Industry practitioners know that construction is plagued by
uncertainties. In their most interesting study, Howell and
Ballard (1996, p. 6) describe prevailing methods for managing
them in the piping function: "Piping success requires
minimizing the extent and effects of uncertainty during
fabrication and installation. At present, uncertainty in the timing
of deliveries of intermediate products from one continuing
activity to another defines the production planning and
management problem. Lacking tools to minimize the
uncertainty in these flows, managers strive for flexibility so that
the project can proceed in the face of erratic deliveries and
unexpected problems. On piping extensive projects, they rely on buffers to assure progress despite variations in the timing,
sequence, and quality of resources from upstream suppliers.
Buffers dampen the effects of variations in the flow of resources
and allow flexibility in the choice of work.