Fire Test Methods Research Articles

Study on the Configuration and Fire-Resistant Property of Cable Tunnel Fireproof Clapboard Based on Equivalent Fire Condition Testing

At present, the selection criteria and configuration methods for fireproof clapboards in cable tunnels are not yet perfect, making it difficult to achieve effective fire protection. Therefore, an equivalent fire condition testing method is proposed to analyze the fire-resistant property of fireproof clapboards of different materials. Firstly, a tunnel fire experiment platform was built to carry out the combustion experiment of the high-voltage cable intermediate joint. The cable combustion equivalent fire source device is developed based on the temperature rise characteristics under different combustion conditions. However, the temperature rise characteristics of the equivalent fire source and the actual cable combustion error are within 10%. Then, four typical fireproof clapboards were tested under equivalent fire sources. The results indicate that the organic molded board has the best performance. In addition, factors such as the thickness, side panel height, and installation method of the fireproof clapboards were tested and analyzed. The results indicate that a minimum thickness of 5 mm for the fireproof clapboard and a height of 200 mm for the side panel of the clapboard are necessary to ensure effective protection. The installation method of hoisting fireproof clapboards can effectively extend the protection time by about 30% compared to the flat method.

Research on the Scale Fire Test and Fire Resistance of the One-Way Slab of a Metro

To address the difficulty in conducting fire tests to verify the fire-resistance limit of large one-way slabs with heavy loads in a metro, a scale fire test method is proposed based on the bearing capacity calculation of the one-way slab under fire. The scale fire test method adapted the hypothesis that the deflection of the one-way slab under fire is close to a half-sine function and the plane section hypothesis. The validity of this hypothesis is verified through fire tests and finite element simulations. The scale fire test method achieves a similar temperature field and mechanical behavior between the scaled model and full-scale model of the one-way slab. The results of the fire tests showed that the temperature field and mechanical behavior of the scaled model were consistent with those of the full-scale model, with an error in fire resistance of 4.7%. The calculation results and fire test results are essentially consistent, with an error of 6.5%, and according to the calculation of the one-way slab fire-resistance limit, the key factor affecting the fire resistance of the one-way slab under fire is the temperature of the bottom rebars. Using the scale fire test method, the size effect of the one-way slab under fire still exists, and larger slabs have a greater deformation capacity.

Thermal Tests of Type B Radioactive Transport Package: Experimental Description and Heat Flux Analysis

ABSTRACTThe design of Type B radioactive transport package should be able to withstand the fire accident scenario in transportation accident conditions. For the simulation of the fire scenario, there are mainly three methods: pool fire test, furnace test and thermal radiation test. This paper tried to carry out the fire test with the furnace method that the conditions in the furnace can be more carefully controlled. The paper described the requirements of fire test, test conditions and measurement test methods and analysed the temperature change of fire site and the heat flux data of the surface of the package during the fire test. The test results seemed that the fire test method could provide satisfactory thermal environment for fire test of Type B radioactive transport package.

Evaluation of exterior wall cavity fires using an intermediate scale test method

AbstractCavities form an integral part of many external wall systems (EWSs). Numerous external wall fires worldwide have been primarily due to combustible exterior cladding. However, the Grenfell Tower and Knowsley Heights fire incidents (in the UK) are examples where wall cavity materials have impacted fire spread. Wall cavity materials are typically regulated by small‐scale fire test methods which do not necessarily represent the actual fire conditions that can exist within wall cavities. This experimental study proposes an intermediate‐scale test (IST) protocol to examine cavity wall fire behaviour. This protocol is a modified version of the FM Global Cavity Fire Test method (within the FM 4411‐2020 series). The study examines a broad range of cavity materials including sarking, polyester insulation, phenolic foam, PIR, and EPS. A low‐intensity (6–8 kW) and high‐intensity (~80 kW) ignition sources were used to represent two types of cavity fire scenarios. These two fire sizes were shown to differentiate reaction to fire behaviour between these materials and explore the “tipping point” in resulting fire behaviour (which may lie between these two intensities). This proposed cavity fire test protocol provides a suitable “elevated fire risk assessment tool” for combustible cavity materials.

