diff --git a/opm/core/transport/SinglePointUpwindTwoPhase.hpp b/opm/core/transport/SinglePointUpwindTwoPhase.hpp
index 87ea6c2f..92d87030 100644
--- a/opm/core/transport/SinglePointUpwindTwoPhase.hpp
+++ b/opm/core/transport/SinglePointUpwindTwoPhase.hpp
@@ -312,7 +312,9 @@ namespace Opm {
                          const std::vector<int>& hf_faces,
                          const std::vector<int>& nb_faces)
         {
-            assert (! p_faces.empty());
+	    if (p_faces.empty()) {
+		return;
+	    }
             assert (p_faces.size()  == hf_faces.size());
             assert (hf_faces.size() == nb_faces.size());