diff --git a/system/libraries/Session.php b/system/libraries/Session.php
index 4f08cf6..94efee5 100644
--- a/system/libraries/Session.php
+++ b/system/libraries/Session.php
@@ -99,7 +99,7 @@
 		 */
 		$expiration = $this->object->config->item('sess_expiration');
 		
-		if (ctype_digit($expiration))
+		if (is_numeric($expiration))
 		{
 			if ($expiration > 0)
 			{