Dunkirk DCC-150 Installation, Operation & Maintenance Manual page 31

Exhaust and combustion air intake are located in same general
location and are of equal length.
Twin Pipe Maximum Vent Lengths
Terminating in same location
125/150
3" [80 mm]
49 ft
Single Wall Elbows - Equivalent Length
Polyproplene
45° bend 0.82 ft [0.25 m]
90° bend 1.64 ft [0.50 m]
PVC/CPVC
45° bend 3.5 ft [1 m]
90° bend 5.0 ft [01.50 m]
Note: Twin Pipe Common Atmospheric Zone termination
can be run horizontal or vertical
6 - COMBUSTION AIR AND VENT PIPING
165/205
3" [80 mm] 2" [50 mm]
100 ft 85 ft
3" 2"
3 ft. [0.91m]
5 ft [1.5 m]
3"
FIGURE 6-11-Twin Pipe Roof Vent
12" (305mm) Min.
Vent
12" (305mm) US,
18" (458mm) Canada
Min. Above
Anticipated Snow Line
FIGURE 6-12 -Twin Pipe Side Wall Vent (Multiple
Appliances)
See Grade,
Snow & Ice
Combustion Air
FIGURE 6-13 - Horizontal Twin Pipe, Exhaust and
Intake
Minimum Separation
27
15"
(381mm)
Max.
Roof Line
Combustion
Air
12" (305mm) Min.
Separation
Manufacturer Recommends
Greater Separation
Vent
12" (305mm)
Manufacturer
Recommends
Greater Separation
240011947 REV B, [03/31/2018]