Abstract
Internal wall insulation is one of the few, possibly, the only feasible solution to efficiently reduce heat losses through the external walls of buildings where the application of external insulation is not an option, for example, in conservation areas. However, the application of this intervention may lead to unintended consequences, such as moisture accumulation and mould growth. Currently, no international standards and regulations exist to evaluate these hazards via non-destructive inspections. Air sampling through impaction and culture-based analysis was suggested in previous research as a potential non-disruptive methodology for interstitial mould testing. The method requires the perforation of the inner side of a wall and the creation of airflow through the operation of a pump, to allow the collection of particles from the confined space of interest. The present study aimed to assess the location of perforations and their effect on the airflow created and the airflow pattern variations due to changes in the airflow velocity at the outlet. Results regarding airflow features such as the turbulence intensity, dynamic pressure and volume-averaged velocity were also extracted and discussed. Practical application: The rapid changes in climate and net-zero emissions targets call for major improvements of the existing building stock towards a more sustainable future. The installation of internal wall insulation is one of the few and might be the only feasible solution for the efficient reduction of heat losses through uninsulated walls. However, this intervention might lead to moisture accumulation and thus moisture-related problems such as mould growth. This study aims to build upon previous work on interstitial mould growth assessment and contribute to the development of a well-defined testing protocol for building professionals.
Highlights
Buildings are estimated to be responsible for more than one-third of the global energy demand,[1] while uninsulated walls can account for more than one-third of a building’s total energy consumption.[2]
In the retrofit of historic buildings, the application of internal wall insulation (IWI) might be the only feasible solution as external wall insulation might be restricted by legislation
The airflow patterns for the four different hole configurations (Cases 1-4 shown in Figure 2) and three outlet airflow rates examined here
Summary
Buildings are estimated to be responsible for more than one-third of the global energy demand,[1] while uninsulated walls can account for more than one-third of a building’s total energy consumption.[2] According to the statistical data published by the department for business, energy and industrial strategy (BEIS)[3] it is estimated that more than 90% (7.7million) of the existing 8.5 million solid wall properties has yet to be applied either external or internal wall insulation. Insulation on uninsulated walls can be a feasible solution for improving a building’s energy performance. External, internal, and cavity wall insulation are the three options available to help reduce heat losses from uninsulated walls and improve thermal comfort. Current legislation, planning regulations and the characteristics of the buildings might limit the applicability of some options. In the retrofit of historic buildings, the application of internal wall insulation (IWI) might be the only feasible solution as external wall insulation might be restricted by legislation. The installation of the IWI, when designed and installed wrong, might lead to the aggregation of moisture, condensation and moisturerelated problems such as mould growth that constitutes a health hazard and can potentially lead to damage to building materials and problems with the overall durability of building components.[4,5]
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