Improvement of Dimensional Tolerance Management in Construction

Tolerance-related problems are amongst the most common, recurring defects in construction projects. They are often dealt with on an ad hoc basis and at the time and place of the assembly process. The existing academic literature and the industrial guidelines provide only general recommendations for the improvement of tolerance management, and a pragmatic and holistic process for this purpose is still missing.

This research aims at developing a process to proactively identify and prevent tolerance problems at the stages preceding assembly on site. Design Science Research is the adopted methodological approach as the focus is on prescribing a solution to solve a practical problem, as well as on contributing to theory. To design a workable solution, the literature not only in construction but also in manufacturing is reviewed, empirical data is collected from three cases, fifteen tolerance problems are documented and analysed, and a detailed root cause analysis is performed for the identified tolerance problems.

The solution devised is a process, called Tolerance Management System (TMS), which has five parts, each comprising a set of steps, documents, methods and techniques implemented through a particular organisational design. The parts of TMS are: identification of tolerance requirements/risks, planning the achievement of tolerance requirements/mitigation of tolerance risks, communication of tolerance information, tolerance compliance measurement, and learning and documentation. Process standardisation and continuous improvement are two foundational elements of lean that are employed in TMS.

Two focus group meetings are conducted to evaluate whether the developed solution fulfils its aim and to refine it further. It was pinpointed during the focus group meetings that many of the TMS steps could be adopted in practice immediately to help practitioners deal with tolerances more systematically.

The research results in contributions to the theory by providing a better understanding of not only a typical but also an advanced practice of tolerance management in the construction industry, and by providing a comprehensive list of root causes of the identified tolerance problems. A contribution to both theory and practice is the developed solution, TMS, by which (a) tolerances can be taken systematically into account from project inception to completion, (b) tolerance information can be effectively communicated amongst designers and construction trades, and (c) the conventional focus on the compliance of deviations of a single component with standards is shifted to whether sub-assemblies function properly within the specified tolerances.