Single Burning Item Test Research Articles

Fire Safety for Green Façades: Part 1: Basics, State-of-the-Art Research and Experimental Investigation of Plant Flammability

This study is the first part of a larger investigation into the fire behaviour of green façades. In this study, the currently known international research status on this topic is presented and discussed. In addition, the flammability of green façades is investigated through 43 fire tests on a medium scale according to the SBI (Single Burning Item) test method EN 13823. The focus of the investigation was placed on climbing plants. A total of 25 different plant species were investigated. A comparison of the heat release rate of all the investigated vital plants shows similar behaviour. In the course of exposure, there are short peaks in the heat release rate. These peaks are “flare-ups” that occur when parts of the plants dry out due to exposure to the flame and then ignite. The plant species itself had no substantial influence on fire behaviour. Horizontal fire spread occurred to a very limited extent within the investigations of vital plants. They were self-extinguishing. The significant factor in the assessment of flammability is the moisture content of the plants. With dried plants, an abrupt heat release occurs at the beginning. Dried-out plants, as well as unmaintained plants with a high content of deadwood, represent the most critical case.Graphical

Evaluation of the Effect of the Composition of the Foam Glass Concrete on Its Flammability and Moisture Characteristics

The purpose of this study was to evaluate the moisture and flammability characteristics of lightweight concrete with different aggregates and different amounts of cement according to different criteria. The moisture properties of the specimens were evaluated by the coefficient of water absorption due to capillary action, short-term water absorption, and water vapour permeability. Short-term water absorption correlated with the density of the specimens, and capillary absorption was evaluated depending on the soaking time, amount of cement, and type of lightweight aggregate. The values of the water vapour diffusion resistance factor were estimated based on the amount of cement, the type of lightweight aggregate, the density, and the porosity. The porosity correlated with the amount of cement and the type of lightweight aggregate. The flammability properties of concrete with lightweight aggregate were evaluated by several methods, such as the single flame source test, the single burning item test, and the non-combustibility test. After assessing the flammability characteristics, a structure analysis of the samples was specifically performed to assess the processes that occur during the combustion of lightweight concrete. It was found that short-term water absorption depended mainly on the density, capillary absorption on the amount of cement, and the water vapour diffusion resistance factor, flammability, and thermal stability of lightweight concrete on the type of granules.

EVALUATION OF THE FIRE REACTION OF CONSTRUCTION PRODUCTS BY THE SBI METHOD (SINGLE BURNING ITEM)

The reconstruction of Ukraine requires progressive and innovative structural solutions that take into account the requirements of usage safety and fire safety of construction products. One of the mostimportant requirements set for building products and materials used inside buildings on walls and ceilings is the requirement forflammability. In Ukraine, the standard DSTU EN 13501-1 [3] regarding the fire classification of construction products is currently in effect.The standard defines testing methods applied to the evaluated product, as well as criteria for assessing the obtained test results, assigningthem corresponding basic classes of reaction to fire.If it is necessary to assess the behavior of the product at the further stage of a fire, testing should be conducted using the Single BurningItem (SBI) method according to DSTU EN 13823 [5]. The SBI method corresponds to the stage of fire development at which the buildingproduct is exposed to the heat of a single burning item. SBI testing can be conducted independently for technological trials and todetermine the basic operational characteristics of construction products.However, a complete classification of the reaction to fire depending on the class should be complemented by testing according to DSTUEN ISO 11925-2 [4], DSTU EN ISO 1182 [6], or DSTU EN ISO 1716 [7].The article provides a description of the process of conducting SBI method tests, how test results are calculated, what parameters themeasurement system on the SBI test stand calculates, and what they mean in relation toreal fire. The results of studies on some constructionproducts during SBI testing are presented.

New intumescent coatings for protection flammable materials interior and outside buildings

The effect of silica on the intumescent fire-retardant coating’s properties. Cone calorimetry and a single burning item test were used to determine flammability. The silica-modified intumescent coating allows obtaining a Bs1d0 class non-flammable material for the protection of wood and wood-based materials (e.g., plywood, chipboard, fiberboard, other lignocellulosic composites).

