Fire Resistance Tests Research Articles

Improved fire resistance of boron nitride/epoxy intumescent coating upon minor addition of nano-alumina

This study presents the fire resistance results of incorporating nano-sized alumina in boron nitride reinforced epoxy-based intumescent fire-retardant coating. Structural steel substrates were coated with the developed coating and exposed at 800 °C for 2 h for furnace fire test to examine the char expansion and morphology. The fire-resistance of the coating was tested by heating the coated substrates using a Bunsen burner for 1 h. The coated substrates were tested for water absorption followed by a fire-resistance test. The furnace fire test showed that boron nitride-alumina (BNA-1) reinforced with 0.1 wt% of nano-sized alumina resulted in 45% higher char compared to boron nitride-alumina reinforced with 0.4 wt% (BNA-4) and boron nitride-alumina reinforced with 0.5 wt% (BNA-5). The increased amount of alumina improved the mass of the char. The lowest substrate temperature of 137 °C was recorded by BNA-5 with a maximum char mass of 43.89 wt%. This was considered due to formation of aluminum oxide and aluminum phosphate on the char surface, reduced char pore size, and increased amount of alumina in the gas emission. X-ray Diffraction (XRD) analysis found boron phosphate, boron nitride, and phosphoric nitride compounds were reliable in protecting the substrate at high temperature. The functional groups of char compounds were observed by FTIR. FESEM micrographs showed the presence of nano-sized alumina. XPS results also suggest that nano-alumina may react with boron nitride and ammonium polyphosphate additives, producing aluminium nitride, boron oxide, and aluminium phosphate that are beneficial to the intumescent process and fire-resistant performance. Pyrolysis GC-MS results showed reduced emission of gaseous product in BNA-5. This concluded that the addition of 0.5 wt% alumina in BNA improved char morphology and increased char mass. No changes in the microstructure and hardness of the substrate were observed after the fire test. The fire resistance of the water-immersed samples showed a small increase in substrate temperature which was within the acceptable range for structural safety.

Scientific Research Basics of Fire Resistance Testing for Reinforced Concrete Structures and Buildings

Breakthroughs in the development of science and technology of fire testing and fire resistance tests, their present state are discussed, and ideas about the future development of fire resistance tests are given, furthermore the directions in which deeper studies are necessary, are marked. The first revolution in fire resistance testing began not so long ago, in the nineteenth century, when basic tools were developed to measure temperature and heat fluxes. The second revolution in the measurement and understanding of fire occurred in the early twentieth century with the worldwide recognition that scientifically well-reasoned fire-fighting standards are needed to protect people's lives and their property. At the same time, engineering innovations were developed for electromechanical equipment that could automatically record data obtained during a fire experimentally. This progress in data recording has made it possible to study fire behaviour in details. The third revolution in fire resistance testing took place in the second half of the twentieth century with the development of accessible digital data and computer recording equipment that improved data analysis and the development of evidence-based forecast models. The widespread application of technology and computational methods have opened up a theoretical world that provides nuanced insight of fire dynamics and gives the means for development of more effective fire test methods.

Design and Verification of Valve Fire-Resistant Experimental Device

The valve plays the role of a switch in the production process of the petrochemical industry, but there are often fire and explosion accidents in actual working conditions. The fire resistance of the valve is the ability of the valve to maintain normal operation in high temperature flames. It is a measure of the safety performance of the valve. Important indicators. This article mainly describes in detail the principle, equipment structure and design schemes of the fire resistance test device. The test of the valve fire test device was successfully carried out. The tests show that the performance parameters of the test device, such as temperature and pressure, meet the relevant requirements of the standard API 607 and API 6FB. Using high-precision sensors and advanced data collectors, it can simultaneously collect data such as pressure, temperature, and leakage. The fire resistance test of the valve was successfully completed, and the problems existing in the test were improved, and the direction of future optimization was proposed.

