Index: Ringtoets/Piping/src/Ringtoets.Piping.Forms/PropertyClasses/PipingFailureMechanismProperties.cs
===================================================================
diff -u -r2a81f01756e227d5ce93717b21b87e8a5cd5fcbb -rbc771ec1743c16b85b12a768f1fa10431be9948d
--- Ringtoets/Piping/src/Ringtoets.Piping.Forms/PropertyClasses/PipingFailureMechanismProperties.cs	(.../PipingFailureMechanismProperties.cs)	(revision 2a81f01756e227d5ce93717b21b87e8a5cd5fcbb)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Forms/PropertyClasses/PipingFailureMechanismProperties.cs	(.../PipingFailureMechanismProperties.cs)	(revision bc771ec1743c16b85b12a768f1fa10431be9948d)
@@ -26,6 +26,7 @@
 using Core.Common.Gui.Attributes;
 using Core.Common.Gui.PropertyBag;
 using Core.Common.Util.Attributes;
+using Ringtoets.Common.Data.AssessmentSection;
 using Ringtoets.Common.Data.Probability;
 using Ringtoets.Common.Forms.PropertyClasses;
 using Ringtoets.Piping.Data;
@@ -60,28 +61,37 @@
         private const int meanDiameter70PropertyIndex = 19;
         private const int sellMeijerReductionFactorPropertyIndex = 20;
 
+        private readonly IAssessmentSection assessmentSection;
         private readonly IFailureMechanismPropertyChangeHandler<PipingFailureMechanism> propertyChangeHandler;
 
         /// <summary>
         /// Creates a new instance of <see cref="PipingFailureMechanismProperties"/>.
         /// </summary>
         /// <param name="data">The instance to show the properties of.</param>
+        /// <param name="assessmentSection">The assessment section the data belongs to.</param>
         /// <param name="handler">Handler responsible for handling effects of a property change.</param>
-        /// <exception cref="ArgumentNullException">Thrown when any input parameter is <c>null</c>.</exception>
+        /// <exception cref="ArgumentNullException">Thrown when any parameter is <c>null</c>.</exception>
         public PipingFailureMechanismProperties(PipingFailureMechanism data,
+                                                IAssessmentSection assessmentSection,
                                                 IFailureMechanismPropertyChangeHandler<PipingFailureMechanism> handler)
         {
             if (data == null)
             {
                 throw new ArgumentNullException(nameof(data));
             }
 
+            if (assessmentSection == null)
+            {
+                throw new ArgumentNullException(nameof(assessmentSection));
+            }
+
             if (handler == null)
             {
                 throw new ArgumentNullException(nameof(handler));
             }
 
             Data = data;
+            this.assessmentSection = assessmentSection;
             propertyChangeHandler = handler;
         }
 
@@ -277,7 +287,7 @@
         {
             get
             {
-                return new RoundedDouble(2, data.PipingProbabilityAssessmentInput.SectionLength);
+                return new RoundedDouble(2, assessmentSection.ReferenceLine.Length);
             }
         }
 
@@ -291,7 +301,7 @@
             get
             {
                 PipingProbabilityAssessmentInput probabilityAssessmentInput = data.PipingProbabilityAssessmentInput;
-                return new RoundedDouble(2, probabilityAssessmentInput.GetN(probabilityAssessmentInput.SectionLength));
+                return new RoundedDouble(2, probabilityAssessmentInput.GetN(assessmentSection.ReferenceLine.Length));
             }
         }
 
