Vent Length Requirements; Equivalent Vent Length Calculation Example - Vertical (Stainless Steel Only); Standard Long Sweep Elbows; Standard Long Sweep Elbows (For Cpvc Pipe Only) - Viessmann Vitocrossal 300 CU3A Installation Instructions Manual

Single Pipe Venting (Room Air Dependent)

Vent Length Requirements

Legend
A Vent pipe 3.3 ft. (1 m)
B 45º elbow
C Vent pipe 1.6 ft. (0.5 m)
D 90º elbow
E Vent adaptor
56
CU3A Venting Systems Installation
Equivalent vent length calculation example - vertical
(stainless steel system)
Vitocrossal 300 CU3A
2 x 90º elbow...........................................6 ft. (1.8 m)
2 x 45º elbow...........................................4 ft. (1.2 m)
3 x vent pipe (0.5 m)..............................4.9 ft. (1.5 m)
2 x vent pipe (1 m).................................6.6 ft. (2 m)
Total equivalent length...........................21.5 ft. 6.5 m)
Above example will change as follows if using CPVC venting
system (first 90º elbows are not included):
2 x 90º elbow.........................................10 ft. (3.1 m)
2 x 45º elbow...........................................6 ft. (1.8 m)
3 x vent pipe (0.5 m)..............................4.9 ft. (1.5 m)
2 x vent pipe (1 m).................................6.6 ft. (2 m)
Total equivalent length..........................27.5 ft. (8.4 m)

Standard long sweep elbows

Material 90° elbow
equivalent
length
ft. (m)
Stainless steel 3 (0.91)
CPVC, ABS, PVC
5 (1.52)
plastic pipe
PP(s)

Standard long sweep elbows (for CPVC pipe only)

Note: If standard sweep elbows are used the allowable
vent lengths are reduced. One standard 90° elbow
is equivalent to 8 ft. (2.4 m) of straight pipe.
Long sweep elbows are recommended for use
with venting system.
45° elbow 87° elbow
equivalent / inspection
length
ft. (m) ft. (m)
2 (0.61)
3 (0.91)
- 1 (0.30) 1.6 (0.50)
tee
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