Control relationships explain how a control point's value is decided in buildings systems. For example, effective heating temperature (EHT) setpoint is commonly decided by occupancy status (OS) and temperature setpoint (TS) for the VAV of a zone. Brick represents such info by ``OS controls EHT`` and ``TS controls EHT``. Refer Section 3.5 in the above paper for more information.
There are sequential relationships across entities in buildings such as ``feeds``. ``AHU feeds VAV``, ``VAV feeds Zone``, etc. With this, we can infer that AHU feeds the Zone. Sequential relationships inherently require the capability of traversing relationships among many entities.
Brick's formality provides more provability of instance models, which enables the consistency across building models and improves the portability of apps. We define tags/classes and how each of them should be used (often called semantics). For this, please check a preprint of our paper coming in this year BuildSys (attached).