Index: Ringtoets/Piping/src/Ringtoets.Piping.Plugin/PipingPlugin.cs
===================================================================
diff -u -racd375042fb10c2774f972b9dfe8a2cf366de1f2 -rbc771ec1743c16b85b12a768f1fa10431be9948d
--- Ringtoets/Piping/src/Ringtoets.Piping.Plugin/PipingPlugin.cs	(.../PipingPlugin.cs)	(revision acd375042fb10c2774f972b9dfe8a2cf366de1f2)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Plugin/PipingPlugin.cs	(.../PipingPlugin.cs)	(revision bc771ec1743c16b85b12a768f1fa10431be9948d)
@@ -75,7 +75,8 @@
         {
             yield return new PropertyInfo<PipingFailureMechanismContext, PipingFailureMechanismProperties>
             {
-                CreateInstance = context => new PipingFailureMechanismProperties(context.WrappedData, new FailureMechanismPropertyChangeHandler<PipingFailureMechanism>())
+                CreateInstance = context => new PipingFailureMechanismProperties(context.WrappedData, context.Parent,
+                                                                                 new FailureMechanismPropertyChangeHandler<PipingFailureMechanism>())
             };
             yield return new PropertyInfo<PipingInputContext, PipingInputContextProperties>
             {
Index: Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/PropertyClasses/PipingFailureMechanismPropertiesTest.cs
===================================================================
diff -u -r2a81f01756e227d5ce93717b21b87e8a5cd5fcbb -rbc771ec1743c16b85b12a768f1fa10431be9948d
--- Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/PropertyClasses/PipingFailureMechanismPropertiesTest.cs	(.../PipingFailureMechanismPropertiesTest.cs)	(revision 2a81f01756e227d5ce93717b21b87e8a5cd5fcbb)
+++ Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/PropertyClasses/PipingFailureMechanismPropertiesTest.cs	(.../PipingFailureMechanismPropertiesTest.cs)	(revision bc771ec1743c16b85b12a768f1fa10431be9948d)
@@ -27,6 +27,7 @@
 using Core.Common.TestUtil;
 using NUnit.Framework;
 using Rhino.Mocks;
+using Ringtoets.Common.Data.AssessmentSection;
 using Ringtoets.Common.Data.Probability;
 using Ringtoets.Common.Data.TestUtil;
 using Ringtoets.Common.Forms.PropertyClasses;
@@ -61,15 +62,16 @@
         private const int sellMeijerReductionFactorPropertyIndex = 19;
 
         [Test]
-        public void Constructor_DataIsNull_ThrowArgumentNullException()
+        public void Constructor_DataNull_ThrowArgumentNullException()
         {
             // Setup
             var mocks = new MockRepository();
+            var assessmentSection = mocks.Stub<IAssessmentSection>();
             var handler = mocks.Stub<IFailureMechanismPropertyChangeHandler<PipingFailureMechanism>>();
             mocks.ReplayAll();
 
             // Call
-            TestDelegate test = () => new PipingFailureMechanismProperties(null, handler);
+            TestDelegate test = () => new PipingFailureMechanismProperties(null, assessmentSection, handler);
 
             // Assert
             string paramName = Assert.Throws<ArgumentNullException>(test).ParamName;
@@ -78,16 +80,20 @@
         }
 
         [Test]
-        public void Constructor_ChangeHandlerIsNull_ThrowArgumentNullException()
+        public void Constructor_ChangeHandlerNull_ThrowArgumentNullException()
         {
+            // Setup
+            var mocks = new MockRepository();
+            var assessmentSection = mocks.Stub<IAssessmentSection>();
+            mocks.ReplayAll();
+
             // Call
-            TestDelegate test = () => new PipingFailureMechanismProperties(
-                new PipingFailureMechanism(),
-                null);
+            TestDelegate test = () => new PipingFailureMechanismProperties(new PipingFailureMechanism(), assessmentSection, null);
 
             // Assert
             string paramName = Assert.Throws<ArgumentNullException>(test).ParamName;
             Assert.AreEqual("handler", paramName);
+            mocks.VerifyAll();
         }
 
         [Test]
@@ -101,14 +107,13 @@
                 IsRelevant = isRelevant
             };
 
-            var mockRepository = new MockRepository();
-            var handler = mockRepository.Stub<IFailureMechanismPropertyChangeHandler<PipingFailureMechanism>>();
-            mockRepository.ReplayAll();
+            var mocks = new MockRepository();
+            var assessmentSection = mocks.Stub<IAssessmentSection>();
+            var handler = mocks.Stub<IFailureMechanismPropertyChangeHandler<PipingFailureMechanism>>();
+            mocks.ReplayAll();
 
