Lisø PhD Dissertation Manuscript - NTNU

cost of repairing process-induced building defects in
Norway amounts to 5% of the annual capital invested
in new buildings (Ingvaldsen, 1994). Ingvaldsen also
found that this estimate was in good agreement with
13 corresponding investigations or sources of information
in other European countries (with a mean estimate
varying between 3 and 5%). Correcting faults
and repairing defects in buildings during the construction
process is estimated to cost roughly the same as
repairing buildings in use, e.g. another 5% (Ingvaldsen,
1994). With an annual investment in refurbishment
and new construction of 130 billion Norwegian
kronor (as of 2003), it is therefore reasonable to estimate
that up to 13 billion kronor is being spent on
repairing defects or damage to buildings every year.
NBI has more than 5000 process-induced building
defect assignment reports in its archives, which is a
considerable source of experience-based knowledge.
Results from a preliminary review of assignments
investigated in the decade between 1993 and 2002
(2378 building defect cases registered and described
in 2045 assignment reports) show that defects related
to the building envelope constitute about two-thirds
of the investigated cases (Lisø et al., 2005a, b). Moisture
as the main source causing the defect accounts for
as much as 76% of all investigated cases in that decade.
Many types of building defect cases are recurring items,
which indicates a general lack of knowledge amongst
the different actors in the construction industry concerning
fundamental principles of building physics.
These findings support earlier investigations concluding
that the construction industry is unable to learn
from past experience and that the exchange of knowledge
in construction projects is unsatisfactory (e.g. Lisø
et al., 2000).
A field investigation of a random sample of 20 existing
low-rise buildings with large spans (e.g. schools, sports
buildings and industrial buildings) situated in areas
exposed to high wind action and extreme snowfall in
Norway shows that 18 of these buildings do not meet
current regulatory requirements relating to safety
against collapse owing to snow loads and wind
action (Meløysund et al., accepted).
Projected changes in climatic conditions will further
enhance vulnerability within the construction industry
and the built environment.
Key de¢nitions
At the outset of this paper, it is sensible to clarify a few
key definitions to be used in further discussions on riskmanagement
and decision-making instruments.
‘Risk’ is termed here as a function of the probability of
undesirable events and the subsequent consequences of
these (Norges offentlige utredninger (NOU), 2000),
Integrated approach to risk management of future climate change impacts
and in the International Standardisation Organisation
(ISO)/IEC Guide No. 73:2002 (ISO, 2002), it is
defined as a ‘combination of the probability of an
event and its consequence’. Risk expresses the potential
loss of important values as a consequence of undesirable
events, e.g. adverse social, economic and technical
implications of climate change in the built environment.
Risk-reducing measures or activities are normally
assessed with reference to quantitative risk
acceptance criteria.
‘Risk management’ is defined in ISO (2002, p. 4) as
‘coordinated activities to direct and control an organization
with regard to risk’. Risk management implies
that undesirable outcomes can be avoided, but where
they are unavoidable, they can be mitigated if connections
between cause and effect are properly defined
(Jaeger et al., 2001).
‘Risk analysis’ provides a basis for the evaluation of
risk and is defined as ‘systematic use of information
to identify sources (having a potential for a consequence)
and to estimate the risk’ (ISO, 2002, p. 5).
The risk of adverse impacts as a consequence of
climate change is not well determined, and the riskmanagement
principle adopted should be the ALARP
principle: the risk should be reduced to a level that is
‘as low as reasonably practicable’.
The Intergovernmental Panel on Climate Change
(IPCC) definitions of sensitivity, adaptability and
vulnerability are as follows (McCarthy et al., 2001):
‘Sensitivity’ is the degree to which a system is
affected either adversely or beneficially, by
climate-related stimuli. Climate-related stimuli
encompass all the elements of climate change,
including mean climate characteristics, climate
variability, and the frequency and magnitude of
extremes. The effect may be direct (e.g. a
change in crop yield in response to a change in
the mean, range or variability of temperature)
or indirect (e.g. damages caused by an increase
in the frequency of coastal flooding due to sealevel
rise).
‘Adaptive capacity’ is the ability of a system to
adjust to climate change, including climate variability
and extremes, to moderate potential
damages, to take advantage of opportunities, or
to cope with the consequences.
‘Vulnerability’ is the degree to which a system is
susceptible to, or unable to cope with, adverse
effects of climate change, including climate variability
and extremes. Vulnerability is a function of
the character, magnitude and rate of climate
change and variation to which a system is
exposed, its sensitivity, and its adaptive capacity.
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