exported
equivalent
sight glass
IRI:
http://www.inf.ufrgs.br/ontologies/copi#Sightglass
Generated on 2026-05-04
Natural Language Definition
EN
An Instrument that bears a VisualInspectionFunction and that consists in a transparent viewing interface that enables direct optical observation of internal conditions, fluid properties, or process states within containers, vessels, or piping systems.
PT-BR
Um Instrumento que porta uma VisualInspectionFunction e que consiste em uma interface de visualização transparente que permite observação óptica direta de condições internas, propriedades de fluidos ou estados de processo dentro de recipientes, vasos ou sistemas de tubulação.
Formal Axioms
Semi-formal (Aristotelian)
Every sight glass is an instrument that bears a visual inspection function and enables direct optical observation of process internals through a transparent viewing interface.
First-Order Logic Theory
Loading…
▸ Stored override
∀x(SightGlass(x) ↔ Instrument(x) ∧ ∃f(VisualInspectionFunction(f) ∧ bearerOf(x,f)))
OWL 2 / Turtle
@prefix copi: <https://www.inf.ufrgs.br/ontologies/copi/> .
@prefix : <https://www.inf.ufrgs.br/ontologies/copi/> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix bfo: <http://purl.obolibrary.org/obo/> .
@prefix iof-core: <https://spec.industrialontologies.org/ontology/construct/> .
@prefix iof-av: <https://spec.industrialontologies.org/ontology/annotation/> .
@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
@prefix qudt: <http://qudt.org/schema/qudt/> .
@prefix dcterms: <http://purl.org/dc/terms/> .
@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@prefix apv: <http://inf.ufrgs.br/ontologies/apv#> .
### COPI — Core Ontology for Petroleum Installations
### Class module: SightGlass
<https://www.inf.ufrgs.br/ontologies/copi>
rdf:type owl:Ontology ;
dcterms:title "Core Ontology for Petroleum Installations (COPI)"@en ;
dcterms:title "Ontologia Core para Instalações de Petróleo (COPI)"@pt-br ;
dcterms:description "BFO/IOF-Core conformant ontology of equipment classes for petroleum production plants, developed using the five-step RDL enrichment method."@en ;
skos:scopeNote "Material artifacts (bfo:material_entity) that (i) are part of a petroleum production plant, and (ii) bear at least one function whose realization involves the transport (e.g. production and injection), processing (separation and other processes), control, monitoring, measurement, containment or offloading of material or energy."@en ;
skos:scopeNote "Artefatos materiais (bfo:material_entity) que (i) fazem parte de uma planta de produção de petróleo, e (ii) possuem ao menos uma função cuja realização envolve o transporte (p. ex. produção e injeção), processamento (separação e outros processos), controle, monitoramento, medição, contenção ou escoamento de material ou energia."@pt-br ;
skos:scopeNote "COPI provides high-level equipment categories defined by function to demonstrate the defined-class mechanism. Equipment subtypes are annotated with references to CFIHOS and PCA RDL terms. COPI is not a reference data library; organizations should use CFIHOS, PCA RDL, or ISO 14224 for comprehensive equipment classification."@en ;
skos:scopeNote "COPI fornece categorias de alto nível de equipamentos definidas por função para demonstrar o mecanismo de classe definida. Os subtipos de equipamentos são anotados com referências aos termos do CFIHOS e do PCA RDL. COPI não é uma biblioteca de dados de referência; organizações devem utilizar o CFIHOS, o PCA RDL ou a ISO 14224 para classificação abrangente de equipamentos."@pt-br ;
owl:versionInfo "1.1.0" ;
owl:imports <https://spec.industrialontologies.org/ontology/core/Core/> ;
owl:imports <http://purl.obolibrary.org/obo/bfo/2020/bfo.owl> ;
dcterms:creator "Nicolau Oyhenard dos Santos"@en ;
dcterms:contributor "Cauã Antunes" ;
dcterms:contributor "Haroldo Rojas" ;
dcterms:contributor "Rafael Petry" ;
dcterms:contributor "Régis Romeu" ;
dcterms:contributor "Mara Abel" ;
dcterms:isPartOf <https://inf.ufrgs.br/projetos/OntoKG> ;
dcterms:publisher "Universidade Federal do Rio Grande do Sul (UFRGS)"@en ;
dcterms:license <https://creativecommons.org/licenses/by/4.0/> ;
dcterms:created "2026-04-08"^^xsd:date ;
dcterms:modified "2026-10-07"^^xsd:date ;
apv:GlobalMinLanguageCoverage "en pt-br" ;
apv:ClassURIFormationRule "https://www[.]inf[.]ufrgs[.]br/ontologies/copi/(COPI_[0-9]{7}|[A-Z][A-Za-z0-9]*)" ;
apv:ClassMinAnnotationCoverage "rdfs:label https://spec.industrialontologies.org/ontology/annotation/naturalLanguageDefinition" .
