Air Supply And Ventilation - andrews 24/39 Installation And Service Manual

3 Installation
3.7

Air supply and ventilation

22
See
For all installations, please refer to the table below for
calculating requirements. Detailed recommendations for
the air supply are given in BS 5440 Part 2, BS 6644
Clause 19 and IGE/UP/10 Pt.1.
Note
The following notes are provided for general guidance
only.
Ventilation shall prevent the heater environment from
exceeding 32°C.
The purpose provided space in which the heater(s) are
installed must have permanent air vents communicating
directly with the outside air, at high and low level. Where
communication with the outside air is possible only by
means of high level air vents, ducting down to floor level
for the lower vents must be used.
For an exposed building, air vents must be fitted on at
least two sides, preferably on all four sides.
Air vents should have negligible resistance and must not
be sited in any position where they are likely to- be easily
blocked or flooded, or in any position adjacent to an
extraction system which is carrying flammable vapour.
Grilles or louvers should be so designed that high velocity
air streams do not occur within the space housing the
heater(s).
The grilles should have a total minimum free area for the
water heater(s) in addition to any other requirements as
follows:-
Where the heater is to be installed in a room the following
permanent ventilation is required:
5cm per kW in excess of 7kW net for installations up to 54kW
2
net.
For installations exceeding 60kW the following permanent
ventilation is required:
Low Level (inlet) 540cm plus 5cm
2
54kW total net input.
High Level (outlet) 270cm
2
54kW total net input.
Where the heater is to be installed in a compartment, permanent
air vents are required in the compartment at high and low level.
These air vents must either communicate with a room or internal
space or be direct to outside air.
per kilowatt in excess of
2
plus 2.5cm per kilowatt in excess of
2
Issue 2 14/07/16