Index: Ringtoets/Piping/src/Ringtoets.Piping.Service/PipingCalculationService.cs
===================================================================
diff -u -r65ea41e01d41d77df1e30bf8e850a44de46e870f -r89488cc05b12fd5720cd28a4eeeb001dc9b1456d
--- Ringtoets/Piping/src/Ringtoets.Piping.Service/PipingCalculationService.cs	(.../PipingCalculationService.cs)	(revision 65ea41e01d41d77df1e30bf8e850a44de46e870f)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Service/PipingCalculationService.cs	(.../PipingCalculationService.cs)	(revision 89488cc05b12fd5720cd28a4eeeb001dc9b1456d)
@@ -37,14 +37,18 @@
     public static class PipingCalculationService
     {
         private static readonly ILog pipingCalculationLogger = LogManager.GetLogger(typeof(PipingCalculation));
+
+        /// <summary>
+        /// The <see cref="IPipingSubCalculatorFactory"/> to use for creating piping sub calculators.
+        /// </summary>
         public static IPipingSubCalculatorFactory SubCalculatorFactory = new PipingSubCalculatorFactory();
 
         /// <summary>
         /// Performs validation over the values on the given <paramref name="calculation"/>. Error and status information is logged during
         /// the execution of the operation.
         /// </summary>
         /// <param name="calculation">The <see cref="PipingCalculation"/> for which to validate the values.</param>
-        /// <returns>False if <paramref name="calculation"/> contains validation errors; True otherwise.</returns>
+        /// <returns><c>False</c> if <paramref name="calculation"/> contains validation errors; <c>True</c> otherwise.</returns>
         public static bool Validate(PipingCalculation calculation)
         {
             pipingCalculationLogger.Info(String.Format(Resources.Validation_Subject_0_started_Time_1_,
@@ -104,7 +108,7 @@
         /// <summary>
         /// Calculates the thickness of the coverage layer based on the values of the <see cref="PipingInput"/>.
         /// </summary>
-        /// <returns>The thickness of the coverage layer, or -1 if the thickness could not be calculated.</returns>
+        /// <returns>The thickness of the coverage layer, or <c>NaN</c> if the thickness could not be calculated.</returns>
         public static double CalculateThicknessCoverageLayer(PipingInput input)
         {
             try
@@ -147,6 +151,10 @@
                 );
         }
 
+        /// <summary>
+        /// Calculates the piezometric head at the exit point based on the values of the <see cref="PipingInput"/>.
+        /// </summary>
+        /// <returns>The piezometric head at the exit point.</returns>
         public static double CalculatePiezometricHeadAtExit(PipingInput input)
         {
             return new PipingCalculator(CreateInputFromData(input), SubCalculatorFactory).CalculatePiezometricHeadAtExit();