PRODUCT DESIGN
21
Masonry Chimneys
Wash
Crown
Clay Tile Size: 8" x 8" x12"
(Each x 24" Length)
Clay Tile Size Generally
12" x 12" (24" Length)
1/2" to 1" Air Space
Second Floor
First Floor
Attic Floor
Roof Line
Throat
Damper
Breech
Clean Out
Fan Assisted
Forced Air
Furnace
Natural Draft
Water Heater
Water Heater
Vent Connector
Basement Floor
F.A.F. Vent
Connector
Typical Multiple Flue Clay Tile Chimney
Checklist Summary
This checklist serves as a summary of the items to be
checked before venting an 80% furnace into a masonry chim-
ney. In addition, we recommend that a qualified serviceman
use this checklist to perform a yearly inspection of the fur-
nace venting system.
This checklist is only a summary. For detailed information
on each of the procedures mentioned, see the paragraph
referenced with each item.
This inspection is based upon a draft topical report, "Ma-
sonry Chimney Inspection and Relining", issued by the Gas
Research Institute. While not yet finalized, we believe this
report represents the best information on this subject which
is currently available.
Proper Chimney
Termination?
(Check 1)
Line, terminate with
listed vent cap
(Fix 1)
No
Yes
Chimney channel
free of solid and
liquid fuel
appliances?
(Check 2)
Change venting
arrangements
(Fix 2)
No
Yes
Crown in good
condition
(Check 3)
Rebuild crown
(Fix 3)
and/or Reline
(Fix 4)
Yes
No
Yes
No
No
Reline
(Fix 4)
Reline
(Fix 4)
Cleanout free of
debris?
(Check 4)
Liner in good
condition?
(Check 5)
Yes
Yes
No
Reline
(Fix 4)
Dilution air
available?
(Check 6)
Complete the
installation.
(Check 7)
Check 1 - Proper chimney termination.
A masonry chimney used as a vent for gas fired equipment
must extend at least three feet above the highest point where
it passes through the roof. It must extend at least two feet
higher than any portion of a building within a horizontal dis-
tance of 10 feet. In addition, the chimney must terminate at
least 3 feet above any forced air inlet located within 10 feet.
The chimney must extend at least five feet above the high-
est connected equipment draft hood outlet or flue collar.
If the chimney does not meet these termination requirements,
but all other requirements in the checklist can be met, it
may be possible for a mason to extend the chimney. If this
will not be practical, see Fix 1.
