Index: Riskeer/AssemblyTool/src/Riskeer.AssemblyTool.KernelWrapper/Calculators/Assembly/FailurePathAssemblyCalculatorException.cs
===================================================================
diff -u
--- Riskeer/AssemblyTool/src/Riskeer.AssemblyTool.KernelWrapper/Calculators/Assembly/FailurePathAssemblyCalculatorException.cs	(revision 0)
+++ Riskeer/AssemblyTool/src/Riskeer.AssemblyTool.KernelWrapper/Calculators/Assembly/FailurePathAssemblyCalculatorException.cs	(revision d11dfd7f052519df5b176d066a2d0dad3567720b)
@@ -0,0 +1,68 @@
+// Copyright (C) Stichting Deltares 2021. All rights reserved.
+//
+// This file is part of Riskeer.
+//
+// Riskeer is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+//
+// All names, logos, and references to "Deltares" are registered trademarks of
+// Stichting Deltares and remain full property of Stichting Deltares at all times.
+// All rights reserved.
+
+using System;
+using System.Runtime.Serialization;
+
+namespace Riskeer.AssemblyTool.KernelWrapper.Calculators.Assembly
+{
+    /// <summary>
+    /// Exception thrown when an error occurs while performing a failure path assembly.
+    /// </summary>
+    [Serializable]
+    public class FailurePathAssemblyCalculatorException : Exception
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FailurePathAssemblyCalculatorException"/> class.
+        /// </summary>
+        public FailurePathAssemblyCalculatorException() {}
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FailurePathAssemblyCalculatorException"/> class 
+        /// with a specified error message.
+        /// </summary>
+        /// <param name="message">The message that describes the error.</param>
+        public FailurePathAssemblyCalculatorException(string message)
+            : base(message) {}
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FailurePathAssemblyCalculatorException"/> class with a specified error message 
+        /// and a reference to the inner exception that is the cause of this exception.
+        /// </summary>
+        /// <param name="message">The error message that explains the reason for the exception.</param>
+        /// <param name="innerException">The exception that is the cause of the current exception,
+        /// or <c>null</c> if no inner exception is specified.</param>
+        public FailurePathAssemblyCalculatorException(string message, Exception innerException) : base(message, innerException) {}
+
+        /// <summary>
+        /// Initializes a new instance of <see cref="FailurePathAssemblyCalculatorException"/> with
+        /// serialized data.</summary>
+        /// <param name="info">The <see cref="SerializationInfo"/> that holds the serialized
+        /// object data about the exception being thrown.</param>
+        /// <param name="context">The <see cref="StreamingContext"/> that contains contextual
+        /// information about the source or destination.</param>
+        /// <exception cref="ArgumentNullException">The <paramref name="info"/> parameter is
+        /// <c>null</c>.</exception>
+        /// <exception cref="SerializationException">The class name is <c>null</c> or
+        /// <see cref="Exception.HResult" /> is zero (0).</exception>
+        protected FailurePathAssemblyCalculatorException(SerializationInfo info, StreamingContext context) : base(info, context) {}
+    }
+}
\ No newline at end of file
Index: Riskeer/AssemblyTool/src/Riskeer.AssemblyTool.KernelWrapper/Calculators/Assembly/IFailurePathAssemblyCalculator.cs
===================================================================
diff -u -rf85d794366242406196101d825856b6e793523b4 -rd11dfd7f052519df5b176d066a2d0dad3567720b
--- Riskeer/AssemblyTool/src/Riskeer.AssemblyTool.KernelWrapper/Calculators/Assembly/IFailurePathAssemblyCalculator.cs	(.../IFailurePathAssemblyCalculator.cs)	(revision f85d794366242406196101d825856b6e793523b4)
+++ Riskeer/AssemblyTool/src/Riskeer.AssemblyTool.KernelWrapper/Calculators/Assembly/IFailurePathAssemblyCalculator.cs	(.../IFailurePathAssemblyCalculator.cs)	(revision d11dfd7f052519df5b176d066a2d0dad3567720b)
@@ -19,6 +19,7 @@
 // Stichting Deltares and remain full property of Stichting Deltares at all times.
 // All rights reserved.
 
