Capacitated emergency facility siting with multiple levels of backup

In many service systems, the primary objective is to provide continuous service and/or service within a prespecified time interval. In the public sector, emergency service systems fit into this category. In the private sector, systems providing repair service to critical production facilities and computers constitute another example. In these systems, the concept of multiple service facilities providing backup to each other becomes an important element in the design process. In this paper, we study the capacitated facility siting problem with multiple levels of backup coverage. The problem is formulated as a mathematical program; an efficient solution procedure is developed and computational experiments are reported.