3DJH
FIGURE 29
COMMON VENTING USING TILE-LINED INTERIOR MASONRY
CHIMNEY AND COMBINED VENT CONNECTOR
G23
OTHER
APPLIANCE
VENT
CONNECTOR
(Double-walled,
single-walled, or
insulated single-
walled pipe)
MINI. LENGTH = AS SHORT
AS PRACTICAL.
INTERIOR
TILE-LINED MASONRY
CHIMNEY
NOTE - CHIMNEY MUST BE
PROPERLY SIZED PER THE PRO-
VIDED VENTING TABLES OR LINED
WITH LISTED METAL LINING SYSTEM.
PERMANENTLY SEALED
FIREPLACE OPENING
A chimney with one or more sides exposed to the outside
of the structure is considered to be an exterior chimney. A
Type B or listed chimney lining system passing through an
unused masonry chimney flue is not considered to be ex-
posed to the outdoors.
Masonry chimneys used to vent Category I central fur-
naces must be either tile-lined or lined with a listed metal
lining system or dedicated gas vent. Unlined masonry
chimneys are prohibited.
A fan assisted furnace may be commonly vented into an
existing lined internal masonry chimney provided:
1 - The chimney is currently serving at least one draft-
hood equipped appliance.
2 - The vent connectors and chimney are sized in accor-
dance with the provided venting tables.
SINGLE APPLIANCE VENTING OF A FAN ASSISTED
FURNACE INTO A TILE-LINED MASONRY CHIMNEY
(INTERIOR OR OUTSIDE WALL) IS PROHIBITED. THE
CHIMNEY MUST FIRST BE LINED WITH EITHER TYPE
“B” VENT OR AN INSULATED SINGLE WALL FLEXIBLE
VENT LINING SYSTEM, SIZED IN ACCORDANCE WITH
THE PROVIDED VENTING TABLES.
See figures 29 and 30 for common venting.
A Type “B” vent or masonry chimney liner shall terminate
above the roof surface with a listed cap or a listed roof as-
sembly in accordance with the terms of their respective
listings and the vent manufacturer’s instructions.
Do not install a manual damper, barometric draft regulator,
or flue restrictor between the furnace and the chimney.
If type “B” double-wall vent is used inside a chimney, no
other appliance can be vented into the chimney. Outer wall
of type “B” vent pipe must not be exposed to flue products.
Insulation for the flexible vent pipe must be an encapsu-
lated fiberglass sleeve recommended by the flexible vent
pipe manufacturer. See figure 30.
The space between liner and chimney wall should
NOT be insulated with puffed mica or any other loose
granular insulating material.
FIGURE 30
COMMON VENTING USING
METAL-LINED MASONRY CHIMNEY
4 IN. MIN.
(102mm)
5 FT.
(1.5m)
MINIMUM
MIN. LENGTH -- AS
SHORT AS PRACTICAL
SEALED
PERMANENTLY
SEALED FIREPLACE
OPENING
EXTERIOR
CHIMNEY WITH
“B” VENT OR
INSULATED
FLEXIBLE VENT
PIPE.