Fire safety risks of external living walls and implications for regulatory guidance in England

External living walls (LWs) have aesthetic and environmental appeal, but these characteristics must not compromise fire safety. A review of legislation indicates there are no specific fire regulations or test standards for LWs in England. Furthermore, the 2013 UK Green wall guidance document (GWGD) contradicts current guidance in Approved Document B (ADB) for certain categories of buildings, yet ADB cites GWGD as “best practice”. We suggest the recommended reaction to fire testing methodology for LW systems (single burning item (SBI) EN13823/ignitability EN ISO11925-2 tests) is inappropriate for assessing their fire performance. Despite some limitations, the BS8414 full-scale test could be used to assess LW installations. While not identified in the GWGD or specifically recommended within ADB as a suitable test method for LWs, it is arguably more appropriate than reduced scale SBI testing, primarily because it accommodates full LW modules with planting, and uses a more appropriate fire size. To reduce testing costs, we propose the use of CFD fire modelling, or a modified SBI test to identify candidate LW products likely to pass BS8414 testing. Given the inherent variable nature of LWs and their associated fire properties, LW maintenance is considered essential for on-going compliance with fire safety requirements.

Transparent fire protective sol-gel coating for wood panels

A transparent fire protective sol-gel coating deposited on wood has been evaluated using different fire tests, such as mass loss cone, mini single burning item and furnace tests. The heat release rate and total heat release during combustion, but also the flame spread behavior and the thermal protection performances of the coatings have been studied. Two processes to apply the sol-gel coating on wood have been assessed to show the thickness dependence of the fire performance. When deposited as a thick coating (800 μm thick) on wood, the sol-gel coating lowers the total heat release, decreases the flame spread and greatly improves the thermal protection of the substrate.

Experimental study of spruce wood reaction to fire in single burning item test

The aim of this work is to study and characterize the fire behavior of vertically oriented spruce wood panels using experiments conducted at the scales of cone calorimeter and single burning item tests. For this purpose, first incombustible panels were exposed to burner powers of 15, 20, 30, and 50 kW in the single burning item tests to obtain a mapping of the total heat fluxes received by the panel. Subsequently, wood panels were exposed to the same burner powers for exposure times of 15, 20, and 30 min. Very thin thermocouples were embedded inside the wood panel to measure accurately the in-depth temperatures while the lateral position of the char front on the exposed surface and the depth of the char layer were also measured for each test. The latter measurement permitted to establish a char depth map according to the burner power and exposure time. Correspondingly, it was observed that for a fixed exposure time, the degraded area on the surface grows linearly with the burner power. Moreover, the in-depth char front position deduced from the 300 °C isotherm was found to comply very well with that obtained from direct measurements. Finally, a comparison is made between the char front depths measured with the single burning item and those measured with the cone calorimeter for similar heat fluxes, showing that the corresponding charring rates from these two tests deviate from one another only at low heat fluxes.

Small-scale single burning item test for the study of the fire behavior of building materials

A small-scale single burning item test has been developed to allow quicker, easier and less costly development studies of building materials presenting high performance. The test is fully described including the dimensions of the equipment, the procedure used to perform the test, but also the methodology used for the calibration of the heat release rate (HRR) and smoke production. To study the efficiency of the test, different rigid polyurethane and rigid polyisocyanurate foams, with and without flame retardants, are used as case studies and their fire behavior evaluated. The small-scale single burning item test allowed discriminating the different foams in terms of HRR and flame spread, but also in terms of FIGRA and SMOGRA index. It also permits an easy use of additional sensors (thermocouples) leading to a better understanding of the fire behavior. The results were compared to data obtained from the mass loss cone (ISO13927). The results in terms of HRR and smoke lead to similar conclusion but compared to mass loss cone, the small-scale single burning item test makes it possible to access the flame spread behavior of the materials, which is a crucial parameter and leads to an additional discrimination of the performance of the materials.

Analysis of the Fire Properties of Blown Insulation from Crushed Straw in the Buildings.

Sustainable development in civil engineering is the clear and necessary goal of the current generation. There are many possibilities for reducing the use of depletable resources. One of them is to use renewable and recyclable materials on a larger scale in the construction industry. One possibility is the application of natural thermal insulators. A typical example is a crushed straw, which is generated as agricultural waste in the Czech Republic. Due to its small dimensions and good thermal insulation parameters, this material can also be used as blown thermal insulation. The research aims to examine the fire resistance of crushed straw as blown insulation. The single-flame source fire test results, thermal attack by a single burning item (SBI) test and large-scale test of a perimeter wall segment are shown. The results show that blown insulation made of crushed straw meets the requirements of fire protection. In addition, crushed straw can be also used to protect load-bearing structures due to its behaviour. This article also shows the production process of crushed straw used as blown insulation in brief.

