diff --git a/ontology/saref4watr.ttl b/ontology/saref4watr.ttl
index 5c9ea0848aea72778ffcadeb612d6e885943cc42..af3841c4dd4b47b42430ec36bec9aa268b27d546 100644
--- a/ontology/saref4watr.ttl
+++ b/ontology/saref4watr.ttl
@@ -319,39 +319,17 @@ sf:Polygon rdf:type owl:Class ;
 
 ###  http://www.w3.org/2006/time#DayOfWeek
 time:DayOfWeek rdf:type owl:Class ;
-               rdfs:comment "The day of week."@en ;
-               rdfs:isDefinedBy <http://www.w3.org/2006/time#> ;
-               rdfs:label "Day of week"@en .
-
-
-###  http://www.w3.org/2006/time#Instant
-time:Instant rdf:type owl:Class ;
-             rdfs:subClassOf time:TemporalEntity ;
-             rdfs:comment "A temporal entity with zero extent or duration"@en ;
-             rdfs:isDefinedBy <http://www.w3.org/2006/time#> ;
-             rdfs:label "Instant"@en .
+               rdfs:isDefinedBy <http://www.w3.org/2006/time#> .
 
 
 ###  http://www.w3.org/2006/time#Interval
 time:Interval rdf:type owl:Class ;
-              rdfs:subClassOf time:TemporalEntity ;
-              rdfs:comment "A temporal entity with an extent or duration."@en ;
-              rdfs:isDefinedBy <http://www.w3.org/2006/time#> ;
-              rdfs:label "Interval"@en .
+              rdfs:isDefinedBy <http://www.w3.org/2006/time#> .
 
 
 ###  http://www.w3.org/2006/time#TemporalDuration
 time:TemporalDuration rdf:type owl:Class ;
-                      rdfs:comment "Time extent; duration of a time interval separate from its particular start position"@en ;
-                      rdfs:isDefinedBy <http://www.w3.org/2006/time#> ;
-                      rdfs:label "Temporal duration"@en .
-
-
-###  http://www.w3.org/2006/time#TemporalEntity
-time:TemporalEntity rdf:type owl:Class ;
-                    rdfs:comment "A temporal interval or instant."@en ;
-                    rdfs:isDefinedBy <http://www.w3.org/2006/time#> ;
-                    rdfs:label "Temporal entity"@en .
+                      rdfs:isDefinedBy <http://www.w3.org/2006/time#> .
 
 
 ###  https://saref.etsi.org/saref4watr/AcceptabilityProperty