diff --git a/BGL/include/CGAL/boost/graph/graph_traits_Triangulation_2.h b/BGL/include/CGAL/boost/graph/graph_traits_Triangulation_2.h
index ae1ecb7efab..8eb58e59a92 100644
--- a/BGL/include/CGAL/boost/graph/graph_traits_Triangulation_2.h
+++ b/BGL/include/CGAL/boost/graph/graph_traits_Triangulation_2.h
@@ -67,9 +67,10 @@ public:
     return *this;
   }
 
-  Face_handle face_handle() const
+  std::size_t hash() const
   {
-    return this->first;
+    std::hash<Face_handle> fct;
+    return fct(this->first);
   }
 
   bool operator==(const Edge& other) const
@@ -273,6 +274,12 @@ public:
         : first(fd), second(i)
       {}
       
+      std::size_t hash() const
+      {
+        std::hash<face_descriptor> fct;
+        return fct(first);
+      } 
+      
       bool operator==(const T2_halfedge_descriptor& other) const
       {
         return (first == other.first) && (second == other.second);
@@ -830,8 +837,16 @@ namespace std {
     std::size_t operator()(const CGAL::detail::Edge<T,EdgeBase>& e)
     {
       std::cerr << "Triangulation_2::Edge HashFct" << std::endl;
-      std::hash<typename CGAL::detail::Edge<T,EdgeBase>::Face_handle> fct;
-      return fct(e.face_handle());
+      return e.hash();
+    }
+  }; 
+
+  template < class Tr>
+  struct hash<CGAL::detail::T2_halfedge_descriptor<Tr> > {
+    std::size_t operator()(const CGAL::detail::T2_halfedge_descriptor<Tr>& e)
+    {
+      std::cerr << "Triangulation_2::halfedge_descriptor HashFct" << std::endl;
+      return e.hash();
     }
   };
 } // namespace std
diff --git a/Surface_mesh/examples/Surface_mesh/unordered_set.cpp b/Surface_mesh/examples/Surface_mesh/unordered_set.cpp
index b8a3f3b3a63..106782b81bd 100644
--- a/Surface_mesh/examples/Surface_mesh/unordered_set.cpp
+++ b/Surface_mesh/examples/Surface_mesh/unordered_set.cpp
@@ -49,7 +49,7 @@ int main()
 
     std::cout << "\ngraph_traits<Triangulation_2>::_descriptor"<< std::endl;
     Unordered<boost::graph_traits<Triangulation_2>::vertex_descriptor> U3;
-    //    Unordered<boost::graph_traits<Triangulation_2>::halfedge_descriptor> U4;
+    Unordered<boost::graph_traits<Triangulation_2>::halfedge_descriptor> U4;
     Unordered<boost::graph_traits<Triangulation_2>::edge_descriptor> U5;
     Unordered<boost::graph_traits<Triangulation_2>::face_descriptor> U6;
   }