R O B E R T S
-
G O R D O N
S E C T I O N
8 :
V E N T I N G A N D D U C T I N G
pg 27
Figure 25. Common Vertical Venting
Roof
At least 1/4" per foot (6 mm per 30 cm)
rise or pitch must be maintained on
horizontal runs from heater to vent.
PLAN VIEW
SIDE VIEW
Vent adapter
Type "B" vent pipe
Type "B" vent cap
18" (46 cm) min.
Roof flashing
D
Approved thimble
(if applicable)
Cleanout cap
'D' Area must equal sum of open
area of individual vents.
Common Vertical Venting (See Figure 25)
a) Open area of common vent must equal the sum of the
open area of individual vents connected to it.
b) Heaters sharing a common vent must be controlled by
the same thermostat.
c) Connections to common stack must be positioned to
avoid direct opposition between streams of
combustion gases.
d) Maximum horizontal length of vent to common vent
15 ft. (4.6 m). Maximum vertical vent 15 ft. (4.6 m).