Superior Fire Performance Research Articles

Development of Flame-Retardant Polylactic Acid Formulations for Additive Manufacturing.

Polymeric materials, renowned for their lightweight attributes and design adaptability, play a pivotal role in augmenting fuel efficiency and cost-effectiveness in railway vehicle development. The tailored formulation of compounds, specifically designed for additive manufacturing, holds significant promise in expanding the use of these materials. This study centers on poly(lactic acid) (PLA), a natural-based biodegradable polymeric material incorporating diverse halogen-free flame retardants (FRs). Our investigation scrutinizes the printability and fire performance of these formulations, aligning with the European railway standard EN 45545-2. The findings underscore that FR in the condensed phase, including ammonium polyphosphate (APP), expandable graphite (EG), and intumescent systems, exhibit superior fire performance. Notably, FR-inducing hydrolytic degradation, such as aluminum hydroxide (ATH) or EG, reduces polymer molecular weight, significantly impacting PLA's mechanical performance. Achieving a delicate balance between fire resistance and mechanical properties, formulations with APP as the flame retardant emerge as optimal. This research contributes to understanding the fire performance and printability of 3D-printed PLA compounds, offering vital insights for the rail industry's adoption of polymeric materials.

The physical, mechanical and fire performance of bamboo scrimber processed with thermal-treated bamboo bundles

Thermal treatment is gaining increasing attention for bamboo modification in practical production due to its advantages of simplicity, effectiveness and environmental friendliness, particularly in the production of bamboo scrimber. The objective of this study is to investigate the effects of two typical thermal modification methods on the physical, mechanical and fire performance of bamboo scrimber, as well as the related physicochemical properties of bamboo bundles for production purpose. The results indicated that the two types of bamboo scrimber processed distinct advantages in terms of physical and mechanical performances. Specifically, the one processed with bamboo bundles treated by superheated steam at a temperature of 200 ℃ (referred to as the “HL group”), exhibited exceptional dimensional stability and fire resistance, while exhibiting slightly lower mechanical properties. Notably, the HL group exhibited a significantly more pronounced hue compared to the LS group, which was treated with saturated vapor at a temperature of 140 ℃. Both demonstrated exceptional water resistance, with the HL group surpassing that of the LS group in either 24-hour room temperature or a combination of boiling-drying cycling treatments. The MORs of the LS group were determined to be 152.3 MPa and 108.5 MPa under dry and wet conditions, respectively, exhibiting significantly higher values than those observed in the HL group. Conversely, the variation of MOEs was found to be opposite. Both MORs and MOEs of the two groups exhibited a significant decrease in wet condition compared to those in dry condition, with reductions linearly correlated to water absorption of the samples. The failure mode of the LS group demonstrated elastoplastic failure characterized by a “Z-shaped”, while the HL group exhibited with a relatively flat cross-section. Furthermore, the HL group demonstrated superior fire performance in comparison to the LS group, and as evidenced by a significantly denser char residue surface with fewer and wider cracks than that of the LS group. The variations of chemical components and microstructures in bamboo can be attributed to variances in the extent of degradation of hemicellulose, lignin, and even cellulose during the thermal modification processes. The water resistance, dimensional stability and fire performance of bamboo scrimber can be significantly improved through thermal treatment, while resulting in a decrease in MOR, particularly for the HL group. The HL and LS groups of bamboo scrimber both exhibited excellent performances, making them suitable for application as structural engineering materials. The work we conducted offers experimental and theoretical support for improve the pre-treatment procedures of bamboo in the manufacturing of bamboo scrimber for structural utilizations.

