diff --git a/htdocs/fourn/class/fournisseur.facture.class.php b/htdocs/fourn/class/fournisseur.facture.class.php
index 74949814577..b9bcaaa4a6c 100644
--- a/htdocs/fourn/class/fournisseur.facture.class.php
+++ b/htdocs/fourn/class/fournisseur.facture.class.php
@@ -46,8 +46,8 @@ class FactureFournisseur extends CommonInvoice
     var $product_ref;
     var $ref_supplier;
     var $socid;
-    //! 0=Standard invoice, 1=Replacement invoice, 2=Credit note invoice, 3=Deposit invoice, 4=Proforma invoice
-    var $type;
+    //Check constants for types
+    var $type = self::TYPE_STANDARD;
     //! 0=draft,
     //! 1=validated
     //! 2=classified paid partially (close_code='discount_vat','badcustomer') or completely (close_code=null),
@@ -87,6 +87,30 @@ class FactureFournisseur extends CommonInvoice
 
     var $extraparams=array();
 
+    /**
+     * Standard invoice
+     */
+    const TYPE_STANDARD = 0;
+
+    /**
+     * Replacement invoice
+     */
+    const TYPE_REPLACEMENT = 1;
+
+    /**
+     * Credit note invoice
+     */
+    const TYPE_CREDIT_NOTE = 2;
+
+    /**
+     * Deposit invoice
+     */
+    const TYPE_DEPOSIT = 3;
+
+    /**
+     * Proforma invoice
+     */
+    const TYPE_PROFORMA = 4;
 
     /**
 	 *	Constructor
@@ -338,7 +362,7 @@ class FactureFournisseur extends CommonInvoice
 
                 $this->ref_supplier			= $obj->ref_supplier;
                 $this->entity				= $obj->entity;
-                $this->type					= empty($obj->type)?0:$obj->type;
+                $this->type					= empty($obj->type)? self::TYPE_STANDARD:$obj->type;
                 $this->fk_soc				= $obj->fk_soc;
                 $this->datec				= $this->db->jdate($obj->datec);
                 $this->date					= $this->db->jdate($obj->datef);
diff --git a/htdocs/fourn/facture/document.php b/htdocs/fourn/facture/document.php
index 6c47f66ec7d..9a228f28802 100644
--- a/htdocs/fourn/facture/document.php
+++ b/htdocs/fourn/facture/document.php
@@ -125,13 +125,13 @@ if ($object->id > 0)
 	// Type
 	print '<tr><td>'.$langs->trans('Type').'</td><td colspan="4">';
 	print $object->getLibType();
-	if ($object->type == 1)
+	if ($object->type == FactureFournisseur::TYPE_REPLACEMENT)
 	{
 		$facreplaced=new FactureFournisseur($db);
 		$facreplaced->fetch($object->fk_facture_source);
 		print ' ('.$langs->transnoentities("ReplaceInvoice",$facreplaced->getNomUrl(1)).')';
 	}
-	if ($object->type == 2)
+	if ($object->type == FactureFournisseur::TYPE_CREDIT_NOTE)
 	{
 		$facusing=new FactureFournisseur($db);
 		$facusing->fetch($object->fk_facture_source);
diff --git a/htdocs/fourn/facture/fiche.php b/htdocs/fourn/facture/fiche.php
index 6d095e48b93..c6aab783018 100644
--- a/htdocs/fourn/facture/fiche.php
+++ b/htdocs/fourn/facture/fiche.php
@@ -1518,13 +1518,13 @@ else
         // Type
         print '<tr><td>'.$langs->trans('Type').'</td><td colspan="4">';
         print $object->getLibType();
-        if ($object->type == 1)
+        if ($object->type == FactureFournisseur::TYPE_REPLACEMENT)
         {
             $facreplaced=new FactureFournisseur($db);
             $facreplaced->fetch($object->fk_facture_source);
             print ' ('.$langs->transnoentities("ReplaceInvoice",$facreplaced->getNomUrl(1)).')';
         }
-        if ($object->type == 2)
+        if ($object->type == FactureFournisseur::TYPE_CREDIT_NOTE)
         {
             $facusing=new FactureFournisseur($db);
             $facusing->fetch($object->fk_facture_source);
@@ -2166,7 +2166,7 @@ else
 			}
 
  	 		// Reopen a standard paid invoice
-            if (($object->type == 0 || $object->type == 1) && ($object->statut == 2 || $object->statut == 3))				// A paid invoice (partially or completely)
+            if (($object->type == FactureFournisseur::TYPE_STANDARD || $object->type == FactureFournisseur::TYPE_REPLACEMENT) && ($object->statut == 2 || $object->statut == 3))				// A paid invoice (partially or completely)
             {
                 if (! $facidnext && $object->close_code != 'replaced')	// Not replaced by another invoice
                 {
diff --git a/htdocs/fourn/facture/note.php b/htdocs/fourn/facture/note.php
index e3963a5f738..12b754dea19 100644
--- a/htdocs/fourn/facture/note.php
+++ b/htdocs/fourn/facture/note.php
@@ -98,13 +98,13 @@ if ($object->id > 0)
 	// Type
 	print '<tr><td>'.$langs->trans('Type').'</td><td colspan="4">';
 	print $object->getLibType();
-	if ($object->type == 1)
+	if ($object->type == FactureFournisseur::TYPE_REPLACEMENT)
 	{
 		$facreplaced=new FactureFournisseur($db);
 		$facreplaced->fetch($object->fk_facture_source);
 		print ' ('.$langs->transnoentities("ReplaceInvoice",$facreplaced->getNomUrl(1)).')';
 	}
-	if ($object->type == 2)
+	if ($object->type == FactureFournisseur::TYPE_CREDIT_NOTE)
 	{
 		$facusing=new FactureFournisseur($db);
 		$facusing->fetch($object->fk_facture_source);