Abstract: A method, system and article of manufacture of siting one or more detectors in a facility represented with zones are provided. Signals Si,j representing an effect in zone j in response to a release of contaminant in zone i for one or more flow conditions are provided. A candidate architecture has one or more candidate zones. A limiting case signal is determined for each flow condition for multiple candidate architectures. The limiting case signal is a smallest system signal of multiple system signals associated with a release in a one zone. Each system signal is a maximum one of the signals representing the effect in the candidate zones from the release in one zone for the flow condition. For each candidate architecture, a robust limiting case signal is determined based on a minimum of the limiting case signals. One candidate architecture is selected based on the robust limiting case signals.