Room Corner Test Research Articles

Numerical modelling of fire test with timber fire protection

PurposeThe purpose of this paper is to present a complex pyrolysis computational fluid dynamics (CFD) model of timber protection exposed to fire in a medium size enclosure. An emphasis is placed on rarely used temperature-dependent thermal material properties effecting the overall simulation outputs. Using the input dataset, a fire test model with oriented strand boards (OSB) in the room corner test facility is created in Fire Dynamics Simulator (FDS).Design/methodology/approachSeven FDS models comprising different complexity approaches to modelling the burning of wood-based materials, from a simplified model of burning based on a prescribed heat release rate to complex pyrolysis models which can describe the fire spread, are presented. The models are validated by the experimental data measured during a fire test of OSB in the room corner test facility.FindingsThe use of complex pyrolysis approach is recommended in real-scale enclosure fire scenarios with timber as a supplementary heat source. However, extra attention should be paid to burning material thermal properties implementation. A commonly used constant specific heat capacity and thermal conductivity provided poor agreement with experimental data. When the fire spread is expected, simplified model results should be processed with great care and the user should be aware of possible significant errors.Originality/valueThis paper brings an innovative and rarely used complex pyrolysis CFD model approach to predict the behaviour of timber protection exposed to fire. A study on different temperature-dependent thermal material properties combined with multi-step pyrolysis in the room corner test scenario has not been sufficiently published and validated yet.

Case Study on Prediction of Temperature in Compartment Considering Fire Conditions in Buildings

Current fire resistance standards for major structural members of buildings require uniform fire resistance performance (in hours). However, buildings may be vulnerable to various local-fire conditions, depending on the industry or business, so it is necessary to examine their differences through simulations. In this study, the existing room corner test (KSF ISO 9705) and simulation results were compared to verify the reliability of the simulations. Next, the similarity of the results was identified. Simulations of actual buildings were performed based on local-fire conditions, and it was verified that the temperature varies by location. Based on the results, it is necessary to focus on performance-based fire resistance design rather than the specification-based design, which requires uniform fire resistance performance in hours. Simulation case studies should be conducted to reflect the diversity of the fire and structural member conditions.

Characteristics of Heat Release Rate Predictions of Fire by a Fire Dynamics Simulator for Solid Combustible Materials

The heat release rate (HRR) of fire for solid combustibles, consisting of multi-materials, was measured using the ISO 9705 room corner test, and a computational analysis was conducted to simulate the fire using an HRR prediction model that was provided by a fire dynamics simulator (FDS). As the solid combustible consisted of multi-materials, a cinema chair composed primarily of PU foam, PP, and steel was employed. The method for predicting the HRR provided by the FDS can be categorized into a simple model and a pyrolysis model. Because each model was applied and computational analysis was conducted under the same conditions, the HRR and fire growth rate predicted by the pyrolysis model had good agreement with the results obtained using the ISO 9705 room corner test.

A methodology for predicting and comparing the full‐scale fire performance of similar materials based on small‐scale testing

SummaryReconstructive fire testing is an important tool used by fire investigators to determine the cause, origin, and progression of a particular fire. Accurate reconstruction of the fire requires the laboratory structure to be outfitted with materials that, in terms of contribution to fire growth, perform similarly to the original materials found at the fire scene. Therefore, a procedure was developed to enable fire investigators to select these replacement materials on the basis of a quantitative assessment of their relative fire performance. This procedure consists of gram‐scale and/or milligram‐scale standard testing accompanied by inverse numerical modeling of these tests, which is used to obtain relevant material properties. A numerical model composed of a detailed pyrolysis submodel and empirical flame heat feedback submodels, which were developed in this study, is subsequently employed to simulate the early stages of the Room Corner Test, which was selected to represent full‐scale material performance. The results of these simulations demonstrate that this procedure can successfully differentiate between fire growth propensities of several commercially available medium density fiberboards.

Combustability of building products versus fire safety

Abstract The combustion process is described and analysed based on the experimental results in the context of building fire safety. Data are obtained by means of five standard methods: ISO 5657 ignitability test, ISO 5657 cone calorimeter, ISO 9705 room corner test, EN ISO 1716 small calorimeter, and EN ISO 1182 small furnace. Various categories of building products were tested: cellulose based products (particle boards, plywoods), solid wood, floor coverings, concrete, ceramics, insulations (thermal and/or acoustic), boards (wall/ceiling), mortars, adhesives, and thin coatings. The studied products exhibited very different fire properties from non-combustible to easily combustible. In order to more effectively differentiate non-combustibles and combustibles within building products, the modified heat of combustion was calculated using all test results according to EN ISO 1716 and EN ISO 1182. The revision of criteria for Euro class A1 and A2 is proposed to obtain more realistic reaction-to-fire evaluation. In conclusion, it is advised to use single limit for heat of combustion for A1 and A2 Euro class. The proposed approach for modified heat of combustion is a convenient tool for the fast and cost-effective initial test method for non-combustibility evaluation and seems to be the proper method for distinguishing between non-combustibles and combustibles within building products. It is a better reflection of the real physical process of combustion than the current one. The third A1 criterion is questionable, regarding time to auto-ignition in EN ISO 1182 cylindrical furnace. The measurement for gross heat of combustion by EN ISO 1716 method is proposed for all Euro classes of building products with different limit values.

