Lennox Hearth MPD-45 Series, MPD-40 Series, MPD-35 Series HORIZONTAL VENT FIGURES/TABLES continued

HORIZONTAL VENT FIGURES/TABLES (continued)

**Wall Firestop/Spacer (SV4.5HF)

H1

H2

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

H

		TABLE K
H + H1 + H2 Maximum		H Maximum		V Minimum
feet	(meters)	feet	(meters)	feet	(meters)
5	(1.524)	2	(0.610)	1	(0.305)
10	(3.048)	4	(1.219)	2	(0.610)
15	(4.572)	6	(1.829)	3	(0.914)
20	(6.096)	8	(2.438)	4	(1.219)

V + H + H1 + H2 = 40 feet (12.2 m) Max.

H = 8 feet (2.438 meters) Max.

H + H1+ H2 = 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 a maximum horizontal run of 20 feet.

See Table 4 on page 18 as an aid in venting component selection for a particular range of exterior wall thicknesses.

Figure 39 - Rear Vent - THREE 90 DEGREE ELBOWS (Square termination SV4.5HT-2 shown.)

	*When using Secure Flex,
	use Firestop/Spacer
	SF4.5VF
H1	**When using Secure
	Flex, use Firestop/Spacer
	SF4.5HF
	*Ceiling
	Firestop/Spacer
	(SV4.5VF)
**Wall Firestop/Spacer	H
(SV4.5HF)	V1

V

**Wall Firestop/Spacer

TABLE L

H 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

(Square termination SV4.5HT-2 shown.)

(SV4.5HF)

5 feet of (H) horizontal run, up to a maxi- mum horizontal run of 20 feet.

See Table 4 on page 18 as an aid in venting component selection for a particular range of exterior wall thicknesses.

Figure 40 - Top Vent - THREE 90 DEGREE ELBOWS

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.

20

NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE.