diff --git a/opm/common/data/SimulationDataContainer.cpp b/opm/common/data/SimulationDataContainer.cpp
index 7901e1696..9cabf925b 100644
--- a/opm/common/data/SimulationDataContainer.cpp
+++ b/opm/common/data/SimulationDataContainer.cpp
@@ -17,7 +17,7 @@
   along with OPM.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-
+#include <opm/common/util/numeric/cmp.hpp>
 #include <opm/common/data/SimulationDataContainer.hpp>
 
 namespace Opm {
@@ -96,12 +96,51 @@ namespace Opm {
             return iter->second;
     }
 
+
     void SimulationDataContainer::registerFaceData( const std::string& name , size_t components , double initialValue) {
         if (!hasFaceData( name )) {
             m_face_data.insert( std::pair<std::string , std::vector<double>>( name , std::vector<double>(components * m_num_faces , initialValue )));
         }
     }
 
+    bool SimulationDataContainer::equal( const SimulationDataContainer& other ) const {
+        if ((m_num_cells != other.m_num_cells) ||
+            (m_num_phases != other.m_num_phases) ||
+            (m_num_faces != other.m_num_faces))
+            return false;
+
+        if ((m_face_data.size() != other.m_face_data.size()) ||
+            (m_cell_data.size() != other.m_cell_data.size()))
+            return false;
+
+        for (const auto& cell_data : m_cell_data) {
+            const auto key = cell_data.first;
+            const auto data = cell_data.second;
+
+            if (other.hasCellData( key )) {
+                const auto& other_data = other.getCellData( key );
+                if (!cmp::double_vector_equal( data , other_data ))
+                    return false;
+            } else
+                return false;
+        }
+
+        for (const auto& face_data : m_face_data) {
+            const auto key = face_data.first;
+            const auto data = face_data.second;
+
+            if (other.hasFaceData( key )) {
+                const auto& other_data = other.getFaceData( key );
+                if (!cmp::double_vector_equal( data , other_data ))
+                    return false;
+            } else
+                return false;
+        }
+
+        return true;
+    }
+
+
 
     /* This is very deprecated. */
     void SimulationDataContainer::addDefaultFields() {
diff --git a/opm/common/data/SimulationDataContainer.hpp b/opm/common/data/SimulationDataContainer.hpp
index da814dbaf..51f1fb396 100644
--- a/opm/common/data/SimulationDataContainer.hpp
+++ b/opm/common/data/SimulationDataContainer.hpp
@@ -27,6 +27,21 @@
 
 namespace Opm {
 
+
+    /// The SimulationDataContainer is a simple container to manage
+    /// simulation data. The container is instantiated with information
+    /// of how many cells, faces and phases are present in the
+    /// reservoirmodel. You can then add data to the container by using the
+    ///
+    ///   registerCellData()
+    ///   registerFaceData()
+    ///
+    /// functions. The container owns and manages the data, but
+    /// mutable references are returned with the getCellData() and
+    /// getFaceData() methods, and the content will typically be
+    /// modified by external scope.
+
+
     class SimulationDataContainer {
     public:
         SimulationDataContainer(size_t num_cells, size_t num_faces , size_t num_phases);
@@ -36,14 +51,19 @@ namespace Opm {
         size_t numCells() const;
 
         bool hasCellData( const std::string& name ) const;
+
         /// Will register a data vector of size numCells() *
         /// components.
         void registerCellData( const std::string& name , size_t components , double initialValue = 0.0 );
         std::vector<double>& getCellData( const std::string& name );
+        const std::vector<double>& getCellData( const std::string& name ) const;
 
         bool hasFaceData( const std::string& name ) const;
         void registerFaceData( const std::string& name , size_t components , double initialValue = 0.0 );
         std::vector<double>& getFaceData( const std::string& name );
+        const std::vector<double>& getFaceData( const std::string& name ) const;
+
+        bool equal(const SimulationDataContainer& other) const;
 
 
         /* Old deprecated */
diff --git a/tests/test_SimulationDataContainer.cpp b/tests/test_SimulationDataContainer.cpp
index 73baab131..3aaf803b1 100644
--- a/tests/test_SimulationDataContainer.cpp
+++ b/tests/test_SimulationDataContainer.cpp
@@ -113,3 +113,63 @@ BOOST_AUTO_TEST_CASE(TestRegisterCellData) {
 }
 
 
+BOOST_AUTO_TEST_CASE(Test_Equal) {
+    {
+        SimulationDataContainer container1(100 , 10 , 2);
+        SimulationDataContainer container2(100 , 10 , 2);
+        BOOST_CHECK( container1.equal( container2 ));
+    }
+
+    {
+        SimulationDataContainer container1(100 , 10 , 2);
+        SimulationDataContainer container2(100 , 10 , 1);
+        BOOST_CHECK( !container1.equal( container2 ));
+    }
+
+    {
+        SimulationDataContainer container1(100 , 10 , 2);
+        SimulationDataContainer container2(100 , 10 , 2);
+
+        container1.registerCellData( "FIELDX" , 1 , 123 );
+        BOOST_CHECK( !container1.equal( container2 ));
+        container2.registerCellData( "FIELDX" , 1 , 123 );
+        BOOST_CHECK( container1.equal( container2 ));
+
+        container1.registerFaceData( "FACEX" , 1 , 123 );
+        BOOST_CHECK( !container1.equal( container2 ));
+        container2.registerFaceData( "FACEX" , 1 , 123 );
+        BOOST_CHECK( container1.equal( container2 ));
+    }
+
+    {
+        SimulationDataContainer container1(100 , 10 , 2);
+        SimulationDataContainer container2(100 , 10 , 2);
+
+        container1.registerCellData( "FIELD1" , 1 , 123 );
+        container2.registerCellData( "FIELD2" , 1 , 123 );
+        BOOST_CHECK( !container1.equal( container2 ));
+    }
+
+    {
+        SimulationDataContainer container1(100 , 10 , 2);
+        SimulationDataContainer container2(100 , 10 , 2);
+
+        container1.registerFaceData( "FIELD1" , 1 , 123 );
+        container2.registerFaceData( "FIELD2" , 1 , 123 );
+        BOOST_CHECK( !container1.equal( container2 ));
+    }
+
+    {
+        SimulationDataContainer container1(100 , 10 , 2);
+        SimulationDataContainer container2(100 , 10 , 2);
+
+        container1.registerFaceData( "FIELD1" , 1 , 123 );
+        container2.registerFaceData( "FIELD1" , 1 , 123 );
+        BOOST_CHECK( container1.equal( container2 ));
+
+        std::vector<double>& f = container1.getFaceData( "FIELD1" );
+        f[0] *= 1.1;
+        BOOST_CHECK( !container1.equal( container2 ));
+    }
+}
+