New Building Siting Using Risk-Based Approach

Growth in the energy and petrochemical sectors has seen a surge in the expansion of existing facilities (brown-fields) and construction of new facilities (green-fields) around the globe. Most brown-field and green-field studies involve construction of new buildings.

Siting of a new building depends on a gamut of factors including their function, hazards, required level of protection and proposed type of construction. The decision making process can be further complicated when multiple options or constraints need to be considered. A risk-based approach can be applied to understand and compare various options using indices such as tolerable risk levels and cost. A cost-benefit risk analyses can be used as an effective tool to assist with the decision making process.

For instance, building function typically governs location for the building. Adequacy of multiple building locations can be explored and assessed to determine variation in cost index. Risk analyses can also be used to construct constant-risk cost contours which depict locations where buildings of conventional construction (non-blast-resistant) can be considered and alternative locations when the material cost is increased.

Building construction type can be a project cost driver, therefore buildings with low cost are typically preferred. Since the inherent blast resistance of a building can vary significantly with construction type, the actual cost of construction can increase much more steeply for weaker building types than their stronger counter parts when blast requirements are to be met. Sensitivity analyses for building cost index for different construction type can assist in the selection of an optimum construction type for a project.

Risk based cost analyses can further be used to understand how material costs may vary as a function of a higher level of protection (lower risk).  This type of sensitivity analyses can be used to balance risk reduction efforts with project costs.

This paper outlines a methodology to perform sensitivity studies to optimally site a new building. The paper includes a case study to show how risk analyses can be used as an effective tool for this decision making process.