Methods for managing tolerance compatibility: Windows in cast-in-place concrete

Managing tolerances is a challenge addressed daily on construction projects, yet tolerance management methods and knowledge of such methods appear to be lacking in the architecture-engineering-construction (AEC) industry. Although tolerance specifications and related practices within a trade may be formulated and understood, challenges stem from how dimensions are indicated in design documents and computer models and from differences between trade-specific tolerance specifications and process capability. This paper highlights industry challenges in specifying and meeting intertrade tolerances, called tolerance compatibility, and illustrates such challenges using a project with windows in cast-in-place concrete openings. It describes the project context and replicates an email sent by one project team member to others describing how a tolerance problem arose. Importantly, the paper introduces nine tolerance management methods, including tolerance loop detection. The contribution to knowledge is to highlight industry challenges related to managing tolerance compatibility, raise awareness of their impact on project delivery, and introduce management methods that can be taught and readily applied in practice. Finally, this paper presents research questions related to managing tolerances that demand further attention.