Smoke data from the Cone Calorimeter for comparison with the room fire test

Smoke production in the full–scale room fire test ISO 9705 (Commonly referred to as the Room Corner Test) and in the Cone Calorimeter ISO 5660 has been analysed for three sets of building products comprising a total of 28 products. The smoke production may be critical for the fire classification of surface products since some products produce large amounts of smoke in the room fire test even if they do not reach flashover within 20 min. Several smoke parameters in the Cone Calorimeter and the room fire test have been analysed. Good correlations have been obtained when the products are divided into two groups: products with more than 10 min to flashover in the room fire test and those with less than 10 min. These two time categories correspond to the two heat output levels in the room fire test: 100 kW for the first 10 min and then 300 kW up to 20 min. For products with more than 10 min to flashover the average rate of smoke production and the total smoke production seem to be useful parameters for predictions of smoke release in the room fire test. Both parameters have good correlations between data from the Cone Calorimeter and the room fire test. For products with less than 10 min to flashover no parameter seems to give useful predictions. For all products evaluated together, the correlations are not so good, but the same regression lines as for products with more than 10 min might be used as a first rough estimate. In this case the total smoke production in the Cone Calorimeter could be used to estimate the total smoke production in the room fire test for different building products, independent of their estimated time to flashover. It is suggested that the average rate of smoke production and the total smoke production from the Cone Calorimeter is reported in addition to the mass-based specific extinction area. This will be helpful in predicting smoke release in the room fire test and will also make the data on smoke release analogous to those on heat release.     

Sensitivity of the Room/Corner test to variations in the test system and product properties

The effects of variations in the ISO 9705 Room/Corner Test equipment and product properties are discussed. Previous experimental results are reviewed and some new results from the EUREFIC fire research programme are reported. The effects considered include the room dimensions, the burner size, the heat output of the burner and the stand-off distance of the burner. The error in the measured peak rate of heat release caused by the finite response time of the oxygen consumption calorimeter due to mixing of the exhaust gases is analyzed in detail. The effect of material properties determined with the cone calorimeter are evaluated by employing models simulating the Room/Corner Test.     

Inherent flammability parameters—Room corner test application

It 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.     

Rate of heat release and ignitability indices for surface linings

Dimensional analysis is applied to one form of fire growth in a compartment to derive two indices for the classification of linings, an ignitability index and a rate of heat release index, that can be combined into a fire growth parameter, which here is made proportional to the time to flashover in the internationally standardized Room/Corner Test. The ignitability index is the inverse of the time to ignition. The rate of heat release index is obtained by integrating the rate of heat release in time, weighted in such a way that the values of rate of heat release immediately after ignition are of higher importance than those at later times. Both indices are determined from test results of the Cone Calorimeter.     

Comparison of simulated wet bench fires with small‐ and intermediate‐scale fire tests

Fire hazard studies of clean room facilities indicated that significant losses due to fire may occur in the semiconductor industry. The present study reports the results of full‐scale wet bench fire tests conducted (1) to assess the fire hazards of existing wet bench materials not meeting the listing requirement of NFPA 318, (2) to assess the impact on wet bench fires of engineered materials with improved flammability characteristics, and (3) to compare the observed fire behavior with the results of simpler small‐ and intermediate‐scale fire tests using the same materials. The full‐scale wet bench fires were observed to be consistent in terms of chemical heat release rate, fire propagation, and smoke generation with the results of the small‐ and intermediate‐scale test results. The simpler fire tests are incorporated in FM Approvals 4910 certification for materials to be used in semiconductor fabrication facilities. The small‐scale test protocol is also standardized in NFPA 287. Copyright © 2008 John Wiley & Sons, Ltd.     

