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

Facing the urgency of therapies for progressive MS — a Progressive MS Alliance proposal

Therapies for infiltrative inflammation in multiple sclerosis (MS) have advanced greatly, but neurodegeneration and compartmentalized inflammation remain virtually untargeted as in other diseases of the nervous system. Consequently, many therapies are available for the relapsing–remitting form of MS, but the progressive forms remain essentially untreated. The objective of the International Progressive MS Alliance is to expedite the development of effective therapies for progressive MS through new initiatives that foster innovative thinking and concrete advancements. Based on these principles, the Alliance is developing a new funding programme that will focus on experimental medicine trials. Here, we discuss the reasons behind the focus on experimental medicine trials, the strengths and weaknesses of these approaches and of the programme, and why we hope to advance therapies while improving the understanding of progression in MS. We are soliciting public and academic feedback, which will help shape the programme and future strategies of the Alliance

Can rigorous impact evaluations improve humanitarian assistance?

Each year billions of US-dollars of humanitarian assistance are mobilised in response to man-made emergencies and natural disasters. Yet, rigorous evidence for how best to intervene remains scant. This dearth reflects that rigorous impact evaluations of humanitarian assistance pose major methodological, practical and ethical challenges. While theory-based impact evaluations can crucially inform humanitarian programming, popular methods, such as orthodox RCTs, are less suitable. Instead, factorial designs and quasi-experimental designs can be ethical and robust, answering questions about how to improve the delivery of assistance. We argue that it helps to be prepared, planning impact evaluations before the onset of emergencies