Index: Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Data/GrassCoverErosionOutwardsFailureMechanismExtensions.cs
===================================================================
diff -u -r5d0dfa9a8b6e98ede2791a93ed50d48ce6ada072 -r9e2f7186181853ea7cce697f737eeca21f82551f
--- Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Data/GrassCoverErosionOutwardsFailureMechanismExtensions.cs	(.../GrassCoverErosionOutwardsFailureMechanismExtensions.cs)	(revision 5d0dfa9a8b6e98ede2791a93ed50d48ce6ada072)
+++ Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Data/GrassCoverErosionOutwardsFailureMechanismExtensions.cs	(.../GrassCoverErosionOutwardsFailureMechanismExtensions.cs)	(revision 9e2f7186181853ea7cce697f737eeca21f82551f)
@@ -24,11 +24,10 @@
 using System.ComponentModel;
 using System.Linq;
 using Core.Common.Base.Data;
-using Ringtoets.AssemblyTool.Data;
-using Ringtoets.Common.Data.AssemblyTool;
 using Ringtoets.Common.Data.AssessmentSection;
 using Ringtoets.Common.Data.FailureMechanism;
 using Ringtoets.Common.Data.Hydraulics;
+using Ringtoets.Common.Util;
 
 namespace Ringtoets.GrassCoverErosionOutwards.Data
 {
@@ -128,44 +127,17 @@
                 throw new ArgumentNullException(nameof(failureMechanism));
             }
 
-            if (assessmentSection == null)
-            {
-                throw new ArgumentNullException(nameof(assessmentSection));
-            }
-
             if (!Enum.IsDefined(typeof(FailureMechanismCategoryType), categoryType))
             {
                 throw new InvalidEnumArgumentException(nameof(categoryType),
                                                        (int) categoryType,
                                                        typeof(FailureMechanismCategoryType));
             }
 
-            IEnumerable<FailureMechanismSectionAssemblyCategory> categories = AssemblyToolCategoriesFactory.CreateFailureMechanismSectionAssemblyCategories(
-                assessmentSection.FailureMechanismContribution.SignalingNorm,
-                assessmentSection.FailureMechanismContribution.LowerLimitNorm,
-                failureMechanism.Contribution,
-                failureMechanism.GeneralInput.N);
-
-            switch (categoryType)
-            {
-                case FailureMechanismCategoryType.MechanismSpecificFactorizedSignalingNorm:
-                    return categories.First(c => c.Group == FailureMechanismSectionAssemblyCategoryGroup.IIv)
-                                     .LowerBoundary;
-                case FailureMechanismCategoryType.MechanismSpecificSignalingNorm:
-                    return categories.First(c => c.Group == FailureMechanismSectionAssemblyCategoryGroup.IIIv)
-                                     .LowerBoundary;
-                case FailureMechanismCategoryType.MechanismSpecificLowerLimitNorm:
-                    return categories.First(c => c.Group == FailureMechanismSectionAssemblyCategoryGroup.IVv)
-                                     .LowerBoundary;
-                case FailureMechanismCategoryType.LowerLimitNorm:
-                    return categories.First(c => c.Group == FailureMechanismSectionAssemblyCategoryGroup.Vv)
-                                     .LowerBoundary;
-                case FailureMechanismCategoryType.FactorizedLowerLimitNorm:
-                    return categories.First(c => c.Group == FailureMechanismSectionAssemblyCategoryGroup.VIv)
-                                     .LowerBoundary;
-                default:
-                    throw new NotSupportedException();
-            }
+            return FailureMechanismNormHelper.GetNorm(assessmentSection,
+                                                      categoryType,
+                                                      failureMechanism.Contribution,
+                                                      failureMechanism.GeneralInput.N);
         }
 
         private static RoundedDouble GetAssessmentLevelFromCalculations(HydraulicBoundaryLocation hydraulicBoundaryLocation,