Showing papers on "Cone calorimeter published in 2007"

Development of fire-retarded materials—Interpretation of cone calorimeter data

Abstract: There is little consensus within the fire science community on interpretation of cone calorimeter data, but there is a significant need to screen new flammability modified materials using the cone calorimeter. This article is the result of several discussions aiming to provide guidance in the use and interpretation of cone calorimetry for those directly involved with such measurements. This guidance is essentially empirical, and is not intended to replace the comprehensive scientific studies that already exist. The guidance discusses the fire scenario with respect to applied heat flux, length scale, temperature, ventilation, anaerobic pyrolysis and set-up represented by the cone calorimeter. The fire properties measured in the cone calorimeter are discussed, including heat release rate and its peak, the mass loss and char yield, effective heat of combustion and combustion efficiency, time to ignition and CO and smoke production together with deduced quantities such as FIGRA and MARHE. Special comments are made on the use of the cone calorimeter relating to sample thickness, textiles, foams and intumescent materials, and the distance of the cone heater from the sample surface. Finally, the relationship between cone calorimetry data and other tests is discussed. Copyright © 2007 John Wiley & Sons, Ltd.

Cone calorimeter analysis of UL-94 v-rated plastics

Abstract: Cone calorimeter analysis was conducted on 18 thermoplastics with different UL-94 vertical burn test (V) ratings. Ratings varied from V-0 to no rating (NR), and the types of thermoplastics included were polycarbonate (PC), acrylonitrile–butadiene–styrene (ABS), PC/ABS blends, high-impact polystyrene (HIPS), polypropylene (PP), and poly(vinyl chloride) (PVC). Our analysis of the cone calorimeter data found that there were correlations between UL-94 V rating and some cone calorimeter measurements (peak heat release rate (HRR) average and HRR at 60 s) and no relationship for other measurements (time to ignition and total heat release). However, no precise correlation was found due to significant differences in flame retardant mechanism and polymer fuel energy values. In this paper, we seek to explain further why a broad quantitative relationship between UL-94 V and cone calorimeter remains elusive, and also to show how the cone calorimeter can be used to understand why a material passes or fails a particular UL-94 V rating. Copyright © 2006 John Wiley & Sons, Ltd.

Flame retardancy mechanisms of triphenyl phosphate, resorcinol bis(diphenyl phosphate) and bisphenol A bis(diphenyl phosphate) in polycarbonate/acrylonitrile–butadiene–styrene blends

Abstract: The flame retardancy mechanisms of three aryl phosphates, triphenyl phosphate (TPP), resorcinol bis(diphenyl phosphate) (RDP) and bisphenol A bis(diphenyl phosphate) (BDP), in a polycarbonate/acrylonitrile–butadiene–styrene (PC/ABS) blend are investigated and compared. Further, the influence of polytetrafluorethylene (PTFE) on viscosity and thermal decomposition is discussed in the systems PC/ABS and PC/ABS + BDP. Mechanisms are proposed based on the results of various methods. Thermogravimetric analysis, Fourier transform infrared spectroscopy and kinetics are used to study the pyrolysis. The fire behaviour is studied by means of cone calorimeter measurements at different heat fluxes and the flammability is specified by limiting oxygen index (LOI) and UL 94. Rheology measurements are used to illuminate the changed dripping behaviour due to PTFE. TPP shows only a gas phase action. RDP shows mainly a gas phase action and some condensed phase action. BDP shows a crucial condensed phase action in addition to a gas phase action. TPP and RDP are somewhat superior in terms of flammability (LOI), whereas BDP shows superior performance in forced flaming combustion (cone calorimeter). Synergistic effects between PTFE and BDP are found. Copyright © 2007 Society of Chemical Industry

Pyrolysis of epoxy resins and fire behavior of epoxy resin composites flame‐retarded with 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide additives

