diff --git a/DESCRIPTION b/DESCRIPTION
index c6d5720..20cbfec 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -18,13 +18,13 @@ BugReports: https://github.com/opensdmx/rsdmx/issues
 LazyLoad: yes
 Collate:
 	Class-SDMXSchema.R Class-SDMXType.R Class-SDMXStructureType.R Class-SDMXHeader.R
-  Class-SDMX.R Class-SDMXGenericData.R Class-SDMXCompactData.R Class-SDMXMessageGroup.R
-  Class-SDMXConcept.R Class-SDMXConceptScheme.R Class-SDMXConcepts.R Class-SDMXCode.R
-  Class-SDMXCodelist.R Class-SDMXCodelists.R Class-SDMXDimension.R Class-SDMXTimeDimension.R
-  Class-SDMXPrimaryMeasure.R Class-SDMXAttribute.R Class-SDMXComponents.R
+  Class-SDMX.R Class-SDMXGenericData.R Class-SDMXCompactData.R Class-SDMXUtilityData.R
+  Class-SDMXMessageGroup.R Class-SDMXConcept.R Class-SDMXConceptScheme.R Class-SDMXConcepts.R
+  Class-SDMXCode.R Class-SDMXCodelist.R Class-SDMXCodelists.R Class-SDMXDimension.R
+  Class-SDMXTimeDimension.R Class-SDMXPrimaryMeasure.R Class-SDMXAttribute.R Class-SDMXComponents.R
   Class-SDMXDataStructure.R Class-SDMXDataStructures.R Class-SDMXDataStructureDefinition.R
-  SDMXSchema-methods.R SDMXType-methods.R SDMXStructureType-methods.R SDMXHeader-methods.R
-  SDMX-methods.R SDMXGenericData-methods.R SDMXCompactData-methods.R SDMXMessageGroup-methods.R
+  SDMXSchema-methods.R SDMXType-methods.R SDMXStructureType-methods.R SDMXHeader-methods.R SDMX-methods.R
+  SDMXGenericData-methods.R SDMXCompactData-methods.R SDMXUtilityData-methods.R SDMXMessageGroup-methods.R
   SDMXConcept-methods.R SDMXConceptScheme-methods.R SDMXConcepts-methods.R SDMXCode-methods.R
   SDMXCodelist-methods.R SDMXCodelists-methods.R SDMXDimension-methods.R SDMXTimeDimension-methods.R
   SDMXPrimaryMeasure-methods.R SDMXAttribute-methods.R SDMXComponents-methods.R
diff --git a/NAMESPACE b/NAMESPACE
index 39dc463..f7cba19 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -11,6 +11,7 @@ exportClasses(
   SDMXStructureType,
 	SDMXGenericData,
   SDMXCompactData,
+  SDMXUtilityData,
   SDMXMessageGroup,
   SDMXConcept,
   SDMXConceptScheme,
@@ -36,6 +37,7 @@ export(
   SDMXStructureType,
 	SDMXGenericData,
   SDMXCompactData,
+  SDMXUtilityData,
   SDMXMessageGroup,
   SDMXConcept,
   SDMXConceptScheme,
@@ -82,6 +84,7 @@ exportMethods(
 
 S3method(as.data.frame, SDMXGenericData)
 S3method(as.data.frame, SDMXCompactData)
+S3method(as.data.frame, SDMXUtilityData)
 S3method(as.data.frame, SDMXMessageGroup)
 S3method(as.data.frame, SDMXConcepts)
 S3method(as.data.frame, SDMXCodelists)
\ No newline at end of file
diff --git a/R/Class-SDMXHeader.R b/R/Class-SDMXHeader.R
index 7cabc2e..94fde8c 100644
--- a/R/Class-SDMXHeader.R
+++ b/R/Class-SDMXHeader.R
@@ -32,19 +32,37 @@ setClass("SDMXHeader",
 		validity = function(object){
 			
