bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of rate of heat release by means of oxygen consumption measurements
Authors: Huggett Clayton
Published: December 2004

Measurement of the rate of oxygen consumption provides a simple, versatile and powerful tool for estimating the rate of heat release in fire experiments and fire tests. The method is based on the generalization that the heats of combustion per unit of oxygen consumed are approximately the same for most fuels commonly encountered in fires. A measurement of the rate of oxygen consumption can then be converted to a measure of rate of heat release. Data on heats of combustion are presented to support this generalization. The applicability of the technique to combustion under fire conditions is examined, possible sources of error in the measurements are discussed, and applications of the method are reviewed. It is concluded that the accuracy of oxygen consumption based rate of heat release measurements should compare favorably with those derived from conventional calorimetric measurements.
A mathematical model for estimating available safe egress time in fires
Authors: Cooper Leonard Y.
Published: December 2004

A mathematical Model for estimating the time available for safe egress from a fire is formulated. The model simulates the conditions which develop during the course of an enclosure fire. Since life safety considerations are primary, the simulation model which is adopted focuses attention only on phenomena which develop between the times of fire ignition and onset of hazardous conditions. This allows significant simplifications in modeling which may not be otherwise justified. Using computed variables of a simulated fire scenario of interest, times of fire detection and onset of hazard which are deduced from realistic detection and hazard criteria would be estimated. The Available Safe Egress Time (ASET) would be defined as the length of the time interval which separates these two events. Quantitative specifications for a variety of detection and hazard criteria are identified. Results of exercising the model are presented, and ASET estimates are obtained for a wide variety of realistic fire scenarios. A comparison between experimental results of a multi‐room fire test and prediction of the single‐room model suggest that the model has potential utility in providing practical simulations of multi‐room fire environments.
Post‐Flashover compartment fires
Authors: Harmathy T. Z. , Mehaffey J. R.
Published: December 2004

Fourteen mathematical models of post‐flashover compartment fires are classified on the basis of fourteen principal modeling aspects. Expressions are presented for the potential of fire to spread by destruction and convection. The assessment of the fire resistance requirements for the compartment boundaries is discussed and measures to counter the potential of fires to spread by convection are outlined.
Ignition resistant upholstery by coating PU flexible foam with vinylidene chloride copolymers
Authors: Edgerley P. G. , Oldland S. R. D.
Published: December 2004

A method is described by which the UK Upholstered Furniture (Safety) Regulations of 1980 may be complied with. By coating the surface of flexible polyurethane foam with vinylidene chloride copolymer latex, a fire retardant surface is obtained. This enables most fabric/foam combinations to pass both the cigarette and the match tests as laid down in BS5852. The coating process can be carried out with a brush, a roller or by spraying. Drying can be at room temperature or by using heat and/or a forced draught. Using about 350 gm−2 only certain deep‐pile fabrics fail, and even hen additionally back‐coating them with PVDC can ensure compliance. The presence of thin wadding or stockingette makes no difference, but thick wadding will burn with the fabric for more than the mandatory two minutes without setting fire to the PU foam. Fabrics successfully tested with the coated PU foam include cottons, polypropylene, acrylic, polyester and ‘Dralon’. After 80 000 indentations in a standard test the coating was still effective, as it was also after heating in a detergent for 4h.
Burning characteristics of beds and bedding—situation and developments
Authors: Rieber Dr Martin
Published: December 2004

The term ‘bed’ has a variety of meanings in different countries. In central Europe, ‘bed’ is used for a bedstead with a mattress, a duvet and a pillow, Following clear definitions of the components of a ‘bed’ the author considers methods for testing the burning characteristics of beds and reports on experiences with model beds in fire tests.
Toxicity of fire effluents: Application of test data
Authors: Sumi K.
Published: December 2004

The application of the results of any fire toxicity test is extremely difficult because of the complexity of the problem and the limitations of the test. This paper will discuss the potential use of test data in the decision‐making process.
The incapacitative effects of exposure to the thermal decomposition products of polyurethane foams
Authors: Purser D. A. , Grimshaw Patricia
Published: December 2004

The mechanisms of incapacitation resulting from exposures to the thermal decomposition products of flexible and rigid polyurethane foams (PUF) were studied over a range of different temperatures under pyrolytic or non‐flaming oxidative decomposition conditions. Individual cynomolgus monkeys were exposed to atmospheres increasing in separate experiments from very low concentrations until early physiological signs of incapacitation were detected. When flexible PUF was pyrolysed at 900°C and rigid PUF was oxidized at 600°C, clear atmospheres containing CO and HCN were produced and the signs of toxicity were very similar to those produced by HCN gas alone, consisting of an episode of hyperventilation followed by a semi‐conscious state. Pyrolysis of flexible PUF at 600°C and 300°C produced a dense yellow smoke but no HCN. The signs, consisting of hyperventilation throughout exposure and dyspnoea afterwards, were consistent with pulmonary irritation, Since TDI monmer is not present at 6000 C it is concluded that some as‐yet unidentified but highly irritant chemical species is present in smoke from flexible PUF.
A procedure to calculate fire resistance of structural members
Authors: Lie T. T.
Published: December 2004