Impact of High-pressure Impregnation and Fire Protective Coatings on the Reaction to Fire Performance of Birch Plywood

Abstract Birch plywood has a wide range of applications for interior and exterior use. The demand for plywood with improved fire protection properties and good visual appearance is increasing year by year. The impregnation at high pressure of the whole plywood panels is one of the options to achieve it. The aim of this study was to develop good visual looking birch plywood product for interior design purposes as well evaluate different influencing factors to reaction to fire properties of fire-retardant treated birch plywood. This study consists of three parts. At the first stage, high pressure industrially impregnated plywood properties were studied by two influencing factors – distribution of fire retardant in plywood panel plane and sanding process influence on reaction to fire performance of product. At the second stage, seven different industrial finishing systems were selected for covering high-pressure impregnated birch plywood and their effect on fire reaction performance was studied. In addition, two surface coating systems were studied on standard birch plywood substrate. At the third stage, intumescent coating consumption effect on reaction to fire performance was studied. The reaction to fire performance of birch plywood was evaluated by performing a flammability test using the Single Burning Item test according to EN 13823:2010. It was found that high pressure impregnation of plywood cannot ensure even saturation of fire retardant throughout the sheet, which significantly affects the fire performance of product. The impact of different finishing materials to reaction to fire performance has been described by the results of this research.

Polyisocyanurate Foam Pyrolysis and Flame Spread Modeling

Polyisocyanurate (PIR) foam is a robust thermal insulation material utilized widely in the modern construction. In this work, the flammability of one representative example of this material was studied systematically using experiments and modeling. The thermal decomposition of this material was analyzed through thermogravimetric analysis, differential scanning calorimetry, and microscale combustion calorimetry. The thermal transport properties of the pyrolyzing foam were evaluated using Controlled Atmosphere Pyrolysis Apparatus II experiments. Cone calorimetry tests were also carried out on the foam samples to quantify the contribution of the blowing agent (contained within the foam) to its flammability, which was found to be significant. A complete pyrolysis property set was developed and was shown to accurately predict the results of all aforementioned measurements. The foam was also subjected to full-scale flame spread tests, similar to the Single Burning Item test. A previously developed modeling approach based on a coupling between detailed pyrolysis simulations and a spatially-resolved relationship between the total heat release rate and heat feedback from the flame, derived from the experiments on a different material in the same experimental setup, was found to successfully predict the evolution of the heat release rate measured in the full-scale tests on the PIR foam.

Influence of compounding conditions, treatment of wood particles with fire-retardants and artificial weathering on properties of wood-polymer composites for fa\xe7ade applications

Various fire-retardants (FR) for the pre-treatment of wood flour, for example, ammonium polyphosphate and different formulations based on phosphorus- and nitrogen-compounds, as well as for application during compounding were tested for their effectiveness in injection-molded and extruded composites based on high-density polyethylene and polypropylene. Small-scale tests for flammability of polymeric materials and for determination of the limiting oxygen index were used to characterize the composite materials. Differences pertaining to the applied compounding conditions, i.e., underwater granulation versus air granulation, were determined. The amount of phosphorus leached from FR during underwater granulation was analyzed. Artificial weathering trials were performed and reaction-to-fire performance and color changes of FR-composites were evaluated. Tensile strength properties of the composites and results for cold water immersion tests are also reported. An optimized formulation based on pre-treated wood flour was developed and extruded into façade profiles for the single burning item test according to DIN EN 13823. The test showed that classification C-s3, d0 according to DIN EN 13501-1 can be achieved if pre-treated wood flour is used. The use of untreated wood flour leads to a lower classification (D-s2, d0). Fire performance of extruded façade profiles can be improved by the use of pre-treated wood flour and enables new applications in the building sector.