Experimental analysis of moisture transfer and phase change in porous insulation exposed to fire and its effect on heat transfer

Water vapour in porous building materials significantly affects the heat transfer. In addition to the regular humidity, materials, such as gypsum, release water vapour when they are heated, leading to a high resistivity to fire exposure. Although the heat and water vapour transfer through porous building materials at atmospheric conditions is well investigated, no data are available for the effective diffusion coefficient or velocity of the water vapour transfer when the structure is exposed to a thermal load or fire. For this purpose, fire resistance tests were carried out for gypsum/mineral wool constructions to determine the transient heating characteristic and water vapour transfer. It was found that for thin gypsum structures up to 2.5 cm the heating from ambient temperature to 65 ∘C is mainly caused by conduction. Further heating to 100 ∘C is related to the condensation of water vapour instead of thermal heat conduction. Furthermore, a significant decrease of the effective diffusion coefficient of water vapour in the mineral wool from 33.3 mm2/s to 26.7 mm2/s was determined during fire exposure. Based on the measurement the mean velocity of the water vapour transport was determined of being between 1 and 3 mm/s.

Numerical Modeling of Fire Resistance Test as a Tool to Design Lightweight Marine Fire Doors: A Preliminary Study

Finite element analysis (FEA) is employed to simulate the thermo-resistance of a marine fire-proof door in the fire-resistance test defined by the International Code for the Application of Fire Test Procedures (2010 FTP Code) and required by the International Maritime Organization (IMO) for marine applications. The appropriate type of simulation adopted (i.e., steady or unsteady) is discriminated on the basis of a comparison between the numerical results and the experimental data. This appropriate model is used to evaluate the critical parameters affecting fire-proof door performance. A remarkable role of the thermal bridge at the door edges in fire resistance is assessed, along with the parameters that allow its reduction. These findings provide insight into how to design a thinner and lighter fire door.

Intumescent coatings using epoxy, alkyd, acrylic, silicone, and silicone–epoxy hybrid resins for steel fire protection

Intumescent coatings are a great alternative for passive protection of metal substrates against fire, with binder polymer being one of the main components of an intumescent system. The objective of this work was to compare five different resin types (epoxy, acrylic, alkyd, silicone, and silicone–epoxy hybrid) in an intumescent formulation and to study the influence of resin concentration on the fire protection performance of the coating. Results from TGA and MCC analysis of resins and coatings indicated that coatings containing silicone are thermally stable and release smaller amounts of heat. In the fire resistance test, samples containing epoxy and silicone resins had lower temperatures (130–160°C) compared to the other samples. It has also been found that it is possible to decrease resin concentration in formulations containing epoxy and silicone resins up to 25.6% and to maintain or even improve their fire protection capability.

Timber beam in virtual furnace

Purpose This paper aims to present a part of a coupled numerical model for prediction the fire resistance of elements in a horizontal furnace. Temperatures calculated inside the timber beam are compared to measured values from the fire test. Design/methodology/approach The paper presents a part of a coupled numerical model for prediction the fire resistance of elements in a horizontal furnace. The presented part lies in a virtual furnace which simulates temperature environment around tested elements in the furnace. Comparison of results show good agreement in the case when burning of timber is included in the numerical model. Findings The virtual furnace presented in this paper allows to calculate temperature environment around three timber beams. After validation of the fire dynamics simulator (FDS) model, the temperature conditions are passed to the FE model which solves heat transfer to the tested element. Temperatures inside the timber beam which are solved in software Atena Science are compared to measured temperatures from the fire test. The comparison of temperatures in three control points shows good accuracy of the calculation in the point closer to the heated edge. An inaccuracy is shown in points located deeper in the beam cross-section – below the char layer. Research limitations/implications In conclusion, the virtual furnace has a great potential for investigating the thermal behaviour of fire-resistance tests. A huge advantage inheres in the evaluation of the thermal effect throughout the volume of the furnace, which allows an accurate prediction of fire-resistance tests and evaluation of large number of technical alternatives and boundary conditions. However, passing the temperature field from the FDS model into FE model may decrease the level of accuracy. The solution lies in a coupled CFD-FE model. A weakly coupled model including fluid dynamics, heat transfer and mechanical behaviour is under development at Faculty of Civil Engineering, Czech Technical University in Prague. The fluid dynamics part which is presented in this paper is solved by FDS and the thermo-mechanical part is computed by object-oriented finite element model (OOFEM). The interconnection of both software is made owing to MuPIF python library. Practical implications The virtual furnace takes advantage of great possibilities of computational fluid dynamics code FDS. The model is based on an accurate representation of a real fire furnace of fire laboratory PAVUS a.s. located in the Czech Republic. It includes geometry of the real furnace, material properties of the furnace linings, burners, ventilation conditions and tested elements. Gas temperature calculated in the virtual furnace is validated to temperatures measured during a fire test. Social implications The virtual furnace has a great potential for investigating the thermal behaviour of fire-resistance tests. A huge advantage inheres in the evaluation of the thermal effect throughout the volume of the furnace, which allows an accurate prediction of fire-resistance tests and evaluation of large number of technical alternatives and boundary conditions. Originality/value The virtual furnace has a great potential for investigating the thermal behaviour of fire-resistance tests. A huge advantage inheres in the evaluation of the thermal effect throughout the volume of the furnace, which allows an accurate prediction of fire-resistance tests and evaluation of large number of technical alternatives and boundary conditions. However, passing the temperature field from the FDS model into FE model may decrease the level of accuracy. The solution lies in a coupled CFD-FE model. A weakly coupled model including fluid dynamics, heat transfer and mechanical behaviour is under development at Faculty of Civil Engineering, Czech Technical University in Prague. The fluid dynamics part which is presented in this paper is solved by FDS and the thermo-mechanical part is computed by OOFEM. The interconnection of both software is made thanks to MuPIF python library.

