addition of thin steel cladding. Replacing cavity insulation with external insulation improved the FRL by about 30% and also its effectiveness in terms of energy efficiency.

Effects of insulation materials and their location on the fire resistance of LSF walls

Lightweight walls incorporate insulation materials to compensate for their low thermal mass and to improve thermal performance. This helps in increasing the energy performance of the buildings. Since insulation materials are sensible heat storage materials, there is an increment in the room temperature. Phase Change Materials (PCMs) are used in lightweight walls due to their high thermal storage capacity and the resulting enhanced thermal comfort levels. However, the performance of the PCM incorporated building products/insulations in fire has not been investigated yet. This research has investigated the fire resistance of Light gauge steel framed (LSF) walls with PCM incorporated cellulose insulation through small-scale fire tests. It has also investigated the effects of using different insulation materials and their location on the fire resistance of LSF walls. Important results of this research are presented in this paper in the form of time-temperature profiles for cavity and externally insulated LSF wall configurations with and without PCM incorporated cellulose insulation. Findings reveal that externally insulated LSF walls have higher fire resistance levels than cavity insulated LSF walls based on insulation failure criterion. Importantly, adding PCM to cellulose insulation improves the fire resistance of both cavity and externally insulated LSF walls. PCM incorporated cellulose insulation can be used externally in LSF walls to enhance their fire and energy performance. However, the fire behaviour of Vacuum Insulation Panel (VIP) incorporated LSF wall is completely different to other wall systems.

Energy performance of fire rated LSF walls under UK climate conditions

Light-gauge Steel Frame (LSF) systems, one of the emerging building practices can be susceptible for catastrophic failure in fire accidents and less energy efficient due to the high thermal conductance of Cold Formed (CF) steel elements and resulting thermal bridging effect. Apart from independent investigations and optimization on LSF walls against fire and energy performance, it is vital to build-up knowledge on energy performance of fire rated LSF walls. Therefore, a series of fire rated conventional and modular LSF wall panels, which covers a wide range of industrial practices in European countries, have been investigated for their thermal transmittance, U-Value in the present study. Firstly, Finite Element Models (FEM) for three LSF wall panels were developed and validated against previous results. Subsequently, these models were extended to analyse the U-Values of the parametric specimens. The results show that, the concepts of back-blocking panels and discontinuous insulation options account for only slight improvements of U-Value (3–5%). Moreover, the variation of U-Value with respect to the cavity insulation ratio is found to be quite interesting, that adding cavity insulation at very low Insulation Ratios (IR) like 0.2 to 0.4, a 40%–60% reduction in the U-Value is obtained while further increase in IR results in less than 10% U-Value reduction. Therefore, 0.2 to 0.4 IR is proposed for conventional and modular LSF walls for appreciable energy performance avoiding unnecessary compensation in terms of costs, weight of the structure and structural fire performance.