Lennox Hearth MPD-33 Series Vertical Vent Figures/Tables, Rear Vent - THREE ELBOWS, continued

VERTICAL VENT FIGURES/TABLES

(continued)

		TABLE C				H1
H+H1 Maximum		H Maximum		V Minimum
feet	(meters)	feet	(meters)	feet	(meters)
5	(1.524)	2	(0.610)	1	(0.305)	*Ceiling
	(3.048)		(1.219)		(0.610)	Firestop/Spacer
10		4		2		(SV4.5VF)
15	(4.572)	6	(1.829)	3	(0.914)
20	(6.096)	8	(2.438)	4	(1.219)	**Wall
	V + V1	+ H + H1 = 40 feet (12.2 m) Max				Firestop/Spacer
						(SV4.5HF)
	H = 8 feet (2.438 meters) Max.
						V1
	H + H1 = 20 feet (6.096 meters) Max.

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 aV maximum horizontal run of 20 feet.

Figure 29 - Rear Vent - THREE ELBOWS

*When using Secure Flex, use Firestop/Spacer SF4.5VF

**When using Secure Flex, use Firestop/Spacer SF4.5HF

*Ceiling

Firestop/Spacer

(SV4.5VF)

H

TABLE D

H + H1 Maximum			V Minimum
feet	(meters)	feet	(meters)
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)

H + H1 = 20 feet (6.096 m) Max.

V + V1 + H + H1 = 40 ft. (12.192 m) Max.

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.

Figure 30 - Top Vent - THREE ELBOWS

		*Ceiling
V	1	Firestop/Spacer	**Wall
		(SV4.5VF)
			Firestop/Spacer
			(SV4.5HF)
		H
		H1	V
		*When using Secure Flex,
		use Firestop/Spacer
		SF4.5VF
		**When using Secure
		Flex, use Firestop/Spacer
		SF4.5HF

NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE.

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