Fire resistance of 3D printed concrete composite wall panels exposed to various fire scenarios

PurposeFire safety of a building is becoming a prominent consideration due to the recent fire accidents and the consequences in terms of loss of life and property damage. ISO 834 standard fire test regulation and simulation cannot be applied to assess the fire performance of 3D printed concrete (3DPC) walls as the real fire time-temperature curves could be more severe, compared to standard fire curve, in terms of the maximum temperature and the time to reach that maximum temperature. Therefore, this paper aims to describe an investigation on the fire performance of 3DPC composite wall panels subjected to different fire scenarios.Design/methodology/approachThe fire performance of 3DPC wall was traced through developing an appropriate heat transfer numerical model. The validity of the developed numerical model was confirmed by comparing the time-temperature profiles with available fire test results of 3DPC walls. A detailed parametric study of 140 numerical models were, subsequently, conducted covering different 3DPC wall configurations (i.e. solid, cavity and rockwool infilled cavity), five varying densities and consideration of four fire curves (i.e. standard, hydrocarbon fire, rapid and prolong).Findings3DPC walls and Rockwool infilled cavity walls showed superior fire performance. Furthermore, the study indicates that the thermal responses of 3DPC walls exposed to rapid-fire is crucial compared to other fire scenarios.Research limitations/implicationsTo investigate the thermal behaviour, ABAQUS allows performing uncoupled and coupled thermal analysis. Coupled analysis is typically used to investigate combined mechanical-thermal behaviour. Since, considered 3DPC wall configurations are non-load bearing, uncouple heat transfer analysis was performed. Time-temperature variations can be obtained to study the thermal response of 3DPC walls.Originality/valueAt present, there is limited study to analyse the behaviour of 3DPC composite wall panels in real fire scenarios. Hence, this paper presents an investigation on the fire performance of 3DPC composite wall panels subjected to different fire scenarios. This research is the first attempt to extensively study the fire performance of non-load bearing 3DPC walls.

Multi elements-based hybrid flame retardants for the superior fire performance of polyamide 66 textiles

Multi-elements based hybrid (i.e., organic/inorganic) flame retardant compounds, namely phenyl dichlorophosphate (PDP) based two different engineered structures synthesized with (3-Aminopropyl) triethoxysilane (APTES) (i.e., containing P, N and Si) and boric acid-doped-APTES (BA-d-APTES) (i.e., containing P, N, Si and B) were considered in escalating the fire performance of polyamide 66 (PA66) textiles. All the treated fabrics irrespective of type and loading % (i.e., 5–10 wt. %) of flame retardant compounds exhibited better thermal stability at a higher temperature range and produced enhanced charring. In line, such treatment increased the limiting oxygen index (LOI) value by up to 25.5 % for the fabric sample modified with 10 wt. % of PDP-APTES (i.e., PA66-PDP-A-10W). Moreover, the applied finishing diminished the serious dripping of PA66 textiles completely and brought a significant reduction in the peak heat release rate (pHRR) by 34 % along with a slight reduction in the total heat release rate (THR) by about 5 %. Even more, such treatment left a negligible impact of mechanical properties of treated textiles while offered a considerable durability against home laundering. Thus, these multi-elemental based hybrid compounds optimized in the condensed phase mechanism were found to be an effective flame retardant for PA66 textiles.

From Cells to Residues: Flame-Retarded Rigid Polyurethane Foams

ABSTRACT Rigid polyurethane foams (RPUFs) exhibit short times to ignition as well as rapid flame spread and are therefore considered to be hazardous materials. This paper focuses on the fire phenomena of RPUFs, which were investigated through a multimethodological approach. Water-blown polyurethane (PUR) foams without flame retardants (FRs) as well as water-blown PUR foams containing triethyl phosphate as a gas phase-active FR were examined. The aim of this study is to clarify the influence of the FR on the fire phenomena during combustion of the foams. Additionally, materials’ densities were varied to range from 30 to 100 kg/m3. Thermophysical properties were studied by means of thermogravimetry; fire behavior and flammability were investigated via cone calorimeter and limiting oxygen index, respectively. During the cone calorimeter test, the temperature development inside the burning specimens was monitored with thermocouples, and cross sections of quenched specimens were examined visually, giving insight into the morphological changes during combustion. The present paper delivers a comprehensive study, illuminating phenomena occurring during foam combustion and the influence of a FR active in the gas phase. The superior fire performance of flame-retarded PUR foams was found to be based on flame inhibition, and on increased char yield leading to a more effective protective layer. It was proven that in-depth absorption of radiation is a significant factor for estimation of time to ignition. Cross sections investigated with the electron scanning microscope exhibited a pyrolysis front with an intact foam structure underneath. The measurement of temperature development inside burning specimens implied a shift of burning behavior towards that of non-cellular materials with rising foam density.

