Limitations of the use of tolerances for communicating design requirements to site

The paper reports an empirical study designed to establish the extent to which adequate concrete cover to reinforcement in a sample of structures was achieved. It was found that the standards fell significantly short of those specified. Two kinds of explanation are considered to account for these findings. The first accepts as given the existing divisions of responsibility and conventions for specifying quality and looks to identify the reasons for non-compliance. The second proposes that the present arrangements and conventions are inappropriate to the conditions of variability and uncertainty standardly met with in construction. On the basis of this second set of assumptions, an alternative approach, using the concept of continuous quality improvement, is described and discussed.