Thermal characterization of intumescent fire retardant paints

Intumescent coatings are now the dominant passive fire protection materials used in industrial and commercial buildings. The coatings, which usually are composed of inorganic components contained in a polymer matrix, are inert at low temperatures and at higher temperatures, they expand and degrade to provide a charred layer of low conductivity materials. The charred layer, which acts as thermal barrier, will prevent heat transfer to underlying substrate. The thermal properties of intumescent paints are often unknown and difficult to be estimated since they vary significantly during the expansion process; for this reason the fire resistance validation of a commercial coatings is based on expensive, large-scale methods where each commercial coating-beam configuration has to be tested one by one. Adopting, instead, approaches based on a thermal modelling of the intumescent paint coating could provide an helpful tool to make easier the test procedure and to support the design of fire resistant structures as well. The present investigation is focused on the assessment of a methodology intended to the restoration of the equivalent thermal conductivity of the intumescent layer produced under the action of a cone calorimetric apparatus. The estimation procedure is based on the inverse heat conduction problem approach, where the temperature values measured at some locations inside the layer during the expansion process are used as input known data. The results point out that the equivalent thermal conductivity reached by the intumescent material at the end of the expansion process significantly depends on the temperature while the initial thickness of the paint does not seem to have much effect

Parameter estimation approach to the thermal characterization of intumescent fire retardant paints

Intumescent paints are widely used as passive fire retardant materials in the building sector. They swell on heating to form a highly insulating char, protecting steel members. Intumescent coatings for use in buildings are typically certified according to the standard cellulosic fire resistance test. This test is expensive, often non-representative of realistic fire conditions, and not enough versatile to gather detailed performance information on the response of reactive coatings. A promising approach, that could offer a helpful tool to the engineering community involved in fire safety, is found in the modelling of the behaviour of the intumescent coating. Under this approach, the knowledge of the equivalent thermal conductivity of the intumescent material is a fundamental issue, since it represents the main parameter that allows predicting the thermal protecting capability of the layer. The purpose of this paper is to optimize an estimation procedure intended to the restoration of the equivalent thermal conductivity of intumescent layers. The thermal stress is activated by the action of a cone calorimetric apparatus, while the estimation procedure is based on the inverse heat conduction problem approach under steady state assumption, where the temperature values measured at some locations inside the layer during the expansion process are used as input known data. This procedure was successfully applied to steel samples protected with an intumescent paint; the estimated equivalent thermal conductivity of the layer results to temperature dependent while the initial thickness of the paint does not seem to have a great effect

thermal characterization of intumescent fire retardant paints

Intumescent coatings are now the dominant passive fire protection materials used in industrial and commercial buildings. The coatings, which usually are composed of inorganic components contained in a polymer matrix, are inert at low temperatures and at higher temperatures, they expand and degrade to provide a charred layer of low conductivity materials. The charred layer, which acts as thermal barrier, will prevent heat transfer to underlying substrate. The thermal properties of intumescent paints are often unknown and difficult to be estimated since they vary significantly during the expansion process; for this reason the fire resistance validation of a commercial coatings is based on expensive, large-scale methods where each commercial coating-beam configuration has to be tested one by one. Adopting, instead, approaches based on a thermal modelling of the intumescent paint coating could provide an helpful tool to make easier the test procedure and to support the design of fire resistant structures as well. The present investigation is focused on the assessment of a methodology intended to the restoration of the equivalent thermal conductivity of the intumescent layer produced under the action of a cone calorimetric apparatus. The estimation procedure is based on the inverse heat conduction problem approach, where the temperature values measured at some locations inside the layer during the expansion process are used as input known data. The results point out that the equivalent thermal conductivity reached by the intumescent material at the end of the expansion process significantly depends on the temperature while the initial thickness of the paint does not seem to have much effect

Amph-IMA97: a hypercard program to determine the name of an amphibole from electron microprobe and wet analyses.

In 1997, the International Mineralogical Association (IMA) revised the amphibole naming scheme making it necessary to amend the previous EMP-AMPH Macintosh program to the new rules. The AMPH-IMA97 program allows single input or automatic input of as many amphibole analyses as are available following a set input format. There are three options for calculation scheme of amphibole analysis: (1) complete chemical analyses can be calculated to 24(O, OH, F, Cl); (2) analyses with determined FeO and Fe2O3 but without H2O can be calculated to 23(O) and (3) electron microprobe analyses with only total Fe determined and without H2O can be calculated to 23(O) with IMA97-recommended normalization for Fe3+ and Fe2+ values. To test the program, over 500 analyses were calculated using the three options. The first comprehensive test of the third option successfully estimated Fe2+ (R2=0.88), but became less successful for Fe3+ (R2=0.42) estimation. Problems in the normalization of Mn3+- and Mn2+-bearing amphiboles and in the IMA97 sodic amphibole classification procedure emerged for Mn-rich amphiboles. This necessitated the proposal and implementation with the program of a simplified sodic amphibole classification scheme. A new coloured amphibole classification chart accompanies the program