Study on the composition and structure of foamed gel for fire prevention and extinguishing in coal mines

The spontaneous combustion of coal in coal mine gob remains a serious threat to workers’ safety, and the present work examined the use of foamed gel to prevent coal ignition. A foamed gel is a polymeric substance consisting of foam agent, gelling agent, cross-linker and water. Gelation time, foaming multiple and water loss are key factors to evaluate the fire suppression properties of these materials. The experiments in this study demonstrated that the optimum volume fractions of the foaming, gelling and cross-linking agents were 0.5%, 2%, and 1% respectively. The average gelation time of the foamed gel was 174s, the foaming multiple was 5.4, and the water loss of the foamed gel over 10min was 11%, which was significantly less than the value of 91% for pure foam. 3D-X ray experiments showed that foamed gel has similar structure as pure foam, and gel skeleton could maintain the intact of foamed gel, enhance the stability, and increase heat capacity. Compared to pure foam, the foamed gel examined in this study exhibits superior fire prevention performance.

N-P-Zn-containing 2D supermolecular networks grown on MoS2 nanosheets for mechanical and flame-retardant reinforcements of polyacrylonitrile fiber

In this work, a novel sandwich-type hybrid denoted as MPZSN-MoS2 was constructed by the self-assembling of melamine, phytic acid and Zn2+ to grow 2D supermolecular networks (MPZSN) onto the surface of molybdenum disulfide (MoS2) nanosheet, which was applied in mechanical and flame-retardant reinforcements of polyacrylonitrile fiber. With the incorporation 2 wt% MPZSN-MoS2, the tensile strength and elongation at break of MPZSN-MoS2/PAN composite fiber were increased by 68.2% and 27.8% compared to pure PAN fiber, respectively. The initial thermal decomposition temperature (T−5%) of MPZSN-MoS2/PAN fiber was increased by 21 °C, suggesting the enhanced thermal stability. Importantly, the single MPZSN-MoS2/PAN composite fiber could not be ignited and exhibited noticeable char formation when directly exposed to a flame, while the pure PAN fiber caught fire immediately and burned out. Moreover, the peak heat release rate and total heat release of MPZSN-MoS2/PAN fiber were remarkably decreased by 49.9% and 38.1% in contrast to pure PAN fiber, indicating its superior fire performance. The gaseous and condensed analysis demonstrated that the addition of MPZSN-MoS2 hybrids inhibited the effusion of pyrolysis products, such as HCN, CO, aliphatic CH compounds, CC compounds and carbonyl compounds, and promoted the generation of graphitized protective char layer on the fiber surface. This work presents a facile strategy for the design of MoS2-based hybrids with multi-components, expanding their potential applications in polymer composites.

Synergy between melamine cyanurate, melamine polyphosphate and aluminum diethylphosphinate in flame retarded thermoplastic polyurethane

The multicomponent flame retardant system of melamine polyphosphate (MPP), melamine cyanurate (MC) and aluminum diethylphosphinate (AlPi) is proposed and investigated for thermoplastic polyurethane (TPU). The synergy between those additives and the resulting superior fire performance are discussed. Systematically varied sets of flame retarded TPU with various MPP/MC/AlPi ratios were investigated in terms of fire behavior, pyrolysis products and mechanical properties. The total amount of the additives was always 30 wt.-%. Further, the influence of various AlPi concentrations was investigated. The optimal MPP:MC ratio was determined while keeping the amount of AlPi constant. The combination of 8 wt.-% MPP, 12 wt.-% MC and 10 wt.-% is proposed as the most promising halogen free flame retardant formulation for TPU, because it yielded a reduction in PHRR from 2660 kW/m2 (TPU) to 452 kW/m2 and enabled V-0 classification in the UL 94 test. Combinations of MPP and MC as well a high concentration of AlPi are beneficial for the mechanical properties e.g. tensile strength and elongation at break of the formulations and could be a strong competitor to commercial flame retarded TPUs.