Progress in the field of theoretical prediction of fire resistance has been rapid in recent years. A procedure has been developed at the National Research Council of Canada for calculation of the fire resistance of structural members. The various steps in the construction of a mathematical model to calculate temperatures, deformations and strength are shown using as an example the calculation of the fire resistance of a cylindrical tubular steel column filled with concrete. A comparison of results calculated using the model with those of a fire test is also discussed.
Development of the cone calorimeter—A bench‐scale heat release rate apparatus based on oxygen consumption
Authors: Babrauskas Vytenis
Published: December 2004

A new bench‐scale rate of heat release calorimeter utilizing the oxygen consumption principle has been developed for use in fire testing and research. Specimens may be of uniform or composite construction and may be tested in a horizontal, face‐up orientation, or, for those which do not melt, in a vertical orientation. An external irradiance of zero to over 100 kW m−2 may be imposed by means of a temperature‐controlled radiant heater. The rate of heat release is determined by measuring combustion product gas flow and oxygen depletion, while the mass loss is also recorded simultaneously. The instrument has been designed to be capable of higher accuracy than existing instruments and yet to be simple to operate and moderate in construction cost. The instrument is thermed a ‘cone calorimeter’ because of the geometric arrangement of the electric heater.
Failure probabilities of constructions designed for fire resistance
Authors: Mehaffey J. R. , Harmathy T. Z.
Published: December 2004

‘Normalized heat load’ is a quantifier of the destructive potential of fires, real‐world compartment fires and test fires alike. For real‐world fires it is subject to some uncertainties owing to the random nature of two of the variables it depends on: ventilation and fire load. For test fires also it is subject to uncertainties owing to a moderate degree of randomness that characterizes the results of test fires. A procedure is described for predicting the failure probability in fire of the boundaries of a compartment designed for fire resistance on the basis of information concerning the characteristics of the compartment and the design value of the fire load. The procedure is essentially deterministic, employing statistical considerations only as far as required by the nature of some of the input variables. With the aid of second‐moment analysis, it is possible, furthermore, to design the compartment boundaries for appropriate target failure probabilities.
A room fire simulation model
Authors: Hägglund B.
Published: December 2004

An interactive computer program for simulating the early fire growth in an enclosure is described. The enclosure is assumed to be divided into distinct homogeneous zones. The rate of heat release is defined for the fire and the conservation equations are solved for the zones, yielding the temperature and radiant heat conditions in the fire room. The purpose of the work was to develop a computer program to be used by people working with fire engineering applications and having little experience in computer calculations. The user converses with the program via a terminal connected to the computer. The dialogue is governed by commands adapted to the concepts of the user. Results of the computer model are compared with measured data of the burning of wood and plastic cribs in an enclosure, showing a good agreement between measured and calculated results.
Fast surface‐temperature measurement for fire tests
Authors: Chitty R.
Published: December 2004

A method of increasing the speed of measurement of surface temperature is described. This would possibly be suitable for improving the determination of temperature of the unexposed face of specimens subjected to a British 476 (part 8) fire‐resistance test. A simple electronic circuit used in conjunction with a disc‐mounted thermocouple allows ‘hot spots’ to be quickly identified. The technique may also find application in other similar standards such as ISO 834.
Burning, pyrolysis, combustion and charoxidation. Need for clarifying terminology
Authors: Harmathy T. Z.
Published: December 2004

The vague meaning of the word ‘burning’ has long created communication difficulties among fire scientists, and has to unwarranted conclusions. It is suggested that the word ‘burning’ be used as an umbrella term, covering up to three dissimilar types of reactions: pyrolysis or gasification, (gas‐phase) combustion, and char‐oxidation.
Generation of hydrogen cyanide from flexible polyurethane foam decomposed under different combustion conditions
Authors: Levin Barbara C. , Paabo Maya , Fultz Mary Lou , Bailey Cheryl S.
Published: December 2004

Experimental thermal conditions conducive to the production of high levels of hydrogen cyanide (HCN) from flexible polyurethane foam were determined. In these experiments the material was exposed to relatively low‐temperature non‐flaming oxidative conditions for a short time period, during which a char was formed. Further heating of the char to temperature above 500°C generated the increased HCN levels. Upon exposure to this same two‐step decomposition process, a fire‐retarded flexible polyurethane foam produced twice as much char and twice as much HCN. Elemental analyses indicated that the HCN concentration was directly related to the amount of char formed and its nitrogen content. Room burns of slabs of flexible polyurethane foam and chairs containing flexible polyurethane foam indicated that this same phenomenon occurs in large‐scale experiments. In these NBS tests, increased concentrations of HCN were produced when the material underwent flaming combustion following a period of smoldering, presumably from heating the char that was formed during smoldering. Investigation of the molecular mechanisms responsible for the increased HCN concentrations was attempted using ion chromatography, electron spectroscopy for chemical analysis (ESCA), Fourier transform infrared (FTIR), pyrolysis/mass spectrometry and 13C solid‐state nuclear magnetic resonance (NMR) techniques. While the molecular structures of the nitrogen‐containing compounds in the char were not elucidated, these analyses provided evidence of multiple compounds containing amine, amide, imine and nitrile functional groups as the most likely sources of the observed HCN.
Intumescent silicate‐based materials: Mechanism of swelling in contact with fire
Authors: Bulewicz E. M. , Pelc A. , Kozlowski R. , Miciukiewicz A.
Published: December 2004

