Fire Performance Of Materials Research Articles

The necessity of accelerated ageing in fire performance assessments of composite materials

The market for lightweight fibre reinforced polymer (FRP) composites is growing. This is seen within advanced applications for e.g. aeronautics, modern ship vessels and railway vehicles. FRPs are often used to save weight, but the downside is that they are ignitable, which implies a potential higher fire risk. It is thus important to thoroughly characterise the material properties of FRPs, including the fire performance, in order to ensure a high safety level. Fire performance testing is made with newly produced materials to show the conformance to required standard test. However, the impact of ageing on the fire performance of materials and products is not mandatory information and hardly ever known. This is still an overlooked matter that is important to address for combustible materials in transport applications, where the requirements of personal safety are especially high.Accelerated ageing is a method to expose materials and products to various environmental parameters for a simulation of long-term usage. Within a few days, weeks or months the damage and degradation of the materials can occur, which normally would be after years in normal climate and after normal usage. Fire performance testing of test samples subjected to accelerated ageing would potentially give important information on the long-term safety of the end-use application of FRPs.The objective of this paper is twofold. One is to find out if the industry, society and research need to deal with the effect of ageing on materials in relation to fire safety as this is not dealt with in fire regulations. And further to identify the state-of-the-art of accelerated ageing methods relevant for Fibre Reinforced Polymer (FRP) materials. In summary, the findings in the literature were limited of reported ageing effects of FRPs, with respect to the fire behaviour. An important conclusion is that there is a major lack of knowledge regarding material aging and fire behaviour, especially for FRPs. However, the identified ageing studies showed that both fire and mechanical properties were affected by ageing. The accelerated ageing methods described in literature was not consequently applied. The ageing methods were special designed for each study and application of material. All methods need a proper validation applying real time ageing.

Natural fibre composites with furanic thermoset resins. Comparison between polyfurfuryl alcohol and humins from sugar conversion

Industrial humins from biorefining process of sugars were used as reactive thermoset matrix for the preparation of humins-jute fibre composites. This material was investigated and benchmarked with jute composites prepared with polyfurfurylalcohol (PFA), a well-known biobased thermosetting resin The Dynamic Mechanical Analyses (DMA) showed glass transition temperature (Tg) associated to the relaxation of the cross-linked humins’ chains at 75 °C similar to the Tg of PFA. The two types of composites revealed tensile properties in the same range and both materials demonstrated very low water uptake and good dimensional stability after immersion in liquid water. Such higher hydrophobicity compared to raw jute mat is the consequence of the good interfacial interaction of both furanic matrix with the jute fibres in agreement with SEM observations. Fire performance of materials was also investigated, demonstrating that the fire hazard of composites was not increased by the presence of furanic matrix. Interestingly, humins composites were slightly better than PFA composites for both the thermal and fire-induced toxicity threats. This study demonstrated the possibility of using industrial humins instead of PFA as a thermoset-like resin for the next generation of biobased composites.

Simulating real compartment fire conditions in a furnace

SummaryIn the United States, wood has been traditionally used in residential construction. However, the combustibility of wood still limits its use as a building material in prescriptive building codes, and to overcome the limitations, performance‐based codes can be used. In order to properly analyze performance‐based designs, more information on the fire performance of materials is required, including fire performance under different fire exposures. The char rate when timber elements are exposed to the standard time‐temperature curve have been well characterized and can be used to determine the fire‐resistance rating. However, much less is known about the rate of char formation under other fire exposures and time‐temperature curves. In this study, we used time‐temperature data from full‐scale compartment fire tests and applied that data in an intermediate‐scale horizontal furnace. By measuring the furnace temperature, fuel consumption, and heat flux during the various tests, we identified that the furnace could closely replicate the shape of a real time‐temperature fire curve from a ventilation controlled compartment. However, the furnace fell short in terms of meeting the peak temperatures at flashover and heat fluxes expected in a real compartment fire.

Experimental Study on Scale Effect on Mass Loss Rate of Some Woods

Experimental measurements have been done for mass loss rate of some woods usingcone calorimeter and radiation platform for studying fire performance of materials at early stage, respectively. The experiments have indicated that both sample scale and apparatus scale affect the mass loss rate obviously. Generally, average mass loss rate of larger sample is higher than that of smaller sample. Scale has little effect on the first peak of mass loss rate, but it shows a distinct effect on the second peak. The second peak of mass loss rate of larger sample is much higher than that of smaller sample. There may be a critical sample size for the second peak existence. The sample in cone calorimeter can be ignited easily with stable and long time continuous flame compared with radiation platform under the same heat flux.

