Understanding the decomposition and fire performance processes in phosphorus and nanomodified high performance epoxy resins and composites

This paper investigates the decomposition mechanism and fire performance of high performance epoxy amine resins and laminate systems, using thermogravimetry (TGA), energy dispersive spectroscopy (EDS), cone calorimetry and Fourier transform infra-red spectroscopy (FTIR). Two different, commercially-important epoxy resins, tetraglycidyl methylene dianiline (TGDDM) and diglycidyl ether of bisphenol A (DGEBA) have been cured separately with diethyl toluene diamine (DETDA) and bis(4-aminophenoxy)phenyl phosphonate (BAPP) and their relative combustion performance has been examined and discussed in terms of their decomposition profile. This paper highlights the close relationship between char yields (TGA and cone calorimetry) and thermal decomposition with the peak heat release rate, highlighting the role of the condensed phase in minimizing combustion. The lower decomposition temperatures and higher char yields of the tetra-functional epoxy (TGDDM) are therefore seen to provide superior fire performance compared to the bi-functional (DGEBA) epoxy. FTIR shows that the decomposition occurs through initial cleavage of P-O-C bonds in preference to other covalent bonds, which allows dehydration and subsequent charring and/or chain scission. TGA demonstrated that the laminated systems did not show a significant difference to the neat resin systems, with respect to initial decomposition of the network and the thermal stability of the char layer. Nanoclay addition was also found to have little effect upon degradation and fire performance.     

Physicochemical processes in modified fire- and thermal-protective two-layer filled epoxy polymers under the action of fire sources

A carbonized layer was formed by means of thermal treatment of the surfaces of glass- and organo-fiber plastics based on an epoxy binder premodified with flame-retardant phosphorus-containing compounds. To improve flame resistance of the carbonized layer, the active coats of swelling type which filled the cracks and pores were studied. The obtained data on the construction fire resistance confirmed the advantages of the two-layer fire and thermal protective coats over conventional ones.Izhevsk. Translated from Fizika Goreniya i Vzryva, Vol. 31, No. 2, pp. 73–79, March–April, 1995.     

Relationship between fire resistance and fire tolerance

Much of the information accumulated on the fire resistance of ‘dividing’ elements can be utilized in the design of buildings for fire safety, if the fire tolerance values are converted into fire resistance. Three methods of conversion, one based on the concept of equal temperature-time areas, the second on the concept of equal maximum temperatures, and the third, Law method, are critically examined and handy conversion tools presented. In the case of the ‘key’ elements of buildings, basing the fire safety design on fire resistance information is not recommended.     

Probabilistic analysis of transport-reaction processes over catalytic particles: Theory and experimental testing

We developed a probabilistic theory of transport-reaction processes over various types of configurations of catalytic particles, particularly for a single particle. The theory describes a single pulse-response experiment which is similar to the single pulse temporal analysis of products (TAP) experiment. The analysis is based on the general theory of Brownian motion with “killing” and the Feynman-Kac formula. Different diffusion-reaction problems, particularly the problem “diffusion-very fast reaction” (infinite rate reaction), have been analyzed. In the latter case, the probability for a reactant to be converted equals a purely geometric characteristic, namely, the probability for a reactant molecule to hit at least one catalyst particle in a configuration of particles. Solving a boundary value problem, the probability of conversion can be found as a function of the apparent kinetic parameter. Based on experimental data on exit flow and conversion this parameter can be extracted. Experimental data in studies of CO oxidation over a single particle of Pt catalyst show a qualitative agreement with data from computational experiments based on the developed probabilistic theory. For two-particle catalyst configurations, it was found computationally a non-trivial dependence of the reactant conversion on some geometric characteristics, especially the distance between particles. A distance was found for which conversion is highest.     

Ceiling heat transfer during fire plume and fire impingement

The impingement of turbulent fires and fire plumes on a horizontal ceiling was considered. Free flame heights, impinging flame lengths along the ceiling and ceiling heat fluxes were measured for both unconfined and confined ceilings. The study was limited to the initial stage of ceiling heating by fire under conditions where convection dominates the flow. Fire sources were simulated by burning liquid methanol, ethanol, 1-propanol or n-pentane from the top surface of a cylindrical wick. Test variables include fire heat release rate of 50–7890 W, ceiling diameters of 610 and 660 mm, ceiling heights of 58–940 mm, wick diameters of 10–107 mm and curtain wall lengths (for confined ceilings) as large as the ceiling height. Simplified models were employed to suggest expressions for data correlation. Flame lengths increased up to 40% when the ceiling was confined. Ceiling heat fluxes were relatively independent of position in the stagnation region (radius along ceiling <20% of the ceiling height). Heat fluxes in the stagnation region for plumes were 25–40% of those measured for impinging jets at comparable conditions. In the ceiling jet region, at larger distances from the point of impingement, the heat flux decreased with increasing radius, in agreement with other studies. Confinement tended to increase ceiling heat fluxes in both regions. Ceiling heat fluxes for impinging flames and plumes were approximately the same, for flame lengths along the ceiling up to 25% of the ceiling height; however, stagnation point heat fluxes decreased for longer flame lengths.     

