(129a) A New Approach for Facility Siting by Mapping Risks On a Plant Area Grid and Optimization

It is well known that for Facility Siting hazard scenarios shall be identified which can have significant effects on occupied buildings, the vulnerability of control rooms or other occupied buildings shall be determined at their location relative to the risk source, and the spacing of process units, and spacing between equipment and employees in occupied buildings be examined. Usually, such study is conducted for evaluating the location of process plant buildings which already exist. However, this problem can be approached from a different point of view which is to decide on locations of facilities in the initial design step instead of changing location later as this can help saving money.

This research focuses on achievement of optimal location of hazardous facilities and other process plant buildings by mapping risks on given land and optimization theory in order to minimize financial risk. Applying event tree analysis possible consequences such as VCE and BLEVE by flammable gas release at a hazardous facility, and their probability can be estimated. Failure frequency of containment gives input to estimating release probability and initial hole size. The given land area is divided in a square grid of a certain mesh size and each grid acquires a risk score given the type of consequence and type of exposed receptor/target relevant to the location. These risk scores such as the probability of certain structural damage are to be multiplied by the costs of potential facilities to be built on the grid finally giving us the financial risk.

Accompanying the suggested safety concept, the new model takes into account economics. The overall cost of placing a facility on a certain location is a function of piping cost to connect it to adjacent facilities, land cost, and financial risk. The proposed approach is an assignment problem that identifies attractive locations by minimizing overall cost. This approach gives the coordinates of each facility, and estimates the total piping length including management cost. The main purpose of this paper is to assist the selection of locations for process plant buildings and managing the risk.