             // Call
-            var properties = new PipingFailureMechanismProperties(
-                failureMechanism,
-                handler);
+            var properties = new PipingFailureMechanismProperties(failureMechanism, assessmentSection, handler);
 
             // Assert
             Assert.IsInstanceOf<ObjectProperties<PipingFailureMechanism>>(properties);
@@ -139,15 +144,14 @@
             Assert.AreEqual(probabilityAssessmentInput.A, properties.A);
             Assert.AreEqual(probabilityAssessmentInput.B, properties.B);
             Assert.AreEqual(2, properties.N.NumberOfDecimalPlaces);
-            Assert.AreEqual(probabilityAssessmentInput.GetN(
-                                probabilityAssessmentInput.SectionLength),
+            Assert.AreEqual(probabilityAssessmentInput.GetN(assessmentSection.ReferenceLine.Length),
                             properties.N,
                             properties.N.GetAccuracy());
             Assert.AreEqual(2, properties.SectionLength.NumberOfDecimalPlaces);
-            Assert.AreEqual(probabilityAssessmentInput.SectionLength,
+            Assert.AreEqual(assessmentSection.ReferenceLine.Length,
                             properties.SectionLength,
                             properties.SectionLength.GetAccuracy());
-            mockRepository.VerifyAll();
+            mocks.VerifyAll();
         }
 
         [Test]
@@ -159,15 +163,13 @@
                 IsRelevant = true
             };
 
-            var mockRepository = new MockRepository();
-            var handler = mockRepository.Stub<IFailureMechanismPropertyChangeHandler<PipingFailureMechanism>>();
+            var mocks = new MockRepository();
+            var assessmentSection = mocks.Stub<IAssessmentSection>();
+            var handler = mocks.Stub<IFailureMechanismPropertyChangeHandler<PipingFailureMechanism>>();
+            mocks.ReplayAll();
 
-            mockRepository.ReplayAll();
-
             // Call
-            var properties = new PipingFailureMechanismProperties(
-                failureMechanism,
-                handler);
+            var properties = new PipingFailureMechanismProperties(failureMechanism, assessmentSection, handler);
 
             // Assert
             PropertyDescriptorCollection dynamicProperties = PropertiesTestHelper.GetAllVisiblePropertyDescriptors(properties);
@@ -317,7 +319,7 @@
                                                                             "Reductiefactor Sellmeijer.",
                                                                             true);
 
-            mockRepository.VerifyAll();
+            mocks.VerifyAll();
         }
 
         [Test]
@@ -329,15 +331,13 @@
                 IsRelevant = false
             };
 
-            var mockRepository = new MockRepository();
-            var handler = mockRepository.Stub<IFailureMechanismPropertyChangeHandler<PipingFailureMechanism>>();
+            var mocks = new MockRepository();
+            var assessmentSection = mocks.Stub<IAssessmentSection>();
+            var handler = mocks.Stub<IFailureMechanismPropertyChangeHandler<PipingFailureMechanism>>();
+            mocks.ReplayAll();
 
-            mockRepository.ReplayAll();
-
             // Call
-            var properties = new PipingFailureMechanismProperties(
-                failureMechanism,
-                handler);
+            var properties = new PipingFailureMechanismProperties(failureMechanism, assessmentSection, handler);
 
             // Assert
             PropertyDescriptorCollection dynamicProperties = PropertiesTestHelper.GetAllVisiblePropertyDescriptors(properties);
@@ -373,7 +373,7 @@
                                                                             "Geeft aan of dit toetsspoor relevant is of niet.",
                                                                             true);
 
-            mockRepository.VerifyAll();
+            mocks.VerifyAll();
         }
 
         [Test]
@@ -386,16 +386,15 @@
         {
             // Setup
             var mocks = new MockRepository();
-            var observer = mocks.StrictMock<IObserver>();
+            var assessmentSection = mocks.Stub<IAssessmentSection>();
             var changeHandler = mocks.Stub<IFailureMechanismPropertyChangeHandler<PipingFailureMechanism>>();
+            var observer = mocks.StrictMock<IObserver>();
             mocks.ReplayAll();
 
             var failureMechanism = new PipingFailureMechanism();
             failureMechanism.Attach(observer);
 
