Influence of fire retardants on the reaction‐to‐fire properties of coextruded wood–polypropylene composites

The reaction‐to‐fire properties of coextruded wood–plastic composites containing different fire retardants (melamine, zinc borate, ammonium polyphosphate, aluminium trihydroxide, natural flake graphite and expandable graphite) in the shell layer have been studied with the cone calorimetry technique. The effect of ammonium polyphosphate in combination with graphite has also been studied with a cone calorimeter test. A coextruded composite manufactured without any fire retardant addition has been used as a reference. The fire properties measured in the cone calorimeter are discussed, including the heat release rate, total heat release, smoke production, specific extinction area, CO yield and mass loss rate. The results show that the introduction of fire retardants in the shell layer of coextruded wood–polypropylene composites has a favourable effect on the fire resistance properties of the composite materials. The reaction‐to‐fire properties have been improved according to the fire classification of construction products based on the Euroclass system. Copyright © 2015 John Wiley & Sons, Ltd.     

Prediction of fire classification for wood based products. A multivariate statistical approach based on the cone calorimeter

Wood has long traditions as a building material, and is often used in construction elements, and as interior and exterior surfaces in the Nordic countries. In most applications, there are reaction to fire requirements to products used as surfaces, e.g. in escape routes and larger public spaces. Most wood products will therefore have to be treated with fire retardant (FR) agents to fulfil the strict requirements to properties connected to heat release and flame spread. Unfortunately, FR agents usually also increase the smoke production, as they cause a more incomplete combustion of the wood. The wood product manufacturers seek to find the optimal amount of FR additives where both heat release and smoke production in the classifying test are within the requirements given in the building regulations. This paper describes models for prediction of the European reaction to fire classes of wood products. The models are based on multivariate statistical analysis, and use test results from the cone calorimeter test as input. The presented models are, with very good precision, able to predict which Euroclass and additional smoke class a wood based product would obtain if it were to be tested in the single burning item test. Copyright © 2006 John Wiley & Sons, Ltd.     

Effectiveness of impregnation of ammonium polyphosphate fire retardant in poplar wood using microwave heating

Poplar samples were impregnated with ammonium polyphosphate fire retardant at various pressures and durations after they were pretreated with microwave heating. The effects of the pressure and duration on the flame‐retardation and smoke‐suppression properties were investigated with cone calorimeter analysis. The peak heat release rate (pk‐HRR), total heat release (THR), and total smoke product (TSP) of treated woods were measured for samples of pretreated and untreated with microwave. After the impregnation, the poplar wood showed the significant improvement in its fire resistance. Compared with non‐impregnation wood, the pk‐HRR, THR, and TSP of wood impregnated with ammonium polyphosphate at pressure of 0.4 MPa and duration of 10 min were 48.29%, 35.58%, and 68.64% less, respectively. The pk‐HRR, THR, and TSP of microwave pretreated wood was 15.89%, 5.69%, and 13.59% less than those without microwave pretreated sample. The microwave pretreatment of wood can increase fire retardant effectiveness of ammonium polyphosphate‐impregnated wood. Copyright © 2015 John Wiley & Sons, Ltd.     

Fire performance studies on glass-reinforced plastic laminates

Polyester, epoxy and phenolic glass-reinforced laminates were compared in terms of their fire properties in the cone calorimeter. The presence of a gel coat on the polyester and epoxy products had some effect, mainly in the FR grades. The FR polyester with a brominated flame retardant showed a marked decrease in rate of heat release and in rate of smoke production. Aluminium hydroxide (commonly called alumina trihydrate of ATH) caused a significant delay in ignition time for the epoxy product and some reduction in rate of heat release but rate of smoke release was still relatively high. Phenolic laminates showed a long ignition time and relatively low rate of heat release (RHR). The peak RHR was further reduced by the presence of aluminium hydroxide and by changing the type of glass reinforcement. The influence of thickness was explored for a series of phenolic laminates in both cone calorimeter and the International Maritime Organization (IMO) surface flammability test. Ignition delay time was significantly affected and the cone calorimeter results showed that the shape of the RHR curve was also changed as the thickness increased. However, the heat release measurements in the IMO test were not sensitive enough to pick up the differences in this property. The type of substrate under the laminate significantly altered the burning rate but this may have been because they were not glued or mechanically fixed.     