화재감식을 위한 생활용품(컴퓨터·책상·전기장판)의 열방출속도 분석 연구 -Room Corner Test-

화재감식을 위한 생활용품(컴퓨터·책상·전기장판)의 열방출속도 분석 연구 -Room Corner Test-

Cone calorimeter and room corner fire testing of balsa wood core/phenolic composite skin sandwich panels

Polymer composite sandwich core panels are of interest for lightweight construction and portable shelter use. In this article, material selection and construction design were considered for an application which required a high level of fire safety performance. Phenolic + fiberglass skin composites with balsa wood core sandwich panels were constructed and first screened for fire performance with the cone calorimeter (ASTM E1354) at different heat fluxes. From these data, fire testing in the room corner test (ISO 9705) was conducted. The results indicated that these composites could only pass the room corner test if an aluminum skin was used to provide some additional fire protection to the underlying composite. Furthermore, it was found that cone calorimeter testing at very high heat flux (100 kW/m2) was not always indicative of fire performance in the room corner test. How the aluminum skin was mechanically attached to the panel as well as underlying composite construction played an important role in the full-scale fire test results.

Evaluating Current Fire Test Methods for Determining Flammability Performance of Ceiling Materials

Many fire tests have been developed to evaluate the flammability performance of a lining material. According to the test methods, specimens are usually mounted vertical as a wall or horizontal as a floor. The only exception is the ISO 9705 room corner test in which ceiling material is installed beneath a ceiling. This study was accordingly designed to discuss the test results of ceiling materials in the ISO 9705 room corner test with the testing capacity of the other commonly-used tests to evaluate the feasibility of the other tests to rank materials mounted beneath a ceiling. Materials used were gypsum board and particle board, which were ranked in the best and the worst classes by the cone calorimeter, a commonly used testing apparatus. Our results showed that the fire behaviors associated with materials tested in the other tests can not completely perform those tested in the ISO 9705 room corner test. A penetration occurred in the gypsum test and led to a severe fire although flashover was not observed. The results from the other tests primarily considered the potential of a material leading to flashover. The penetration of flames through ceiling materials cannot be assessed in the other tests. A modification of an existing test is recommended when ceiling materials are tested.

A two‐step method for predicting time to flashover in room corner test fires using cone calorimeter data

ABSTRACTA method to predict time to flashover in ISO 9705 room corner fire tests based on cone calorimeter data is proposed in this paper. The method involves classification of materials and estimation of time to flashover as two steps in sequence. In the first step, the investigated material is classified into discriminating material groups. In the second step, the time to flashover is calculated with a derived formula for the corresponding material group, which contains material density, time to ignition and heat release rate collected from small‐scale experiments. Compared with two existing models, the proposed method has improved the prediction precisions in both the time to flashover and classification of material categories for a wide range of materials. Copyright © 2012 John Wiley & Sons, Ltd.

룸코너 시험기의 발열량 측정에 대한 불확도 산정

화재시험에 있어서 정확한 발열량의 측정은 시험체의 화재 안정성을 결정하기 위한 중요한 정보이다. 발열량 측정값은 측정 인자들의 오차에 기인하여 영향을 받는다. 본 연구에서는 한국철도기술연구원에 설치된 룸코너 시험기에 대한 불확도의 인자를 분석하였고 이를 이용하여 KTX 내장재 화재시험의 발열량 측정 불확도를 계산하였다. 화재 발열량 불확도 계산 결과, 화재시작단계에서 불확도가 매우 높은 값으로 나타났고 화재가 성장하면서 불확도는 점차적으로 감소하였다. 불확도 인자들 중 산소 농도가 발열량 측정 불확도에 가장 크게 기여하는 것으로 나타냈다. In fire test, accurate heat release rate measurements provide important information to define the fire safety characteristics of products. The calculation of heat release rate depends on the errors of measuring parameters in experimental set-up. In this study, the uncertainty factors of heat release rate in the room corner test facility, which is installed at Korea Railroad Research Institute, were analyzed. Through the fire testings for the KTX interior materials, the uncertainties of heat release rate were calculated. Results showed that uncertainty was high in the initial stage of fire test and gradually decreased with the growth of fire. The oxygen concentration was a major factor contributing to the combined relative standard uncertainty.