iof-av:naturalLanguageDefinition rdf:type owl:AnnotationProperty ;
apv:MinAnnotationLength 20 .
### Identity-giving function
:COPI_0000686 rdf:type owl:Class ; # VisualInspectionFunction
rdfs:subClassOf :COPI_0000029 ; # InstrumentationFunction
rdfs:subClassOf [
rdf:type owl:Restriction ;
owl:onProperty bfo:BFO_0000054 ; # realizedIn
owl:allValuesFrom :COPI_0000687 # VisualInspectionProcess
] ;
rdfs:subClassOf [
rdf:type owl:Restriction ;
owl:onProperty bfo:BFO_0000054 ; # realizedIn
owl:someValuesFrom :COPI_0000687 # VisualInspectionProcess
] ;
rdfs:label "visual inspection function"@en ;
rdfs:label "função de inspeção visual"@pt-br ;
iof-av:naturalLanguageDefinition "A DesignedFunction that is realized in a VisualInspectionProcess and that consists in enabling direct optical observation of internal conditions, fluid properties, or process states within containers, vessels, or piping systems for operational monitoring, safety verification, or maintenance purposes."@en ;
skos:definition "A DesignedFunction that is realized in a VisualInspectionProcess and that consists in enabling direct optical observation of internal conditions, fluid properties, or process states within containers, vessels, or piping systems for operational monitoring, safety verification, or maintenance purposes."@en .
:COPI_0000029 rdf:type owl:Class . # InstrumentationFunction
### Process type
:COPI_0000687 rdf:type owl:Class ; # VisualInspectionProcess
rdfs:subClassOf iof-core:PlannedProcess ;
rdfs:label "visual inspection process"@en ;
rdfs:label "processo de inspeção visual"@pt-br ;
iof-av:naturalLanguageDefinition "A PlannedProcess in which an operator or automated vision system directly observes the interior of a vessel or piping system through a transparent window or port to assess fluid level, flow conditions, phase behavior, contamination, or other visual indicators of process state."@en ;
skos:definition "A PlannedProcess in which an operator or automated vision system directly observes the interior of a vessel or piping system through a transparent window or port to assess fluid level, flow conditions, phase behavior, contamination, or other visual indicators of process state."@en .
:COPI_0000687 # VisualInspectionProcess
rdfs:subClassOf [
rdf:type owl:Restriction ;
owl:onProperty iof-core:hasInput ;
owl:someValuesFrom :COPI_0000037 # PortionOfFluid
] ;
rdfs:subClassOf [
rdf:type owl:Restriction ;
owl:onProperty iof-core:hasSpecifiedOutput ;
owl:someValuesFrom :COPI_0000046 # VisualIndication
] .