Abstract: The pyrolysis of an epoxy resin and the fire behavior of corresponding carbon fiber-reinforced composites, both flame-retarded with either 10-ethyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide or 1,3,5-tris[2-(9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide-10-)ethyl]1, 3,5-triazine-2,4,6(1H,3H,5H)-trione, are investigated The different fire retardancy mechanisms are discussed, and their influence on the fire properties assessed, in particular for flammability (limiting oxygen index, UL 94) and developing fires (cone calorimeter with different external heat fluxes of 35, 50, and 70 kW m−2) Adding the flame retardants containing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide affects the fire behavior by both condensed phase and gas phase mechanisms Interactions between the additives and the epoxy resin result in a change in the decomposition pathways and an increased char formation The release of phosphorous products results in significant flame inhibition The fire properties achieved are thus interesting with respect to industrial exploration © 2007 Wiley Periodicals, Inc J Appl Polym Sci 104: 2260–2269, 2007

Flammability properties and mechanical performance of epoxy modified phenolic foams

Abstract: This work has been mainly focused on the development and optimization of the processing methodology to produce epoxy modified phenolic foams. This study analyzes the relation between the composition and the structure as well as the mechanical and flammability performance of epoxy-phenolic (E-P)-based foams. Phenolic foams modified with different types and compositions of epoxy resin were successfully synthesized and characterized, showing uniform pore structure. Two epoxy resins were used for this approach. One is regular diglycidyl ether of bisphenol A (Epon 826) type and the other is a brominated bisphenol A (DER 542), which has halogen groups in the structure to improve the flammability properties of the resulting foams. Cone calorimeter (ASTM E 1354) was used to measure the heat release rate, the time to ignition, and other flammability properties of the E-P foams with different types of epoxy resins, under well-controlled combustion conditions. The mechanical performance of the system was studied and compared with competing foams, such us phenolic, epoxy, and polyurethanes, in aspects of compression, friability, and shear performances. Compared with conventional phenolic foams, E-P foams exhibit significant improvement in mechanical performance, lower friability and similar resistance to flame. These results demonstrate the potential of the E-P foam as a flame resistant and high performance core material for sandwich structure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1399–1407, 2007

(Plasticized) Polylactide/clay nanocomposite textile: thermal, mechanical, shrinkage and fire properties

Abstract: Various quantities of Cloisite® 30B (from 1% to 4% in weight) have been added to a polylactide matrix by melt blending to produce polylactide-based nanocomposites. Then, these blends have been melt-spun to produce multifilaments yarns. It is demonstrated that it is necessary to use a plasticizer to spin a blend with 4% in weight of Cloisite® 30B. The properties of these yarns have been studied (dispersion of the clay, thermal, mechanical and shrinkage properties). A decrease of the tensile properties is observed when the quantity of Cloisite® 30B increases, but an improvement of the thermal and shrinkage properties is highlighted. These multifilaments have been knitted and the flammability studied using cone calorimeter at 35 kW/m2. A strong decrease, up to 38%, of the heat release rate has been measured.

Thermal degradation behaviors and flame retardancy of PC/ABS with novel silicon-containing flame retardant

Abstract: A novel flame retardant (DVN) containing silicon, phosphorus, and nitrogen has been synthesized from the reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), vinylmethyldimethoxy silane (VMDMS) and N-β-(aminoethyl)-γ-aminopropyle methyl dimethoxy silane (NMDMS), then incorporated into polycarbonate/acrylonitrile butadiene styrene (PC/ABS) alloy. The flame retardancy of PC/ABS/DVN is evaluated by cone calorimeter and limited oxygen index (LOI) and the thermal degradation behavior is investigated by thermogravimetric analysis under nitrogen and air. The PC/ABS/DVN sample was thermally degraded at 400°C for different amounts of time and studied by Fourier transform infrared spectroscopy to better understand the mechanism of flame retardancy. The results show that the thermal stability and flame retardancy of PC/ABS are improved by incorporation of DVN. Scanning electric microscopy results show that the outer surface of the char layer of PC/ABS/DVN after the LOI test is smooth and the internal structure is like swollen cells, which benefits the flame retardancy of PC/ABS. Copyright © 2007 John Wiley & Sons, Ltd.