Effect of nanoclay and conventional flame retardants on asphalt mixtures fire reaction

Fires in highway tunnels produce high temperatures, heat radiation, low visibility, and several toxic and dangerous gases. Thus, materials used in tunnel structures should be designed in order to limit such problems. The present work addresses the formulation of asphalt mixtures with fire retardant properties based on: (i) the substitution of traditional mineral filler with specific flame retardants (FR) like aluminium hydroxide (ATH) and magnesium hydroxide (MH); (ii) the use of asphalt binders nano-modified with organo-clays. The fire behaviour and the smoke release properties of the mixtures were evaluated by means of cone calorimeter test. Among the FR fillers, ATH gave the most encouraging results in terms of heat and smoke releases. The simultaneous use of FR and nanocomposite asphalt binder gives a synergic effect which significantly changes and improves the fire behaviour of the mixtures

PERMAQUA: permafrost and its impacts on water resources and water ecology in high mountain areas

Permafrost has become an important issue in the European Alps. In South Tyrol (Italy), the area of permafrost covers about 440 km2, and in the Austrian Alps about 2000 km2. Active rock glaciers are a common feature of high mountain permafrost and due to their location near the lower boundary of permafrost, their mean annual surface temperature is close to melting conditions (Haeberli et al., 2006), which indicates their particular sensitivity to climate warming. Air temperature in the Alps has substantially increased during the past decades and climate warming is projected to become even more pronounced until the end of the 21th century. Increasing instability of slopes, landslides and floods, as well as alterations in the hydrological regime can be anticipated. Up to now, studies on the effects of active rock glaciers on hydrology and water chemistry of adjacent surface waters are still rare (e.g. Williams et al., 2006; Krainer et al., 2007; Thies et al., 2007; Baron et al., 2009). Results from the previous EU-RTD project EUROLIMPACS and the Interreg IV-Alpine Space project PermaNET showed that waters draining from active rock glaciers may contain high concentrations of solutes and at some sites also metals (e.g. nickel, aluminium), which can exceed the limit for drinking water by far. The origin of these metals is yet unresolved. Potential effects of solutes and metals on the ecology and on freshwater biota in high mountain lakes and streams in the Alps are still unknown. The current PERMAQUA project (Interreg IV Italy-Austria, European Regional Development Fund) combines studies on geology, hydrology, contemporary aquatic chemistry and freshwater biota, the analysis of lake sediment cores, peat cores and rock glacier ice cores near selected rock glaciers in South Tyrol (Italy) and North Tyrol (Austria). The PERMAQUA project aims to assess the impact of permafrost melt on high mountain freshwaters. The state-of-the-art knowledge about potential ecological impacts of permafrost melt and its consequence for man and the environment will be transferred to decision makers, managers, local residents and the general public. The present permafrost monitoring system, anchored at international level, will be updated and further developed in order to assure the future recording of permafrost variations due to climatic changes and to release estimation of danger situations arising in permafrost areas. Guidelines for possible risk mitigation strategies will be proposed and their implementation shall be tested in cooperation with public authorities, alpine associations, managers of protected sites, national parks, and of mountain shelters

Parameter estimation approach to the thermal characterization of intumescent fire retardant paints

Intumescent paints are widely used as passive fire retardant materials in the building sector. They swell on heating to form a highly insulating char, protecting steel members. Intumescent coatings for use in buildings are typically certified according to the standard cellulosic fire resistance test. This test is expensive, often non-representative of realistic fire conditions, and not enough versatile to gather detailed performance information on the response of reactive coatings. A promising approach, that could offer a helpful tool to the engineering community involved in fire safety, is found in the modelling of the behaviour of the intumescent coating. Under this approach, the knowledge of the equivalent thermal conductivity of the intumescent material is a fundamental issue, since it represents the main parameter that allows predicting the thermal protecting capability of the layer. The purpose of this paper is to optimize an estimation procedure intended to the restoration of the equivalent thermal conductivity of intumescent layers. The thermal stress is activated by the action of a cone calorimetric apparatus, while the estimation procedure is based on the inverse heat conduction problem approach under steady state assumption, where the temperature values measured at some locations inside the layer during the expansion process are used as input known data. This procedure was successfully applied to steel samples protected with an intumescent paint; the estimated equivalent thermal conductivity of the layer results to temperature dependent while the initial thickness of the paint does not seem to have a great effect