Determining the boundaries of any process/design where feasible and safe operation is guaranteed has long been recognized as a major concern in process industries. Of additional value is identifying the range of operating conditions where the design is most profitable. Although there is a lot of discussion in the open literature regarding design feasibility in terms of uncertainty of process variables, these techniques are rather limited due to the underestimation of the feasible space. A new approach is presented based on the ideas of inner and outer approximation of the feasible region to identify the operating envelopes where process operation is feasible, safe, and profitable. A number of example problems are presented including two case studies to illustrate the applicability of this approach.