Experimental study on polystyrene with intumescent flame retardants from different scale experiments

In this study, the fire performance and toxicity of intumescent flame retardant (IFR) polystyrene composites were investigated experimentally. Ammonium polyphosphate, pentaerythritol, and melamine were selected as IFR. The flammability of the polystyrene (PS) composites was evaluated by microscale combustion calorimetry and cone calorimetry and in the ISO Room. The results suggested that the thermal stability and the peak heat release rate of PS composites decreased with the increasing content of IFR. In the cone calorimeter and ISO 9705 testing, the carbon monoxide yield of PS composites also decreased markedly with the addition of IFR. Scanning electron microscope images show that the char from cone calorimetry testing was more compact and smoother than that from the ISO 9705 testing. The comparison between bench‐ and full‐scale tests demonstrated that the flammability and the toxicity of PS composites are decreased markedly due to the incorporation of the flame retardant, but considerable differences exist. Copyright © 2014 John Wiley & Sons, Ltd.     

Fire safety of thermoplastic polyurethane based on pyromellitic dianhydride

In this paper, pyromellitic dianhydride (PMDA) was firstly used as fire safety agent for thermoplastic polyurethane (TPU). And, the fire safety improvement of PMDA in TPU was intensively investigated by limiting oxygen index (LOI), smoke density test (SDT), cone calorimeter test, and thermogravimetric/infrared spectroscopy, respectively. It has been found that PMDA could significantly improve the ignition level, and the LOI value increase to 28.5% when 8.0 wt% PMDA was incorporated into TPU; PMDA also could effectively suppress the smoke production and heat release during the combustion process. The peak heat release rate and total smoke release of the sample with 8.0 wt% PMDA were decreased by 68% and 22% compared with pure TPU in cone calorimeter test. The thermogravimetric/infrared spectroscopy results showed that PMDA could improve the thermal stability of TPU composites at high temperature and increased the release of CO₂, H₂O, and so on. All results confirmed that PMDA would have a good prospect in reducing the fire hazard of TPU.     

Analysis of work on smoke component yields from room‐scale fire tests

Smoke Component Yields from Room‐Scale Fire Tests (NIST Technical Note TN 1453) has recently been published. This was expected to be an important work in developing concentrations and yields of toxicants that could be used for evaluating the usefulness of small scale smoke toxicity apparatuses (or fire models) for use in the prediction of the toxicity of materials and products in real fires. However, the work has a number of uncertainties that limit its potential for use as a reference. There are three major problems with this work. First, the post‐flashover concentrations of CO are too low (as recognized by the authors who recommend that this part of the data not be used). Second, the post‐flashover concentrations of the main toxicants measured (HCN and HC1) were much higher than found in most studies. Third, the precision of the data was inadequate. The consequence of the first two issues is that the work seriously overestimates the toxicological importance of gases known to have only minor effects in post‐flashover fires, such as HCN and HCl. The very low concentrations of toxicants measured at pre‐flashover conditions might have a value not discussed by the authors: an indication that pre‐flashover fires of the type conducted here do not generate extremely toxic atmospheres. Accordingly, the report does not provide reliable characteristic room scale combustion gas data that can be used for validating small‐scale furnaces. Copyright © 2005 John Wiley & Sons, Ltd.     

Combustibility of cyanate ester resins

Flaming and non‐flaming combustion studies were conducted on a series of polycyanurates to examine the effect of chemical composition and physical properties on the fire behavior of these crosslinked, char forming, thermoset polymers. Heats of complete combustion of the polymer and fuel gases were determined by oxygen bomb calorimetry and pyrolysis‐combustion flow calorimetry, respectively. Fire calorimetry experiments were conducted to measure the total heat released, the rate of heat release and the smoke generation in flaming combustion. Fire response parameters derived from the data include the thermal inertia, heat of gasification, effective heat of combustion and combustion efficiency. Halogen‐containing polycyanurates exhibited extremely low heat release rate in flaming combustion compared with the hydrocarbon resins yet produced significantly less smoke and comparable levels of carbon monoxide and soot. Published in 2005 by John Wiley & Sons, Ltd.     

