diff --git a/ontology/saref4ehaw.ttl b/ontology/saref4ehaw.ttl
index a2b4fbf0bde09f4ed7b2db8d479cf95053c41fe5..70af0a36b54337bde2059004d1b25927ba3c5bb1 100644
--- a/ontology/saref4ehaw.ttl
+++ b/ontology/saref4ehaw.ttl
@@ -412,7 +412,7 @@ s4envi:hasFrequencyMeasurement rdf:type owl:ObjectProperty ;
 ###  https://saref.etsi.org/saref4ehaw/activityDuration
 s4ehaw:activityDuration rdf:type owl:DatatypeProperty ;
                         rdfs:domain s4ehaw:Activity ;
-                        rdfs:range xsd:duration ;
+                        rdfs:range xsd:float ;
                         rdfs:comment "The duration of an activity, in second."@en ;
                         rdfs:label "activity duration"@en .
 
@@ -678,7 +678,7 @@ s4ehaw:lastName rdf:type owl:DatatypeProperty ;
 ###  https://saref.etsi.org/saref4ehaw/latency
 s4ehaw:latency rdf:type owl:DatatypeProperty ;
                rdfs:domain s4ehaw:MeasurementFunction ;
-               rdfs:range xsd:duration ;
+               rdfs:range xsd:float ;
                rdfs:comment "The latency is the time interval between the stimulation and response of a measurement function (in ms)."@en ;
                rdfs:label "latency"@en .
 
@@ -686,8 +686,8 @@ s4ehaw:latency rdf:type owl:DatatypeProperty ;
 ###  https://saref.etsi.org/saref4ehaw/lifetime
 s4ehaw:lifetime rdf:type owl:DatatypeProperty ;
                 rdfs:domain s4ehaw:Ban ;
-                rdfs:range xsd:duration ;
-                rdfs:comment "The BAN lifetime, e.g. BAN for entertainment purposes should have a lifetime of weeks or few years whereas BAN dedicated for assisted living or anomaly monitoring should last for many years."@en ;
+                rdfs:range xsd:float ;
+                rdfs:comment "The BAN lifetime (in month), e.g. BAN for entertainment purposes should have a lifetime of weeks or few years whereas BAN dedicated for assisted living or anomaly monitoring should last for many years."@en ;
                 rdfs:label "lifetime"@en .