Combustion characteristics of north-eastern usa vegetation tested in the cone calorimeter: invasive versus non-invasive plants

Abstract: In the north-eastern United States, invasive plants alter forest fuels, but their combustion characteristics are largely unknown. We assessed unground samples of foliage and twigs in the cone calorimeter for 21 non-invasive, native species, paired with 21 invasive species (18 non-native). Variables included sustained ignition, peak heat release rate, total heat release, and especially average effective heat of combustion, which is independent of initial sample mass. Heat of combustion was overall slightly lower for invasive species than for counterpart non-invasive species, and was significantly lower for Norway maple, black locust, and glossy buckthorn than for three non-invasive trees. It was low for invasive Japanese stiltgrass, sheep sorrel, and glossy buckthorn, and for non-invasive whitegrass, interrupted fern, grape, sphagnum moss, and three-lobed bazzania. Heat of combustion was high for invasive roundleaf greenbrier (native), scotchbroom, tree-of-heaven, Japanese honeysuckle, Japanese barberry, swallow-wort, and garlic mustard, and for non-invasive plants of fire-prone ecosystems: black huckleberry, pitch pine, bear oak, northern bayberry, and reindeer lichen. Heat content of twigs and foliage interrelates with other factors that affect fire behaviour, yet the cone calorimeter results enabled comparison of combustion properties among many species. These data have potential application as improved inputs for fire behaviour modelling.

Fire Retardancy of Natural Fibre Reinforced Sheet Moulding Compound

Abstract: Due to environmental awareness and economical considerations, natural fibre reinforced polymer composites seem to present a viable alternative to synthetic fibre reinforced polymer composites such as glass fibres. This is a feasibility study to asses the potential application of natural fibre reinforced sheet moulding compound materials (NF-SMC) for the use in building applications, with particular emphases to their reaction to fire. The reinforcing fibres in this study were industrial hemp fibres. The cone calorimeter which asses the fire hazard of materials by Heat Release Rate (HRR) was used, radiant heat fluxes of 25 and 50 kW/m2 were utilised to simulate an ignition source and fully developed room fire conditions respectively. The results acquired here demonstrate that the NF-SMC can compete with current building materials in terms of their fire behaviour. The peak heat release value for the fire retardant (FR) NF-SMC was 176 kW/m2 conversely for a non-FR NF-SMC was 361 kW/m2.

Influences of catalysis and dispersion of organically modified montmorillonite on flame retardancy of polypropylene nanocomposites

Abstract: The degradation and flame retardancy of polypropylene/organically modified montmorillonite (PP/OMMT) nanocomposite were studied by means of gas chromatography-mass spectrometry and cone calorimeter. The catalysis of hydrogen proton containing montmorillonite (H-MMT) derived from thermal decomposition of (alkyl) ammonium in the OMMT on degradation of PP strongly influence carbonization behavior of PP and then flame retardancy. Bronsted acid sites on the H-MMT could catalyze degradation reaction of PP via cationic mechanism, which leads to the formation of char during combustion of PP via hydride transfer reaction. A continuous carbonaceous MMT-rich char on the surface of the burned residues, which work as a protective barrier to heat and mass transfer, results from the homogeneous dispersion of OMMT in the PP matrix and appropriate char produced.

Combustion and thermal properties of OctaTMA-POSS/PS composites

Abstract: Inorganic–organic composites of octa(tetramethylammonium) polyhedral oligomeric silsesquioxanes (OctaTMA-POSS) and polystyrene (PS) were prepared by melt-mixing method. The composites were characterized by Fourier-transform infrared spectrometry (FT-IR), Transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), and thermal gravimetric analysis (TGA). Their flammability was evaluated by cone calorimeter test. The experimental results indicate that OctaTMA-POSS, when present in low ratios (1%–5%, weight ratio) in the composites, can decrease the peak heat release rate (HRR) by 15%, while high ratios of OctaTMA-POSS (20% and 30%) can decrease the peak HRR and the average HRR approximately linearly. Concentration and release rate of carbon monoxide (CO) in the composites combustion are also decreased evidently. Thermal gravimetric analysis under nitrogen and air atmosphere both show that the char yield increases obviously. These advances are attributed to the special properties of OctaTMA-POSS and its dispersion in PS.