Flammability evaluation of clean room polymeric materials for the semiconductor industry

A new methodology, identified as the 4910 Test Protocol, has been developed to evaluate the fire propagation and smoke development behaviour of polymeric materials for use in clean rooms for the semiconductor industry. This paper reviews the scientific basis of the concepts and criteria contained in the 4910 Test Protocol. For the acceptance of polymeric materials, two criteria are used: (a) Fire Propagation Index (FPI) ⩽6 (ms^−1/2)/(kWm⁻¹)^2/3 and (b) Smoke Development Index (SDI) ⩽0.4 (gg⁻¹) (ms^−1/2)/(kWm⁻¹)^2/3. Materials are tested in the ASTM E 2058 Fire Propagation Apparatus (previously identified as the Factory Mutual Research Flammability Apparatus). The Fire Propagation Index (FPI) is formulated from: (a) the Thermal Response Parameter (TRP), which relates the time‐to‐ignition to the net heat flux to the sample surface, and (b) the chemical heat release rate measured during the upward fire propagation in air having a 40% oxygen concentration to simulate flame heat transfer at large scale. The SDI is related to the smoke release rate and is obtained by multiplying the FPI value by the smoke yield. The smoke yield is defined as the ratio of the total mass of smoke released per unit mass of the vapours of the polymeric material burned. Small and large‐scale fire test data have been included in the paper in support of the 4910 Test Protocol criteria. Highly halogenated and high temperature specialty polymeric materials and highly modified ordinary thermoplastics are found to satisfy the criteria. Copyright © 2001 John Wiley & Sons Ltd.     

Investigation of a combustible material in the fire of Hengyang merchant's building

Agaric, a kind of important combustible material in the fire of Hengyang merchant's building, was investigated using different experiment equipments. Its degradation and pyrolysis behavior were studied by means of thermogravimetric and kinetic analysis and pyrolysis gas chromatography–mass spectroscopy analysis. External radiation heat and internal heat were used to ignite the agaric. For external radiation ignition, a series of bench‐scale fire tests were done in cone calorimeter in accordance with ISO 5660. As for the internal heat ignition, a fire test was carried out in a full‐scale room in accordance with ISO 9705. Multi‐parameter measurement, including heat release rate (HRR), mass loss rate (MLR), temperature field and species concentration, has been accomplished. Meanwhile, the process of a full‐scale fire test was numerically simulated. The computational results were consistent with experiment data, which will lay down a good foundation for further study in fire reconstruction of the whole fire. Copyright © 2008 John Wiley & Sons, Ltd.     

A comparison of fire retarded and non‐fire retarded wood‐based wall linings exposed to fire in an enclosure

Full‐scale fire experiments were carried out in an ISO room to study the behaviour of commonly used cellulosic lining materials in real fire conditions. In addition to the temperature measurements recommended by the ISO 9705, temperature recordings were made at each node of grid lines on the wall lining surfaces. Four lining materials were chosen to represent different types of products and the surface spread of classifications determined using the BS 476 Part 7 flame spread test environment. The linings included fire retarded, melamine faced and non‐fire retarded boards which facilitated a comparative study of the behaviour of these materials with respect to ignition, flame spread, heat release rate and time to flashover. Corner fire scenarios were used in all the experiments. A T shape flame spread pattern on the surface of the two adjacent walls was observed prior to flashover. Prior to the onset of flashover conditions, downward opposed flow surface flame spread to the wall/ceiling intersection. For the non‐retarded wood based materials, such as plywood and medium density fibre board, flashover conditions occurred approximately 4 min after the start of the experiment. However, the fire retarded chipboard ignition was delayed by some 11 min 45 s after which flame spread was very rapid with flashover occurring within a further 1 min 45 s. An explanation for this particular behaviour is the considerable pre‐heating which occurred during the pre‐ignition period. For the fire retarded linings, much higher surface temperatures were recorded compared with those for non‐fire retarded linings. It was found that the areas of the fire retarded linings facing the source flame suffered extensive pyrolysis and charring which penetrated to the rear surface of the lining. Copyright © 1999 John Wiley & Sons, Ltd.     