+using System;
 using System.Collections.Generic;
 using Riskeer.AssemblyTool.Data;
 
@@ -29,6 +30,14 @@
     /// </summary>
     public interface IFailurePathAssemblyCalculator
     {
+        /// <summary>
+        /// Assembles a failure path based on the input.
+        /// </summary>
+        /// <param name="failurePathN">The length effect factor 'N' for an entire failure path.</param>
+        /// <param name="sectionAssemblyResults">A collection of <see cref="FailureMechanismSectionAssemblyResult"/>.</param>
+        /// <returns>A probability representing the assembly result of the failure path.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="sectionAssemblyResults"/> is <c>null</c>.</exception>
+        /// <exception cref="FailurePathAssemblyCalculatorException">Thrown when an error occurs while assembling.</exception>
         double Assemble(double failurePathN, IEnumerable<FailureMechanismSectionAssemblyResult> sectionAssemblyResults);
     }
 }
\ No newline at end of file
Index: Riskeer/AssemblyTool/test/Riskeer.AssemblyTool.KernelWrapper.Test/Calculators/Assembly/FailurePathAssemblyCalculatorExceptionTest.cs
===================================================================
diff -u
--- Riskeer/AssemblyTool/test/Riskeer.AssemblyTool.KernelWrapper.Test/Calculators/Assembly/FailurePathAssemblyCalculatorExceptionTest.cs	(revision 0)
+++ Riskeer/AssemblyTool/test/Riskeer.AssemblyTool.KernelWrapper.Test/Calculators/Assembly/FailurePathAssemblyCalculatorExceptionTest.cs	(revision d11dfd7f052519df5b176d066a2d0dad3567720b)
@@ -0,0 +1,32 @@
+// Copyright (C) Stichting Deltares 2021. All rights reserved.
+//
+// This file is part of Riskeer.
+//
+// Riskeer is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+//
+// All names, logos, and references to "Deltares" are registered trademarks of
+// Stichting Deltares and remain full property of Stichting Deltares at all times.
+// All rights reserved.
+
+using System;
+using Core.Common.TestUtil;
+using NUnit.Framework;
+using Riskeer.AssemblyTool.KernelWrapper.Calculators.Assembly;
+
+namespace Riskeer.AssemblyTool.KernelWrapper.Test.Calculators.Assembly
+{
+    [TestFixture]
+    public class FailurePathAssemblyCalculatorExceptionTest :
+        CustomExceptionDesignGuidelinesTestFixture<FailurePathAssemblyCalculatorException, Exception> {}
+}
\ No newline at end of file
Index: Riskeer/AssemblyTool/test/Riskeer.AssemblyTool.KernelWrapper.Test/Calculators/Assembly/FailurePathAssemblyCalculatorTest.cs
===================================================================
diff -u -refffeffbef15761667281ffcf6b2cb48280e4a29 -rd11dfd7f052519df5b176d066a2d0dad3567720b
--- Riskeer/AssemblyTool/test/Riskeer.AssemblyTool.KernelWrapper.Test/Calculators/Assembly/FailurePathAssemblyCalculatorTest.cs	(.../FailurePathAssemblyCalculatorTest.cs)	(revision efffeffbef15761667281ffcf6b2cb48280e4a29)
+++ Riskeer/AssemblyTool/test/Riskeer.AssemblyTool.KernelWrapper.Test/Calculators/Assembly/FailurePathAssemblyCalculatorTest.cs	(.../FailurePathAssemblyCalculatorTest.cs)	(revision d11dfd7f052519df5b176d066a2d0dad3567720b)
@@ -116,6 +116,7 @@
 
                 // Assert
                 Assert.AreEqual(failurePathN, kernel.LenghtEffectFactor);
+                Assert.IsFalse(kernel.PartialAssembly);
                 AssertFailurePathSectionAssemblyResults(sectionAssemblyResults, kernel.FailurePathSectionAssemblyResults);
             }
         }