Index: Ringtoets/Piping/src/Ringtoets.Piping.Data/PipingInput.cs
===================================================================
diff -u -r2a7be595bf1251849a3c5f3be000f0e40f8fa874 -rbbfd376aee76613b471f70d2b1214d7e7b08fb1f
--- Ringtoets/Piping/src/Ringtoets.Piping.Data/PipingInput.cs	(.../PipingInput.cs)	(revision 2a7be595bf1251849a3c5f3be000f0e40f8fa874)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Data/PipingInput.cs	(.../PipingInput.cs)	(revision bbfd376aee76613b471f70d2b1214d7e7b08fb1f)
@@ -58,7 +58,10 @@
             {
                 Mean = 1.0
             };
-            ThicknessCoverageLayer = new LognormalDistribution();
+            ThicknessCoverageLayer = new LognormalDistribution
+            {
+                Mean = double.NaN
+            };
             SeepageLength = new LognormalDistribution();
             SeepageLength.StandardDeviation = SeepageLength.Mean * SeepageLengthStandardDeviationFraction;
             Diameter70 = new LognormalDistribution();