An Experimental Study on Fire Resistance Performance of a Bended Type Cladding Column System

As buildings are growing higher and larger, more composite structures have been used. However, the steel member used for composite structure tends to rapidly lose its strength at elevated temperatures. For this reason, it is required to apply a fire resistance mechanism, but it is difficult to implement because of the cost and technical limitations in the case of fire-resistant paint. In case of fireproof spray coat, scattering phenomena, poor work conditions for wet application, and construction delay are the main challenges to be addressed. In this study, a full-scale fire resistance test of non-fire resistant cladding column was conducted in accordance with KS F 2257-7. According to the test results, the specimens CC-01, CC-02, and CC-03 failed to meet the requirements for a 3-hour fire resistance rating because of the joint deformation and less cover thickness, while CC-04, CC-05, and CC-06 with increased thickness and reinforced joints satisfied the requirements for a 3-hour fire resistance rating.

Thermal Response of Timber Slabs Exposed to Travelling Fires and Traditional Design Fires

Engineered timber is an innovative and sustainable construction material, but its uptake has been hindered by concerns about its performance in fire. Current building regulations measure the fire performance of timber using fire resistance tests. In these tests, the charring rate is measured under a series of heat exposures (design fires) and from this the structural performance is deduced. Charring rates are currently only properly understood for the heat exposure of a standard fire, not for other exposures, which restricts the use of performance-based design. This paper studies the charring rates under a range of design fires. We used a multiscale charring model at the microscale (mg-samples), mesoscale (g-samples), and macroscale (kg-samples) for several wood species exposed to different heating regimes and boundary conditions. At the macroscale, the model blindly predicts in-depth temperatures and char depths during standard and parametric fires with an error between 5% and 22%. Comparing simulations of charring under travelling fires, parametric fires, and the standard fire revealed two findings. Firstly, their charring rates significantly differ, with maximum char depths of 42 mm (travelling), 46 mm (parametric), and 59 mm (standard fire), and one (standard fire) to four (travelling fire) charring stages (no charring, slow growth, fast growth, steady-state). Secondly, we observed zero-strength layers (depth between the 200 °C and 300 °C isotherm) of 7 to 12 mm from the exposed surface in travelling fires compared to 5 to 11 mm in parametric fires, and 7 mm in the standard fire. Both traditional design fires and travelling fires, therefore, need to be considered in structural calculations. These results help engineers to move towards performance-based design by allowing the calculation of charring rates for a wide range of design fires. In turn, this will help engineers to build more sustainable and safe structures with timber.