溴锑阻燃体系对PS-HI／有机蒙脱土复合材料的阻燃性研究

采用熔融法制备包括溴锑阻燃剂（TBBPA—Sb2O3）和有机蒙脱土（OMMT）并用体系的阻燃PS-HI复合材料；利用琏于耗氧原理的锥形量热仪测试并分析复合材料的燃烧性能，用扫描电子显微镜表征复合材料的微观结构肜貌，结果表明：TBBPA-Sb2O3与OMMT并用阻燃的PS-HI复合材料热释放速率、峰值热释放速率、平均热释放速率以技中烟速率均明显降低，火灾性能指数明显增加；形成的PS-HI／OMMT复合材料与TBBPA—Sb2O3体系之间具有阻燃协同效应，当TBPA—Sb2O3添加7．5份和2．5份，OMMT添加5份时，三者之间的阻燃协同作用最佳。     

Enhancement of fire retardancy properties of glass fibre–reinforced polyesters composites

This paper presents the results of an experimental investigation on the fire retardancy properties of glass fibre–reinforced polyester (GFRP) composites with bisphenol‐A vinylester and isophthalic polyester as matrices and low electrical conductivity E‐glass fibres as reinforcement. The fire protection systems tested were alumina trihydrate (ATH), decabromodiphenyl ether (DBDE), and antimony trioxide (Sb₂O₃). A mass loss cone calorimeter was used to obtain the properties of heat release rate (HRR), peak HRR, total heat released, total mass loss, time to ignition, and time of combustion. Moreover, limiting oxygen index (LOI), UL‐94, and glow‐wire tests were also performed. The fire tests were carried out in order to investigate if the combination of ATH and DBDE could have “additive,” “antagonistic,” or “synergistic” effects on the flame retardant properties of the GFRP studied in this work. In addition, the influence of the ATH content variation on flame retardant properties was also evaluated. The results indicate that the sole addition of ATH at 47.7 phr could lead to the complete inhibition of the composites ignition, while the materials containing DBDE exhibit ignition and flame propagation in the cone calorimeter test.     

Combustion behaviour of ethylene vinyl acetate copolymer-based intumescent formulations using oxygen consumption calorimetry

This work compares the fire degradation of ethylene-vinyl acetate 8% copolymer (EVA8) with two flame-retarded formulations, using the cone calorimeter. The first one, EVA8/ammonium polyphosphate (APP) leads to the protection of the material, in the conditions of a fire, by means of blowing up and weak carbonization. The addition of polyamide-6 (PA-6) in EVA8/APP improves the protection by forming an intumescent carbonaceous shield. The fire hazard of the virgin polymer and of the FR systems are quantified, in terms of rate of heat release, weight loss, effective heat of combustion, volume of smoke production and CO and CO₂ production. It assesses the effectiveness of the fire retardant additives APP and APP/PA-6 in EVA8-based materials under simulated real fire test conditions. The respective temperatures of the degradation front are deduced from the weight loss data recorded in the course of the cone calorimeter experiments and the results of the invariant kinetic parameters method applied to the different specimens. The addition of APP/PA-6 in EVA8 leads to a superficial phenomenon; the degradation zone is thus located on the upper volume of the specimen during all the exposure to the heat flux. © 1998 John Wiley & Sons, Ltd.     

Red phosphorus–controlled decomposition for fire retardant PA 66

The thermal degradation and the combustion behavior of glass fiber–reinforced PA 66 materials containing red phosphorus were investigated. Thermogravimetry (TG), TG coupled with FTIR, and TG coupled with mass spectroscopy were used to investigate the thermal decomposition. The flame retardant red phosphorus was investigated with respect to the decomposition kinetics and the release of volatile products. The combustion behavior was characterized using a cone calorimeter. Fire risks and fire hazards were monitored versus external heat fluxes between 30 and 75 kW/m². Red phosphorus acts in the solid phase and its efficiency depends on the external heat flux. The use of red phosphorus results in an increased amount of residue and in a corresponding decrease in total heat release. The decrease of the mass loss rate peak results in a corresponding decrease of the peak heat release. With increasing external heat flux applied the first effect on the total heat release decreases linearly, whereas the second effect on the peak heat release expands linearly. The investigation provides insight into the mechanisms of how the fire retardant PA 66 is achieved by red phosphorus controlling the degradation kinetics. Taking into account that a decrease of the volatile products also leads to a decrease of heat production in the flame zone and that the char acts as heat transfer barrier, a reduced pyrolysis temperature is suggested as a further feedback effect. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2060–2071, 2002     

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.     