Experimental Study on the Burning Behavior of Pool Fires in Rooms with Different Wall Linings

An experimental test series, comprising 10 experiments with varying pool sizes, lining materials and amounts of liquid burning, was conducted under free burn and room burn conditions. The thermal feedback from the enclosure (ISO 9705 Room Corner Test facility) enhanced the burning rate of the pools and resulted in a thermal runaway in some of the runs. The onset of the thermal runaway, which can be associated with flashover, varied with all the input parameters. The lining with the lowest thermal inertia lead to the fastest increase in the heat release rate (HRR) in the enclosure and caused flashover in the shortest time. Given the profound difference between the enclosure tests and the free burn tests and also between enclosure tests with different linings, it is recommended to show great caution if free burn tests are to be used in design fire scenarios.

Inherent flammability parameters—Room corner test application

AbstractIt has been hypothesized that four parameters are solely responsible for a material's performance in a flammability scenario. This excludes effects of material physical integrity, i.e. melting, delamination, etc. They are (1) the critical heat flux below which piloted ignition cannot occur (CHF), (2) the ratio of heat of combustion to heat of gasification (HRP), (3) the thermal response parameter related to the thermal inertia and the ignition temperature (TRP), and (4) the available energy per unit area (AEP). The fire scenario controls the process by its initial heat flux and region of ignition. The hypothesis is applied to 54 tests of the ISO Room Corner Test to assess its validity. It is shown that these four parameters give good correlations in predicting the time to flashover and whether it occurs. In principle, different correlations could be developed for other scenarios of tests and fire configurations. Copyright © 2009 John Wiley & Sons, Ltd.

Application of upward flame spread for the prediction of SBI and ISO room corner (and parallel wall) experiments and classification

The flammability hazard assessment of wall and ceiling linings has occupied the attention of fire scientists and engineers and regulators over the last fifty years. Several tests (small, medium, and large) have been developed to classify the flammability of linings and predict their burning behavior in real enclosure fire situations. We examine in some detail three such efforts: (a) the development of an experimental room and a 9 ft vertical wall full scale test by Ferris leading to the Early Fire Hazard test in Australia, (b) the ISO room corner test, and (c) The new SBI (Single Burning Item test) which maybe the most thoroughly examined test in the history of flammability testing. Of these tests, the experimental room used by Ferris and the ISO room corner test may be considered as end use applications for medium size rooms whereas the SBI test and the vertical wall test by Ferris are intermediate scale test designed to represent the room fire behavior in a more controlled way. Performance criterion in the ISO room corner test is the time to reach flashover. Performance criteria in the SBI test are related to the fire growth in an open corner (no ceiling) configuration due to upward flame spread. Performance criterion in the experimental room of Ferris was the time to reach untenable conditions in the room. Finally, performance criterion in the vertical wall of Ferris was the time interval from ignition until the flames reach the top of the wall. Examination of all these efforts has led to consistently validating a new correlation of the performance criteria of these tests with small-scale cone calorimeter tests whenever both data are available. Previous correlations are also discussed. The new correlation compares well with essential features of upward flame spread as this is related to flammability properties. Comparison between the ISO room corner test and the SBI test leads to suggestions regarding the suitability of these tests as a regulatory tool. Some comments are also directed towards a new test method of parallel wall panels recently proposed by Fmglobal. This test method can be analyzed using the same methodology outlined in this paper.

Temperature effects on the mass flow rate in the SBI and similar heat‐release rate test equipment

AbstractIn various medium‐to‐large‐scale fire test equipments like the ISO room corner test (RC), and more recently, the single burning item test (SBI) the mass flow rate measurement of the combustion gases plays a key role in the determination of the heat‐release rate and smoke‐production rate.With the knowledge of the velocity profile and the temperature of the flow, the mass flow rate is obtained by measuring the velocity on the axis of the duct. This is done by means of a bi‐directional probe based on the pitot principle.However, due to the variation of the mean temperature and the temperature gradient in any cross section of the duct, introduced by ever changing combustion gas temperatures, the velocity nor the density profile are constant in time. This paper examines the resulting uncertainty on the mass flow rate. Copyright © 2006 John Wiley & Sons, Ltd.

Development of a velocity pressure probe

In intermediate and large scale fire test applications, a bi-directional low-velocity pressure probe is used to obtain the volume flow. The probe was presented by McCaffrey and Heskestad in 1976 and has found its way to several international standards including the Room Corner test and the Single Burning Item test (SBI). The probe is considered ‘state of the art’ for measuring flow rate in fire test applications. The main disadvantage however is that the probe factor changes with pitch and/or yaw angle variations. The modified SBI pressure probe is less sensitive to angular variations but then again is Reynolds dependent. A new pressure probe design has been developed that combines a low angular sensitivity with a Reynolds independency over a wide range. Although the probe has been developed for intermediate and large scale fire test applications, its use is not limited thereto. Copyright © 2005 John Wiley & Sons, Ltd.