Fire Phenomena of Rigid Polyurethane Foams.

Rigid polyurethane foams (RPUFs) typically exhibit low thermal inertia, resulting in short ignition times and rapid flame spread. In this study, the fire phenomena of RPUFs were investigated using a multi-methodological approach to gain detailed insight into the fire behaviour of pentane- and water-blown polyurethane (PUR) as well as pentane-blown polyisocyanurate polyurethane (PIR) foams with densities ranging from 30 to 100 kg/m3. Thermophysical properties were studied using thermogravimetry (TG); flammability and fire behaviour were investigated by means of the limiting oxygen index (LOI) and a cone calorimeter. Temperature development in burning cone calorimeter specimens was monitored with thermocouples inside the foam samples and visual investigation of quenched specimens’ cross sections gave insight into the morphological changes during burning. A comprehensive investigation is presented, illuminating the processes taking place during foam combustion. Cone calorimeter tests revealed that in-depth absorption of radiation is a significant factor in estimating the time to ignition. Cross sections examined with an electron scanning microscope (SEM) revealed a pyrolysis front with an intact foam structure underneath, and temperature measurement inside burning specimens indicated that, as foam density increased, their burning behaviour shifted towards that of solid materials. The superior fire performance of PIR foams was found to be based on the cellular structure, which is retained in the residue to some extent.

10.12: Numerical modelling of steel sheathed LSF walls under fire conditions

ABSTRACTFire performance of light gauge steel framed (LSF) walls sheathed with gypsum plasterboards has been investigated using experimental and numerical studies by many researchers in the past. Provision of cavity or external insulation, improving the thermal‐mechanical properties of plasterboard, and changing the stud geometry are several options previously employed to enhance the Fire Resistance Level (FRL) of such wall systems. Past studies of steel sheathed cold‐formed steel (CFS) framed walls have shown that the use of steel sheathing improves the shear strength of LSF walls. However, such studies have not investigated the possible improvements to the fire performance of LSF walls due to the use of steel sheathing in addition to plasterboards. This numerical study investigates the thermal performance of three common LSF wall configurations sheathed with steel sheets on both sides under fire conditions. Three steel sheathing configurations (internal and/or external sheathing) were considered for each LSF wall. Thermal Finite Element (FE) models were developed and used to simulate the heat progression across the walls, following validation using previous experimental studies. The walls were exposed to ISO 834‐1 standard fire curve on one side. Results were then compared with those from LSF walls sheathed only with plasterboards. Internal steel sheathing was found to be capable of reducing the ambient side temperatures compared to plasterboard only walls due to the lower emissivity of steel, whereas external steel sheathing increased them further. Although the stud hot flange (HF) temperatures are generally increased with the addition of steel sheets, provision of back‐blocking was able to eliminate this deficiency. A novel arrangement is proposed for back‐blocking which is found to significantly delay the stud temperature rise and improve the FRL. The use of corrugated steel sheet profiles is found to reduce both the stud and ambient side plasterboard temperatures. The results from this study give useful information to develop load bearing and non‐load bearing LSF walls with superior fire performance. This paper presents the details of this numerical study and the results.