The Thermo-Phase Change Reactivity of Textile and Cardboard Fibres in Varied Concrete Composites

The building and construction industry heavily relies on the use of concrete and cementitious composites due to their exceptional attributes, including strength and durability. However, the extensive use of these materials has led to significant environmental challenges, including resource depletion, carbon emissions, and waste accumulation. In response to these challenges, recent advancements in fibre cementitious composites have shown promise in mitigating these detrimental effects. The integration of waste materials to supplement manufactured fibres represents a promising development in reinforced concrete composite materials. Waste materials like textiles and cardboard are emerging as potential fibre supplements in cementitious composites. While these materials have primarily been investigated for their mechanical characteristics, understanding their thermal properties when applied in construction materials is equally crucial. Incorporating fibres within composite designs often requires matrix modification to reduce degradation and enhance fibre longevity. This study aims to investigate the thermo-phase change properties of both textile and cardboard fibres within varied concrete matrices. Additive materials offer a range of advantages and challenges when used in composite materials, with additional complexities arising when incorporating fibre materials. Understanding the thermal reactivity of these materials is crucial for optimizing their application in construction. This study demonstrates the potential of waste fibres used with gypsum, metakaolin, and silica fume as matrix modifiers in concrete. This research provides valuable insights for future studies to explore specific material combinations and investigate complex fire testing methods, ultimately contributing to the development of sustainable construction materials.

A Novel IoT-Based Performance Testing Method and System for Fire Pumps

Fire pumps are the key components of water supply in a firefighting system. At present, there is a lack of fire water pump testing methods that intelligently detect faulty states. Existing testing approaches require manual operation, which leads to low efficiency and accuracy. To solve the issue, this paper presents an automatic and smart testing approach that acquires measurements of the flow, pressure, shaft power and efficiency from smart sensors via an IoT network, so that performance curves are obtained in the testing processes. An IoT platform is developed for data conversion, transmission and storage. The Discrete Fréchet Distance is applied to evaluate the similarities between the acquired performance curves and metric performance curves, to determine the working condition of the fire pump. The weights of the measurement dimensions for distance computation are optimized by the Genetic Algorithm to improve the distinction between normal and faulty performance curves. Finally, the experimental results show that the proposed method can completely detect faulty states and prove its high practicality for real firefighting systems.

전력용 변압기의 고장 메커니즘 분석을 통한 실규모 화재폭발 시험 기법 개발

Failures in high voltage power transformers are classified as a kind of disaster accompanied by fires and explosions. It could lead enormous loss of property due to equipment damage and restoration, and black-out of power grid can take place by separating the fault section from the power system. In particular, power facilities including transformers have been intensively installed in Republic of Korea since the 1988 Seoul Olympics. These power equipment is operated for more than 30 years from then. The power transformers in long-term operation are aged and a number of failures tend to increase, therefore, necessity of developing transformer fire prevention and suppression technology is emerging. This paper deals with the development of 154 kV class power transformer real-scale fire test method through its fire and explosion mechanism analysis to advancement fire prevention and suppression technology on power transformer. The test method includes, test items, subjects, facilities, and test site. The established transformer fire mechanism could be applied to develop new investigation method for cause of transformer fire, and real-scale test methodology could be widely utilized for various research such as transformer fire and explosion test, development of its extinguishing technology.

Fire safety of interior materials of buses

AbstractThis study provides an analysis on the fire safety of passengers and the fire protection of coaches and buses. A brief review of major bus fire incidents, an overview of current regulations in Europe, and their limitations are presented. The study finds that the current small‐scale fire test methods described in UN ECE Reg No. 118 need to be replaced by test methods that can assess the reaction to fire of materials when exposed to ignition sources of varying sizes. To address these shortcomings, the study proposed an expert recommendation to update the material fire safety requirements and testing for buses. Additional measures are proposed, derived from objectives and strategies applied in other transport sectors, and can be tested through existing European and international standards, which are widely used by several industries. These measures aim to extend the time with tenable conditions for a safe evacuation in case of fire, reduce the degree of damage to buses, reduce the risk for fast and excessive thermal exposure on modern energy carriers needed for a more sustainable transport sector.

