exported
equivalent
level sight glass
IRI:
http://www.inf.ufrgs.br/ontologies/copi#Levelsightglass
Generated on 2026-04-13
Natural Language Definition
EN
A level sight glass is a sight glass that bears a designed function to indicate liquid level through visual inspection.
PT-BR
Um visor de nível é um visor que possui uma função projetada para indicar o nível de líquido através de inspeção visual.
Formal Axioms
Semi-formal (Aristotelian)
Every level sight glass is a sight glass that has the function of level indication.
First-Order Logic Theory
Loading…
▸ Stored override
∀x (LevelSightGlass(x) ↔ SightGlass(x) ∧ ∃f (LevelIndicationFunction(f) ∧ hasFunction(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: LevelSightGlass
<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 "2026-10-08"^^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_0000172 rdf:type owl:Class ; # LevelIndicationFunction
rdfs:subClassOf :COPI_0000028 ; # IndicationFunction
rdfs:subClassOf [
rdf:type owl:Restriction ;
owl:onProperty bfo:BFO_0000054 ; # realizedIn
owl:allValuesFrom :COPI_0000564 # LevelIndicationProcess
] ;
rdfs:subClassOf [
rdf:type owl:Restriction ;
owl:onProperty bfo:BFO_0000054 ; # realizedIn
owl:someValuesFrom :COPI_0000564 # LevelIndicationProcess
] ;
rdfs:label "level indication function"@en ;
rdfs:label "função de indicação de nível"@pt-br .
:COPI_0000028 rdf:type owl:Class . # IndicationFunction
### Process type
:COPI_0000564 rdf:type owl:Class ; # LevelIndicationProcess
rdfs:subClassOf iof-core:MeasurementProcess ;
rdfs:label "level indication process"@en ;
rdfs:label "processo de indicação de nível"@pt-br .
iof-core:MeasurementProcess rdf:type owl:Class .
:COPI_0000564 # LevelIndicationProcess
rdfs:subClassOf [
rdf:type owl:Restriction ;
owl:onProperty iof-core:hasInput ;
owl:someValuesFrom :COPI_0000038 # PortionOfLiquid
] ;
rdfs:subClassOf [
rdf:type owl:Restriction ;
owl:onProperty iof-core:hasSpecifiedOutput ;
owl:someValuesFrom :COPI_0000046 # VisualIndication
] .
### Equipment universal: LevelSightGlass
:COPI_0000130 rdf:type owl:Class ; # LevelSightGlass
owl:equivalentClass [
rdf:type owl:Class ;
owl:intersectionOf (
:COPI_0000085 # SightGlass
[
rdf:type owl:Restriction ;
owl:onProperty iof-core:hasFunction ; # Object branch (MaterialArtifact/Assembly/Object/FiatObjectPart)
owl:someValuesFrom :COPI_0000172 # LevelIndicationFunction
]
)
] ;
rdfs:label "level sight glass"@en ;
rdfs:label "visor de nível"@pt-br ;
iof-av:naturalLanguageDefinition "A level sight glass is a sight glass that bears a designed function to indicate liquid level through visual inspection."@en ;
skos:definition "A level sight glass is a sight glass that bears a designed function to indicate liquid level through visual inspection."@en ;
iof-av:naturalLanguageDefinition "Um visor de nível é um visor que possui uma função projetada para indicar o nível de líquido através de inspeção visual."@pt-br ;
iof-av:semiFormalNaturalLanguageAxiom "Every level sight glass is a sight glass that has the function of level indication."@en ;
iof-av:firstOrderLogicAxiom "∀x (LevelSightGlass(x) ↔ SightGlass(x) ∧ ∃f (LevelIndicationFunction(f) ∧ hasFunction(x,f)))"@en ;
skos:altLabel "level gauge glass"@en ;
skos:altLabel "glass level gauge"@en ;
skos:definition "[ISO 15926-4] A <LEVEL SIGHT GLASS> is an <INSTRUMENTATION ITEM> and a <SIGHT GLASS> mounted in or on a pipe or vessel to see inside for liquid level inspection"@en .
# Disjointness: LevelSightGlass and FlowMeter
[] rdf:type owl:AllDisjointClasses ;
owl:members ( :COPI_0000130 :COPI_0000278 ) . # LevelSightGlass, FlowMeter
# Disjointness: LevelSightGlass and PressureGauge
[] rdf:type owl:AllDisjointClasses ;
owl:members ( :COPI_0000130 :COPI_0000143 ) . # LevelSightGlass, PressureGauge
Axiomatization Decision Log
1
Identity-Giving Function
Function class
LevelIndicationFunction
⊑ IndicationFunction
Realized in
LevelIndicationProcess
⊑ MeasurementProcess
The identity-giving function is providing visual indication of liquid level - this is what makes it a level sight glass rather than just a general sight glass or other instrumentation item
2
Genus Determination
SightGlass
ISO 15926 explicitly states it is a SIGHT GLASS - this is the most specific superclass. SightGlass is not yet enriched in our ontology but is the natural genus. INSTRUMENTATION ITEM is too broad as genus. SightGlass would be a MaterialArtifact as it is a causally unified transparent window component.
3
Necessary Parts
No necessary parts recorded (concept may be primitive at this level).
Level sight glasses inherit basic sight glass components but add level measurement specific parts like graduated scales or reference markings
4
Process Participation Signature ⟨I, O, T⟩
Inputs (I)
PortionOfLiquid
— contained in vessel/pipe
Outputs (O)
VisualIndication
— level indication to human observer
Transformation (T)
optical transduction - liquid level position to visual signal
Takes liquid level as input and transforms it into visual indication for human observation - no material transformation of the liquid itself
5
Axiom Mode Decision
Necessary + Sufficient
— modelled as a defined class
(≡, EquivalentClass). Automatic classification is
appropriate for this concept.
Disjointness Axioms
FlowMeter
PressureGauge
C?: FlowMeter [kind_ambiguous]. C?: PressureGauge [kind_ambiguous]. Level indication signature is incompatible with flow measurement, pressure measurement, or temperature measurement signatures
Cross-Standard Observations
Only one source definition available (ISO 15926). Definition is clear and functional, emphasizing the measurement purpose rather than structural details.
Reviewer Notes
Colleague backlog term 'Glass Level Gauge' resolved to ISO 15926-4's LEVEL GAUGE GLASS ('a glass tubular device or vertical cylindrical device... that indicates the level or amount of liquid in a tank or vessel') during the enrich-term skill's Step 2 genus research. This is a near-duplicate of ISO 15926-4's own separate LEVEL SIGHT GLASS term ('mounted in or on a pipe or vessel to see inside for liquid level inspection') already enriched as this row (genus SightGlass, LevelIndicationFunction, equivalent) -- a T3/T1 divergence WITHIN ISO 15926-4 itself (two parent terms, LEVEL GAUGE vs SIGHT GLASS, for the same real equipment). Added as alt_labels rather than creating a duplicate row, matching the ElectricalConnection/ElectricalConnector precedent from 2026-09-04.
Source Definitions
1 source
ISO 15926-4
LEVEL 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 | #59 |
| Cluster | level sight glass |
| Status | exported |
| Axiom mode | equivalent |
| Created | 2026-04-13 |
| Updated | 2026-09-08 |
ISA 5.1-2022 P&ID Symbol
5_4_3/003_flow_sight_glass.png