Improving the Fire Performance of LSF Wall and Floor Systems Using External Insulation

The load-bearing light-gauge steel-framed (LSF) wall systems used in buildings are protected against fire by attaching fire-resistant gypsum plasterboard layers on both sides. They are also provided with cavity insulation to improve the thermal comfort of buildings during severe hot and cold weather conditions. However, recent research studies have shown that cavity insulation reduces the fire performance of load-bearing LSF walls. Therefore, researchers at the Queensland University of Technology proposed the use of externally insulated LSF walls and floors where insulation is sandwiched between the inner and outer layers of plasterboard instead of being placed inside the cavity. This article reviews and evaluates the results from the small- and full-scale fire tests and numerical studies performed on such externally insulated wall and floor systems exposed to standard and code-prescribed parametric fire curves. Comparison of the fire-resistance ratings and time–temperature profiles of the cavity-insulated and externally insulated wall and floor systems confirmed the superior fire performance of externally insulated load-bearing LSF walls and floors compared with cavity-insulated systems. The reasons for the superior fire performance are discussed in this article. This research also found that placing the plasterboard joints along the studs had minimum detrimental effects on the fire performance of externally insulated LSF wall systems. Overall, this research recommends the use of externally insulated wall and floor systems instead of cavity-insulated systems because of their thermal comfort and superior fire performance. This article includes the details of an efficient LSF wall construction process based on the use of composite panels consisting of two plasterboard layers with insulation sandwiched between them.

Prefabricated Timber Concrete Composite Floors

Timber-concrete-composite (TCC) floors are an example of hybrid systems that integrate different materials to achieve superior performance than the individual materials can provide. The structural and non-structural benefits of TCC floors over generic timber floors include increased capacity and stiffness, hallower depth, improved sound protection, and superior fire performance. Rapid erection due to the use of the timber as formwork, more economical gravity systems and foundations due to lighter weight, lower embodied energy, and reduced carbon footprint are advantages when comparing TCC systems to concrete slabs. This paper gives an overview of recent developments including research carried out on three novel solutions: 1) the äóìSwiss-Wood-Concrete-Flooräó�; 2) adhesively bonded TCC; and 3) äóìFT connectorsäó� that are embedded in precast concrete. All three solutions are well suited for modular and off-site construction and show the potential of using wood products beyond current limitations.

Synthesis, Structure-Property Relationships of DOPO-Phosphonamidates and their Flame Retardant Application

Three bis-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-phosphonamidates were successfully synthesized and well characterized. The influence of these DOPO-phosphonamidates on fire performance of epoxy resin was comparatively investigated. UL-94 tests results of various EP formulations indicated that DOPO-phosphonamidates exhibited superior fire performance. The EP composite containing extremely low loading of PiP-DOPO (0.5 wt% P) may pass the UL-94 V-0 rating, while EDA-DOPO and DDM-DOPO made the EP pass the V-1 rating. Thermal degradation results of the DOPO-phosphonamidate indicated the higher thermal stability with the initial degradation temperature over 340 °C under nitrogen. Moreover, only a very small residue was observed at 800 °C for DOPO-phosphonamidates and all EP formulations under air and nitrogen, indicating the limited condensed phase interaction. DDM-DOPO with richer aromatic structures presented the highest thermal stability and left more char residues. Large amount of gas products during the combustion of PiP-DOPO rapidly released in a short time, promoting flame inhibition, which may explain its superior flame retardant efficacy among all the DOPO-phosphonamidates investigated in this study.

Thermal performance of LSF floors made of hollow flange channel section joists under fire conditions

Light gauge steel frame (LSF) floor systems used in the building industry are made of cold-formed lipped channel section (LCS) joists and lined using gypsum plasterboards. The recently developed LSF floor systems made of welded hollow flange channel (HFC) section joists exhibited superior fire performance in the full scale fire tests. Since full scale fire tests are expensive and time consuming, finite element (FE) models were used in this research on LSF floor systems. In this paper 2-dimensional FE models were developed using a finite element analysis software SAFIR to predict the thermal performance of LSF floors made of HFC joists, and validated using the fire test results. The developed FE models predicted the thermal performance of LSF floor systems exposed to standard fires reasonably well. The validated model was then modified to include plywood subfloor and was used to investigate the effects of important parameters such as joist size, shape and subfloor thickness on the time–temperature profiles of the outer hot and cold flanges of HFC joists. These time–temperature profiles can be directly used to estimate the fire resistance ratings (FRR) of LSF floors made of HFC joists without performing expensive full scale fire tests. This paper presents the details of this thermal analysis study and the results.