 			# ID validation
-			if(is.null(object@ID)) return(FALSE)
-			if(attr(regexpr("[a-zA-Z0-9@-_@\\$]", object@ID),"match.length") == -1) return(FALSE)
-			
+			if(is.null(object@ID)){
+        message("Missing 'ID' in header")
+        return(FALSE)
+			}
+      if(attr(regexpr("[a-zA-Z0-9@-_@\\$]", object@ID),"match.length") == -1){
+        message("Invalid 'ID' in header")
+        return(FALSE)
+      }
+        
 			#Test/Truncated
-			if(!is.logical(object@Test)) return(FALSE)
-			if(!is.logical(object@Truncated)) return(FALSE)
-			
+			if(!is.logical(object@Test)){
+			  message("Invalid 'Test' value in header")
+        return(FALSE)
+			}
+			if(!is.logical(object@Truncated)){
+			  message("Invalid 'Truncated' value in header")
+        return(FALSE)
+			}
+        
 			#Dates/Time validation
-			if(is.na(object@Prepared)) return(FALSE)
+			if(is.na(object@Prepared)){
+			  message("Invalid 'Prepared' value in header")
+        return(FALSE)
+			}
 			
 			#Sender/Receiver validation
-			if(is.na(object@Sender$id) || nchar(object@Sender$id) == 0) return(FALSE)
-			if(nchar(object@Receiver$id) == 0) return(FALSE)
+			if(is.na(object@Sender$id) || nchar(object@Sender$id) == 0){
+			  message("Missing 'Sender' id in header") 
+        return(FALSE)
+			}
+      if(nchar(object@Receiver$id) == 0) return(FALSE)
 			
 			#TODO KeyFamilyRef validation
 			#TODO KeyFamilyAgency validation
diff --git a/R/Class-SDMXType.R b/R/Class-SDMXType.R
index 3ca183f..c542277 100644
--- a/R/Class-SDMXType.R
+++ b/R/Class-SDMXType.R
@@ -10,11 +10,12 @@ setClass("SDMXType",
 		validity = function(object){
 			type <- getType(object);
 			valid <- switch(type,
-                      "StructureType" = TRUE,
-                      "GenericDataType" = TRUE,
-                      "CompactDataType" = TRUE,
-                      "MessageGroupType" = TRUE,
-					FALSE
+                      "StructureType"     = TRUE,
+                      "GenericDataType"   = TRUE,
+                      "CompactDataType"   = TRUE,
+                      "UtilityDataType"   = TRUE,
+                      "MessageGroupType"  = TRUE,
+					            FALSE
 			);
 			if(valid == FALSE)
 				warning(paste("Unknown SDMXType ", type, sep=""));
diff --git a/R/Class-SDMXUtilityData.R b/R/Class-SDMXUtilityData.R
new file mode 100644
index 0000000..79cd37e
--- /dev/null
+++ b/R/Class-SDMXUtilityData.R
@@ -0,0 +1,13 @@
+# E.Blondel - 2015/01/13
+#=======================
+
+#SDMX UtilityData class
+setClass("SDMXUtilityData",
+         contains = "SDMX",
+         representation(),
+         prototype = list(),
+         validity = function(object){
+           #eventual validation rules
+           return(TRUE);
+         }
+)
diff --git a/R/SDMXUtilityData-methods.R b/R/SDMXUtilityData-methods.R
new file mode 100644
index 0000000..68faa66
--- /dev/null
+++ b/R/SDMXUtilityData-methods.R
@@ -0,0 +1,18 @@
+# E.Blondel - 2015/01/13
+#=======================
+
+SDMXUtilityData <- function(xmlObj){
+  new("SDMXUtilityData",
+      SDMX(xmlObj)
+  )  	
+}
+
+#methods
+#=======
+
+as.data.frame.SDMXUtilityData <- function(x, ...){
+  return(as.data.frame.SDMXCompactData(x))
+}
+
+setAs("SDMXUtilityData", "data.frame",
+      function(from) as.data.frame.SDMXUtilityData(from));
diff --git a/R/readSDMX.R b/R/readSDMX.R
index 4489bd5..2471c27 100644
--- a/R/readSDMX.R
+++ b/R/readSDMX.R
@@ -6,7 +6,7 @@
 readSDMX <- function(file, isURL = TRUE){
 	