An intumescnt material has been developed, based on alkali silicates, which can be used in fire protection in the form of sheets or boards which can be joined to various materials, ranging from wood and wood products to metal. The swelling of the material on heating to over 100°C or on contact with a flame is due to and endothermic process and is associated with the emission of water vapour. The solid foam formed is rigid and consists of hydrated silica. The phenomena observed during the preparation of the boards and their behaviour on heating can be explained in terms of silicate chemistry.
Comparison of three test methods for measuring rate of heat release
Authors: Östman B. A‐L. , Svensson I. G. , Blomqvist J.
Published: December 2004

Three test methods for measuring the rate of heat release, RHR, have been compared on the same building materials. The test methods are the OSU‐box modified for O2‐consumption, the STFI open arrangement and the NBS cone calorimeter. All methods are based on the oxygen‐consumption technique. Radiation intensities up to 50 k Wm−2have been applied. Thirteen different materials were tested. The results obtained using the three methods seem to be quite similar in spite of the different equipment used. The minor deviations observed in the results seem to be systematic and may be due to the different testing arrangements. There is a good correlation between results, e.g. total heat release up to 1min after ignition, obtained by the different methods. Additional information about the time to ignition is obtained simultaneously. Heat‐release rates in the vertical and horizontal orientations are also compared in the NBS cone calorimeter.
Fire and upholstered furniture
Authors: Paul K. T.
Published: December 2004

Both ignition and rate of fire development tests are required to determine the fire performance of upholstered composites. Current practice uses small‐model specimens for ignitability tests but rate of burning tests are usually carried out on actual furniture. This paper discuss small‐ and large‐scale tests for upholstered furniture.
A novel method for measuring nitrogen‐containing species in combustion effluents
Authors: Murrell Janet M.
Published: December 2004

A sensitive method is described for the determination of hydrogen cyanide and organic nitriles in atmospheres created by the combustion or thermal degradation of nitrogen‐containing polymeric materials. The technique also allows for the determination of other hydrocarbon species from the same sample using a gas chromatograph‐mass spectrometer system without entailing too many divisions in the sample quantity The method utilizes an NOx analyzer will only respond to nitrogen‐containing compounds and response factors for these compounds can be calculated.
Larger specimens for determining rate of heat release in the cone calorimeter
Authors: Nussbaum Ralph M. , Östman Birgit A.‐L.
Published: December 2004

A larger cone heater for the cone calorimeter has been developed in order to measure the rate of heat release from building materials. The aim was to facilitate the testing of inhomogeneous materials and to minimize edge effects. Specimens of two different sizes, 100 × 100mm and 200 × 200mm, were tested in the horizontal orientation. The maximum rate of heat release and the average rate of heat release during 1 min after ignition are generally higher for the larger specimens than for the smaller ones. The time to ignition is generally shorter for larger specimens. Results from tests with 13 different building materials, including wood‐based materials, gypsum board, wall‐coverings and plastics, are presented at different heat flux levels up to 75 kW m−2.
Polystyrenes: A review of the literature on the products of thermal decomposition and toxicity
Authors: Gurman Joshua L. , Baier Laura , Levin Barbara C.
Published: December 2004

The current English literature through 1984 on the products of pyrolysis and combustion from polystyrenes and the toxicity of those products is reviewed. Among 57 compounds detected by chemical analyses of the thermal decomposition products produced under various atmospheric conditions (vacuum, inert and oxidative), the main volatile component is the styrene monomer, Evidence is provided that the mass fraction of styrene increases with furnace temperatures at least through 500°C. At 800°C and above, the concentration of styrene decreases. In oxidative atmospheres, carbon monoxide (CO), carbon dioxide (CO2) and oxidative hydrocarbons are formed. The concentrations of CO and CO2 are a function of temperature and combustion conditions, i.e. greater amounts are produced in the flaming than in the non‐flaming mode. Eleven different test procedures were used to evaluate the toxicity of the pyrolysis and combustion atmospheres of polystyrenes. The more toxic environments produced under flaming conditions appear to be mainly attributed to CO and CO2 but rather to some other toxicant, probably the styrene monomer. When compared with other common materials used in buildings and residences, polystyrenes, in general, are among the least toxic.
The influence of pressure on combustible and toxic properties of materials
Authors: Trzeszczyński Jerzy , Wlodarczak Daniela , Bójko Teresa
Published: December 2004