Experimental and numerical studies on axially restrained cold-formed steel built-up box columns at elevated temperatures

Experimental and numerical studies on the fire resistance of cold-formed steel (CFS) columns with built-up box-shape sections were conducted in this paper. A series of coupon tensile tests were also performed before the fire resistance tests of the columns to obtain the stress–strain relationship of the steel plate from 20 °C to 800 °C. As a benchmark, the load-bearing capacity tests of the columns at ambient temperature were conducted first, and then the fire resistance tests were performed for eight specimens considering different load ratios and axial restraining stiffness. Afterward, numerical models, including heat transfer and structural analyses, were developed to reproduce the fire-resistance behavior of the columns and verified via test results. Finally, parametric analyses were performed to investigate the influence of load ratio, axial restraint, and rotational restraint on the fire-resistance behavior of the columns. Results indicated that the primary failure mode of the specimens was a combination of local and global flexural buckling, which was sensitive to the longitudinally non-uniform temperature field. Moreover, the increase in load ratio and axial restraining stiffness led to a significant decrease in the critical temperature and failure time. Moreover, even a low level of rotational restraint could enhance the fire-resistance behavior of the column.

Enhancing the thermal stability of silica-mineralized wood via layer-by-layer self-assembly

Employing a combination of a layer-by-layer self-assembly and sol gel methods, a negatively charged silica sol was successfully deposited into the cell wall and cell cavity of wood by the electrostatic attraction of cationic polyelectrolytes. The physical and mechanical properties, microscopic morphology and the chemical structure of the silica-mineralized wood were characterized using mechanical testing, scanning electron microscopy (SEM–EDS), Fourier-transform infrared spectroscopy and X-ray diffraction (XRD). The thermal performance of the treated wood was investigated using a cone calorimeter, thermogravimetry analysis (TG). SEM images and XRD results showed that the mineralization layer of the treated wood had various forms of amorphous nano-SiO2 particles, which could be attributed to multi-layers of polyelectrolytes. The mechanical strength of the mineralized wood was greatly improved. Based on the TG results, the major thermal degradation (mass loss at about 50%) began at higher temperatures for the silica-mineralized wood. Fire resistance testing demonstrated that the maximum heat release rate of the modified wood was less than that of the untreated wood, indicating that the silica mineralized layer had effectively altered the combustion mechanism. In addition, this work also considered the hydrophobic properties of silica-mineralized wood. In conclusion, the thermal stability and dimensional stability of silica-modified wood was insignificantly improved.

Assessment of lignin as a carbon source in intumescent coatings containing polyaniline

Lignin, a vegetable compound, is the second most abundant biorenewable and biodegradable polymer in nature. In this study, the addition of this compound to paints containing ammonium polyphosphate (APP) and expandable graphite as pigments was investigated to improve the fire protection performance of intumescent coatings. The combination of lignin with polyaniline (PANI) in the formulations was also evaluated, as previous studies have shown that PANI-based paints show promising results in intumescent coatings. For this purpose, the thermal protection of mild steel samples coated with these organic coatings was evaluated during a fire resistance test, with the sample exposed to a Bunsen torch. During the test, temperature data and thermography images for the steel surface were collected. The coatings were also evaluated by thermogravimetric analysis and microscale combustion calorimetry. It was found that all coatings formulated provided good fire protection to the steel substrate and the lignin could be a good option to replace nonrenewable sources in intumescent paints, since the sample coated with the paint containing 10 wt% lignin reached 230°C after 30 min of assay. In addition, when this compound was used in combination with PANI, the flame protection was even better. The best performance was observed for the paint formulated with combination of 10 wt% lignin and 10 wt% PANI-ES, whose metal substrate temperature was 170°C after 30 min of assay.

Preparation and study of fireproof materials with high‐waterproof performance

AbstractA new high waterproof and flame‐retardant material was developed by using polylactic acid as a binder. Fireproof composite materials have excellent physical, mechanical, and flame‐retardant properties. The water resistance property of fireproof composites increases as the polylactic acid doping ratio increases. Also, the mechanical performance test showed that the flexural strength of the composite materials reached 14.75 MPa a polylactic acid amount of 25 wt%. More so, the surface of the inorganic materials (magnesium hydroxide and aluminum hydroxide), were uniformly covered by the polylactic acid providing good interfacial compatibility between the inorganic materials and polylactic acid. The results of scanning electron microscopy showed that the fracture cross‐section of the composites was smooth and dense. Thermogravimetric analysis and fire resistance testing further confirmed that the fireproof materials have good thermal stability. The as‐prepared composite materials with improved physical and mechanical properties could be utilized to partitions in public buildings, non‐load bearing walls, and a sandwich for fire doors.