The rise of the Euroclass: Inside the black box of fire test standardisation

This paper charts the initiation, development, and finalisation of Europe's harmonised system for reaction-to-fire classification. Technical literature, archival material, and original interviews are drawn upon to document and explain the process by which this system was created. It is shown that early attempts to retain existing national fire test methods were abandoned, but that from these existing tests grew a novel (but not wholly new) system. We document and detail how and why key thresholds and test parameters were agreed. We show how a relatively small number of civil servants and their technical advisors were empowered to create this system and how, once they had completed their task, they were promptly disempowered. The result of this process of harmonisation was that new agreements were forged; these agreements were embodied in standards, and embedded in each nation's building regulations. Our account shows not only that ideological, national, and business interests competed to influence this ‘Euroclass’ process, but also that the creation of useable standards necessarily distilled complex judgements into a simplified standard, with the reasoning behind the choices then becoming opaque to users.

Unveiling the structure, chemistry, and formation mechanism of an in-situ phosphazene flame retardant-derived interphase layer in LiFePO4 cathode

The safety risks posed by the liquid electrolytes of lithium-ion batteries have drawn large-scale concern recently due to the increased reports of fires in electric vehicles and portable devices fuelled by these electrolytes. Efforts to address the fire safety of electrolytes have predominantly focused on the incorporation of flame retardant additives which generally lead to poor electrochemical properties when used in large quantities. Conversely, low amounts (∼5 vol%) of fluorinated phosphazene-based flame retardants have been reported to yield non-flammable electrolytes while improving the electrochemical properties. Herein, an advanced fire testing method, cone calorimetry, is employed to analyze a model electrolyte (ethoxy (pentafluoro) cyclotriphosphazene (EPCP) based electrolyte), which reveals that the flourinated phosphazene-based flame retardant electrolyte with up to 6 vol% only exhibits ignition delay rather than the widely acknowledged non-flammable behavior. Besides, for the first time, by employing a time-of-flight secondary-ion mass spectrometry (TOF-SIMS) and transmission electron microscopy, we clarify the chemistry and structure of a flame retardant-derived cathod electrolyte interphase (CEI) layer formed on the LiFePO4 cathode surface. The CEI layer is characterized by a phosphorus and nitrogen (PN) rich layer, which inhibits the formation of a thick parasitic LiF layer, which improves the electrochemical integrity of cells.

Fire behavior of novel Thread-anchored One-side bolted connection with internal component

Anchorage of the novel Thread-anchored One-side Bolt (TOB) is provided by the threads inside the bolt hole and the TOB could be installed from one side only, which provides an alternative way to install the connection of the Square Hollow Section (SHS) column. But the TOB might be pulled out from the threaded bolt hole when the SHS column wall is deformed, especially in fire conditions. The strengthening component could be installed inside the SHS column to restrict the deformation of the column wall and increase the depth of the threaded bolt hole. The tensile behavior of the TOB bolted SHS column connection and the influence of the internal strengthening component on the connection at fire scenario were studied and compared with Standard High-strength Bolted (SHB) connections by experimental method. Both steady-state fire test method and transient-state fire test method were used in the test. The TOB bolted SHS column connection had two typical failure modes, which were the yielding of the column wall (mode 1) and the yielding of the T-stub flange accompanied with the bolt failure (mode2), depending on the thickness of column wall. The internal strengthening component could change the failure mode from mode 1 to mode 2 and enhance the fire behavior of the SHS column connection when the thickness of the column wall was small. In the steady-state test, the resistance of the connection decreased obviously with the increase of the fire temperature. In transient-state test, the ductility and the failure temperature decreased obviously with the increase in load ratio. The internal component is an effective way to improve the fire behavior of the TOB bolted SHS column connection. The strengthened TOB bolted SHS column connection could replace SHB bolted connection with the same SHS column wall thickness under the same circumstance. Equations to calculate the yielding resistance of the TOB bolted SHS column connections at different temperatures were given. Comparison with test results showed the proposed equations could predict the failure mode of the TOB bolted connections precisely and predict the yielding load of the connections with acceptable accuracy.