Fire design rules for LSF walls made of hollow flange channel sections

Cold-formed Hollow Flange Channel (HFC) sections can be used in Light gauge Steel Frame (LSF) wall systems due to their structural efficiency. Recent experimental and finite element analysis based investigations conducted by the authors have demonstrated the superior fire performance of LSF walls made of welded HFC sections. The authors have developed a wide range of fire performance data of LSF walls through a finite element analysis (FEA) based extensive parametric study. This paper investigates the applicability of the available fire design rules to predict their structural capacities. Since fire design rules were not available for HFC sections, the latest design rules for LCS studs subjected to non-uniform temperature distributions were selected for evaluation from the pool of various design rules given in standards and previous studies. Suitable modifications were then incorporated for simplification and improved accuracy. Two improved design methods based on AS/NZS 4600 and Eurocode 3 were proposed. The structural capacity of HFC section stud found from the design rule predictions was converted into load ratio which is the ratio between the structural capacities under fire and ambient conditions, and the load ratio versus FRR curve were produced for different LSF walls. These were then compared with the FEA results, to verify the accuracy of the proposed design rules. This paper also presents suitable DSM based design method proposed for HFC section studs subject to non-uniform temperature distributions in LSF walls, and verifies its accuracy.

Combustion performance of engineered bamboo from cone calorimeter tests

The combustion and charring properties of two types of engineered bamboo for structural applications: laminated bamboo sheets and bamboo scrimber were investigated through cone calorimeter tests conducted at three levels of heat flux, 25, 50 and 75 kW/m2. The test was conducted with the grain both perpendicular and parallel to incident heat flux. The ignitability and combustibility parameters of these two types of engineered bamboo were calculated and the time to ignition, heat release and mass loss rates, specific extinction area, effective heat of combustion, and carbon monoxide and carbon dioxide yield were compared. Based on observations for timber, the average measured charring rates from the cone calorimeter tests at a heat flux of 50 kW/m2 and exposure time of 30–60 min were taken as equivalent charring rates for standard furnace tests and compared with those promulgated by European and Australian standards. Bamboo scrimber, having a density almost twice that of laminated bamboo, demonstrated superior fire performance in all parameters considered and approached the performance of a representative hardwood. The orientation of the grain was observed to have negligible influence on their charring performance for laminated bamboo, while for bamboo scrimber, the charring rate when the grain was perpendicular to the incident heat flux was slightly smaller than when the grain was parallel to incident heat flux. Finally, this study demonstrates the utility of the relatively inexpensive cone calorimeter test, for the rapid assessment of combustion and particularly charring performance of bamboo.

A numerical analysis on the performance of buckling restrained braces at fire-study of the gap filler effect

Buckling Restrained Braces (BRB) have been widely used in the construction industry as they utilize the most desirable properties of both constituent materials, i.e., steel and concrete. They present excellent structural qualities such as high load bearing capacity, ductility, energy-absorption capability and good structural fire behaviour. The effects of size and type of filler material in the existed gap at the steel core-concrete interface as well as the element's cross sectional shape, on BRB's fire resistance capacity was investigated in this paper. A nonlinear sequentially-coupled thermal-stress three-dimensional model was presented and validated by experimental results. Variation of the samples was described by three groups containing, the steel cores with the same cross section areas and equal yield strength but different materials (metal and concrete) and sizes for the gap. Responses in terms of temperature distribution, critical temperature, heating elapsed time and contraction level of BRB element were examined. The study showed that the superior fire performance of BRB was obtained by altering the filler material in the gap from metal to concrete as well as by increasing the size of the gap. Also, cylindrical BRB performed better under fire conditions compared to the rectangular cross section.

