diff --git a/src/app/formulaire/definition/form-prebarrage.ts b/src/app/formulaire/definition/form-prebarrage.ts
index 143a6991de916dacb0dad8b7fb48b2772e4c36a2..ebe3ea8ffdda5ae94f096a9dd6c0a3ceefa1089f 100644
--- a/src/app/formulaire/definition/form-prebarrage.ts
+++ b/src/app/formulaire/definition/form-prebarrage.ts
@@ -10,6 +10,7 @@ import { CalculatorResults } from "../../results/calculator-results";
 import { PrebarrageResults } from "../../results/prebarrage-results";
 import { NgParameter } from "../elements/ngparam";
 import { longestVarParam } from "../../util";
+import { FormulaireNode } from "../elements/formulaire-node";
 
 /**
  * Formulaire pour les PréBarrage
@@ -324,7 +325,7 @@ export class FormulairePrebarrage extends FormulaireFixedVar {
     /**
      * Set value of all single parameters to undefined, except for the given parameter ids
      */
-    public emptyFields(except: string[] = [ "Cd0", "CdWS", "CdGR", "CdGRS", "CdCunge", "CdWR", "CdO", "CdT", "CdWSL" ]) {
+    public emptyFields(except: string[] = FormulaireNode.NeverEmptyFields) {
         // save current calculated param, as setting value on a CALC param will
         // change its mode and choose another calculated param by default
         const paramCalculated = this.currentNub.calculatedParam;
diff --git a/src/app/formulaire/elements/formulaire-node.ts b/src/app/formulaire/elements/formulaire-node.ts
index 7731dfd43029def02f02d3299a9508ad350c653e..dca5bbe5d21d768c66b9692b81b385801b1bad14 100644
--- a/src/app/formulaire/elements/formulaire-node.ts
+++ b/src/app/formulaire/elements/formulaire-node.ts
@@ -9,6 +9,11 @@ import { NgParameter } from "./ngparam";
  */
 export abstract class FormulaireNode implements IObservable {
 
+    /**
+     * fields in fieldset that must not be empty due to enableEmptyFieldsOnFormInit option
+     */
+    protected static NeverEmptyFields = ["Cd0", "CdWS", "CdGR", "CdGRS", "CdCunge", "CdWR", "CdO", "CdT", "CdWSL"];
+
     /** aide en ligne */
     protected _helpLink: string;
 
@@ -143,7 +148,7 @@ export abstract class FormulaireNode implements IObservable {
     /**
      * Set value of all single parameters to undefined, except for the given parameter ids
      */
-    public emptyFields(except: string[] = [ "Cd0", "CdWS", "CdGR", "CdGRS", "CdCunge", "CdWR", "CdO", "CdT", "CdWSL" ]) {
+    public emptyFields(except: string[] = FormulaireNode.NeverEmptyFields) {
         // save current calculated param, as setting value on a CALC param will
         // change its mode and choose another calculated param by default
         let calcP: NgParameter;