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.     

绿色化学与消防

在绿色化学的理论与原则基础上,提出了消防友好过程的概念。通过分析比较绿色工艺流程与传统工艺流程在火灾危险性方面的差异,指出绿色化学的研究与消防安全密切相关。     

Transition of the forest ground fire to crown fire

Translated from Fizika Goreniya i Vzryva, Vol. 26, No. 6, pp. 27–35, November–December, 1990.     

多层民用建筑消防水箱和消防水泵的作用及设置建议

本文针对多层民用建筑设置消防水箱和消防水泵的现状进行分析,对因为国家消防技术规范中规定不够明确导致消防水箱和消防水泵设置不合理的问题,从实际作用出发,提出了应考虑市政水源压力、管网条件、消防队保护范围及建筑物规模、灭火用水量、经济条件等因素,分别、合理设置消防水箱和消防水泵,使建筑物消防给水系统兼顾消防安全与经济效率。     

What fire statistics tell us about our fire and building codes for housing and small buildings and fire risk for occupants of those structures

Annual reports on fire losses in Canada and the United States are in part, report cards on the efficacy of fire safety provisions in our building and fire codes and on the efforts to reduce risk for the occupants of those buildings. This paper attempts to assess what recent fire‐loss statistics indicate about how successful those efforts have been. Copyright © 2002 John Wiley & Sons, Ltd.     

Photochemical ECE and DISP processes. The self-inhibiting disproportionation (SID) mechanisms. Theory and experiment

Channel electrodes are used to characterize the photochemical DISP2 mechanism in respect of the photoelectro-reductions of

1. (i) 9,10-diphenylanthracene,

2. (ii) benzophenone and

3. (iii) 4-fluorobenzophenone.

Quantitative measurements show that the simple DISP2 mechanism requires extension to allow for the possibilities of first a conproportionation step acting as a back-reaction to the disproportionation, and of second quenching of the excited state which leads to reaction. Both these steps, if present, serve to inhibit the overall DISP2 process. Accordingly a general scheme of Self-Inhibiting Disproportionation (SID) Mechanisms is introduced and characterized in the channel electrode geometry by computer simulations. A general protocol is established for identifying the various possible sub-cases of the general SID mechanism and illustrated with reference to the three experimental systems of interest, in all of which both conproportionation and quenching are shown to be mechanistically significant.     

消防稳压装置在消防系统中的应用

阐述了消防稳压装置在消防系统中的应用情况。介绍了装置的工作原理、特点和日常注意事项。     

Evaluation of residual fire endurance of concrete slabs after fire exposure

One of the important factors that must be considered in evaluating the integrity of structures for further use after exposure to fire is whether the fire endurance of specific structural elements or a structural assembly has been reduced to a value less than that required by the building code. While a building may appear to remain structurally sound after a fire, its structural members' fire endurance may have been impaired to the extent that occupancy cannot be permitted. Re-usability of concrete structures after fire is of economic concern to the owner, especially when there is no visible damage to the structural members. The objective of this research is to conduct a small-scale pilot study and use statistical analysis to investigate the possible cause-and-effect relationships of three factors on the residual fire endurance: exposure severity, recovery conditioning method, and recovery conditioning time lapse. This research provides information for predicting fire endurance loss of concrete slabs after exposure to fire and, as a consequence, for making decisions on the re-usability of the structure. The research results indicate that once the concrete slabs (102 mm thick, no reinforcement and no load) are exposed to a standard fire for more than 30 min their fire endurance will decrease by at least 20%.     

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

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

Improving fire retardancy of fast growing wood by coating with fire retardant and surface densification

Fire retardant fast-growing wood product was developed by coating with fire retardant and densifying the surface of wood. Trimethylol melamineformaldehyde resin mixed with phosphoric acid was coated on the wood surface, preheated and followed by hot pressing. Effects of the amount of coating, preheating temperature, and densifying ratio on the fire retardancy of sugi (Cryptomeria japonica D. Don) wood, and pressing temperature and pressing time on that of albizia (Paraserianthes falcataria Becker) wood were discussed. Bending strength, creep performance under fire and fire retardancy were evaluated. The results showed that the treatments improved the fire retardancy of woods without reduction in the bending strength. © 1998 John Wiley & Sons, Ltd.     

池火与喷射火联合作用下液化气储罐的热及力学响应规律研究进展

介绍了国内外对液化石油气储罐在不同火灾环境下的热及力学响应规律的研究成果和现状,总结了与其相关的重要研究领域的研究进展,包括火灾环境、储罐热响应和储罐力学响应等,同时提出了在这些研究领域需进一步研究的课题。