用锥形量热仪研究阻燃聚丙烯的燃烧行为

采用锥形量热仪比较了溴系阻燃聚丙烯、无卤阻燃聚丙烯的燃烧行为。结果表明:按UL94标准测试V-0阻燃等级的阻燃聚丙烯复合材料,采用无卤阻燃体系比采用溴系阻燃体系具有更低的热释放速率、烟生成速率和总烟释放量。     

Synergistic effects between red phosphorus and alumina trihydrate in flame retardant silicone rubber composites

Abstract

The synergistic flame retardant effects between red phosphorus (RP) and alumina trihydrate (ATH) in silicone rubber (SR) composites were evaluated using limiting oxygen index, UL 94 rating, cone calorimeter, thermogravimetric analysis and digital photographs. It has been found that the SR composite containing only ATH does not show good flame retardancy at 39·0 wt-% loading. The cone calorimeter results showed that the heat release rate, mass loss rate, mass and total heat release of SR/ATH/RP composites decrease greatly in comparison with the SR/ATH composites. The digital photographs demonstrated that 1·0 wt-%RP could promote the formation of the homogenous and compact char layer. Thus, a suitable amount of RP has a synergistic effect with ATH in the flame retardant SR composite system.     

Prediction of heat release in the single burning item test

This paper presents a modification of an existing mathematical model that uses cone calorimeter test results to predict heat release rate in the single burning item (SBI) test. A method for classification of cases based on multivariate statistical analysis is incorporated in the modified model. This makes it possible to determine the development of the heat release curve in the SBI test with better precision than the original version was able to. The model has been applied to 100 cases of cone calorimeter test results from 33 different products. For most of the products the predicted shape and level of the heat release curves are close to measurements in the SBI test. Using the predicted heat release results as input to calculation of FIGRA_0.2MJ and THR_600s within the new European system for reaction‐to‐fire classification, we were able to predict membership of the correct class in 90% of the analysed cases. Copyright © 2002 John Wiley & Sons, Ltd.     

Flame retardants and heat release: review of data on individual polymers

This is part of a project considering whether flame retardants affect polymer heat release, a critical issue to assess whether adding flame retardants decreases fire hazard. The work investigated the following. (1) Fire properties affecting fire hazard, confirming that heat release rate is the key fire property most strongly influencing fire hazard. (2) Ways to assess heat release and whether full‐scale fire heat release rate can be predicted from small‐scale test results, confirming that cone calorimeter and Ohio State University data are adequate to predict full‐scale heat release. (3) Analysis of key 1988 NBS/NIST study comparing the fire hazard of flame retarded products versus non‐flame retarded products for the same application. This confirmed that the study demonstrated that flame retardants lower fire hazard and that the levels of additives in the flame retarded products used were not excessive. (4) Review of studies investigating effects of flame retardants on various polymeric systems. The overall conclusion is that flame retardants does indeed improve fire safety (when used appropriately) primarily because they decrease heat release. Part 2 of the project (separately) considers the key polymers that need to be potentially flame retarded and reviews recent studies on effects of flame retardants on heat released by such polymers. Copyright © 2014 John Wiley & Sons, Ltd.     

用锥形量热仪研究聚氨酯泡沫的阻燃性能

在50 kW/m2辐射功率下,利用锥形量热仪研究了氢氧化铝、卤系阻燃剂、氮系阻燃剂和磷系阻燃剂阻燃聚氨酯泡沫(PUF)的阻燃特性,获得了点燃时间、最大热释放速率、总热释放、比消光面积及质量损失速度等参数。结果表明,将热释放速率、燃烧总释放热和烟气释放量作为材料阻燃性能好坏的评价指标,阻燃剂聚磷酸铵（APP）和三聚氰胺磷酸盐（MP）是PUF的理想阻燃剂。     

Effect of flame heat flux on thermal response and fire properties of char‐forming composite materials

This study evaluates the effect of flame heat flux on the prediction of thermal response and fire properties of a char‐forming composite material. A simplified two‐layer flame model was developed and incorporated into a heat transfer thermal model to predict the thermal response and fire reaction characteristics of a burning material. A typical char‐forming material, E‐glass reinforced polyester composite, was used in the study. A cone calorimeter was used to measure the fire reaction characteristics of the composite. The flame heat flux in a cone calorimeter test setup was estimated using the simplified flame model. Thermal response and fire property predictions with and without the effect of flame heat flux were compared with experimental data obtained from the cone calorimeter tests. Results showed that the average flame heat flux of the composite in a cone calorimeter was 19.1 ± 6 kW/m² from model predictions. The flame had a significant effect on the thermal response and fire properties of the composite around the first heat release peak but the effect decreased rapidly afterwards. Copyright © 2012 John Wiley & Sons, Ltd.     

