When investigating the building industry, it is useful to distinguish between two different types of risks: structural failures and safety failures.
When buildings collapse, the structure of the building is usually to blame. Levy & Salvadori emphasize the importance of "structural redundancy", which means that a building is structured in a way that allows the loads to be carried through more than one path in the structure (Levy & Salvadori 1994/2002:55-56). Structural redundancy is necessary in all large structures in order to diminish risk of collapse. In the case of the Hancock Tower (card #B2), a failure in the excavation for the building’s foundation combined with a structural weakness against wind oscillations put the tower in risk of collapsing. This was discovered when engineers investigated the shedding of the building’s windows -which turned out to have nothing to do with the structural failures.
Safety failures, which lead to building accidents, are usually what Charles Perrow (1984/1999) calls component failures. That is, one or more components in the system fail, but it does not necessarily have the breakdown of the entire system as a consequence. In most cases, the component failure is detected and corrected before it causes severe damage to the system. This means that most of these failures could have been prevented by thoroughly testing the materials or by applying safety procedures, e.g. to prevent fires.
Fires in buildings are good examples of Charles Perrows’ point that accidents happen in spite of safety measures, and sometimes even because of them (Perrow 1984/1999:79-84). In the Iroquis Theatre, for example, the faith people had in the safety measures and the lack of an alternative emergency plan, led to the death of more than 600 people when the safety measures did not work during a fire.
Another type of building accidents, which occur due to safety failures, are the incidents where people are exposed to toxic building materials, such as asbestos. The effects of this type of accident are delayed and the victims are not always aware of the causes of their illness.
Building accidents are not included in Slovic’s psychometric study, however a few issues are worth discussing in relation to the public perception.
Firstly, the notion of familiarity implies that people tend to perceive lesser risk in relation to technologies they know well and are surrounded by every day (Waddick, p.4). This is the case with buildings - most of the time we are inside of them, and it would be terrible to fear a collapse all the time. Niklas Luhmann has written about how trust serves to reduce complexity (Luhmann 1979), and in the case of buildings, we can assume that people tend to trust the structure and safety of the building in order to cope with everyday life.
Secondly, the concept of relevance indicates that people are not unwilling to take risks, but they do not want them to be uncontrollable and irrelevant (Waddick, p.5). From a pragmatic point of view, the risk of building accidents is a relevant risk. Thus, even though a psychometric study is not available, we can assume that people generally perceive the benefit of buildings as being greater than the risk.
Levy, M. and Salvadori, M. (1994/2002). How Structures Fail. Why Buildings Fall Down, W.W. Norton & Company.
A paper on building risks in the construction industry by Phil Waddick:
Perrow, C. (1984/1999). Normal Accidents: Living with High-Risk Technologies, pp. 72-79, Princeton University Press.
About trust as a reduction of complexity:
Luhmann, N. (1979). Trust and Power - two works, Wiley & Chichester.
Comment this page
A. Air Transport
C. Land Transport
D. Marine Transport
E. Bridges and Dams
F. Oil Tankers
G. Chemical Industry
H. Medical Industry
I. Nuclear Industry
Quantitative Risk Assessment
Normal Accident Theory
High Reliability Organisations
Fear Factor (0-10)
Media Effect (0-100)