Smoke and fire assessment with the fire propagation test

Assesing the total potential fire hazard of modern interior surfacing of buildings requires a method which includes determination of smoke toxicity concurrently with fire and smoke production parameters. The Fire Propagation Box Test (British Standards Institution BS 476, Part 6) is a promising contender. It has been examined in the flaming mode as a method for evaluating smoke production concurrently with fire propagation indices for a range of surfacings, rather than resorting to a separate procedure by using fans with the same apparatus, as described in the former British Standards Institution Draft for relation to rate of burning the concurrent procedure is shown to be the more valied method.     

锥型量热仪对聚氨酯泡沫塑料阻燃抑烟性能的评估

本文采用新一代的评估手段一锥型量热仪分别对添加ＡＴＨ／ＤＭＭＰ的硬聚氨酯泡沫塑料和添加Ｔ１０１及Ｔ１０１／三聚氰胺的软聚氨酯泡沫塑料的燃烧性能进行了实验测试。对在真实火情下的燃烧危险性进行了分析研究，为上述两种泡沫塑料的火安全性评估提供了重要的参考依据。     

Correlation between cone calorimeter data and time to flashover in the room fire test

Correlations based on linear regressions between data as time to ignition and heat release in the cone calorimeter and time to flashover in the room fire test have been developed. They are a further development of an earlier approach which has been modified and extended to a wider range of surface linings. The correlations apply so far only to surface linings on both walls and ceilings. When the density of the linings as a simplified measure of the thermal inertia is included, the correlations are improved significantly. The new correlations are based on data readily available from the cone calorimeter test at one heat flux level, 50 kWm^?2. The correlation coefficient for the basic relationship, including the density of the linings, is now 0.98 when applied to the 13 linings investigated earlier. This is slightly better than the previous study, in which the best correlation coefficient was 0.96. When applied to 28 linings, the correlation coefficient remains about the same (0.97). Very similar regression equations have been obtained when analysing only 13 products and all 28. This is a strong indication of the general predictive capacity of this approach. The inclusion of other data such as thickness of linings or mass loss during fire does not improve the correlation coefficients. The approach is quite straightforward and simple. However, it has provided a useful prediction which is also valid for an extended range of linings.     

利用锥形量热仪研究聚氨酯硬泡的燃烧性能

利用锥形量热仪对硬质聚氨酯泡沫(RP UF)的燃烧特性进行了研究.通过对RP UF燃烧过程中的热释放速率、热释放总量、烟生成速率和总产烟量等进行系统性测试,讨论了聚醚多元醇、聚酯多元醇以及异氰酸酯指数(R值)对RP UF热危险性和烟气危险性的影响.结果表明,聚酯多元醇替代聚醚多元醇制备的RP UF燃烧过程中的热释放速率...     

Comparison of Nordtest FIRE 007, CEN draft proposal (Radiant Panel) and Cone Calorimeter methods in the fire testing of floor coverings

Different types of floor coverings were tested using three different methods: the Cone Calorimeter (ISO 5660), the Nordtest floor covering test NT FIRE 007 and the German Radiant Panel Method (DIN 4102 Teil 14). The results of the comparisons between both flame spread and smoke production are given. Some correlation is found between the results of the Cone Calorimeter and the NT FIRE 007. Between other methods, no correlations seem to exist.     

Toxicity of fire effluents: Application of test data

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.     

用锥形量热法研究EVA/EG复合材料的阻燃性能

采用哈克转矩流变仪将阻燃剂可膨胀石墨(EG)、乙烯-乙酸乙烯酯共聚物(EVA)树脂和其它助剂进行熔融混和均匀,制备阻燃EVA/EG复合材料,并通过锥形量热仪研究其阻燃性能。研究结果表明:经膨胀石墨阻燃的EVA/EG复合材料的热释放速率峰值(PHRR)、总热释放速率(THR)、烟发生速率(SPR)、总释烟速率(TSR)逐渐降低,火灾性能指数(FPI)、点燃时间(TTI)及燃烧残渣逐渐增加,表现出明显的阻燃性和抑烟性特点。阻燃EVA/EG复合材料燃烧时,其EG片层受热膨胀形成保护层,有效延缓了热、氧传递,降低了材料的热分解和扩散速率,促进了成炭,是阻燃性提高的关键因素。     

