My last two columns dealt with point selection and sequence writing. These determine the majority of a BAS project’s scope of work; however, there is one other issue necessary to the core of the design: the system architecture. In this case, I am referring to the physical architecture that deals mainly with the layout/quantity of the controllers of various types along with the wiring topology and transport technology used to connect them. (In my June 2018 column, I covered BAS application architecture, which is a different issue typically only important to integration challenges.) Why is it important to define the physical architecture (or simply “architecture” in this column) in the design?