Experimental study of corner wall fires with one or two combustible walls

The corner fire characteristics with two inert walls are compared against those with one or two combustible corner walls through a set of standard Single Burning Item (SBI) tests. The study examines how the corner fire behavior is affected by flame spread over one or two walls. In the case of flame spread over one corner wall, the inert side is a Calcium Silicate (CS) panel. As for the combustible wall, two different materials have been tested, namely, plywood and Medium-Density Fiberboard (MDF) panels. The results indicate that the simultaneous burning of two panels in the corner geometry increases the Heat Release Rate (HRR) contribution of each panel by 45–50%. This is because the burning of one corner wall increases the temperatures on the adjacent wall significantly, occasionally by more than 200 °C, and increases the heat fluxes on both corner walls at the same time, sometimes by nearly 20%. The results of HRR, Smoke Production Rate (SPR), flame heights, pyrolysis front propagation, panel temperatures, and total heat fluxes at several characteristic locations are presented.

Fire Behavior of Electrical Installations in Buildings

Electrical installations are a significant component of fire load inside a building, although they are often neglected in the overall fire safety analysis and are not subjected to any kind of fire safety evaluation of a building. A typical electrical installation unconnected to the mains was experimentally studied using a single burning item (SBI) test apparatus, fixed to two types of popular non-combustible or combustible (wooden-based) backgrounds simulating a typical building internal wall or ceiling. The semi-real scale test showed that poly(vinyl chloride) (PVC) cable, commonly used in installations in buildings in Europe and used in SBI tests, showed high fire properties related to heat release, smoke production and flame spread to other interior elements. The results of the electrical circuit connected to the main measurements carried out showed a significant impact of the heating effect towards the uncovered surface socket, causing the possibility of easy ignition inside the installation. In conclusion, it was found that even a relatively simple and short section of electrical installation resulted in a significant increase in the heat release rate and smoke generation parameters, obtained during the SBI tests, and as a consequence a reduction of one or two reaction to fire euroclasses of construction materials for internal walls.

Analysis of the influence of thickness on fire reaction performance in polyisocyanurate core sandwich panels

Sandwich panels (also known as insulated panels) have been traditionally used for industrial buildings and warehouses, but nowadays are being increasingly a favorable choice in building construction, mainly in wall cladding and roofing systems. This paper presents the results of an experimental and statistical comparative analysis of Fire Reaction development in sandwich panels consisting of steel sheeting and Polyisocyanurate (PIR) foam core. All these PIR core sandwich panels with joints kept the same dimensions (1000 mm × 1500 mm) + (500 mm × 1500 mm), but different thicknesses (30, 50, 100 and 150 mm). Five Single Burning Item (SBI) tests were carried out on individual PIR sandwich panels with vertical joints and their results were compared between themselves. It was possible to observe through an analysis of variance that there is an influence of the sample thickness in the individual results of the SBI test parameters; however, this variability has no significant influence on the Fire Reaction performance of the samples. Overall, the importance of these alternative sandwich panels is the increase in performance in the constructive processes and the offered comfort through its thermal insulation characteristics.

Testing for knowledge: Application of machine learning techniques for prediction of flashover in a 1/5 scale ISO 13784‐1 enclosure

AbstractA machine learning algorithm was applied to predict the onset of flashover in archival experiments in a 1/5 scale ISO 13784‐1 enclosure constructed with sandwich panels. The experiments were performed to assess whether a small‐scale model could provide a better full‐scale correlation than the single burning item test. To predict the binary output, a regularized logistic regression model was chosen as ML environment, for which lasso‐regression significantly reduced the amount of variance at a negligible increase in bias. With the regularized model, it was possible to discern the predictive variables and determine the decision boundary. In addition, a methodology was put forward on how to use the to update the learning algorithm iteratively. As a result, it was shown how a learning algorithm can be used to facilitate ongoing experimentation. At first as a crude guideline, and in later stages, as an accurate prediction algorithm. It is foreseen that, by iteratively updating the algorithm, by compiling existing and new experiments in databases, and by applying fire safety knowledge, the final learned algorithm will be able to make accurate predictions for unseen samples and test conditions.

Preparation and Characterization of the Flame-Retardant Decorated Plywood Based on the Intumescent Flame Retardant Adhesive.

