The phrase ‘building failure’ conjures images of fatal effects such as sudden collapse, material loss, and major structural defects. But for decades the industry has embraced broader definitions – all representative of conditions that adversely affect the intended service life of components or assemblies. For example, the Canadian Standards Association (S478-95) defines failure as the loss of performance as defined by the onset of any of the following limit states:
- collapse, as related to human safety or to loss of function of the building;
- local damage, as related to loss of function of the building component or to appearance;
- displacement, as related to loss of function of the building component or to appearance; or
- discolouration, as related to appearance of components having an aesthetic function.
The Canadian Standards Association (S478-95) further describes the types of failures with the following categories:
- No exceptional problems (example: replacement of light fittings)
- Security compromised (example: broken door latch)
- Interruption of building use (example: repair requires temporary discontinuation of service)
- Costly due to repeated condition (example: window hardware replacement)
- Costly repair (example: extensive material or component replacement)
- Danger to health (example: excessive dampness, mold, soil gases, asbestos)
- Risk of injury (example: loose handrail)
- Danger to life (example: sudden collapse of structure)
The above categories provide insight into the broader meaning of building failures and their financial consequences, which may be trivial, costly, or very expensive – depending on the mechanisms of cause and the stage of degradation. Current building codes and standards reflect the premiss that components whose failure threatens life or health (Categories 6-8) should be designed to provide greater reliability for the intended service life.