Combustible and toxic properties greatly influence the application of materials in shipbuilding. These materials, especially plastics, create a serious toxic hazard during fire. Under fire conditions they decompose thermally, giving off considerable amounts of smoke and volatile toxic substances which cause a serious hazard to people overcome by fire inside a compartment.1–3Lethal poisoning by the thermal degradation products of plastics has attracted the attention of many investigators to toxic hazards during a fire.1,4 Underwater systems create, in particular, a serious fire hazard. Fire in a decompression chamber spreads in a different way to land fires and usually causes the death of the crew and complete destruction of equipment in the chamber. Theoretically, complete fire protection in a chamber could be achieved by the total elemination of combustible materials and their replacement by incombustible ones. However, from a practical point of view this is impossible. The general principles of materials selection used in underwater systems are defined by Det Norske Veritas.5 Unfortunately, these do not describe the methods of testing materials nor the criteria of materials selection. There is also a lack of information in the literature on toxic hazards under elevated pressures. This problem has been studied in detail with oxygen‐enriched atmospheres in aerospace programmes,6 but because those studies are classified there is only fragmentary information in the literature.
Flammability of plastics I: Ignition temperatures
Authors: Thomson H. E. , Drysdale D. D.
Published: December 2004

The Piloted ignition of six common thermoplastics has been studied by exposing horizontal samples (65 times; 65 times; 6 mm thick) to irradiance levels in the range 10–40 kw m−2. Fine thermocouples were attached to the exposed face and allowed the surface temperature to be monitored continuously. Times to sustained ignition from a small pilot flame and the corresponding surface temperature were recorded. Within experimental error, ignition temperatures showed no systematic dependence on surface area when this was reduced to ca 20 mm square. Times to ignition were dependent not only on radiant intensity but also on the spectral characteristics of the source.
Evaluation of quarter‐scale compartment fire modeling for constant and stepped heat inputs
Authors: Dingyi Huang
Published: December 2004

Quarter‐scale tests of ten full‐scale room fire tests were conducted by using an existing scaling technique developed at the National Bureau of Standards. Test results confirmed earlier studies which showed that, under constant fire exposure conditions, quarter‐scale room testing ranked interior finish materials in the same order as did full‐scale tests based on their times to achieve room flashover. In general, quarter‐scale tests were less severe and took longer to reach peak room fire buildup because of a lower convective and radiative heat transfer in the quarter‐scale room. These tests also generated more CO per unit mass of material and experienced lower combustion efficiencies than did their corresponding full‐scale tests.
Breaking of window glass close to fire
Authors: Keski‐Rahkonen Olavi
Published: December 2004

A heat conduction equation with linerized radiation cooling boundary conditions is used to calculate the thermal field in a long‐strip window pane heated by thermal radiation (fire), except on narrow strips along edges built into the frame. This temperature field is used to calculate a quasi‐static thermal stress field in the pane in the first‐order planar stress approximation. Derived analytic equations of stresses are presented graphically. Thermal stresses build up at the edges in a narrow strip of a few times the pane thickness. In cool spots of the order of 100 K lower than the average temperature, stress build‐up can cause a microcrack to become a fast‐propagating fracture.
Characteristics of smoke in different thermal regimes
Authors: Hill B J , McIlhagger R , Shields J , Silcock G , Stephens G G
Published: December 2004

This paper examines the smoke emission and properties of polypropylene and flame retarded polypropylene injection moulded plaques. The prepared samples were irradiated in a Stanton Redcroft NBS type smoke box with an incident radiant energy of 2.5 W/cm2. Nucleating agents were also introduced to increase the particle size of the smoke produced. The conclusions reached from this work on the emission of smoke in a non‐flaming mode were that as the flame retardant additive content was increased, the optical density decreased, thus extending the time for escape. The emission of smoke from these polymers subjected to other radiant sources and in a flaming and non‐flaming mode is being investigated further.
Thermal bowing and how it affects the design of fire separating construction
Authors: Cooke G M E
Published: December 2004

This paper provides new data, both experimental and theoretical, on the thermal bowing of building elements such as walls and floors, when exposed to fire on one side, and suggests how the data can be used in design to tolerate unwanted thermal bowing in fire walls.
Problems in retaining technical and economic benefits whilst improving fire safety
Authors: Hurd R.
Published: December 2004

In attempting to develop products of improved firesafety it is important that other properties which are essential forthe satisfactory performance of the product should not be sacrificed.