Assessing the performance of intumescent coatings using bench-scaled cone calorimeter and finite difference simulations

Abstract: A method was developed to assess the heat insulation performance of intumescent coatings. The method consists of temperature measurements using the bench-scaled experimental set-up of a cone calorimeter and finite difference simulation to calculate the effective thermal conductivity dependent on time/temperature. This simulation procedure was also adapted to the small scale test furnace, in which the standard time–temperature curve is applied to a larger sample and thus which provides results relevant for approval. Investigations on temperature and calculated effective thermal conduction were performed on intumescent coatings in both experimental set-ups using various coating thicknesses. The results correspond to each other as well as showing the limits of transferability between both fire tests. It is shown that bench-scaled cone calorimeter tests are a valuable tool for assessing and predicting the performance of intumescent coatings in larger tests relevant for approval. The correlation fails for processes at surface temperatures above 750°C, which are not reached in the cone calorimeter, but are attained in the small scale furnace set-up. Copyright © 2006 John Wiley & Sons, Ltd.

Synergist flame retarding effect of ultrafine zinc borate on LDPE/IFR system

Abstract: The flame retardancy of low-density polyethylene (LDPE) treated with complex flame retardant composed of ultrafine zinc borate (UZB) and intumescent flame retardant (IFR) have been investigated by limited oxygen index (LOI), UL-94 test, thermogravimetric analysis (TGA), cone calorimeter test, scanning electron micrograph (SEM), energy-dispersive spectrometer (EDS), and X-ray diffraction (XRD). The results of LOI and UL-94 test indicate the desired flame retardancy of LDPE is obtained when the mass ratio of UZB to IFR is 4.2 : 25.8 and the complex flame retardant mass content is 30% (based on LDPE). The results of cone calorimeter show that heat release rate (HRR) peak, total heat release (THR), and mass loss of LDPE/IFR/UZB decrease substantially when compared with those of LDPE/IFR. TGA results show that the residue of LDPE/IFR/UZB increases obviously than that of LDPE/IFR when the temperature is above 600°C. SEM indicates the quality of char forming of LDPE/IFR/UZB is superior to that of LDPE/IFR. The results of EDS and XRD indicate that boron orthophosphate (BPO4) and zinc-contained compounds are formed in the residual char and these substances may play an important role in stabilizing the intumescent char structure and decrease the degradation speed substantially when subjected to high temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3667–3674, 2007

The Development of a European Fire Classification System for Building Products - Test Methods and Mathematical Modelling

Abstract: The fire technical properties of products are determining factors for the initiation and growth of fires. Measurement of fire technical properties and the understanding of how they relate to real hazards are therefore important for fire safety. This work deals with the fire technical properties of building products, their tendency to ignite and release heat in different fire scenarios. Building products have traditionally been tested and classified according to national building codes in most countries of the world. In Europe, the different countries all used to have different fire tests and classification systems and it was not possible to translate data between them. Therefore, a common European system for reaction to fire testing and classification, known as the Euroclasses, was created. The SBI (Single Burning Item), used for testing and the FIGRA (FIre Growth RAte) parameter used for evaluation of a products reaction to fire properties were introduced. This work deals with this development and its significance for the European evaluation system for reaction to fire properties. A fire growth that leads to full room involvement, flashover, can happen fast. Predicting flashover times using product data is therefore important for fire safety. Frequently used are the so-called thermal models that by calculations of the products surface temperature predict ignition time and flame spread rate. Alternatively, the ignition time for different heat fluxes are used directly. The products heat release rate, HRR, from a small-scale test is also needed. This work discusses some of the thermal models and presents a straightforward analytical formulation that works well for different room sizes and for the SBI test. In the model formulations heat release rate divided by ignition time appears. These parameters when taken from a small-scale test can be seen as a product property for example for linings in a room fire scenario. In addition, the FIGRA parameter, defined as the maximum of heat release rate divided by time, is shown to predict well the tendency to fire growth for a number of different products in different scenarios. FIGRA is also shown to predict HRR and time to flashover in the Room Corner Test for interior linings. (Less)

Modeling study on the combustion of intumescent fire-retardant polypropylene

Abstract: The heat transfer and burning behavior of intumescent fire-retardant polypropylene were studied by cone calorimeter at heat flux levels of 50 kW·m -2 to establish an essential physical model for the intumescence process in fire. A mathematical model for the burning process of fire-retardant intumescent polymer was put forward based on the assump- tion that an intumescent front existed between the char layer and virgin layer. The model emphasizes the thermodynamic aspect of the intumescence process and a corresponding submodel is presented. Meanwhile the thicknesses and mass loss rates of the intumescent polypropylene during burning were measured for the validation of the modeling results. Thermal conductivity and heat capacity of polymer material were also measured as input parameters of the model. The validation results showed that the intumescent thicknesses and mass loss rates predicted by the model were in good agreement with the experimental results. The model was also used to predict the temperature distribution across the sample thickness during burning. The study shows that the present model can appropriately describe the intumescent behavior of the polymer and numerically predict its mass loss rates and temperature distribution in fire.