锥形量热仪在饰面型防火涂料防火性能研究中的应用

用锥形量热仪的方法研究了不同阻燃剂含量的饰面型防火涂料点燃时间、热释放速率、有效释放热及总烟气释放量等项目,结果表明:随着阻燃剂含量的增加,热释放速率、有效释放热等参数随之降低;此外,在市面上选取3种饰面型防火涂料,用大板法和锥形量热仪法进行了研究,结果表明:随着耐火极限的延长,有效释放热、热释放速率等参数数值明显减小,同理论分析一致。     

Comparison of test protocols for the standard room/corner test

As part of international efforts to evaluate alternative reaction‐to‐fire tests, several series of room/corner tests have been conducted. Materials tested were mostly different wood products but included gypsum board and a few foam plastics. This is a review of the overall results of related studies in which the different test protocols for the standard room/corner test were used. Differences in the test protocols involved two options for the ignition burner scenario and whether or not the ceiling was also lined with the test materials. The test materials were placed on three walls of the room in all the tests. The two burner scenarios were (1) 40 kW for 300 s followed by 160 kW for 300 s and (2) 100 kW for 600 s and 300 kW for 600 s. The 40 and 160 kW burner scenario without the ceiling lined did not provide a severe enough test for flashover to occur with fire‐retardant‐treated materials. Use of the 100 and 300 kW burner scenario without lining the ceiling provided the ability to differentiate between wood products with ASTM E 84 flame spread indexes of 70 to 125 and those with higher flame spread indexes. Lining the ceiling with test material creates a more severe test.     

Surface temperature measurements on burning wood specimens in the Cone Calorimeter and the effect of grain orientation

Surface temperatures were measured on dry Douglas fir sapwood specimens during Cone Calorimeter tests using thermocouples and an infra-red pyrometer. Good agreement between the thermocouples and the pyrometer was obtained when (1) the emissivity was assumed to be 1.0 and (2) the thermocouples were in good contact with the surface and were not located in the proximity of a fissure. The major fissures were normal to the grain of the wood and the volatiles vented through the fissures. Char oxidation in the region between the vertical fissures resulted in higher surface temperatures.     

用锥形量热仪研究磷酸酯和酚醛环氧树脂阻燃高抗冲聚苯乙烯

采用锥形量热仪对酚醛环氧树脂(NR)和磷酸三苯酯(TPP)对高抗冲聚苯乙烯(HIPS)阻燃性能的影响进行研究.结果表明,NR主要通过成炭作用在凝聚相中发挥作用,而TPP则主要通过自身挥发在气相来抑制燃烧.两者并用具有明显的阻燃和抑烟协同效应,同时有效地降低了材料的有效燃烧热.     

Some factors influencing fire spread over room linings and in the ASTM E–84 tunnel test

An examination of the correlative relationship between room fire intensity (temperature) and flammability data for materials, ASTM E–84 flame ratings and energy release rate from calorimertry devices is presented for fire spread on lings. The results of the analysis show the significance of two modes of flame spread—wind-aided and opposed-flow spread. The factors important in these spread modes are considered from approximate solutions developed for turbulent flow. As the importance of energy release rate to flame spread in the tunnel test (E–84) and in upward or wind-aided spread is illustrated. The results suggest a possible reason why the ASTM E–84 and in upward or wind-aided spread is illustrated. The results suggest a possible reason why the ASTM E–84 ratings may not be applicable to the performance of low-density combustible linings in wall fires. In the analyses, flame radiation has not been considered. Also the interpretation of energy release rate data for difference scale and orientation effects has been ignored. These two factors must ultimately be addressed.     

