10

DEFINITIONS

for the following symbols used in the venting calcula- tions 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 off- sets (HO) in feet

HR - combined horizontal vent lengths in feet

HO - offset factor: .03(total degrees of offset - 135°*) in feet

VT - combined vertical vent lengths in feet

ELBOW VENT LENGTH VALUES

 

feet

inches

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 first 45º and 90° offset has a zero value and is shown in the formula as -45°and -90ºrespectively or -135ºwhen combined.

HORIZONTAL TERMINATION

when (HT) < (VT)

Simple venting configuration (only one 45º and 90° elbow)

90°

FIGURE 5

For vent configurations requiring more than one 45º and 90° elbow, the following formulas apply:

Formula 1: HT

< VT

 

 

 

Formula 2: HT

+ VT

< 40 feet

 

Example 1:

 

 

 

 

 

 

 

 

90°

 

H2

 

 

 

 

 

 

 

FIGURE 6V1

45º45º

H1 90°

REQUIRED

VERTICAL RISEINFEET (VT)

CALCULATED HORIZONTAL VENT RUN PLUS OFFSETS IN FEET (HT)

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

V1

=

8 ft

VT

= V1 = 8 ft

H1

=

2.5 ft

H2

=

2 ft

HR

= H1 + H2 = 2.5 + 2 = 4.5 ft

HO

= .03(one 45º elbow + two 90º elbows - 135º)

=0.3(225-135º) = 2.7ft

HT

= HR + HO = 4.5 + 2.7 = 7.2 ft

HT + VT = 7.2 +8 =15.2ft

Formula 1: HT < VT

7.2< 8

Formula 2: HT + VT < 40 feet

15.2 < 40

Since both formulas are met, this vent configuration is ac- ceptable.

W415-0484 / A / 07.26.06

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Napoleon Fireplaces B36DFP, B36DFN manual Horizontal Termination, Definitions, Elbow Vent Length Values, When HT VT