Problems and perspectives of fire resistance for wooden constructions in high-storey buildings

Introduction. A significant problem in construction area in theRussian Federation is the impossibility of high-rise wooden building. To solve this problem, it is necessary to study the state of the issue abroad and in theRussian Federation, and analyze the development prospects of this area. Main (analytical) part. The article provides examples of modern facilities (inBerlin,London,Melbourne and other cities), reflecting the state of high-rise wooden construction abroad. In the buildings considered, together with the predominant wooden structural and wood-containing finishing materials, reinforced concrete structural elements necessary for the implementation of complex technical systems are used, which can significantly reduce the time of their construction. In addition, the chosen approach allows to enhance environmental friendliness of buildings and structures, — due to the use of wood-containing materials, huge volumes of carbon dioxide are preserved and its emissions into the atmosphere during construction work are significantly reduced. The paper reflects the main provisions of technical regulation in the field of fire safety of building materials and structures in theRussian Federation. It is shown that the main reasons for the impossibility of using wooden structures in high-rise buildings are related to the peculiarities of technical regulation in theRussian Federation, in particular, the lack of the necessary methods for testing and certification of wooden building structures in high-rise construction. The necessity to optimize existing methods for testing wooden building structures is shown. Examples of various documents regulating the production and use of wooden and composite building structures are given. The work reflects in detail the international experience in the implementation of the main provisions of regulatory documents, as well as European tests for fire resistance, which shows the possibility of implementing such an experience in theRussian Federation. Conclusions. To develop a regulatory framework for the possibility of using wood structures in high-rise construction, it is necessary to conduct large-scale experiments on wooden structures in order to study their fire resistance. In this case, it is necessary to take into account the features of combustible building materials.

Effect of charring agents on solvent‐free fireproof coatings

The choice of charring agent is one of the major issues for solvent‐free fireproof coatings. The effects of processing method and charring agent on the thermal insulation and fire resistance of the coatings were investigated in simulated fire scenarios. Dipentaerythritol (DPER), triazine agent (CFA), and pentaerythritol phosphate (PEPA) were compared as charring agent, and the thermal, combustion, fire resistance, and charring behaviors in different fire scenario were characterized for the fireproof coatings. Compared with high‐speed dispersing equipment, kneading processing equipment is favorable for improving the thermal stability and fire resistance of the coatings, because the stronger shearing force has promoted mixing and dispersion of the ingredients in solvent‐free fireproof coatings. As for charring agents, it is found that the fireproof coatings containing CFA or PEPA show better thermal and flame‐retardant performances. More residue was observed under nitrogen atmosphere in thermogravimetric analysis, less heat and smoke were released in cone calorimetry test. However, during the high temperature fire resistance test, their char layers were prone to delaminate while DPER‐containing coatings produced intact and stronger char layer with better heat insulation. For practical applications, the coating formulations need to be optimized to achieve both fire resistance and flame retardancy.

Development of a numerically efficient approach based on coupled CFD/FEM analysis for virtual fire resistance tests—Part B: Deformation process of a steel structure

SummaryIn the present study, the structural analysis of a three‐parted steel door during a fire resistance test was examined by FEM simulation. The structural analysis is part of a coupled CFD/FEM simulation approach developed for the prediction of fire resistance tests. The basis of this follow‐up work was the calculated temperature in the test specimen from CFD to predict the thermal stresses, deformation and gap formation between the door parts. The spatial information of the temperature in the test specimen was exported. Subsequently, the thermal expansion of the door and the resulting stresses and gaps were calculated. To validate the FEM simulation, the deformation of the steel door was observed. It was found that the simulation predicted the deformation of the steel door in close accordance to the measurement. The maximum displacement was found in the centre of the construction with 141 mm, whereas the simulation predicted a value of 133 mm. In addition to the deformation of the door, also the prediction of the gap formation was validated against the flue gas leakage. The first flue gas exit occurred already after 120 seconds, which was in spatial and temporal conjunction with the maximum gap predicted in the simulation.