 	#load data
-  	status <- 0
+  status <- 0
 	if(isURL == FALSE){
 		if(!file.exists(file))
 			stop("File ", file, "not found\n")
@@ -46,24 +46,25 @@ readSDMX <- function(file, isURL = TRUE){
 	
 	#encapsulate in S4 object
 	obj <- NULL
-  	if(status){ 
-  		type <- SDMXType(xmlObj)@type
-  		obj <- switch(type,
-  			"StructureType" = getSDMXStructureObject(xmlObj),
-  			"GenericDataType" = SDMXGenericData(xmlObj),
-  			"CompactDataType" = SDMXCompactData(xmlObj),
-  			"MessageGroupType" = SDMXMessageGroup(xmlObj),
-  			NULL
-			)	
-  
-    	if(is.null(obj)){
-      		if(type == "StructureType"){
-        		strTypeObj <- SDMXStructureType(xmlObj)
-        		type <- getStructureType(strTypeObj)
-      		}
-  			stop(paste("Unsupported SDMX Type '",type,"'",sep=""))
-  		}
-  	}
+	if(status){ 
+		type <- SDMXType(xmlObj)@type
+		obj <- switch(type,
+			"StructureType"     = getSDMXStructureObject(xmlObj),
+			"GenericDataType"   = SDMXGenericData(xmlObj),
+			"CompactDataType"   = SDMXCompactData(xmlObj),
+      "UtilityDataType"    = SDMXUtilityData(xmlObj),
+			"MessageGroupType"  = SDMXMessageGroup(xmlObj),
+			NULL
+		)	
+
+  	if(is.null(obj)){
+    		if(type == "StructureType"){
+      		strTypeObj <- SDMXStructureType(xmlObj)
+      		type <- getStructureType(strTypeObj)
+    		}
+			stop(paste("Unsupported SDMX Type '",type,"'",sep=""))
+		}
+  }
 	return(obj);
 }
 
diff --git a/man/SDMXType-class.Rd b/man/SDMXType-class.Rd
index 6bde63e..881909c 100644
--- a/man/SDMXType-class.Rd
+++ b/man/SDMXType-class.Rd
@@ -29,7 +29,9 @@ SDMXType(xmlObj)
 
 \author{ Emmanuel Blondel, \email{emmanuel.blondel1@gmail.com}}
 \note{
-At now, the following types have been implemented and tested: \code{GenericDataType}, \code{CompactDataType}, and {MessageGroupType}. At now the \code{MessageGroupType} was only modeled to allow reading OECD generic data which is provided. Other message types handled in \code{MessageGroup} document type are not yet supported.
+At now, the following types have been implemented and tested: \code{GenericDataType}, \code{CompactDataType}, \code{UtilityDataType} and {MessageGroupType}.
+
+The \code{MessageGroupType} was only modeled to allow reading OECD generic data which is provided. Other message types handled in \code{MessageGroup} document type are not yet supported.
 }
 
 \section{Warning }{this class is not useful in itself, but all SDMX non-abstract classes will encapsulate itas slot, when parsing an SDMX-ML document}
diff --git a/man/SDMXUtilityData-class.Rd b/man/SDMXUtilityData-class.Rd
new file mode 100644
index 0000000..501529a
--- /dev/null
+++ b/man/SDMXUtilityData-class.Rd
@@ -0,0 +1,23 @@
+\name{SDMXUtilityData-class}
+\docType{class}
+\alias{SDMXUtilityData-class}
+\alias{SDMXUtilityData}
+\alias{SDMXUtilityData-method}
+
+
+\title{Class "SDMXUtilityData"}
+\description{ A basic class to handle a SDMX-ML utility data set}
+\section{Objects from the Class}{are never to be generated; will be used by the \link{readSDMX} main parser function}
+
+
+\usage{
+SDMXUtilityData(xmlObj)
+}
+
+\arguments{
+\item{xmlObj}{an object of class "XMLInternalDocument"}
+}
+
+\author{ Emmanuel Blondel, \email{emmanuel.blondel1@gmail.com}}
+
+\keyword{classes}
\ No newline at end of file