--- a/iro/validate.py	Sun Feb 19 17:49:23 2012 +0100
+++ b/iro/validate.py	Wed Feb 22 03:47:25 2012 +0100
@@ -31,10 +31,10 @@
     except TypeError:
         raise ValidateException(field=field)
 
-    if minv and ret < minv:
+    if minv is not None and ret < minv:
         raise ValidateException(field=field)
 
-    if maxv and ret > maxv:
+    if maxv is not None and ret > maxv:
         raise ValidateException(field=field)
 
     return ret