Warning – TOA Electronics SSDVT-4035CNM User Manual
Page 17
 
NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE.
17
V
H
H
V
V1
Figure 26
- Top Vent - STRAIGHT
Notes:
• It is very important that the horizontal/in-
clined run be maintained in a straight (no 
dips) and recommended to be in a slightly 
elevated plane, in a direction away from the 
fi replace of 1/4" rise per foot (20 mm per 
meter) which is ideal, though rise per foot 
run ratios that are smaller are acceptable all 
the way down to at or near level.
• SV4.5VF (Secure Vent), SF4.5VF (Secure
Flex) fi restop/spacer must be used anytime 
vent pipe passes through a combustible 
fl oor or ceiling. SV4.5HF (Secure Vent), 
SF4.5HF (Secure Flex)fi restop/spacer must 
be used anytime vent pipe passes through 
a combustible wall.
• Two 45 degree elbows may be used in place
of one 90 degree elbow. The same rise to 
run ratios, as shown in the venting Figures 
for 90 elbows, must be followed if 45 degree 
elbows are used. 
• AN ELBOW IS ACCEPTABLE AS 1 FOOT OF
VERTICAL RISE EXCEPT WHERE AN ELBOW 
IS THE ONLY VERTICAL COMPONENT IN 
THE SYSTEM (See Figure 35).
Table B
H Maximum
V Minimum
feet
(meter)
feet
(meter)
5
(1.524)
Elbow Only
5
(1.524)
1
(0.305)
10
(3.048)
2
(0.610)
15
(4.572)
3
(0.914)
20
(6.096)
4
(1.219)
V + V
1
+ H = 40 feet (12.2 m) Max.
H = 20 feet (6.096 meters) Max.
A Vent Restrictor, as shown in Figure 18 
Page 13, must be used in this application
40 feet
(12.2 meters)
Maximum
When using Secure Flex, use Firestop / Spacer
SF4.5VF
Ceiling Firestop /
Spacer (SV4.5VF)
Ceiling Firestop /
Spacer (SV4.5VF)
Wall Firestop/
Spacer (SV4.5HF)
When using Secure Flex, use Firestop / 
Spacer SF4.5VF.
When using Secure Flex, use Firestop / 
Spacer SF4.5HF.
Table A
H Maximum
V Minimum
feet
(meter)
feet
(meter)
2
(0.610)
1
(0.305)
4
(1.219)
2
(0.610)
6
(1.829)
3
(0.914)
8
(2.438)
4
(1.219)
V + H = 40 feet (12.2 meters) Max.
H = 8 feet (2.4 meters) Max.
Ratio V to H ratio is 1:2
Example:  If 8 feet of (H) horizontal vent run 
is needed, then 4 feet minimum (V) vertical 
vent will be required.
This table shows a 1(V) to 2(H) ratio. For 
every 1 foot of (V) vertical, you are allowed 2 
feet of (H) horizontal run, up to a maximum 
horizontal run of 8 feet.
Figure 27
- Rear Vent - ONE 90 DEGREE ELBOW
Figure 28
- Top Vent - TWO 90 DEGREE ELBOWS
Example:  If 20 feet of (H) horizontal vent run 
is needed, then 4 feet minimum of (V) vertical 
vent will be required. 
This table shows a 1(V) to 5(H) ratio. For 
every 1 foot of (V) vertical, you are allowed 5 
feet of (H) horizontal run, up to a maximum 
horizontal run of 20 feet.
An elbow is acceptable as 1 foot of vertical 
rise except where an elbow is the only vertical 
component in the system. See Figure 35.
When using Secure Flex, use Firestop /
Spacer SF4.5VF.
Ceiling Firestop /
Spacer (SV4.5VF)
VERTICAL VENT FIGURES/TABLES
Note: Secure Vent  (rigid vent pipe) is shown 
in the Figures; Secure Flex (fl exible vent pipe) 
may also be used.
WARNING
Under no circumstances, may sepa-
rate sections of concentric fl exible 
vent pipe be joined together.