diff --git a/ontology/saref4city.ttl b/ontology/saref4city.ttl
index 609139ad0b6630b71c596df53f73f6d45e17e750..7fd4b622d929cacc90a5c115cbfa0c8bc6ab577d 100644
--- a/ontology/saref4city.ttl
+++ b/ontology/saref4city.ttl
@@ -551,7 +551,7 @@ s4city:Facility a owl:Class ;
 s4city:KeyPerformanceIndicator a owl:Class ;
 	rdfs:subClassOf [	a owl:Restriction ;
 						owl:onProperty s4city:hasCalculationPeriod ;
-						owl:allValuesFrom time:TemporalEntity ] ,
+						owl:allValuesFrom time:TemporalDuration ] ,
 
 					[	a owl:Restriction ;
 						owl:onProperty s4city:isKPIOf ;