Experimental Characterisation of the Fire Behaviour of Thermal Insulation Materials for a Performance-Based Design Methodology

A novel performance-based methodology for the quantitative fire safe design of building assemblies including insulation materials has recently been proposed. This approach is based on the definition of suitable thermal barriers in order to control the fire hazards imposed by the insulation. Under this framework, the concept of “critical temperature” has been used to define an initiating failure criterion for the insulation, so as to ensure there will be no significant contribution to the fire nor generation of hazardous gas effluents. This paper proposes a methodology to evaluate this “critical temperature” using as examples some of the most common insulation materials used for buildings in the EU market, i.e. rigid polyisocyanurate foam, rigid phenolic foam, rigid expanded polystyrene foam and low density flexible stone wool. A characterisation of these materials, based on a series of ad-hoc Cone Calorimeter and thermo-gravimetric experiments, serves to establish the rationale behind the quantification of the critical temperature. The temperature of the main peak of pyrolysis, obtained from differential thermo-gravimetric analysis under a nitrogen atmosphere at low heating rates, is proposed as the “critical temperature” for materials that do not significantly shrink and melt, i.e. charring insulation materials. For materials with shrinking and melting behaviour it is suggested that the melting point could be used as “critical temperature”. Conservative values of “critical temperature” proposed are 300°C for polyisocyanurate, 425°C for phenolic foam and 240°C for expanded polystyrene. The concept of a “critical temperature” for the low density stone wool is examined in the same manner and found to be non-applicable due to the inability to promote a flammable mixture. Additionally, thermal inertia values required for the performance-based methodology are obtained for PIR and PF using a novel approach, providing thermal inertia values within the range 4.5 to 6.5\ua0×\ua010\ua0W\ua0s\ua0K\ua0m

Comprehending conodonts

Conodonts were small, thin, elongate jawless creatures that were a common component of the marine fauna from the late Cambrian, throughout the Palaeozoic and into the Triassic. For the majority of conodont research history, speculations on conodont affinity were restricted to the histology and arrangement of their mineralized tissues—‘conodont elements’. These conodont elements comprise millimetre-scale phosphatic microfossils that superficially resemble teeth, and are commonly recovered from the residues of appropriately aged, disaggregated sedimentary rocks. It has only been in the last three decades, since the discovery of exceptionally preserved soft tissues, that the debate on conodont affinity has been refined, though it has hardly been less vigorously debated. Despite being studied extensively for over more than a century and a half, conodonts retain significant enigmatic qualities. Although many geologists today are familiar with the name, knowledge of conodont biology and ecology are often surprisingly lacking or confused, and conodonts remain as largely disembodied microfossil curiosities. Despite this, conodont elements are extensively and variously used in biostratigraphy, thermal maturation studies and palaeoenvironmental reconstructions, while conodonts themselves occupy a potentially critical position in the evolutionary tree of our own phylum—the chordates

Agricultural biotechnology and the public good

On May 18, 1994, the U.S. Food and Drug Administration (FDA) approved the first genetically engineered food product for commercial sale and dozens of other products are in the pipeline promising to provide a vast array of new agricultural products. But is this development in the best interest of the public? NABC 6 was the first NABC meeting to specifically address the global nature of agriculture. The workshops determined eight comprehensive key issues ranging from ownership and access to germplasm to the need for more unified biosafety standards.Biotechnology can have enormous positive impact on public good, but policy issues are critical in determining who benefits from technology transfer on the national and global level. However, we need to see biotechnology as a point on a continuum of technologies and make sure that it does not replace other valid technologies and thus limit the tools available to producers and consumers.Certain members of the audience were concerned about negative effects of agricultural biotechnology on human health and the environment, and doubted whether biotechnology can bring universal benefit to developing countries. However, feeding the growing world population using current agricultural practices, the amount of land used for agriculture would have to be expanded from a land mass about the size of South America to that of Eurasia. Increasing agricultural productivity per acre is vital and can be aided by new products developed through agricultural biotechnology. However, public acceptance remains uncertain. Communication and education are important in placing biotechnology solidly on the continuum of technologies and remove the stigma of “Frankenfood”. The current trend of removing funding for public research and handing it over to the private sector has the potential of putting possibly lucrative developments squarely in the hands of corporations rather than in those of the public – a type of “biopiracy” that forces producers, especially in developing countries, to pay for patented life forms previously free for them to use