Formalizing Tag-Based Metadata With the Brick Ontology

Abstract

Current efforts establishing semantic metadata standards for the built environment span academia, industry and standards bodies. For these standards to be effective, they must be clearly defined and easily extensible, encourage consistency in their usage, and integrate cleanly with existing industrial standards, such as BACnet. There is a natural tension between informal tag-based systems that rely upon idiom and convention for meaning, and formal ontologies amenable to automated tooling. We present a qualitative analysis of Project Haystack, a popular tagging system for building metadata, and identify a family of inherent interpretability and consistency issues in the tagging model that stem from its lack of a formal definition. To address these issues, we present the design and implementation of the Brick+ ontology, a drop-in replacement for Brick with clear formal semantics that enables the inference of a valid Brick model from an informal Haystack model, and demonstrate this inference across five Haystack models.

Metadata Schemas and Ontologies for Building Energy Applications: A Critical Review and Use Case Analysis

“…Fourteen different schemas have been identified that describe metadata about controls and metering in commercial buildings, but from this high-level review, the overlaps between them and their gaps are unclear. An extensive comparison between Brick and Project Haystack is presented in [148], but no publication compares all these schemas in depth. Gilani et al tried to evaluate the scope of several ontologies by identifying what type of data they describe (e.g., external conditions, energy use), but these categories are too broad to clearly identify the differences between schemas.…”

An overview of data tools for representing and managing building information and performance data

“…Brick, conversely, is a more structured, formal, and expressive ontology, but it requires more specialized software tools, and it is still under development. A more formal comparison of the two schemas is presented by Fierro et al [75].…”

Development and Application of Schema Based Occupant-Centric Building Performance Metrics

“…In addition to development in occupant-centric metrics and occupancy sensing technologies, there has been significant advancement in the standardized representation of operational building data [27][28][29]. Many different forms of digital information are produced over the lifespan of a building, capturing design, construction, commissioning, operations and controls, maintenance, and audit information.…”

“…Until recently, neither the schema nor accompanying documentation were provided in a machine readable format. The newest version, Haystack 4 (currently in prerelease), has addressed this while also defining concepts in a taxonomic structure to address some previous critiques [28]. The Brick Schema was developed to provide a more formalized class hierarchy than Haystack 3 originally implemented.…”

“…While it is well known that Haystack and Brick are used by energy management information systems (EMIS) to support energy analysis and fault detection and diagnostics applications (FDD) [28,37], documentation for the implementation of algorithms using standardized concepts defined by either schema has not been demonstrated. Although detailed descriptions of control and FDD algorithms are provided in many previous publications [38][39][40][41][42], they merely include point name descriptions and don't reference any data schema objects, which we believe is a serious opportunity missed and a novelty of the research performed by our study.…”