Index: Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Data/HeightStructuresInput.cs
===================================================================
diff -u -r88e625c7d47b0efd2a5ea8ea118e524c8f8e36ca -rd5daf17a6ed66dddef590069e4db152f6250c2c3
--- Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Data/HeightStructuresInput.cs	(.../HeightStructuresInput.cs)	(revision 88e625c7d47b0efd2a5ea8ea118e524c8f8e36ca)
+++ Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Data/HeightStructuresInput.cs	(.../HeightStructuresInput.cs)	(revision d5daf17a6ed66dddef590069e4db152f6250c2c3)
@@ -203,12 +203,17 @@
             }
             set
             {
+                if (double.IsNaN(value))
+                {
+                    structureNormalOrientation = (RoundedDouble) double.NaN;
+                    return;
+                }
+
                 RoundedDouble newOrientationValue = value.ToPrecision(structureNormalOrientation.NumberOfDecimalPlaces);
-                if (double.IsNaN(newOrientationValue) || newOrientationValue < 0 || newOrientationValue > 360)
+                if (newOrientationValue < 0 || newOrientationValue > 360)
                 {
                     throw new ArgumentOutOfRangeException("value", RingtoetsCommonDataResources.Orientation_Value_needs_to_be_between_0_and_360);
                 }
-
                 structureNormalOrientation = newOrientationValue;
             }
         }