Fire hazard evaluation of thermoplastics based on analytic hierarchy process (AHP) method

Combustibility performance of 14 compositions including five main thermoplastics (polycarbonate (PC), polypropylene (PP), high impact polystyrene (HIPS), acrylonitrile butadiene styrene (ABS) and poly (vinyl chloride) (PVC)) was tested by cone calorimeter. The fire growth index, total heat release amount index, total smoke release amount index and toxicity product index were calculated, based on which an index system for evaluating fire hazard was set up. All factors in this index system had been analyzed by the analytic hierarchy process, and the specific weight for each factor had been determined. Then fire hazard of thermoplastics was evaluated considering integrated fire hazard index. The results show that fire hazards of HIPS‐phosphate fire retardant (PFR), PVC‐non‐flame retardant, ABS‐brominated flame retardant (BFR) and PC/ABS‐PFR are higher than PC‐BFR and PP‐non‐halogenated flame retardant. Copyright © 2009 John Wiley & Sons, Ltd.     

Evaluation of passenger train car materials in the cone calorimeter

Recent advances in fire test methods and hazard analysis techniques make it useful to re‐examine passenger train fire safety requirements. The use of test methods based on heat release rate (HRR), incorporated with fire modelling and hazard analysis, could permit the assessment of potential hazards under realistic fire conditions. The results of research directed at the evaluation of passenger train car interior materials in the cone calorimeter are presented. These measurements provide data necessary for fire modelling as well as quantitative data that can be used to evaluate the performance of component materials and assemblies. The cone calorimeter test data were also compared with test data resulting from individual bench‐test methods specified in the FRA fire safety guidelines. The majority of the tested materials which meet the current FRA guidelines show comparable performance in the cone calorimeter. Copyright © 1999 John Wiley & Sons, Ltd.     

Application of a one‐dimensional thermal flame spread model on predicting the rate of heat release in the SBI test

A one‐dimensional thermal flame spread model was applied to predict the rate of heat release in the single burning item (SBI) test on the basis of the cone calorimeter data. The input parameters were selected according to the features of the SBI test and using particle board as a model tuning material. The features of the measured and calculated rate of heat release curves were compared for a series of 33 building products. The fire growth rate (FIGRA) indices were calculated to predict the classification in the forthcoming Euroclass system. The model gave correct classification for 90% of the products studied. An essential feature of the model is that only one cone calorimeter test at the exposure level of 50 kW m^?2 is needed. The model, therefore, provides a practical tool for product development and quality control. Copyright © 2001 John Wiley & Sons, Ltd.     

Investigation of fire behavior of rigid polyurethane foams containing fly ash and intumescent flame retardant by using a cone calorimeter

Cone calorimeter is one of the most useful bench‐scale equipment which can simulate real‐world fire conditions. Therefore, cone calorimeter tests have been the most important and widely used tests for research and development of fire behavior of polymeric materials. In this study, fire behavior of rigid polyurethane foams containing fly ash (up to 5 wt %) and intumescent flame retardant (up to 5 wt %) composed of ammonium polyphosphate/pentaerythritol was investigated by using a cone calorimeter. In addition, thermogravimetric analysis of the additives and the foams were also carried out to explain the effects of fly ash and intumescent flame retardant on fire behavior of the foams. Experimental results indicated that rigid polyurethane foam containing fly ash and the intumescent flame retardant in comparison with pure rigid polyurethane foam shows significantly enhanced fire resistance and thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of glass fibres and fire retardant on the combustion behaviour of composites,glass fibres–poly(butylene terephthalate)

The oxygen index (OI) of poly(butylene terephthalate) (PBT) tends to decrease when it is combined with milled-glass fibres either with or without the sizing treatment. This shows that the previously found apparent increase of flammability of PBT glass fibre composites (GFPBT) as compared to PBT is not due to the introduction of the flammable sizing together with the glass fibres in the polymer which was one suggested explanation in the literature, but rather to the wick and anti-dripping effects of glass fibres. The effectiveness of a typical brominated organic compound-antimony trioxide fire retardant system (FR), as measured by OI, is found to be larger in GFPBT as compared to PBT. A linear increase of the temperature index (TI) of PBT and of GFPBT is observed with increasing concentration of the FR. The fire retardant increases the time to ignite while it decreases the maximum rate of heat release and increases the smoke optical density and CO evolution on burning in the cone calorimeter. The dependence of fire risk and hazard assessement on the combustion model of the combustion test method is discussed for OI and cone calorimeter in the case of PBT, GFPBT and FR corresponding materials. © 1998 John Wiley & Sons, Ltd.