Study on the Analysis of the Temperature-Rise Tendencies of Insulated Steel Fire Doors According to the Properties of the Core Materials

In this study, the relationship between the temperature-rise tendencies and properties of mineral wool was analyzed for cases of mineral wool being used as a filler inside insulated fire doors installed in the evacuation space of apartments. The density and thickness of the mineral wool were separately analyzed; as a result, it was found that the higher the density and the greater the thickness, the more suppressed the temperature rise. However, the difference in the rising temperature between the highest density (150 kg/m<sup>3</sup>) and lowest density (100 kg/m<sup>3</sup>) mineral wools was 10 K, which did not appear to be significant. The temperature difference between the highest thickness (60 mm) and lowest thickness (45 mm) mineral wools was 60 K, indicating that the temperature rise was more affected by the thickness than the density of the mineral wool. In addition, it was suggested that the performance tests of fire doors, which are currently performed on both sides of a door in accordance with the fire resistance test method, are performed twice on the side from which the door is pulled, which corresponds with the direction in which insulated fire doors are actually installed.

A Review of the Structural Fire Performance Testing Methods for Beam-to-Column Connections

The structural fire performance tests for beam-to-column connections are critical in determining their fire performance at high temperatures. The current standard fire testing methods provide the procedures for establishing the fire resistance of each construction element exposed to a standard fire. However, these methods cannot verify the fire behaviour of the connections between building elements. Researchers have performed numerous fire tests on beam-to-column connections despite the lack of structural fire performance testing methods. This paper presents a comprehensive literature review of the structural fire performance testing methods for beam-to-column connections. The major areas in this review are travelling fires, development of travelling fires on beam-to-column connections, fire testing considerations, fire testing criteria, recent fire testing, and loading applications. This paper identifies the key issues and challenges of the structural fire performance testing methods for beam-to-column connections. Finally, this paper provides recommendations and discusses the way forward for structural fire performance tests on beam-to-column connections.

Predicting and comparing the fire performance of a small-scale composite structure

The purpose of this paper is to investigate a strategy for the fire testing of reduced scale structural models which will help engineers design safer structures and reduce the loss from fires. The concept of this work is how composite frame floor arrangements, beam-column connections might be modelled at a small scale suitable for fire testing. Testing full-scale is expensive, besides the testing of scaled model produces reasonable results which help us to understand the failure mechanism and all significant thermo-structural responses involved in a fire. Thermal effects within a structural element generate fire curve, thermal input and structural displacement output, in other words cause and impact. Dimensional analysis, which is a condition for dynamic similarity between prototype and model, can be achieved when all the dimensionless groups are set equal for both model and prototype. On the other hand, scaling rules are used to decide how much insulating material will be used on a structure. 5-storey composite building with composite floors and steel columns has been modelled at small scale with 1/5. The obtained results from various parametric investigations show that the reduced scale model fire test method would be a feasible way to investigate the fire performance of composite structures.

Development of a new intermediate‐scale box test on sandwich panel products compared with ISO 13784‐1 room test and EN 13501‐1 classification system

