An open standard for the operational understanding of buildings — the points, plans, sequences, setpoints, and hard-won knowledge that today are rebuilt from nothing every time a building changes systems.
Read the standardWhen a building automation system is replaced, the software goes — and the understanding goes with it. Which sensor serves which room. Why the setpoint is 68 and not 70. The override someone placed in 2017, and the reason. The floor plans an engineer spent months drawing and binding.
Owners pay to rebuild this understanding over and over, at hundreds of engineering hours per building, because it has never had a form the owner could keep.
BUS gives it a form. One package, exported without vendor assistance, complete enough to reconstruct operation on whatever comes next.
If it describes the building, it belongs to the standard. If it describes the software experience, it belongs to the vendor.
Every point and what it measures. Every space, asset, and relationship. Setpoints, schedules, and the intent behind them. Alarms and their routing. Events and the notes that explain them. Floor plans, symbols, and their live bindings — everything a draughtsman or engineer decided.
The rendering, the workflow, the speed, the polish — everything a user sees and feels. A better BAS is still worth paying for. That is the point.
Every number on this page links to the file that proves it.
$ pip install busref $ busref validate cedar-street-building-a.buspkg ALL CHECKS PASSED — 751 checks, 13 documents, 137 entities
What does your system hold that the model cannot express?
Which completeness reason codes did you need, and which were missing?
How many symbol roles were unavailable?
What could the export not do without vendor assistance? — the one the charter cares about most.
Buildings do not forget. Systems do.
The Building Understanding Standard is an open specification. Versioned artifacts are immutable: once published, their URLs and bytes never change. This site sets no cookies and runs no trackers. Working draft — a governance body does not yet exist, and this site says so plainly until one does.