Equivalent Vent Length Calculation Example - Stainless Steel System With Plastic Air Intake Pipe - Viessmann Vitodens 100-W WB1B Series Installation Instructions Manual

Rigid Venting Systems Installation Instructions
Vent Length Requirements
Equivalent vent length calculation example - stainless steel
system with plastic air intake pipe
Table 28
Vent type
Exhaust vent pipe
Air intake pipe
IMPORTANT
Always include vent termination length in calculations.
(continued)
Type of fitting
90° elbow (stainless steel)
45° elbow (stainless steel)
90° elbow (ABS/PVC)
45° elbow (ABS/PVC)
Equivalent vent length calculation example
(Vitodens WB1B system diameter 3 in.)
Maximum allowable equivalent length is 164 ft. (50 m)
(see table 26 and fig. 56 on page 55)
2 x 90º stainless steel elbow....................6 ft. (1.83 m)
2 x 45º stainless steel elbow....................4 ft. (1.22 m)
Air intake pipe
1 x 90º plastic (ABS/CPVC/PVC) elbow.....5 ft. (1.52 m)
1 x 45º plastic (ABS/CPVC/PVC) elbow.....3 ft. (0.91 m)
Exhaust vent pipe..................................10 ft. (3.05 m)
Air intake pipe.......................................10 ft. (3.05 m)
Combined total equivalent vent length
(a+b)...................................................38 ft. (11.58 m)
Direct Venting (Two-pipe System)
Equivalent length ft. (m)
3 (0.91)
2 (0.61)
5 (1.52)
3 (0.91)
57