In considering the improvements in fire performance possible in flexible foam for upholstered furniture, tests on sample foam/fabric composites may not be sufficient since design and the other components present in commercial furniture, plus the total room environment, may negate the improvements achieved in the foam itself.
The influence of aluminium oxide trihydrate particle size on the combustion of polydimethylsiloxane
Authors: Zdorikova G. A. , Kolesnikov A. A. , Troitskaya T. A. , Surov I. V. , Rudakova T. A. , Khalturinskiy N. A.
Published: December 2004

The regularities of thermal degradation of Al(OH)3 powders and the compositions of polydimethylsiloxane and fire retardant with different particle sizes (from 2 μm to 45 μm) were studied by the use of dynamic thermogravimetry (TG), mass spectrometry (MS) and high‐temperature pyrolysis. It was shown that the size of the flame‐retardant particles influences the physico‐mechanical characteristics and combustion of polymeric compositions based on polydimethylsiloxane. The filling of polymer with fine flame retardants improves the tensile properties of vulcanizates but the flame retardance is reduced markedly. The time of free combustion and the length of the burnt parts are increased, the oxygen index and time of ignition delay are decreased while the flame temperature near the surface of the burning sample rises.
Application of a transport and decay model for hydrogen chloride to hydrogen chloride generation in the presence of various fluids and surfaces but without poly(vinyl chloride)
Authors: Galloway F. Merrill , Hirschler Marcelo M.
Published: December 2004

In a total of 63 experiments, all of them carried out in a 200 L Plastic chamber, a large amount of HCI (800–1000 ml) was injected. In no case was the HCI generated from decomposition of poly(vinyl chloride). The chamber contained a variety of surfaces. Furthermore, various fluids were injected into the chamber together with the HCI. The fluids used were: water, ethylene glycol, ethylene glycol/water 50/50 mixture, a model for airborne smoke particulates (and several partial models for such synthetic smoke) and mineral oil. The surfaces used were PMMA, painted gypsum board, ceiling tile and soot. The results showed the efficiency of many of these fluids as sinks for HCI: hydrophilic fluids are good HCI sinks, with water and synthetic smoke being the most effective. A previously developed zone model for HCI transport and decay, contained within the NIST fire model Hazard 1.1 and used most often to investigate HCI formation from PVC combustion or pyrolysis, was used to predict the results of the experiments in this work. The correlation between experimental and predicted atmospheric HCI concentrations was made without fitting any new parameters. The results were excellent. This work shows that the HCI transport and decay model is robust enough to be applied to a number of scenarios where HCI is present, even in the absence of PVC. The model is thus of particular use in fire hazard assessment.
Comparison of large‐and small‐scale heat release tests with electrical cables
Authors: Hirschler Marcelo M.
Published: December 2004

A total of 21 electrical cables were made, all with identical construction but differing in the chemical composition of their plastic components, both jacket (or sheath) and insulation. All the compounds used were commercially available materials, but they covered a variety of polymers, both halogenated and non‐halogenated. All cables were tested in a large‐scale cable tray test, the proposed ASTM D9.21 test, based on the IEEE 1202 or the CSA FT‐4 test, modified to measure heat and smoke release in the duct and with a total length of 2.44 m. The peak rate of heat release measured served as an excellent criterion for distinguishing between cables passing and failing the test (the traditional criterion being char length). The average rate of heat released also served to distinguish the two classes of cables. Moreover, cables passing the test tended to release less smoke than those failing the test. The cables were also tested in the IEC 332‐3 cable tray test. The small‐scale fire test used for the cables was the cone calorimeter, ASTM E 1354. The trends observed in this heat release test were similar to those in the large‐scale test. The results indicate that cables with excellent fire performance can be made by using a variety of materials, so that it would seem to follow that it is important to specify fire performance and leave material choice to manufacturers.
Determining degrees of combustibility of building materials—national building code of canada
Authors: Richardson Leslie R.
Published: December 2004

Many jurisdictions are attempting to replace the prescriptive specifications in their building codes with performance based requirements. However, if this transition is not carried out prudently, the changes could make the codes more difficult to interpret, harder to administer and, instead of providing an equitable foundation for the selection of construction materials and building designs, render those codes unnecessarily restrictive. To illustrate some of the difficulties which can be faced when changing prescriptive specifications to performance‐based requirements, suggestions about how the prescriptive specifications regarding combustible and noncombustible construction in the National Building Code of Canada could be replaced with performance requirements based upon ‘degrees of combustibility’ of building materials are outlined.
The importance of char‐forming reactions in thermoplastic polymers
Authors: Carty P. , White S.
Published: December 2004

The flammability and smoke generated from burning blends of acrylonitrile–butadiene–styrene (ABS) and polyvinylchloride (PVC) are discussed. Flammability was measured using standard oxygen index techniques and smoke production determined by the NBS method. The incorporation of some specific iron containing inorganic compounds into a range of blends of ABS and PVC considerably changes the burning characteristics of the polymer blend. Thermal stability at elevated temperatures and carbonaceous char formation are also discussed. The chemical role of iron compounds in reducing both the flammability and smoke production in ABS/PVC is considered.
Time—temperature profile across a lumber section exposed to pyrolytic temperatures
Authors: Shrestha D. , Cramer S. , White R.
Published: December 2004

