Lisø PhD Dissertation Manuscript - NTNU

Lisø, K.R./ Building envelope performance in harsh climates: Methods for geographically dependent design
3 Concluding remarks
The presented work is a first step towards methods and approaches allowing for
geographically dependent climate considerations to be made in the development of
design guidelines for high-performance building envelopes, and also approaches to
assess the risks associated with the future performance of building envelopes due to
climate change. Approaches to risk assessments associated with the potential
implications of climate change on building envelope performance are presented,
identifying main areas of vulnerability. For large, complex building projects there is
an established tradition of using risk analysis methods. It is shown that there are
benefits to be gained from the introduction of risk management strategies also in
small-scale building. A way of analysing the building economics of climate change is
also proposed. The performed analyses of empirical data from process induced
building defect assignments clearly illustrate the vulnerability of building envelopes
under varying climatic exposure.
New and improved methods for geographically dependent design of building
envelopes are proposed, enabling both historical weather data and scenarios for
future climate change to be considered. A method for assessing the relative potential
of frost decay or frost damage of porous, mineral building materials exposed to a
given climate is presented, as well as a national map of the potential for decay in
wood structures. Detailed scenarios for climate change for selected locations in
Norway are in the latter method used to provide an indication of the possible future
development of decay rates in wood structures. A method for assessing driving rain
exposures based on multi-year records of present weather, wind speed and direction
is also developed. These and other indices, with quantified relations between climatic
impact and material behaviour or building performance, can be used as a very
suitable tool for evaluation of changes in performance requirements or decay rates
due to climate change under global warming incorporating data from regional- and
local-level climate change scenarios. Historical records of climate data have also
been used to illuminate challenges arising when introducing international standards
at the national level, without considering the need for adjustments to reflect local
climatic conditions. The work will also contribute to the pre-normative research for
the continued development of Norwegian and international standards. This is
particularly important with respect to the preparation of additional Norwegian
appendices associated with the various types of climatic impact.
The ongoing establishment of an electronic building defects archive, initiated as part
of this work, will be an important tool in both the continuous efforts towards higher
quality in the construction industry and the development of strategies aiming at
learning from experience. The archive will also be an important element in the
continuous development of more accurate criteria and Codes of Practice regarding
the design and functionality of critical elements of buildings in the Building
Research Design Series. And, the building defects archive will be an important
educational tool in the establishment of knowledge on building defects amongst
academic institutions and different actors in the construction industry.
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