14
1.9 Ventilation Requirements
AmbiRad tube heaters can be operated as
flued or unflued appliances in accordance with
the relevant national requirements in the
country of installation.
1.9.1 Unflued Radiant Heater
Radiant tube heaters can be operated as
unflued appliances so that the concentration of
Carbon Dioxide (CO
2
) at positions where the air
will be inhaled does not exceed 0.28%.
BS EN 13410:2001 is a guide to achieving this
requirement.
If the building air change rate exceeds 1.5 per
hour or if the heat input is less than 5W/m³, no
additional ventilation is required.
In addition to the ventilation requirements, con-
sideration needs to be given to the possibility of
condensation forming on cold surfaces.
It should be noted that the clearance distance
around the burner increases when the unit is
operated unflued (see section 1.6). It should be
ensured that the combustion gases do not
impinge on any combustible materials.
Mechanical Ventilation
Mechanical ventilation must be installed to
meet a minimum of 1.5 air changes per hour
using appropriately sized fans and interlocked
with the heaters.
Natural Ventilation
BS EN 13410:2001 should be used to size air
vents to provide adequate ventilation, an
example of this calculation is given below:
Site Details:
20°c Internal Operating Temperature
0°c Outside Air Temperature
5m between high and low level vents
Following the sizing procedure in BS EN
13410:2001 gives an air exit velocity of 1.6m/s.
This equates to a free area vent at both high
level and low level of 17.36cm²/kW free area.
1.9.2 Flued Radiant Heater
In buildings having an air change rate of less
than 0.5 per hour, additional mechanical or
natural ventilation is required. For detailed
information, please see BS6896:2005 section
5.2.2.2.1
Mechanical Ventilation
Mechanical ventilation must be installed to meet
a minimum of 0.5 air changes per hour using
appropriately sized fans and interlocked with the
heaters.
Natural Ventilation
Low level ventilation openings with a free area
of at least 2cm²/kW shall be provided. See
section 5.2.2.2.2.1.
1.10 Flue and Combustion Air Inlet -
Options
Induced Burners without Heat Exchangers
Please refer to Figure 12 for options.
Burner 2
Burner 1
Burner 3
1 phase
Isolator
Tail Pipe
1 phase 230V
Exhaust Fan
230V 50Hz 13A
Mains Supply
Controller
0.75mm²
Screened
Cable
Isolator
Sensor
Zone A
Isolator
Isolator
Isolator
Figure 11. Typical VSLH/VSALH
Wiring Connections