20
STRATA1
14.1 calculating
flue resistance
The excess pressure available for
overcoming the frictional resistance of a flue
system is 100 Pa.
The adjacent table of flue component
resistances will assist the designer in calculating
total flue system frictional loss.
If the total installed flue system resistance
exceeds 100 Pa., then the result will be a
reduction in boiler output. Reference to the
“Effect of Flue System Resistance On Boiler
Output”, graphs will assist. If the resistance of a
proposed flue system has an unacceptable
effect on boiler output, then a larger diameter
flue tube should be selected.
Thermal up-draught is generated in a
vertical flue system, reducing the resistance of
the system. Reference to the “Thermal Up-
draught Graph” will provide a figure in Pa.,
which may be deducted from the total
calculated flue system resistance.
NB. Thermal updraught does not apply to
horizontal sections of a flue system.
If a flue terminal is positioned within 2 m above ground level or any upper part of a building where
people have general access (e.g. balcony etc) then the terminal should be fitted with an appropriate guard.
The flue terminal of a Strata 1 boiler will plume heavily and care must be taken when selecting a
terminal position to ensure that a "nuisance situation" is not created.
Component Resistance P.a.
45
60
75
80/125 Concentric Wall Terminal
7.5
11.0
16.0
80/125 Concentric Roof Terminal Without Rain Cap
7.5
11.0
16.0
80/125 Concentric Roof Terminal With Rain Cap
11.25
16.5
24.0
1m length 80/125 Concentric Tube
5.5
8.5
12.0
93° 80/125 Concentric Bend
5.5
8.5
12.0
45° 80/125 Concentric Bend
2.75
4.25
6.0
80/125 Concentric To 2 x 80 Tubes Adaptor
4.0
6.0
10.0
1m length DN 80 PPS Tube Carrying Fluegas
5.0
7.5
11.0
1m length DN 80 PPS Tube Carrying Combustion Air
3.0
5.0
7.0
90° DN 80 PPS Bend Carrying Fluegas
5
7.5
11.0
90° DN 80 PPS Bend Carrying Combustion Air
3.0
5.0
7.0
45° DN 80 PPS Bend Carrying Fluegas
2.5
4.0
5.5
45° DN 80 PPS Bend Carrying Combustion Air
1.5
2.5
3.5
Room Sealed Chimney Cap DN 80
7.0
10.0
15.0
DN 80 x 100 PPS Increaser Piece-Fluegas or Air
1.0
1.0
1.0
90° DN 100 PPS Bend Carrying Fluegas
2.0
2.5
4.0
90° DN 100 PPS Bend Carrying Combustion Air
1.5
2.0
2.0
45° DN 100 PPS Bend Carrying Fluegas
1.0
1.3
2.0
45° DN 100 PPS Bend Carrying Combustion Air
0.8
1.0
1.0
1m length DN 100 PPS Tube Carrying Fluegas
2.0
2.5
4.0
1m length DN 100 PPS Tube Carrying Combustion Air
1.5
2.0
2.0
DN 80 Open Termination With Mesh
4.0
5.5
8.0
DN 100 Open Termination with Mesh
2.0
3.0
4.0
80/125 Concentric Wall Terminal With Vertical Discharge
7.5
11.0
16.0
80/125 To 100/150 Concentric Increaser
2.0
3.0
5.0
100/150 Concentric Wall Terminal
3.0
4.0
7.0
100/150 Concentric Roof Terminal
3.0
4.0
7.0
1m length 100/150 Concentric Tube
2.0
3.0
5.0
93° 100/150 Concentric Bend
2.0
3.0
5.0
45° 100/150 Concentric Bend
2.0
2.0
3.0
Boiler Model
15.0 flue
terminal positions
Flue Terminal Positions
Fig. 19
H,I
J
M
A
G
F D
E
P
Q
A
G
N
B,C
F
F
L
K
L
K
N
M