This paper presents a closed‐form solution with empirical adjustments to predict the time–temperature profile across a lumber section when the exposure history of its surface is known. The formulation is based on the two‐dimensional heat‐conduction equation that includes the effects of moisture evaporation and pyrolysis of wood. The kinetic constants and adjustment factors needed in the model were estimated from the temperature profile test data of dimension lumber and other published sources. This technique offers a simple practical means to estimate the internal temperatures of structural lumber exposed to high temperatures, and has been effectively implemented in the analyses of protected wood assemblies exposed to fire situations.
Flammability of GRP for use in ship superstructures
Authors: Egglestone G. T. , Turley D. M.
Published: December 2004

The burning characteristics of glass‐reinforced panels with an isophthalic polyester resin, the same resin with an inorganic flame retardant, two differing vinylester resins or a resole phenolic as the matrix were tested at a range of incident heat flux values using a cone calorimeter. The phenolic composite was superior at all levels showing a longer ignition time, reduced heat output, less contribution to a low‐level sustained fire (25 kWm−2) and lower smoke yield.
A model for predicting heat transfer through gypsum‐board/wood‐stud walls exposed to fire
Authors: Mehaffey J. R. , Cuerrier P. , Carisse G.
Published: December 2004

To facilitate the development of cost‐effective and flexible design options there is a need to develop models to predict the fire resistance of wood‐frame building assemblies. Such assemblies often derive much of their fire resistance from a protective membrane composed of gypsum board. A simple two‐dimensional computer model is presented to predict heat transfer through gypsum‐board/wood‐stud walls exposed to fire. Input data for the thermophysical properties of gypsum board were measured exploying standard bench‐scale tests. Input data for wood were selected from the literature. Small‐and full‐scale fire resistance tests were conducted on gypsum‐board/wood‐stud wall assemblies to provide data for the validation of the model. The model is shown to predict heat transfer through these walls rather well.
On the evaluation of a ‘time constant’ for studying the smoke‐filling processes in atrium spaces
Authors: Chow W. K.
Published: December 2004

The time constant which has been previously proposed to characterize the smoke‐filling time in an atrium space for design purposes is further evaluated in this paper using the CFAST, FAST and CCFM. VENTS zone models developed at the Building and Fire Research Laboratory, NIST, USA. A design fire of thermal power and area related to the volume of the atrium space is proposed in order to evaluate the time constant. Results of the zone‐modelling simulation supported the fact that the time required to fill 80% of the atrium space with smoke is related to its time constant. Full‐scale experimental results on smoke‐filling processes in atria available in the literature are compared. Use of this quantity to specify the smoke‐filling time for an atrium space is recommended for design purposes.
Welding methods with reduced fire hazard for single‐ply polymer‐modified bituminous roofing materials
Authors: Oba Koichi , Duhrin Urban , Björk Folke
Published: December 2004

Fire accidents caused by the use of open gas torching during roof‐installation work have led to considerable costs, and between 1985 and 1990 such costs reached 249 Million SKr. The Swedish Fire Protection Association together with the roofing contractors association reached agreement on the education and certification of roofers. Meanwhile, the insurance companies started to demand welding methods with lower temperatures and less fire hazard. This resulted in a marked decrease in fires and in a sharp decrease in the amounts paid out by insurance companies (187 million SKr in 1989, 25 million SKr in 1990 and 2.4 million SKr in 1991). This paper summarises the results of a study of the new welding methods, replacing conventional gas torching, for the installation of polymer‐modified bituminous roof‐coverings on flat roofs. In all eight different welding methods were evaluated in Stockholm during the installation in October 1992. Four different products of single‐ply roof‐coverings, namely one of atactic polypropylene (APP)‐modified bitumen and three of styrene–butadiene–styrene copolymer (SBS)‐modified bitumen, were studied. The study comprises temperature measurements during welding jobs on‐site to evaluate fire hazard, and laboratory measurements of T‐peel strength of the seams in order to evaluate the quality of the seam samples prepared on‐site. The results showed that by these new welding methods a remarkable decrease in temperatures by weld was made without any significant change in the quality of the seams. However, the mechanical strength of the seam was related to welding speed, which should be limited to form sufficiently strong seams using heat welding.
Simulation of sprinkler—hot layer interaction using a field model
Authors: Chow W. K. , Cheung Y. L.
Published: December 2004