SummaryWith respect to the reaction to fire performance of sandwich panel products, in ISO/TC92/SC1/WG7 “Large and intermediate scale fire test methods,” ISO 13784‐1 “Reaction to fire test for sandwich panel building systems—Part 1: Small room test” is specified as a method of test for determining the reaction to fire behavior of sandwich panel building systems. On the other hand, according to EN 13501‐1 “Fire classification of construction products and building elements,” EN 13823 (SBI test) and EN ISO 11925‐2 (ignitability test) are used especially for evaluating the classes B, C, and D in the Euroclass system. The authors have developed a new intermediate‐scale box test for sandwich panel products, pertaining to the correlation with ISO 13784‐1 especially on the flashover occurrence, which was locally standardized as JIS A 1320:2017, and is now internationally being discussed as ISO/WD TS 23657 at ISO/TC92/SC1/WG7. In this paper, regarding five sandwich panel specimens, various fire tests were conducted according to ISO 13784‐1, EN 13501‐1, and ISO/WD TS 23657, and those results were compared with each other, indicating that ISO/WD TS 23657 has a good correlation with ISO 13784‐1 in terms of flashover, and that evaluation results based on ISO/WD TS 23657 could be similar to those based on EN 13501‐1. Furthermore, a new tentative classification system was proposed based on those limited experimental results conducted in this research.

Fire performance of masonry under various testing methods

Masonry, as a construction material, is known to perform well under elevated temperatures, which makes it an attractive choice for structural applications. This superior performance is a reflection of its inert thermal characteristics, good stability, and slow degradation of mechanical properties. Still, and similar to other construction materials, masonry undergoes a series of temperature-dependent physio-chemical and phase changes once exposed to high temperatures. Such changes are determined through temperature-dependent material models often obtained by means of physical tests on representative masonry specimens. A deep dive into the open literature shows that not only we lack standardized procedures for testing masonry under fire conditions, but existing researcher-derived methods vary significantly. As a result, available temperature-dependent material models also vary given their sensitivity to testing parameters (i.e., set-ups, heating history etc.). It is primarily due to the aforenoted observations that we continue to lack a holistic understanding of the fire behavior of masonry which also extends to limiting advancements in performance-based design of masonry structures. In order to bridge this knowledge gap, this paper reviews commonly adopted fire testing methods on masonry and the wide scatter of corresponding temperature-dependent material models to provide researchers and practitioners with much-needed knowledge that is currently missing in this domain. Findings from this review can then be used to develop modern and up-to-date temperature-dependent material models to facilitate the design of new masonry constructions or analysis of existing ones (including historical buildings).

Facade Fire Hazards of Bench-Scale Aluminum Composite Panel with Flame-Retardant Core

Facade fires in tall buildings are currently occurring more than once a month globally that are responsible for many casualties and billions of dollars in losses. In particular, the tragic Grenfell Tower fire in London with more than 70 fatalities raised the profile of facade fire hazard. This work used well-controlled irradiation up to 60 kW/m2 to re-assess the fire hazard of typical flame-retardant aluminum composite panels (ACPs) with a dimension of 10 cm × 10 cm × 0.5 cm. We found that the vertically oriented ACPs with the “non-combustible” A2-grade and “limited-combustible” B-grade cores could still be ignited above 35 kW/m2 and 25 kW/m2, after the front aluminum layer peeled off. The peak heat release rate per unit area of these ACPs could be higher than common materials like timber and PVC. Moreover, compared to the B-core panel, the A2-core panel showed a greater fire hazard in terms of a shorter ignition delay time, a higher possibility of the core peel-off, and a longer flaming duration under current test size and fixing condition. Because the ACP is a complex system, its fire hazard is not simply controlled by the core material. The structural failure of ACP in fire, including peel-off, bending, softening and cracking, may further increase the fire hazard depending on the scale effect, boundary and fixing conditions. This research improves our understanding of the systematic fire behaviors of facade panels and helps rethink the fire risk and test methods of the building facade.