Flame retardancy and char microstructure of nylon‐6/layered silicate nanocomposites

Abstract: We investigated the effect of organically modified clay alone and in combination with zinc borate on the thermal/flammability behavior of nylon-6 nanocomposites. Differential thermogravimetric analysis indicated that the peak decomposition temperature was not affected by the addition of clay, but the rate of weight loss decreased with increase in clay concentration. Nanocomposite films of approximately 0.5 mm thickness with 2.5 and 5 wt % clay burned for almost the same duration as neat nylon-6 but with reduced dripping in horizontal flame test. The 10 wt % clay nanocomposite sample burned without any dripping and the flame spread rate was reduced by 25–30%. Zinc borate/clay containing nanocomposite developed into a very good intumescent system in cone calorimeter test, swelling about 10–13 mm height prior to ignition forming a cellular char structure. This was found to be an effective composition in reducing the heat release and mass loss rate of nylon-6 by about 65% and at par with 10 wt % clay nanocomposite. Flame retardant behavior could be attributed to distinct char morphologies observed through scanning electron microscopy. Fourier transform infrared spectroscopy of the 10 wt % clay nanocomposite char showed the presence of amides, indicating possible residual polymer within the shielded char. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1540–1550, 2007

Fire Safety Assessment of Halogen-free Flame Retardant Polypropylene Based on Cone Calorimeter

Abstract: This study addresses the fire performance of polypropylene compounded with different flame retardants in the cone calorimeter tests and UL-94 burning tests. The parameters measured include heat release rate, time to ignition, smoke, and CO/CO2 yields, on the basis of which fire hazard analysis is carried out. By injection-molding different burn-rated polypropylene composites into television back-enclosures and testing them in a full-scale cone calorimeter, we find that the one formulation of V-0 rating in the vertical burning test shows excellent flame retardance.

Flame retardancy of thermoplastic polyurethane and polyvinyl chloride by organoclays

Abstract: Thermooxidative stability and peak of heat release rates of thermoplastic polyurethane nanocomposites are improved by organoclays; but time to ignition of these composites is reduced. A cable with a thermoplastic polyurethane nanocomposite jacket does not pass a simple flame spread test by a Bunsen burner, indicating that the reduction of the peak of heat release rate does not prevent the flame spread. Polyvinyl chloride (PVC) with organoclays shows a fast HCl release by an accelerated chain-stripping reaction of the polymer catalyzed by the quaternary ammonium compound within the organoclays resulting in strong discolorations. Synthesis routes based on ethylene-vinyl acetate copolymer (EVA) or thermoplastic polyurethane (TPU) masterbatches of organoclays strongly diminish the darkening of the PVC compounds. Cone calorimeter experiments do not show remarkably improved flame retardancy properties of PVC filled with organoclays.

Investigation of Thermal Degradation and Flammability of Polyamide-6 and Polyamide-6 Nanocomposites

Abstract: In this paper, polyamide-6 and polyamide-6 nanocomposites were prepared by direct melt intercalation technique. The thermal degradation behavior of both polyam- ide-6 and polyamide-6 clay nanocomposites has been studied. The apparent activation energy of the nanocomposites is almost the same with that of pure polymer under nitrogen, but the apparent activation energy of the nanocomposites is greatly enhanced in air atmosphere. This increasing trend coincides with the thermal analysis and the cone calorimeter results, which may suggest that the polymer/clay nanocomposites have a higher thermal stability and lower flammability. The kinetic analysis also indicates that the pyrolytic degradation and the thermal oxidative degradation of PA6 and PA6/ OMT nanocomposites are two kinds of different reaction mo- dels. 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2297-2303, 2007