This paper reports a study of the interaction of a sprinkler water spray with the fire‐induced hot layer using the field modelling technique. Data obtained in the large test room of the recent Swedish experiments reported by Ingason and Olsson (1992) are used to validate the results. The problem is divided into a gas phase and a liquid phase. For the gas phase, the set of conservation equations for mass, momentum and enthalpy of air flow induced by the fire is solved numerically using the Pressure Implicit Splitting Operator (PISO) algorithm. For the liquid phase, the sprinkler water spray is described by a number of droplets with initial velocity and diameter calculated by empirical expressions for the nozzle at different operating water pressures and flow rates. The trajectory of each droplet is calculated by solving the equation of motions, by including the dragging and heat transfer with the hot layer. The water droplet is assumed to be non‐evaporating and only the source terms in the gas momentum and enthalpy equations of the air flow included the interaction effects with water droplets, i.e. the ‘Particle‐Source‐in‐Cell’ method. The predicted results include the gas flow, temperature and smoke concentration field; the shape of the water spray; and some relevant macroscopic parameters such as amount of convective cooling, drag‐to‐buoyancy ratio, etc. The average smoke layer temperature and the smoke layer interface height are also calculated. The effect of the mean droplet size on those parameters is illustrated. Finally, a comparison of the water density received at floor level in cases with and without the fire is made.
Communication: Autoignition temperatures of carbon‐filled fluoroelastomers at elevated oxygen pressure
Authors: Hshieh Fu‐Yu , Bryan Coleman J. , Pedley Michael D.
Published: December 2004

The autoignition temperature and composition of 15 carbon‐filled fluoroelastomers have been determined. These experimental data and three sets of literature data are used to examine the relationship between autoignition temperature and rubber composition. The autoignition temperature at an elevated oxygen pressure is strongly affected by the carbon black content in rubbers. An empirical equation is derived and can be used to predict the autoignition temperature of carbon‐filled fluoroelastomers based on the carbon black content.
Mechanism of action of phosphorus‐based flame retardants in nylon 6. I. Ammonium polyphosphate
Authors: Levchik S. V. , Camino G. , Costa L. , Levchik G. F.
Published: December 2004

Comparison of oxygen and nitrous oxide indices indicates that ammonium polyphosphate (APP) should act in the condensed phase when added to nylon 6 (PA‐6). A detailed study of the thermal degradation mechanism of PA‐6/APP mixtures is carried out. A polyphosphate ester is formed on heating, which is the precursor of an intumescent char. Evidence is given of the thermal insulating action of the intumescent char which slows down the rate of combustion of the polymer.
Effect of instrument response time on heat release rate measurements
Authors: Lyon Richard E. , Abramowitz Allan
Published: December 2004

A linear hereditary integral technique provides simple analytic solutions for deconvoluting thermopile and oxygen consumption data to remove the effect of instrument response time on peak and integrated heat release rate values. A comparison of corrected and uncorrected thermopile and oxygen sensor data obtained on an Ohio State University (OSU) apparatus for various materials indicates that significant errors in peak and integrated heat release rate can result from delayed instrument response to repidly changing heat flows. However, correcting for temporal effects alone using this procedure does not account for differences between heat release rate values obtained by thermopile and oxygen consumption methods.
Mortars containing wood‐based fibres under thermal exposure using cone calorimeter heating
Authors: Sarvaranta Leena , Mikkola Esko
Published: December 2004

The behaviour of concrete structures under fire can be improved by adding fibers. However, relatively little is known of the details of the possible beneficial features of the fibre addition. The aim of this study was to compare the effects of different wood‐based fibres on the thermal properties of a standard laboratory cement mortar at conditions of a developing fire. The cone calorimeter heating method was used, and the sample thickness and heat flux were varied (25 mm or 50 mm, 25 kWm−2 or 50 kWm−2) to compare test conditions. The fibres comprised chemical pulp, chemi‐thermomechanical pulp, recycled fibres and viscose fibres. The fibre content in the mortar was 0.15–0.5% by weight. Temperature and mass loos measurements of oven‐dried specimens (moisture content <0.1%) showed no differences between different wood‐based fibre mortars and plain mortar. With increasing moisture content (about 5%), however, the presence of fibres affected the release of moisture from the fibre mortar material. With rapid heating of mortars, which have a moisture content of about 5%, local pressures are easily built up. These pressures are mainly caused by free water vaporization. The rear surface temperature measurements indicate that in mortars containing wood‐based fibres (0.15–0.5% by weight) the vaporization temperatures may be 20 –25% lower than in the reference mortar. Some effects on heat transfer can also be observed due to differences in water vaporization and movement processes.
Transient plane source (TPS) technique for measuring thermal transport properties of building materials
Authors: Log T. , Gustafsson S. E.
Published: December 2004

The electrical circuit for the recently developed transient plane source (TPS) technique for fast and precise measurements of thermal transport properties of solids has been modified for more convenient and more automated measurements. The technique has been tested for measurements of thermal conductivity and thermal diffusivity for a series of building materials ranging from thermally insulating materials (extruded polystyrene and PMMA) to good thermal conductors (stainless steel and aluminium). The results obtained in this work agree well with other techniques and international standard materials. This agreement indicates that the TPS method is accurate to within ±5% over a thermal conductivity range of four orders of magnitude (0.02 W m−1K−1to 200 W m−1k−1).
Modelling the heat release rate of aircraft cabin panels in the cone and OSU calorimeters
Authors: Parker William , Filipczak Robert
Published: December 2004