ОЦІНЮВАННЯ ВОГНЕСТІЙКОСТІ ВОГНЕЗАХИЩЕНИХ СТАЛЕВИХ КОНСТРУКЦІЙ

Purpose. Evaluation of fire resistance of fire-resistant steel structures using the developed calculation and experimental method. Methods. Finite difference method, landfill fire test method, mathematical and computer modeling of non-stationary heat exchange processes, determination of thermophysical characteristics of fire-retardant coatings based on solving direct and inverse thermal conductivity problems. Results. Geometric, physical, computer models have been developed, with the help of which the fire resistance of fire-resistant steel structures has been evaluated by the calculation-experimental method. The adequacy of the developed method for assessing the fire resistance of fire-resistant steel structures in assessing the fire resistance of fire-resistant I-beam steel column has been checked. The analysis of tests on fire resistance of fire-resistant steel columns exposed to fire at the standard temperature of the fire without the load applied to them has been carried out. A computer model of the “steel column – reactive flame retardant coating” system has been built for numerical simulation of non-stationary heating of such a system. The fire resistance of fire-resistant steel columns of I-beam section without load applied to them has been evaluated using the calculation-experimental method. Verification of results of experimental research with results of numerical modeling has been carried out. Scientific novelty. The convergence of the results of experimental data on the duration of fire exposure at the standard temperature of the fire to reach the critical temperature of steel with the results of numerical simulations has been determined. Based on the comparison of the experimental results and numerical modeling, the adequacy of the developed model to the real processes that occur when heating fire-retardant steel columns without applying a load under fire conditions at a standard fire temperature has been confirmed. The efficiency of the proposed calculation and experimental method for assessing the fire resistance of fire-resistant steel structures has been confirmed. Practical significance. It consists in the implementation of the results on objects of different purposes in assessing the fire resistance of fire-resistant steel structures by evaluating the effectiveness of fire-retardant coatings of steel building structures.

Experimental Investigation of the Effect of Heat Flux on the Fire Behavior of Engineered Wood Samples

This paper presents the experimental study results on the effect of heat flux emitted by a standard source on the charring and ignition characteristics of wood construction materials (plywood, chipboard, and oriented strand board) using infrared thermography (IRT) in the narrow spectral ranges of infrared wavelength. The time to ignition (TTI), charring rate and depth were obtained for the samples. In addition, the effect of several fire retardants on the charring rate and depth of the samples and TTI was analyzed. All fire retardants contribute to an increase in TTI, which confirms their main function—fire protection. However, the effect of fire retardants differs noticeably depending on the material. A new experimental technique is suggested, with the infrared imaging of the temperature distribution along the end of a sample under the heat flux effect on its frontal surface. The uniqueness of this approach consists in the registration of the entire process of ignition and combustion of the presented materials, which occurs in real time without contact with high spatial and temporal resolution. Using the infrared camera of the research class, it becomes possible to record the entire process from the occurrence of the temperature exposure region to the deep carbonized crater in the body of the material. The results can serve as additional recommendations in the development of fire hazard testing methods for construction materials and fire retardants.

Cleaner production of flame-retardant-glass reinforced epoxy resin composite for aviation and reducing smoke toxicity

The flame-retardant glass fiber reinforced epoxy composites have been examined for the aviation and defense industry recently. The fire risks and fire hazards on the environment and human health must be taken into consideration in the case flame-retardant usage when improving their thermal performance. In this study, the flame-retardant glass fiber reinforced epoxy composites were produced with low cost environmentally friendly flame retardant (red phosphorus) and smoke suppressants (zinc borate and aluminum three hydrate) instead of high-cost and harmful halogenated flame retardants. The possible fire risk and hazard of the flame-retardant glass fiber reinforced epoxy composites were investigated with the laboratory scale fire risk test methods. The simultaneous usage red phosphorus, zinc borate and aluminum three hydrate improved the glass fiber reinforced epoxy composites thermal resistance decreasing heat release rate value with larger than 55% in the Ohio State University-Heat Release Rate, test in parallel with Cone Calorimeter. These composites passed from Vertical Burning test with a burn length lower than 152 mm for 60-s test with 20%, 16% and 16% loading ratio respectively. The toxic smoke and gas emissions released from the composites under thermal exposure were meaningfully reduced as a results of fire hazard analysis in the Smoke Density Cabinet with the instrumental gas detection and Microtox. Volatile organic compounds, toxic compounds and irritating gases released in the fire conditions were suppressed by approximately 65%. This study demonstrated the holistic cleaner production approach that did not ignore the environment and human health effects of fire risk and hazards on, and could be apply for the all polymer composite requiring thermal resistance, first time in the literature.