6.10 Flexible Vent System
Flexible Pipe Maximum Vent Lengths
3" [80 mm] Diameter Pipe
Exhaust
Natalini
Intake
Exhaust
DuraVent
®
Intake
Exhaust
Centrotherm
Intake
Exhaust
Z-Dens
Intake
Single Wall Elbows - Equivalent Length
3" [80 mm]
45° bend
0.82 ft [0.25 m]
90° bend
1.64 ft [0.50 m]
Flexible vent systems shall only be run vertical. Horizontal runs before adapting to flexible must be rigid pipe.
• Maximum vent lengths based on equivalent straight runs only. Include rigid pipe and fittings in overall equivalent length
calculations.
• Flexible venting installations use single wall polypropylene to pass flue gasses to base of chimney, then flexible venting to get
them to termination at the top.
• Combustion air is not supplied through masonry chimney. Combustion air must be from outside using 3" [80 mm] single wall
polypropylene.
• Position boiler to use minimum of rigid single wall polypropylene venting to the chimney.
• Follow venting manufacturer's instructions on assembly and clearances to maintain.
• Avoid sharp bends in flexible venting.
240012485 REV A [12/30/2018]
165/205
50 ft [15.2m]
50 ft [15.2m]
50 ft [15.2m]
50 ft [15.2m]
50 ft [15.2m]
50 ft [15.2m]
50 ft [15.2m]
50 ft [15.2m]
Combustion Air
NOTICE
30
FIGURE 6-26 - Flexible Venting System
Vent Terminal
Flexible Vent
Rigid Vent