Waste Management Project Contingency Analysis

Abstract

The purpose of this report is to provide the office of Waste Management (WM) with recommended contingency calculation procedures for typical WM projects. Typical projects were defined as conventional construction-type activities that use innovative elements when necessary to meet the project objectives. Projects involve treatment, storage, and disposal of low level, mixed low level, hazardous, transuranic, and high level waste. Cost contingencies are an essential part of Total Cost Management. A contingency is an amount added to a cost estimate to compensate for unexpected expenses resulting from incomplete design, unforeseen and unpredictable conditions, or uncertainties in the project scope (DOE 1994, AACE 1998). Contingency allowances are expressed as percentages of estimated cost and improve cost estimates by accounting for uncertainties. The contingency allowance is large at the beginning of a project because there are more uncertainties, but as a project develops, the allowance shrinks to adjust for costs already incurred. Ideally, the total estimated cost remains the same throughout a project. Project contingency reflects the degree of uncertainty caused by lack of project definition, and process contingency reflects the degree of uncertainty caused by use of new technology. Different cost estimation methods were reviewed and compared with respect to terminology, accuracy, and Cost Guide standards. The Association for the Advancement of Cost Engineering (AACE) methods for cost estimation were selected to represent best industry practice. AACE methodology for contingency analysis can be readily applied to WM Projects, accounts for uncertainties associated with different stages of a project, and considers both project and process contingencies and the stage of technical readiness. As recommended, AACE contingency allowances taper off linearly as a project nears completion.