Enhancement of fire safety in epoxy resin composites through incorporation of microencapsulated diatomite

Diatomite (DIA) particles are commonly employed as flame-retardant additives for polymers, yet their intrinsic inefficiency requires substantial quantities for optimal efficacy. To address this issue, we proposed a novel approach involving the microencapsulation of DIA with polyethylene glycol phosphate (PEGP) to enhance the flame retardancy of epoxy resin (EP). Characterization of the prepared DIA@PEGP utilized scanning electron microscopy with energy-dispersive x-ray spectrometry and Fourier transform infrared spectroscopy. The resulting EP composite, DIA@PEGP-4/EP, achieved a limiting oxygen index of 33.2% and achieved a V-0 level in vertical combustion tests. Compared to EP, DIA@PEGP-4/EP demonstrated significantly improved fire performance, with 38.6%, 47.8%, 25.0%, 41.3%, and 60.4% reduction in peak heat release rate, total heat release, peak smoke production rate, total smoke production, and CO yield. Furthermore, the highest FPI value of 0.080 m²·s/kW for DIA@PEGP-1/EP and the lowest FGI value of 8.734 kW/m²·s for DIA@PEGP-4/EP, indicate that the incorporation of DIA@PEGP into EP enhances its fire safety. The flame retardancy mechanism of DIA@PEGP-4 involves the formation of a phosphorus-containing aromatic carbon layer during EP char formation, capturing radicals in the gas phase during combustion.     

Toxic gas and smoke assessment studies on vinyl floor covering with the fire propagation test

The Fire Propagation Test (BS 476 Part 6) has been used with the discharge of combustion products into a small test room, to provide a fire hazard assessment of some polyvinylchloride floor covering systems, and includes measurements of fire propagation, smoke, CO and HCI production. Particular attention has been given to the change in the HCI concentration of the Room atmosphere during the test and the influence of relative humidity and the nature of the surface linings of the room. The results have been discussed as a contribution to the understanding of the role of HCI in toxicity of fire atmospheres. Some approaches for improving further the reproducibility of the test method are indicated and support is given to the Japanese proposal that such a test be standardized to enable comparison of fire hazard potential of lining systems used in buildings.     

Fire effluent component yields from room‐scale fire tests

Estimation of the time available for escape (ASET) in the event of a fire is a principal component in fire hazard or risk assessment. Valid data on the yields of toxic smoke components from bench‐scale apparatus is essential to accurate ASET calculations. This paper presents a methodology for obtaining pre‐flashover and post‐flashover toxicant yields from room‐scale fire tests. The data are to be used for comparison with bench‐scale data for the same combustibles: a sofa, bookcases, and electric power cable. Each was burned in a room with a long adjacent corridor. The yields of CO₂, CO, HCl, HCN, and soot were determined. Other toxicants (NO₂, formaldehyde, and acrolein), whose concentrations were below the detection limits, were of limited importance relative to the detected toxicants. The uncertainty values were comparable to those estimated for calculations used to determine ASET and were sufficiently small to determine whether a bench‐scale apparatus is producing results that are similar to the real‐scale results here. The use of Fourier transform infrared spectroscopy was useful for obtaining toxicant concentration data; however, its operation and interpretation are not routine. The losses of CO, HCN, and HCl along the corridor were dependent on the combustible. Copyright © 2009 John Wiley & Sons, Ltd.     

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

Reconstructive 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.     

