Existing B-Vent (Not Certified for Exterior Applications) which has been Installed Outdoors.
Download Director's Order FS-051-04 - Here (http://hvactechgroup.com/files/order/FS05204.pdf)
Download Director's Advisory FS-052-04 - Here (http://hvactechgroup.com/files/advisory/fs05204.pdf)
UPDATE 2014 - This Order has now been added to the B149.1-10. See Clause 8.17.3 and Annex N.