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VENT PIPE LENGTH AND SIZING
Refer to Table 6 and Table 7 for vent pipe sizing. If the
installation requires a vent riser, suitable drainage must
be provided to ensure condensation does not accumulate
(see Figure 47). The specified maximum lengths are for
each
of the intake and exhaust systems and
not
for the
combined lengths of both systems. Minimum pipe length
is 2’ with a minimum of one 90° elbow per side (intake
and exhaust).
1. Determine termination type and pipe size.
2. Determine number of elbows in vent system. Do not
include termination elbow. Calculate the maximum
equivalent length of the exhaust and air intake system
using Table 5 to determine equivalent length values.
90° LONG SWEEP ELBOW
(LESS RESTRICTIVE)
90° SHORT SWEEP ELBOW
(MORE RESTRICTIVE)
Figure 37.
Elbow Type
Equivalent Length Of Straight Pipe
Short Sweep/
Radius
Long Sweep/
Radius
90°
8’
5’
45°
4’
2.5’
Table 5.
