diff --git a/examples/heatingsystem.ttl b/examples/heatingsystem.ttl
index 73e88bd99c112af6e78f629a30b84608b1050b85..4b53c36cd1ab29ed84f7a98450d217adc7a2dcc5 100644
--- a/examples/heatingsystem.ttl
+++ b/examples/heatingsystem.ttl
@@ -15,6 +15,13 @@
   dcterms:title "Example heatingsystem"@en ;
   dcterms:description "Example heatingsystem"@en .
 
+time:Instant a owl:Class .
+time:DateTimeInterval a owl:Class .
+time:inXSDDateTime a owl:DatatypeProperty .
+time:hasBeginning a owl:ObjectProperty .
+time:hasEnd a owl:ObjectProperty .
+time:hasDurationDescription a owl:ObjectProperty .
+
 time:Beginning_PowerProfile-1-HS0001
   rdf:type time:Instant ;
   rdfs:label "Beginning Power profile-1-HS0001"^^xsd:string ;