Flammability hazards of typical fuels used in wind turbine nacelle

This study aims to develop a complete methodology for assessing flammability hazards of typical fuels (ie, transformer oil, hydraulic oil, gear oil, and lubricating grease) used in a wind turbine nacelle by combining different experimental techniques such as thermogravimetric analysis and cone calorimetry. Pyrolysis properties (onset temperature, temperature of maximum mass loss rate, and mass residue) and reaction‐to‐fire properties (ignition time, heat release rate, mass loss rate, and smoke release rate) were determined and used for a preliminary assessment of thermal stability and flammability hazards. Additional indices, for ignition and thermal behavior (effective heat of combustion, average smoke yield, and smoke point height, heat release capacity, fire hazard parameter, and smoke parameter, were calculated to provide a more advanced assessment of the hazards in a wind turbine. Results show that pyrolysis of transformer oil, lubricating grease, hydraulic oil, and gear oil occur in the range of 150°C to 550°C. Lubricating grease and transformer oil show the higher and lower thermal stabilities with maximum pyrolysis rate temperatures of 471°C and 282°C, respectively. The measured relation between ignition time and radiant heat flux agrees well with Janssens method (a power of 0.55). The aforementioned indices appear to provide a reasonable prediction of performance under real fire conditions according to a full‐scale fire test documented by Declercq and Van Schevensteen. The results of the study indicate that transformer oil is the easiest to ignite while lubricating grease is the most difficult to ignite but also has the highest smoke production rate; that transformer oil has the highest heat release rate while gear oil has the lowest; and that the fire hazard parameter is the highest for transformer oil and the smoke parameter is the highest for lubricating grease. The potential of this type of work to design safer wind turbines under performance‐based approaches is clearly clarified.     

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

A 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.     

Screening tests for fire safety of composites for marine applications

Demands for reduced maintenance, reduced manning and reduced cost are resulting in the need for new and alternative materials for introduction in the fleet. The new materials in many cases tend to be non‐metallic and organic (combustible) materials. In order to maintain a minimum level of fire safety, the US Navy has set performance requirements for new materials in many applications. These include the use of composite materials in ships and submarines. Performance requirements for composites, in most cases, are based on full‐scale fire tests. The use of composites for structural applications in submarines is covered by MIL‐STD‐2031. The use of composites aboard US Navy ships for topside applications is now covered by Fire Safety testing criteria. The recommended fire performance criteria contain requirements for fire growth, smoke toxicity, visibility (ISO 9705), fire resistance and structural integrity under fire (UL 1709). When developing new composite systems, it is expensive to repeatedly conduct these typical full‐scale fire tests to determine the performance of the most recent design. Instead, more cost‐effective small‐scale testing is preferable to evaluate performance. To facilitate the introduction of new and modified fire tolerant materials/systems/designs, and to reduce the financial burden on small business, the US Navy has developed a low cost composite system fire screening protocol which offers the potential of predicting the full‐scale fire performance. Fire growth potential of new composite systems and designs can be screened by using small‐scale test data from cone calorimeter (ASTM E‐1354) and Lateral Ignition Flame spread Test (ASTM E‐1321) in conjunction with the Composite Fire Hazard Analysis Tool (CFHAT). The small‐scale burn‐through test (2×2 ft) was shown capable of screening fire resistance performance determined in furnace testing with a UL‐1709 fire curve. These screening techniques provide cost‐effective approaches for evaluating fire performance of new technologies, which in turn aids in the product development process. Full‐scale fire testing is still required before inclusion of products onboard US Navy submarines and surface ships. Published in 2002 by John Wiley & Sons, Ltd.     

Fire reaction properties of concrete made with recycled rubber aggregate

This study investigates the fire reaction properties of concrete made with recycled rubber aggregate (CRRA). Four different concrete compositions were prepared: a reference concrete (RC) made with natural coarse aggregate and three concrete mixes with replacement rates of 5, 10 and 15% of natural fine and coarse aggregate by recycled rubber aggregate (RRA) obtained from used tyres. Specimens of CRRA were tested in a cone calorimeter according to the test standard ASTM E1354, submitted to heat fluxes of 25, 50 and 75kW/m². These tests evaluated the effects of incorporating RRA in the fire reaction properties of concrete, namely in the heat release rate, the time to ignition (TTI), the remaining mass, the production of smoke, and the release of carbon dioxide and carbon monoxide. Owing to the organic nature of RRA, with the exception of the carbon monoxide yield, higher replacement rates of natural aggregates by RRA and increasing heat flux led to a worse fire reaction response, particularly in terms of TTI, heat release rate and smoke production. Results of these experiments were then used to estimate the European fire reaction classes of each concrete composition, using a flame spread model. All CRRA compositions tested were provisionally rated as class A2 or B and such ratings allowed defining the field of application of each solution under analysis, according to building code requirements. Copyright © 2011 John Wiley & Sons, Ltd.