Fabrication and Fireproofing Performance of the Coal Fly Ash-Metakaolin-Based Geopolymer Foams.

This paper aims to investigate the influence of coal fly ash (CFA) addition on the fireproof properties of the metakaolin-based geopolymer foams. The physical properties, thermal conductivity and fire resistance of the CFA-metakaolin-based geopolymer foams are discussed. The CFA-metakaolin-based geopolymer foams achieve a dry density between 259.43 kg/m3 and 349.73 kg/m3, a porosity between 71.78% and 72.98%, a thermal conductivity between 0.0871 W/(m·K) and 0.0944 W/(m·K) and a compressive strength between 0.38 MPa and 0.56 MPa, exhibiting better physical properties than that of the porous blocks without CFA addition. It is also found that the CFA addition could decrease the viscous sintering temperature and change the phase compositions of sintering products, resulting in the porous structure deterioration in a certain extent and obvious rise of the final reverse-side temperature during the fire-resistance tests. Fortunately, the conversion of the amorphous geopolymer gel to ceramics has helped to maintain the main skeleton structure stability. The CFA-metakaolin-based geopolymer foams still exhibit excellent fire resistance, and the reverse-side temperatures are always within 250 °C after 3 h fire-resistance tests.

Fire Risk Analysis of Glass Installed in an Opening

This is an experimental study that analyzes the fire resistance performance of the types of glass installed in an opening to prevent a fire from spreading through the opening. The fire resistance test for glazed elements (KS F 2845) was performed on four materials: laminated glass, general glass, double-layer glass, and toughened glass. To analyze the risk of fire of each glass type, the temperature prediction of the fire room in the building was analyzed. As a result, the laminated glass ruptured at 617 ℃, and it was found to be the most resistant to heat amongst all the glass types. Additionally, the temperature of the fire in the compartment was predicted to reach 617 ℃ in 3 min. A performance review is required for the glass installed in the opening to prevent the fire from spreading.

The Heat Conductivity Properties of Hemp-Lime Composite Material Used in Single-Family Buildings.

The main goal of the paper is to calculate the heat conductivity for three experimental hemp–lime composites used for structural construction purposes with the use of the experimental stand inside two compartments. Due to current construction trends, we are constantly searching for eco-friendly materials that have a low carbon footprint. This is the case of the analyzed material, and additional thermographic heat distribution inside the material during a fire resistance test proves that it is also a perfect insulation material, which could be applied in addition of popular isolating materials. This paper presents the results of certain hemp–lime composite studies and the potential for using hemp–lime composite for the structural construction industry. Hemp–lime composite heat transfer coefficient, fire resistance, and bulk density properties are compared to those of other commonly used construction materials. The obtained results show that the material together with supporting beams made of other biodegradable materials can be the perfect alternative for other commonly used construction materials.

Effects of surfactant on thermo-mechanical behavior of geopolymer foam paste made with sodium perborate foaming agent

Geopolymer foams (GFs), in which macro-porosity is introduced on purpose into the micro- and meso-porous geopolymer matrix, have received wide interests as for energy conservation. In this study, fly ash based geopolymer foams were prepared using sodium perborate as a foaming agent and washing liquid as a surfactant. Effects of the surfactant contents on mechanical and thermal properties of the prepared foams have been focused on our studies. With additions of surfactant from 0.1 to 0.5%, pores of the GFs became finer. All GFs prepared with and without the surfactant showed 28 day-curing compressive strength in the range of 4.21–4.82 MPa with improvement when the surfactant was added. Thermal conductivity of GFs fell in the range of 0.27–0.32 W/m.K. In addition, fire resistance test on 40 mm-thick GF panels showed satisfactory behavior. When temperature on the hot side was increased to 1000 °C and beyond, the temperature on the cold side remained only around 300 °C for up to 120 min. However, the GFs with 0.3 and 0.5% surfactant showed superior fire resistance to those without and with 0.1% surfactant. In general, residual compressive strength of all GFs after the high temperature exposure was slightly higher than the unexposed ones, with an exception for the ones being heated at 1000 °C possibly due to densification of the geopolymer networks.