A novel type of flame-retardant decorated plywood (FDP) was designed and prepared based on one kind of intumescent flame-retardant adhesive. The flame-retardant adhesive was composed of the phosphorous-nitrogen flame retardant and melamine urea formaldehyde (MUF) resin. An adhesive was placed between the plywood substrate and the decorative veneer. The shear strength of the FDP satisfied the Class II (GB/T 9846) when the ratio of flame-retardant and MUF was less than 0.65. The thermal stability of the flame-retardant adhesive was measured by thermogravimetric analysis (TGA). The intumescent behaviors of adhesives were systematically investigated. The morphological and chemical structures of the intumescent char of the flame-retardant adhesive were characterized by the scanning electron microscopy (SEM) and Fourier transform infrared spectra (FTIR), respectively. The fire performance of FDP was assessed by the cone calorimeter and the single burning item test. The FDP exhibited the most effective barrier when the optimized ratio of ammonium polyphosphate (APP) and pentaerythritol (PER) in the adhesive is 3. The flame-retardant class of FDP could be up to class B1(B) according to GB/T 8624.

Fire safety of FAÇADES with polystyrene foam insulation

SummaryAs part of energy‐efficient renovations or for the construction of new buildings often external thermal insulation composite (ETIC) are used. In 2015, in Germany almost 37 million square meters were installed. But several fires involving ETIC systems with polystyrene foam (EPS) insulation in Germany led to an extensive discussion about fire safety of such systems. A collection initiated by the Frankfurt fire service of façade fires which include polystyrene insulation foam shows that more than two thirds of all reported fires started in front of buildings. In half of these fires burning waste containers were the first burning objects. Consequently, German building authorities called for tests of existing approved ETIC systems with EPS insulation in a fire scenario representing a burning waste container. As these tests revealed weaknesses in the existing ETIC systems measures were introduced to enhance the systems. However, the recently introduced German test standard DIN 4102‐20 does not take these changes into account. The DIN test represents a fire where flames emerge an opening but is downscaled regarding the size of the fire load and therefore does not represent a fully developed fire in a room. In ETIC systems with EPS insulation, the render is an important factor for the fire performance of these systems as collapse of the render usually leads to very rapid fire development. Intermediate scale tests with ETICs specimens indicate that mechanical damages of the render weaken the system significantly. Challenges and possible measures to enhance fire safety of ETIC systems are discussed.

Fire retardancy of polypropylene composites reinforced with rice husks: From oxygen index measurements and cone calorimetry to large‐scale single‐burning‐item tests

ABSTRACTRice husks containing 12 wt % inorganic silica were incorporated together with halogen‐free fire retardants in a polypropylene matrix and extruded into facade profiles. An increase in the amount of rice husks resulted in an increase in the oxygen index. The cone calorimetry measurements showed that all of the fire retardants tested significantly reduced the peak heat‐release rate (pHRR) and maximum average rate of heat emission (MARHE) of the formulations and moderately reduced total heat release. The best results in terms of MARHE were achieved for the formulation including 24% melamine‐coated ammonium polyphosphate. pHRR and MARHE were reduced with increasing amount of rice husks. Single‐burning‐item (SBI) tests were performed for the extruded profiles based on rice husks and, for comparison, wood flour. In the best case, a B‐s2, d0 classification was obtained. The results obtained from cone calorimetry and SBI tests were in agreement. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46654.

Experimental study of corner fires—Part I: Inert panel tests

Corner fires are known to spread more intensely in comparison with single wall fires. In view of the challenges associated with prediction of such fire behavior, the fire growth in a corner configuration of Medium Density Fiberboard (MDF) panels is investigated to provide a set of experimental data, performing Single Burning Item (SBI) tests. First, though, test results with inert calcium silicate panels are discussed for three values of HRR (10, 30 and 55 kW), allowing to address the main physics involved. The experimental data for 30 kW, the default SBI HRR, is used for detailed discussion of the observations. The SBI testing methodology, materials, and set-up are described. The results of total Heat Release Rates (HRR) and Smoke Production Rates (SPR), as well as the panel temperatures and total heat fluxes at several characteristic locations are analyzed. Moreover, the puffing frequency of the corner fire is characterized thanks to Video Fire Analysis (VFA) of the experimental footage. Additionally, flame heights are discussed, including the concept of mirroring. A new correlation for mean flame height is introduced, using the hypotenuse of the triangle as characteristic length for entrainment of air into the fire plume, and expressing that the flame height increases proportional to the square root of the fire heat release rate. The 30 kW propane burner of the standard SBI test is shown to feature a mean flame height of nearly 0.9 m and a puffing frequency of 2 ± 0.3 Hz, and an average total heat flux exceeding 44 kW/m2 near the burner early on in the test. The completeness of the dataset is expected to be useful for testing and development of CFD codes for corner fire scenarios.