A computer model was developed to calculate the heat release rate of aircraft cabin panels in the OSU calorimeter based on their thermophysical, thermochemical and geometrical properties. It calculates the temperature profile through the panel as a function of time and uses the measured kinetic constants of the individual materials to deduce the mass loss rate. The mass loss rate is multiplied by the heat of combustion of the volatiles to obtain the heat release rate which would be measured in the Cone calorimeter. This heat release rate is used in an energy balance at the surface of the specimen to calculate the rise in enthalpy of the flue gases in the OSU calorimeter and thus the specimen's heat release rate in that apparatus. The calculated heat release rates are in reasonable agreement with measurements in the Cone and OSU calorimeters.
Neural network techniques applied to predict flammability limits of organic compounds
Authors: Suzuki Takahiro , Ishida Masaru
Published: December 2004

The application of the neural networks to correlate lower and upper flammability limits with chemical structures or basic physical properties for 150 organic compounds of diverse structures and functionalities was investigated. The prediction results based on a three‐layer neural network with a back‐propagation algorithm were compared with those obtained by multiple regression analysis. The comparison showed showed that the neural networks gave better versatility (range of applicability) and reliability. The predictive ability of the methods developed were tested for a new set of 50 compounds not included in the training data set and good agreement with observed lower and upper flammability limits was confirmed. The required information for the calculation were six easily available properties: standard enthalpy of combustion, molecular weight, critical temperature, critical pressure, oxygen balance, and diffusion coefficient in air. By using these calculable properties from the molecular structure, the method could be used to predict flammability limits of new compounds containing C, H, O, N, S, Cl, F and Br atoms.
Modelling of polymer ignition and burning adopted for cone calorimeter measurments: The correlation between the rate of heat release and oxygen index
Authors: Rychly Jozef , Costa Luigi
Published: December 2004

The model of polymer combustion based on heat (at two points in the polymer surface and in the gas), fuel and oxygen balance in the gas was used for a description of heat relese rate‐time curve observed in Cone Calorimeter measurements. It was shown that for the proper set of parameters, which were taken either form the Literature data or by a trial‐and‐error approach, a relatively good agreement with experimental heat release rate‐time curves may be obtained. The changes of various parameters of the model leading to different limiting oxygen indices as well as to different heat release rate‐time curves are discussed.
Specimen heat fluxes for bench‐scale heat release rate testing
Authors: Babrauskas Vytenis
Published: December 2004

When a specimen is testd for its heat release rate (HRR) behaviour using a bench‐scale such as ISO 5660 or equivalent, one very important test condition is not pre‐standaridized and must be set: the heat flux to be imposed on the specimen by the heater. The heat flux cannot be ligitimately standardized, since the value appropriately to be used will differ according to purpose or application. The present paper sets forth the considerations which should govern the correct choice of heat flux. A discussion is given of minimum ignitiability level; statistical variability at low heat fluxes; the ranges of heat fluxes associated with small actual ignition sources; the heat fluxes associated with fires away from the ignition sources, all the way up to fully‐involved room fires; the application of the product; and the needs associated with mathematical modeling of room fires. Correlational approaches are also illustrated and contrasted to physics‐based ones. Finally, the empirical nature of the present situation is emphasized. Judged from first principles, it would appear that successful prediction of room fire results from bench‐scale test data would require both the testing at a large number of different heat fluxes and the use of algorithms to permit time‐dependent interpolation. Such algorithms have been proposed; however, some very successful predictions are noted with much simpler techniques.
Flow rate defective boundary conditions in haemodynamics simulations
Authors: Veneziani A. , Vergara C.
Published: December 2004

In the numerical simulation of blood flow problems it might happen that the only available physical boundary conditions prescribe the flow rate incoming/outgoing the vascular district at hand. In order to have a well‐posed Navier–Stokes (NS) problem, these conditions need to be completed. In the bioengineering community, this problem is usually faced by choosing a priori a velocity profile on the inflow/outflow sections, that should fit the assigned flow rates. This approach strongly influences the accuracy of the numerical solutions. A less perturbative strategy is based on the so‐called ‘do‐nothing’ approach, advocated in Heywood et al. (Int. J. Num. Meth. Fluids 1996; 22:325–352). An equivalent approach, however, easier from the numerical discretization viewpoint, has been proposed in Formaggia et al. (SIAM J. Numer. Anal. 2002; 40(1):376–401). It is based on an augmented formulation of the problem, in which the conditions on the flow rates are prescribed in a weak sense by means of Lagrangian multipliers. In this paper we extend this analysis to the unsteady augmented NS problem, proving a well‐posedness result. Moreover, we present some numerical methods for solving the augmented problem, based on a splitting of the computation of velocity and pressure on one side and the Lagrangian multiplier on the other one. In this way, we show how it is possible to solve the augmented problem resorting to available NS solvers. Copyright © 2004 John Wiley & Sons, Ltd.