Index: Ringtoets/Common/src/Ringtoets.Common.Data/AssessmentSection/AssessmentSectionExtensions.cs
===================================================================
diff -u -raef20c08e43fb95b037791c98c8e088352061c5e -r56b15dc5a50c0a36b0a8949a35f8dd20437e6cda
--- Ringtoets/Common/src/Ringtoets.Common.Data/AssessmentSection/AssessmentSectionExtensions.cs	(.../AssessmentSectionExtensions.cs)	(revision aef20c08e43fb95b037791c98c8e088352061c5e)
+++ Ringtoets/Common/src/Ringtoets.Common.Data/AssessmentSection/AssessmentSectionExtensions.cs	(.../AssessmentSectionExtensions.cs)	(revision 56b15dc5a50c0a36b0a8949a35f8dd20437e6cda)
@@ -24,6 +24,8 @@
 using System.ComponentModel;
 using System.Linq;
 using Core.Common.Base.Data;
+using Ringtoets.AssemblyTool.Data;
+using Ringtoets.Common.Data.AssemblyTool;
 using Ringtoets.Common.Data.Contribution;
 using Ringtoets.Common.Data.Hydraulics;
 
@@ -144,6 +146,56 @@
             return GetAssessmentLevelFromCalculations(hydraulicBoundaryLocation, calculations);
         }
 
+        /// <summary>
+        /// Gets the norm based on <see cref="AssessmentSectionCategoryType"/>.
+        /// </summary>
+        /// <param name="assessmentSection">The assessment section to get the norm from.</param>
+        /// <param name="categoryType">The category type to use while obtaining the norm.</param>
+        /// <returns>The norm corresponding to the provided category type.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="assessmentSection"/>
+        /// is <c>null</c>.</exception>
+        /// <exception cref="InvalidEnumArgumentException">Thrown when <paramref name="categoryType"/>
+        /// is an invalid <see cref="AssessmentSectionCategoryType"/>.</exception>
+        /// <exception cref="NotSupportedException">Thrown when <paramref name="categoryType"/>
+        /// is a valid but unsupported <see cref="AssessmentSectionCategoryType"/>.</exception>
+        public static double GetNorm(this IAssessmentSection assessmentSection,
+                                     AssessmentSectionCategoryType categoryType)
+        {
+            if (assessmentSection == null)
+            {
+                throw new ArgumentNullException(nameof(assessmentSection));
+            }
+
+            if (!Enum.IsDefined(typeof(AssessmentSectionCategoryType), categoryType))
+            {
+                throw new InvalidEnumArgumentException(nameof(categoryType),
+                                                       (int) categoryType,
+                                                       typeof(AssessmentSectionCategoryType));
+            }
+
+            IEnumerable<AssessmentSectionAssemblyCategory> categories = AssemblyToolCategoriesFactory.CreateAssessmentSectionAssemblyCategories(
+                assessmentSection.FailureMechanismContribution.SignalingNorm,
+                assessmentSection.FailureMechanismContribution.LowerLimitNorm);
+
+            switch (categoryType)
+            {
+                case AssessmentSectionCategoryType.FactorizedSignalingNorm:
+                    return categories.First(c => c.Group == AssessmentSectionAssemblyCategoryGroup.A)
+                                     .LowerBoundary;
+                case AssessmentSectionCategoryType.SignalingNorm:
+                    return categories.First(c => c.Group == AssessmentSectionAssemblyCategoryGroup.B)
+                                     .LowerBoundary;
+                case AssessmentSectionCategoryType.LowerLimitNorm:
+                    return categories.First(c => c.Group == AssessmentSectionAssemblyCategoryGroup.C)
+                                     .LowerBoundary;
+                case AssessmentSectionCategoryType.FactorizedLowerLimitNorm:
+                    return categories.First(c => c.Group == AssessmentSectionAssemblyCategoryGroup.D)
+                                     .LowerBoundary;
+                default:
+                    throw new NotSupportedException();
+            }
+        }
+
         private static RoundedDouble GetAssessmentLevelFromCalculations(HydraulicBoundaryLocation hydraulicBoundaryLocation, IEnumerable<HydraulicBoundaryLocationCalculation> calculations)
         {
             return calculations.FirstOrDefault(c => ReferenceEquals(c.HydraulicBoundaryLocation, hydraulicBoundaryLocation))?.Output?.Result