Vertical

Flues

(Twin Pipe)

Y

X

Vertical

Flues

Y

X

8.0Flue Options

8.2Twin & Vertical Flue Systems

1.Maximum permissible equivalent flue lengths are:-

 

(60/100)

(80/125)

Vertical Concentric

10 metres

20 metres

Vertical Twin Pipe

15 metres

 

2.Any additional “in line” bends in the flue system must be taken into consideration.

Their equivalent lengths are:- Concentric Pipes:

135° bend

0.5 metres

93° bend

1.0 metres

Twin Flue Pipe

 

135° bend

0.25 metres

91.5° bend

0.50 metres

The elbow supplied with the standard horizontal telescopic flue kit is not included in any equivalent length calculations

NOTE: Flue length is measured from point X to Y as shown.

Total Equivalent Length =

A+B+C+1x90°Bend

All vertical and angled runs must be included, measured from the boiler adaptor (point X) to the joint with the flue terminal (point Y). One 91.5° bend or two 135° bends can be included without reduction of the flue length.

If further elbows are required the flue length must be reduced by the following amounts:-

Roof

Terminal

The total equivalent length for this example is

1 metre for each 91.5° bend

Y

= 6.5 metres.

0.5 metre for each 135° bend

C

B

This bend is equivalent to 1 metre

A

X

20© Baxi Heating UK Ltd 2008

 

 

AIR DUCT

 

 

Equivalent

No of

Sub total

 

Length Value

fittings/pipes

 

1m extension

1m

5

5.0m

135°bend

0.25m

2

0.5m

 

 

 

 

91.5°bend

0.5m

2

1.0m

 

 

 

 

 

Equivalent Length Air Duct = 6.5m

 

 

 

 

 

 

 

 

 

 

FLUE DUCT

 

 

Equivalent

No of

Sub total

 

Length Value

fittings/pipes

 

1m extension

1m

5

5.0m

135°bend

0.25m

2

0.5m

 

 

 

 

91.5°bend

0.5m

2

1.0m

 

 

 

 

 

Equivalent Length Flue Duct = 6.5m

 

 

 

 

Page 20
Image 20
Baxi Potterton Gold HE A Range manual Vertical Flues Twin Pipe, Twin & Vertical Flue Systems, Metre for each 91.5 bend