Critical considerations on the use of a bi-directional probe in heat release measurements

In various medium to large scale fire test equipment, such as the ISO room corner (RC) test and more recently the single burning item (SBI) test, the mass flow measurement of the combustion gases plays a key role in the determination of the heat release rate and smoke production rate. To date a bi-directional low-velocity pressure probe has been used to calculate this flow based on a differential pressure measurement on the axis of the exhaust duct. The objectives of this paper were to evaluate this bi-directional probe—and the modified SBI version—when used for measuring flows in exhaust ducts. Recommendations are given on the future use of pressure probes measuring exhaust gas mass flows. Copyright © 2005 John Wiley & Sons, Ltd.

Effect Of Fuel Sootiness On The Heat Fluxes To The Walls In Enclosure Fires

Even though considerable work has been performed regarding gas temperatures and burning rates in enclosures, scant information is available for the heat fluxes and their distributions on the walls of an enclosure. These heat fluxes are necessary input for determining the thermal response and performance of the wall materials and especially glazing. The heat fluxes on the wall of an experimental enclosure were deduced from the temperatures in several thermally thin small steel plates (25.4 mm x 25.4 mm x 3 mm thick) and in the insulation surrounding the steel plates. In addition, the mass loss rate and gas temperatures near these heat flux gauges were measured. The experimental enclosure was the 1/3 linear scale of the ISO room corner test having six openings and three square- pans of variable size burning Methanol, IMS (Industrial Methylated Spirits) and Toluene at the corner and in the center of the enclosure. By choosing fuels with an increased degree of sootiness it was found that the heat fluxes do not depend only on the gas temperature, as claimed before for heat fluxes on the floor, but also on the magnitude of the heat release rate and the fuel sootiness. Moreover, comparison of the heat fluxes for methanol, IMS and toluene allow the separation of convective from radiative heat fluxes owing to hot gases (and the enclosure walls) and from the radiative heat fluxes from the fire plume.

Prediction of heat release in the single burning item test

AbstractThis paper presents a modification of an existing mathematical model that uses cone calorimeter test results to predict heat release rate in the single burning item (SBI) test. A method for classification of cases based on multivariate statistical analysis is incorporated in the modified model. This makes it possible to determine the development of the heat release curve in the SBI test with better precision than the original version was able to. The model has been applied to 100 cases of cone calorimeter test results from 33 different products. For most of the products the predicted shape and level of the heat release curves are close to measurements in the SBI test. Using the predicted heat release results as input to calculation of FIGRA0.2MJ and THR600s within the new European system for reaction‐to‐fire classification, we were able to predict membership of the correct class in 90% of the analysed cases. Copyright © 2002 John Wiley & Sons, Ltd.

Prediction of time to flashover in the ISO 9705 room corner test based on cone calorimeter test results

AbstractThe ISO room corner test is used for classification of surface materials in a number of countries, and as the reference scenario test for the new European single burning item test, its importance increases even more. Time to flashover may be regarded the most important result from the room corner test. In this paper we describe three different calculation models for predicting in which period of testing time flashover in the room corner test will occur. The predictions are all based on test results from the cone calorimeter. The models are a modified version of the Wickström/Göransson model, the model by Östman/Tsantaridis and a model based on multivariate statistical analysis. The three models were applied to a data set containing test results from 57 different products. We found that the modified Wickström/Göransson model and the statistical model generally calculated time to flashover with high precision. The Östman/Tsantaridis model was excellent in prediction of time to flashover within 10 min of testing time, but performed poorer for time to flashover above 10 min. Based on these analyses, a simple, but efficient method for predicting the interval of time when flashover occurs is suggested. Copyright © 2002 John Wiley & Sons, Ltd.

Developing cone calorimeter acceptance criteria for materials used in high speed craft

This paper presents an overview of a research programme to develop reaction-to-fire acceptance criteria for materials tested in the cone calorimeter. This work, sponsored by the U.S. Coast Guard, includes the testing of eight composite materials and one textile wall covering in several standard test methods. Materials were tested in the ISO 9705 room corner test, the cone calorimeter, the International Maritime Organization's surface flammability test apparatus, the smoke chamber, and in real-scale configurations as furniture items and overhead luggage racks. Summary data from these tests are presented, with particular emphasis on correlations between the room corner test and the cone calorimeter. Data from this research programme were used to develop cone calorimeter acceptance criteria for materials used in furniture and other room contents in high-speed craft. Future work will include more data analysis and fire growth modelling in order to further develop acceptance criteria for other materials, especially compartment Linings. This programme has served as an example of how well-planned and coordinated research can be effective tool in the evaluation of existing regulations and the development of new safety standards, helping to ensure public safety through technically justified standards.