diff --git a/pisi-spec.rng b/pisi-spec.rng
index cde2c740..72a75019 100644
--- a/pisi-spec.rng
+++ b/pisi-spec.rng
@@ -513,6 +513,7 @@
                 <value>Tinker</value>
                 <value>UCAR-Unidata</value>
                 <value>UCL</value>
+                <value>UFL</value>
                 <value>VGBA</value>
                 <value>VIGRA</value>
                 <value>VOSTROM</value>