Output-oriented plant capacity in a non-parametric framework is a concept that has been rather widely applied since about twenty-five years. Conversely, input-oriented plant capacity in this framework is a notion of more recent date. In this contribution, we unify the building blocks needed for determining both plant capacity measures and define new graph or non-oriented plant capacity concepts. We empirically illustrate the differences between these various plant capacity notions using a secondary data set. This shows the viability of these new definitions for the applied researcher.