Survey of American test methods associated with fire performance of materials or products

Various organizations throughout the world write fire standards. These include both national and international organizations. In the United States, the most important fire standards writing organization is the American Society for Testing and Materials (ASTM). Fire standards are also, however, developed by the National Fire Protection Association (NFPA), and Underwriters Laboratories (UL), but they are often similar to the ones issued by ASTM. The International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) are the primary international standards making bodies. All of these organizations create various types of fire standards, mainly guidance documents and test methods addressing most of the major fire properties. It is interesting that fire standards throughout the world are all tending in the same direction: away from simple ranking tests and geared towards test results that can be used as input into mathematical fire models or fire hazard assessment and research, and real-scale tests to be used for validation of the small-scale tests and models. This is particularly noticeable when considering the geometrical increase in work on heat release standards, a type of fire property which is crucial for fire safety, but was unknown only a few years ago. ASTM has a total of over 100 standards associated with various aspects of fire, including guides, terminologies and specifications as well as test methods. Within ASTM, committee E5 is specifically dedicated to writing generic fire standards. However, many other committees, which have different primary responsibilities, also write fire standards which are specific to the materials, products or occupancies of their concern. Thus, for example, committees D7 (on Wood), D9 (on Electrical Insulation Materials), D11 (on Rubber), D13 (on Textiles) and D20 (on Plastics) all write fire standards for their materials, as do committees F15 (Consumer Products) and F23 (Protective Clothing). Committees interested in Aircraft (F7), Ships (F25) or Correctional Facilities (F33), also write standards that deal with fire issues. The process by which ASTM develops consensus standards is public, and every concern expressed must be addressed, through a relatively strenuous procedure. At NFPA, all fire tests are developed by the Fire Test committee, the members of which are appointed, and the results of whose deliberations are published. Comments can then be made by others and the final recommendations are voted on in public meetings by the entire membership. Such standards generally tend to contain pass-fail criteria, while those of ASTM tend to be generic. UL standards are not generated by public consensus: UL is a private organization which canvases industrial opinions, and makes its own decisions. These decisions can be questioned, but UL makes the final determinations themselves.

Assessment of toxic hazards of smoke: Toxicological potency and intoxication rate thresholds

AbstractSmoke toxicity test methods which determine only lethal toxicological potency under ‘worst case’ conditions do not satisfactorily address the critical issue of relative hazard, including time‐to‐escape and tenability limits resulting from the fire performance of materials under comparable conditions. Since threats to escape from a fire are largely time‐dependent, toxic insults produced by burning materials should also be considered as rate processes. Assessment of time thresholds exhibited by burning materials under test conditions to effect performance impairment (incapacitation) of an animal model would appear to be more relevant than lethal toxicological potencies in estimating probability of successful escape from fires. A model is advanced in which intoxication rate thresholds for materials are obtained using a rodent exposure test method. Concentration‐time curves, obtained from experimentally derived concentration‐time‐response surfaces, are the basis for estimating rate thresholds which are distinctively different for each material and which vary as a function of test conditions. it is this performance impairment response surface which is potentially a key to the modeling of toxic hazards of smoke in perspective with other hazards presented by fire.

Toxic products from fires.

The role of toxic combustion products in causing fire deaths has received considerable public attention in recent years. This paper outlines critical aspects of the problem, including the identification of common combustion products, the toxicological effects of these products and the dependence of their formation on the combustion process itself. The significance of escape as the key to survival in a fire is particularly emphasized. This paper then focuses on the development of test methods for assessment of toxic hazards produced by burning materials, with the objective being to enable decisions to be made as to whether the use of one material, as opposed to another, would result in any significant difference in hazard to life safety in a fire. It is argued that smoke toxicity test methods which determine only lethal toxicological potency under “worst case” conditions do not satisfactorily address the critical issue of relative hazard, including time-to-escape and tenability limits resulting from the fire performance of materials under comparable conditions. Since threats to escape from a fire are largely time-dependent, toxic insults produced by burning materials should also be considered as rate processes. Assessment of time thresholds exhibited by burning materials under test conditions to effect performance impairment (incapacitation) of an animal model would appear to be more relevant than lethal toxicological potencies in estimating probability of successful escape from fires. A model is advanced in which intoxication rate thresholds for materials are obtained using a rodent exposure test method. Concentration-time curves, obtained from experimentally derived concentration-time-response surfaces, are the basis for estimating rate thresholds which are distinctively different for each material and which vary as a function of test conditions. It is this performance impairment response surface which is potentially a key to the modeling of toxic hazards of smoke in perspective with other hazards presented by fire. Only when overall hazards are appropriately assessed can smoke toxicity tests be meaningful as tools in choosing materials to reduce risk to life safety in fires.

Flammability, Toxicity and Smoke

Fire performance of materials used in transportation vehicles has become of increasing concern in recent years. Bus fires in Washington, DC, in Cincinnati, and in St Louis have highlighted that concern.