Redefining Building Failure

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:

      1. No exceptional problems (example: replacement of light fittings)
      2. Security compromised (example: broken door latch)
      3. Interruption of building use (example: repair requires temporary discontinuation of service)
      4. Costly due to repeated condition (example: window hardware replacement)
      5. Costly repair (example: extensive material or component replacement)
      6. Danger to health (example: excessive dampness, mold, soil gases, asbestos)
      7. Risk of injury (example: loose handrail)
      8. 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.

Resources
    1. Building Failure Studies (U.S.)
    2. Building Failure Studies (Canada)