38
ROOM VENTILATION
The room carrying the appliance should have
an air vent either direct to an external air
source or vented into a room that has an
external vent direct to an air source. This
is required to provide adequate air supply
to allow the appliance and flue to operate
efficiently. These requirements are specified in
the Building Regulations (Document J) also by
CIBSE and BS5440.
COMMERCIAL INSTALLATIONS
Schiedel can provide a full design & flue sizing
advice service for commercial installations,
using both ICID Plus and our ICS product
ranges.
PROVISION FOR CONDENSATE DISPOSAL
(subject to appliance manufacturer
recommendations)
Normally solid fuel and atmospheric gas and
oil appliances will not need a drain unless
rain ingress is significant. Most condensing
appliances however need provision for
drainage. As a rule of thumb a condensing
boiler produces 1 to 1.5 litres of condensate
per hour per 10kW of input.
This is a significant amount of acidic liquid
which must be drained from the system.
Choose appropriate flue drainage components,
normally fitted at the base of the stack and
close to the appliance outlet.
On high efficiency or on condensing systems,
a 3° slope on horizontal runs is advised, using
the appropriate 87° bend and 93° tee.
P
O
N
M
A
D
B
C
A
600mm
min
600mm
min
less
than
600mm
1500
1500
600 min
Chimney should
not penetrate
within the
shaded area
600
600
2000
P
O
N
M
A
D
B
C
A
600mm
min
600mm
min
less
than
600mm
1500
1500
600 min
Chimney should
not penetrate
within the
shaded area
600
600
2000
Fig. C
BS 5440-1Outlet siting for
Gas Appliances (<70kW)
1.
The weather surface is the building external surface, such as its roof, tiles or external walls.
2.
A flat roof has a pitch less than 10˚.
3.
The clearance for A or B, as appropriate, will also apply.
4.
A vertical flue fixed to an outside wall should be treated as equivalent to an inside flue emerging at the nearest edge of the
roof.
System Design
