Napoleon Fireplaces BGD90NT manual Horizontal Termination, Definitions, Elbow Vent Length Values

DEFINITIONS

for the following symbols used in the venting calculations and examples are:

>- greater than

>- equal to or greater than < - less than

< - equal to or less than

HT - total of both horizontal vent lengths (HR) and offsets (HO) in feet

HR - combined horizontal vent lengths in feet

HO - offset factor: .03(total degrees of offset - 90°*) in feet

VT - combined vertical vent lengths in feet

7

ELBOW VENT LENGTH VALUES

	feet	inches
1°	0.03	0.5
15°	0.45	6.0
30°	0.9	11.0
45°	1.35	16.0
90°*	2.7	32.0

*the fi rst 90° offset has a zero value and is shown in the formula as -90°

HORIZONTAL TERMINATION

When (HT) < (VT )

Simple venting confi guration (only one 90° elbow)

FIGURE 4

See graph to determine the required vertical rise VT for the required horizontal run HT.

For vent confi gurations requiring more than one 90° elbow, the following formulas apply:

Formula 1: HT < VT

Formula 2: HT + VT < 40 feet

Example 1: 90° H2

VERTICAL

RISE IN

FEET

VT

HORIZONTAL VENT RUN PLUS OFFSET IN FEET HT

The shaded area within the lines represents acceptable values for HT and VT .

FIGURE 5 V2

90°

H1

90°

V1

V1	=	3 ft
V2	=	8 ft
VT	= V1 + V2 = 3 + 8 = 11 ft
H1	=	2.5 ft
H2	=	2 ft
HR	= H1 + H2 = 2.5 + 2 = 4.5 ft
HO	= .03 (three 90° elbows - 90°) = .03(270° - 90°) = 5.4
ft
HT	=	HR + HO = 4.5 + 5.4 = 9.9 ft

HT + VT = 9.9 + 11 = 20.9 ft

Formula 1: HT < VT 9.9 < 11

Formula 2: HT + VT < 40 feet 20.9 < 40

Since both formulas are met, this vent configuration is acceptable.

W415-0580 / C / 04.07.08