Thermal conductivity of building materials: an overview of its determination

A range of instruments are available to measure thermal conductivity of building materials. Some of these tools are heat-flow meter, hot plate, hot box and heat transfer analyzer. Thermal conductivity data derived by using different instruments can be different from each other. Implication of these variations in thermal conductivity is significant in terms of commercial profile of the insulations and also in terms of calculating energy saving in large scale use of that specific insulation. Thus it is important to know which of the measuring instrument for thermal conductivity can produce relatively accurate and representative result. This paper firstly looks at the methods and instrument for measuring thermal conductivity of building materials and secondly compares and analyses the results of testing thermal conductivity of fibrous insulations using a heat analyzer and a hot plate.

Fabric formwork – prototype to typology

When developmental vernacular practice is telescoped into industrial activity, the role played by construction workers in the honing of a craft is rapidly bypassed. An almost political act is required to maintain the contribution that the hand makes to the uniformity of result that is demanded by the standard classification of typologies of building and technique. Research into fabric formwork techniques conducted by Alan Chandler utilises the flexibility of the concrete mould to explore the meaning of the making ‘process’ and the workers’ role in relation to the formal ‘result’. Chandler’s ‘Wall One’ exemplifies the exploratory prototype and its potential for variety and the trace of the hand in making. The shift to a mass production typology involved in realising the 325,000 square-metre Heatherwick studio project in Shanghai, presented the problem of how to orchestrate the fabric into a fully industrialised process. Part of the research then became how to make the shift from play to profit - and can anything of craft survive the transition into the international development marketplace? Through managing the inherent variety available to the fabric itself, a fabric based formwork solution for realising a building at the scale of a landscape offered the Chinese form work maker the opportunity to be present within the results of a fully industrialised process – a ghost in the machine.