Numerical study of LSF floors made of hollow flange channels in fire

Light gauge steel frame (LSF) floor systems are generally made of lipped channel section joists and lined with gypsum plasterboards to provide adequate fire resistance rating under fire conditions. Recently a new LSF floor system made of welded hollow flange channel (HFC) section was developed and its fire performance was investigated using full scale fire tests. The new floor systems gave higher fire resistance ratings in comparison to conventional LSF floor systems. To avoid expensive and time consuming full scale fire tests, finite element analyses were also performed to simulate the fire performance of LSF floors made of HFC joists using both steady and transient state methods. This paper presents the details of the developed finite element models of HFC joists to simulate the structural fire performance of the LSF floor systems under standard fire conditions. Finite element analyses were performed using the measured time–temperature profiles of the failed joists from the fire tests, and their failure times, temperatures and modes, and deflection versus time curves were obtained. The developed finite element models successfully predicted the structural performance of LSF floors made of HFC joists under fire conditions. They were able to simulate the complex behaviour of thin cold-formed steel joists subjected to non-uniform temperature distributions, and local buckling and yielding effects. This study also confirmed the superior fire performance of the newly developed LSF floors made of HFC joists.

Fire tests of load-bearing LSF walls made of hollow flange channel sections

Fire resistant and load bearing Light gauge Steel Frame (LSF) wall systems are generally made of cold-formed steel stud sections lined with gypsum plasterboards. Structural stability of these steel frames at elevated temperatures is important for the load bearing LSF walls for survival during fire events. The studs in these frames are usually Lipped Channel Section (LCS) studs. However, there are other more structurally efficient stud sections such as the hollow flange section studs, which can be effectively used in LSF walls. However, lack of fire research on these sections has inhibited their usage in LSF walls. This paper proposes the use of hollow flange channel (HFC) section studs in LSF walls with a view to increase their fire resistant ratings (FRR). In this study, five full scale fire tests of LSF walls made of welded hollow flange channel section studs were conducted under standard fire conditions. Three different wall configurations and three load ratios were considered in these tests. This paper presents the details of fire tests and their results including the time-temperature profiles of plasterboard and steel stud surfaces, lateral displacement and axial deformation profiles, failure modes and failure temperatures. It also presents the effects of using different wall configurations and load ratios on the FRR of LSF walls. Comparison of the fire performance of LSF walls made of welded HFC section studs with those made of conventional LCS studs demonstrated the superior fire performance through the use of welded HFC section studs.

Combustion and charring properties of five common constructional wood species from cone calorimeter tests

Cone calorimeter tests conducted at three levels of heat flux, 25, 50 and 75kW/m2, were employed to investigate the combustion and charring properties of five common constructional wood species: three softwood species: Douglas fir (Pseudotsuga menziesii), Scots Pine (Pinus sylvestris) and Southern pine (genus Pinus), and two hardwood species: Shorea (genus Dipterocarpaceae) and Merbau (Intsia bijuga). The ignitability and combustibility parameters of these five species were calculated and the time to ignition, heat release and mass loss rates, specific extinction area, effective heat of combustion, and CO and CO2 yield compared. The measured charring rates from the cone calorimeter tests were transformed to equivalent charring rates for standard furnace tests and compared with those promulgated by European and Australian standards. It is shown that transforming cone calorimeter data obtained under conditions of 50kW/m2 and fire exposure greater than 30min to equivalent furnace data using the concept of ‘local fire intensity’ resulted in relative good with standard-promulgated values for charring depths less than 30mm. Merbau, having a density almost twice the other four species, demonstrated superior fire performance in all parameters considered. The other four species were essentially indistinguishable in terms of their overall performance. Finally, this study demonstrates the utility of the relatively inexpensive cone calorimeter test, for the rapid assessment of combustion and particularly charring performance of timber.