Index: Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Data/HeightStructuresInput.cs
===================================================================
diff -u -r6954e174ae758a8ef11bfdfce0da0aa135460fb6 -r88e625c7d47b0efd2a5ea8ea118e524c8f8e36ca
--- Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Data/HeightStructuresInput.cs	(.../HeightStructuresInput.cs)	(revision 6954e174ae758a8ef11bfdfce0da0aa135460fb6)
+++ Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Data/HeightStructuresInput.cs	(.../HeightStructuresInput.cs)	(revision 88e625c7d47b0efd2a5ea8ea118e524c8f8e36ca)
@@ -204,7 +204,7 @@
             set
             {
                 RoundedDouble newOrientationValue = value.ToPrecision(structureNormalOrientation.NumberOfDecimalPlaces);
-                if (newOrientationValue < 0 || newOrientationValue > 360)
+                if (double.IsNaN(newOrientationValue) || newOrientationValue < 0 || newOrientationValue > 360)
                 {
                     throw new ArgumentOutOfRangeException("value", RingtoetsCommonDataResources.Orientation_Value_needs_to_be_between_0_and_360);
                 }