### Equipment universal: SightGlass
:COPI_0000085 rdf:type owl:Class ; # SightGlass
owl:equivalentClass [
rdf:type owl:Class ;
owl:intersectionOf (
:COPI_0000091 # Instrument
[
rdf:type owl:Restriction ;
owl:onProperty iof-core:hasFunction ; # Object branch (MaterialArtifact/Assembly/Object/FiatObjectPart)
owl:someValuesFrom :COPI_0000686 # VisualInspectionFunction
]
)
] ;
rdfs:label "sight glass"@en ;
rdfs:label "visor"@pt-br ;
iof-av:naturalLanguageDefinition "An Instrument that bears a VisualInspectionFunction and that consists in a transparent viewing interface that enables direct optical observation of internal conditions, fluid properties, or process states within containers, vessels, or piping systems."@en ;
skos:definition "An Instrument that bears a VisualInspectionFunction and that consists in a transparent viewing interface that enables direct optical observation of internal conditions, fluid properties, or process states within containers, vessels, or piping systems."@en ;
iof-av:naturalLanguageDefinition "Um Instrumento que porta uma VisualInspectionFunction e que consiste em uma interface de visualização transparente que permite observação óptica direta de condições internas, propriedades de fluidos ou estados de processo dentro de recipientes, vasos ou sistemas de tubulação."@pt-br ;
iof-av:semiFormalNaturalLanguageAxiom "Every sight glass is an instrument that bears a visual inspection function and enables direct optical observation of process internals through a transparent viewing interface."@en ;
iof-av:firstOrderLogicAxiom "∀x(SightGlass(x) ↔ Instrument(x) ∧ ∃f(VisualInspectionFunction(f) ∧ bearerOf(x,f)))"@en ;
skos:definition "[ISO 15926-4] A <SIGHT GLASS> is a <FunctionalObject> whose purpose is to enable seeing the internals of a <CONTAINER>"@en ;
skos:definition "[CFIHOS] A physical object that is transparent and intended for viewing a vessel or piping system interior."@en .
Axiomatization Decision Log
1
Identity-Giving Function
Function class
VisualInspectionFunction
⊑ InstrumentationFunction
Realized in
VisualInspectionProcess
⊑ PlannedProcess
Visual inspection is the identity-giving function that distinguishes sight glasses from other instrumentation. The function encompasses all operational uses: level monitoring, flow observation, phase detection, and general process visualization. InstrumentationFunction is the appropriate parent as sight glasses are instrumentation devices that provide process information through visual means.
2
Genus Determination
Instrument
Both source hierarchies classify sight glass under instrumentation categories: ISO 15926-4 relates subtypes to 'INSTRUMENTATION ITEM' and CFIHOS classifies under 'general instrument'. Sight glass is more specific than the generic 'Instrument' class but belongs to that category as it provides process information through visual indication. Assembly is the appropriate BFO root as sight glasses are causally unified artifacts with removable components (glass, frame, gaskets, mounting hardware) assembled into a single maintainable unit.
3
Necessary Parts
No necessary parts recorded (concept may be primitive at this level).
No component terms are available in the Known Component Terms list, and the source definitions do not explicitly name necessary parts beyond the general reference to transparent material. While sight glasses typically have glass/transparent elements, frames, gaskets, and mounting hardware, these specific components are not named in the provided sources and are not in the Known Component Terms list, so no parts can be formally specified.
4
Process Participation Signature ⟨I, O, T⟩
Inputs (I)
PortionOfFluid
— contained within vessel or piping system being observed
Outputs (O)
VisualIndication
— visual information about fluid state, level, flow, or other observable characteristics
Transformation (T)
light transmission through transparent medium enables direct optical observation of process fluid characteristics and behavior
Sight glass enables visual observation by transmitting light through a transparent barrier, allowing operators to observe fluid characteristics without direct contact. The input is the contained fluid being observed, and the output is visual information about that fluid's state. This constitutes measurement transduction as it converts physical process states into observable information for human interpretation.
5
Axiom Mode Decision
Necessary + Sufficient
— modelled as a defined class
(≡, EquivalentClass). Automatic classification is
appropriate for this concept.
Cross-Standard Observations
Strong consistency across sources on functional definition. Both ISO 15926-4 and CFIHOS emphasize the viewing/observation purpose. ISO 15926-4 provides more detailed subtype classification with shape and application variants (level, flow, pressure), while CFIHOS maintains a simpler definition. No significant divergences detected.
Source Definitions
2 sources
ISO 15926-4
SIGHT GLASS ↗
Definition text withheld (copyrighted standard) — follow the source link above.
CFIHOS
sight glass
Definition text withheld (copyrighted standard) — follow the source link above.
Metadata
| Ontology | COPI |
| Research group | INF-UFRGS-Ontologies |
| Funding | CNPq INF-UFRGS-ENERGIA |
| Project | OntoKG / Petrobras |
| ID | #388 |
| Cluster | sight glass |
| Status | exported |
| Axiom mode | equivalent |
| Created | 2026-05-04 |
| Updated | 2026-09-08 |
ISA 5.1-2022 P&ID Symbol
5_4_3/003_flow_sight_glass.png
