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EFFECTIVE LENGTH PRE FAN IS CALCULATED BY THE
FOLLOWING EQUATION:
Equation 1
Effective length = Vertical Run Up + (2 x Vertical Run Down) +
Horizontal Run + (3 x # of 90° bends) + (1.5 x # of 45° bends) +
length of wire reinforced ducting
EXAMPLE 1
Fireplace
Height
A₁
A₂
B₁
C Bends
Total
Effective
Length
A₁
2ft 6ft 10ft 1ft
2
28.5ft
Vertical Run Up = ( Fireplace B1 ) = 3ft. 5in + 10ft =
13ft. 5in.
Vertical Run Down = 0ft.
Horizontal Run = (A1 + A2) = (2ft. + 6ft.) = 8ft
Number of Bends = 2
Effective Length = Vertical Run Up + (2 x Vertical Run Down) +
Horizontal Run + (3 x # of 90° bends) + (1.5 x # of 45° bends) +
length of wire reinforced ducting
Effective Length = 13ft. 5in + (2 x 0 ft.) + 8ft. + (3 x 2 bends) +
(1.5 x 0 bends) + 1ft.
Effective Length = 28ft. 5in.
DUCT VENT INSTALLATION
B1
A2
C
D
R2
R1
A1
3 Way
Splitter
10” Wire
Reinforced
Flexible Ducting
6” Wire
Reinforced
Flexible Ducting
Duct Fan
Assembly
6” Duct Joiner
6” Aluminium Flexible
Ducting or Solid Pipe
FIREPLACE