The Accumulation of Flammable Gases in Cone Calorimeter Tests is Responsible for Flash Ignition of Wool and Cotton Samples

In this paper a possible explanation is presented for the differences found between the fire behaviour of materials in small-scale cone calorimeter tests and the large-scale furniture calorimeter. The results obtained with cone calorimeter/FTIR equipment at 35 kW m⁻² will show that the early flash ignitions of typical materials like cotton and wool are due to the liberation of flammable gases during the pyrolysis phase and the typical ignition situation on the cone calorimeter, that is, the presence of a sparking igniter above the sample. This fast flash ignition and the early heat release behaviour on the cone calorimeter may be in contradiction to the early fire growth in other fire tests where the ignition conditions are clearly different from pyrolysis circumstances, that is, ignition via a burning newspaper, match, gas flame, etc.     

Evaluation of the fire-retardant properties of zinc hydroxystannate and antimony trioxide in halogenated polyester resins using the Cone Calorimeter method

An investigation of the burning behaviour of a series of halogenated polyester resin formulations has been carried out using the Cone Calorimeter technique. The data obtained clearly indicate that zinc hydroxystannate (ZHS) is more effective than antimony trioxide (Sb₂O₃) in reducing the average and peak rates of heat release in a chlorinated resin and in decreasing the peak rate of heat release in a brominated resin. The decreases in average heat release rate in the brominated resin are similar for ZHS and Sb₂O₃. Hence, at an addition level of 2 phr (parts per hundred of resin), ZHS reduces the average heat release rates of a chlorinated and a brominated resin by 41% and 26%, respectively, and the peak heat release rates of the same resins by 38% and 39%, respectively. The degree of smoke suppression exhibited by ZHS in these Cone experiments is significantly greater than that given by Sb₂O₃. In general, the correlation between Cone Calorimeter data and results obtained using other laboratory fire tests (UL-94, LOI) is poor, except in the case of smoke density measurements, where the correlation with NBS Smoke Box data is remarkably good. No correlation is observed between the measured values of CO and CO₂ output by different test methods, although it is now generally considered that small-scale fire tests cannot be used to predict gaseous concentrations in real-fire situations.     

A comparison of flashover times in small-scale fires using test data

Reaction to fire standard tests on materials used as linings are not sufficient in themselves to predict the behaviour of growing fires. However, flashover times with cellulosic linings have been correlated qualitatively with the British test, but generally there is wide divergence in the test results from different countries. This report paper discusses some aspects of this problem.     

外压作用下带锥壳设备的设计

通过一个实例介绍了按ASME第Ⅷ卷第一分册中的规定——外压作用下带锥壳设备的设计过程,并给出了锥壳与简体连接处截面组合有效惯性矩的计算方法。     

Digital comparison of x-ray diffraction data from cotton textiles

It is proposed that step-scanned digital x-ray diffraction data from closely similar samples be compared only after averaging several scans. The comparison of averaged data for two samples is shown directly by a running difference curve; more subtle differences are indicated by a running sum of difference curve. In order to compensate for inequalities arising from experimental difficulties, scaling of the two data sets may be optionally accomplished by either equating the total intensity sums or performing a least-squares fitting. Comparison of the two scale factors and consideration of the intercept (background) and resulting standard deviation provide a quantitative estimate of the difference between samples. The proposed techniques are illustrated for hydrocellulose II, cotton treated with acid, flame retardant, and permanent-press agent, and for the experimental differences of intact cloth versus pressed pellet and different beam-current settings on the diffractometer.     

A laboratory-scale gallery fire test on rubber conveyor belts with fabric skeletons

The authors have conducted a laboratory-scale gallery fire test on nine different rubber conveyor belts with fabric skeletons. The interior of the gallery used in this test was 2.5 m long, 0.35 m wide and 0.35 m high. The fire test on each sample was conducted in the upward airflow of the inclined gallery as well as in the horizontal one, and both 60 mm and 90 mm wide specimens, whose length was about 1.5 m, were provided for each test. The test results were compared with those from some other small-scale flammability tests; i.e. the small-scale flame, the oxygen index and the hot plate ignition tests. In addition, some problems in the laboratory-scale gallery fire test were also discussed. As a result, it has been found empirically that determination of both the time to ignition and the flame-propagation speed could be significant in case the flame propagated over the whole length of the belt specimen in the gallery, so that the fire resistance of the belt samples could be classified in detail.     

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

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