-            var properties = new PipingFailureMechanismProperties(
-                failureMechanism,
-                changeHandler);
+            var properties = new PipingFailureMechanismProperties(failureMechanism, assessmentSection, changeHandler);
 
             // Call
             TestDelegate call = () => properties.A = value;
@@ -416,17 +415,16 @@
         {
             // Setup
             var mocks = new MockRepository();
+            var assessmentSection = mocks.Stub<IAssessmentSection>();
+            var changeHandler = mocks.Stub<IFailureMechanismPropertyChangeHandler<PipingFailureMechanism>>();
             var observer = mocks.StrictMock<IObserver>();
             observer.Expect(o => o.UpdateObserver());
-            var changeHandler = mocks.Stub<IFailureMechanismPropertyChangeHandler<PipingFailureMechanism>>();
             mocks.ReplayAll();
 
             var failureMechanism = new PipingFailureMechanism();
             failureMechanism.Attach(observer);
 
-            var properties = new PipingFailureMechanismProperties(
-                failureMechanism,
-                changeHandler);
+            var properties = new PipingFailureMechanismProperties(failureMechanism, assessmentSection, changeHandler);
 
             // Call
             properties.A = value;
@@ -450,19 +448,19 @@
             var roundedValue = (RoundedDouble) value;
 
             var mocks = new MockRepository();
+            var assessmentSection = mocks.Stub<IAssessmentSection>();
             var observable = mocks.StrictMock<IObservable>();
+            mocks.ReplayAll();
+
             var changeHandler = new FailureMechanismSetPropertyValueAfterConfirmationParameterTester<PipingFailureMechanism, RoundedDouble>(
                 failureMechanism,
                 roundedValue,
                 new[]
                 {
                     observable
                 });
-            mocks.ReplayAll();
 
-            var properties = new PipingFailureMechanismProperties(
-                failureMechanism,
-                changeHandler);
+            var properties = new PipingFailureMechanismProperties(failureMechanism, assessmentSection, changeHandler);
 
             // Call            
             TestDelegate test = () => properties.WaterVolumetricWeight = roundedValue;
@@ -486,8 +484,10 @@
             var roundedValue = (RoundedDouble) value;
 
             var mocks = new MockRepository();
+            var assessmentSection = mocks.Stub<IAssessmentSection>();
             var observable = mocks.StrictMock<IObservable>();
             observable.Expect(o => o.NotifyObservers());
+            mocks.ReplayAll();
 
             var changeHandler = new FailureMechanismSetPropertyValueAfterConfirmationParameterTester<PipingFailureMechanism, RoundedDouble>(
                 failureMechanism,
@@ -497,12 +497,8 @@
                     observable
                 });
 
-            mocks.ReplayAll();
+            var properties = new PipingFailureMechanismProperties(failureMechanism, assessmentSection, changeHandler);
 
-            var properties = new PipingFailureMechanismProperties(
-                failureMechanism,
-                changeHandler);
-
             // Call            
             properties.WaterVolumetricWeight = roundedValue;
 
@@ -520,16 +516,15 @@
         {
             // Setup
             var mocks = new MockRepository();
+            var assessmentSection = mocks.Stub<IAssessmentSection>();
             var changeHandler = mocks.Stub<IFailureMechanismPropertyChangeHandler<PipingFailureMechanism>>();
             mocks.ReplayAll();
 
             var pipingFailureMechanism = new PipingFailureMechanism
             {
                 IsRelevant = isRelevant
             };
-            var properties = new PipingFailureMechanismProperties(
-                pipingFailureMechanism,
-                changeHandler);
+            var properties = new PipingFailureMechanismProperties(pipingFailureMechanism, assessmentSection, changeHandler);
 
             // Assert
             Assert.IsTrue(properties.DynamicVisibleValidationMethod(nameof(properties.Name)));