Abstract
A case from the authors’ experience reveals that dimensional tolerance, in terms of physical
dimensions of components and their position within the system; interact to compound the
process variability and uncertainty within a project. Variability adds to the costs of a process
with long cycle times, high work in progress levels; wasted capacity due to low utilization of
resources; lost throughput, and a general increase in waste (poor quality and increased scrap)
(Hopp and Spearman 2000). Early construct ability research supports this observation: as it
identified dimensional tolerances as a major factor in ease of construction and subsequently cost
and schedule (O’Connor 1989 and CII 1986). Though construct ability research has developed
many tools for application to design, none appear to have focused on how to identify appropriate
tolerances. In addition, other industries outside AEC have made significant improvements by
carefully measuring and understanding the effects of tolerances within their systems. Quantifying
dimensional tolerances for construction operations and materials, and developing strategies to
mitigate their effects is therefore an important objective in research and design practice. Based
on a case study, a strategy is recommended in which product designers are challenged to design
systems that accommodate most process variability without compromising project goals.