Thermal conductivity common use in the construction and textile industries. The construction industry makes use of units such as the R-value (resistance) and the U-value (transmittance). Although related to the thermal conductivity of a material used in an insulation product, R- and U-values are dependent on the thickness of the product. Likewise the textile industry has several units including the tog and the clo which express thermal resistance of a material in a way analogous to the R-values used in the construction industry. There are a number of ways to measure thermal conductivity. Each of these is suitable for a limited range
History of construction History of construction The History of construction overlaps many other fields like structural engineering and relies on other branches of science like archaeology, history and architecture to investigate how the builders lived and recorded their accomplishments. Those fields allow us to analyse constructed buildings and other structures built since prehistory, the tools used and the different uses of building materials. History of building is evolving by different trends in time, marked by few key principles : durability of the materials used, the increasing of height and span, the degree of control exercised over the interior environment and finally the energy