1 Scope§
AGREED
1.1 Purpose§
This document specifies a vendor-neutral information model for the operational understanding of a building, a portable model for the graphics through which that building is operated, and a package format for moving both between systems without loss of meaning.
Its object is not interoperability at run time. Systems that exchange live values already have protocols for that. Its object is continuity: the ability of a building owner to take the accumulated understanding of a building out of one system and stand it up in another, years or decades later, without the cooperation of the system it came from.
1.2 What this version specifies§
- An encoding-neutral information model for building identity, spatial structure, systems and assets, points, typed relationships, operational intent, alarms, events, and provenance (clauses 6 to 14).
- A portable presentation model: drawings, coordinate systems and georeferencing, layers, elements with symbol roles or embedded figures, and bindings including command actions (clause 13).
- A neutral vector figure format,
bus-vector-1, defined as a closed profile of SVG with a fixed element list (13.4.3). - A requirement that every property carry a definition declaring its datatype, unit, and meaning (7.8).
- A governed extension mechanism, including the rules that keep an extension from being silently discarded (clause 15).
- An exchange package: container, manifest, integrity, an actuation declaration, and a mandatory completeness declaration (clause 16).
- A JSON binding with schema documents and a canonical form (clause 17), and conformance profiles and round-trip test methodology (clause 2, Annex A).
1.3 What is deferred§
Time-series history, deferred by both prior versions, is deferred no longer: it is specified by BUS-2: Time Series, Part 2 of this standard. Within this document, points declare whether durable history exists and over what extent (8.8); BUS-2 specifies how the history itself travels, and 8.8 states where the two parts meet. What follows is what remains deferred.
| Domain | In v0.3 | Deferred to |
|---|---|---|
| Structured knowledge | bus:KnowledgeNote carries free text with a kind, an author, a review state, and typed attachment predicates (8.9). | BUS-3, structured knowledge types |
| Deployed control logic | A sequence declares whether it is design intent or what a controller is running, and carries the controller, the program identifier, and a checksum (10.5). The logic itself is referenced, not extracted. | unscheduled; no prior art exists |
| Analytic results | The attachment interface is normative (clause 15). The internal shape of an insight, diagnosis, or forecast is not. | BUS-4, analytic results |
NOTE The vector figure format was the one place v0.2 knowingly named something it did not define. It is defined in this version as a closed profile of SVG (13.4.3), which is what makes an element in figure mode portable in practice rather than only in principle. Where a symbol role exists, still prefer it: a role lets the receiving vendor apply its own design system and a figure cannot.
1.4 What is out of scope§
- Field and transport protocols — BUS-1 records how a point is reached (8.6). It does not define how to reach it.
- Proprietary method — How a vendor arrives at a conclusion is not specified and not disclosed. Only the durable result is portable.
- Rendering and interaction — No requirement constrains artwork, color, animation, transitions, typography, responsive layout, navigation design, or interaction model. Clause 13 is explicit about where this line falls.
- Three-dimensional geometry — Presentation is two-dimensional. A 3D or BIM model is referenced as a resource. IFC already exists and is better at this.
- Equipment taxonomy — A small structural class set, with external classifications preserved verbatim (7.7). Not intended to compete with the ontologies that define taxonomies.