INSTALLATION
SECTION 3
AIR SUPPLY
AND
VENTILATION
11
The following notes are intended to give general guidance:
Where the heater is to be installed in a room or internal space the heater requires the
room or internal space containing it to have a permanent air vent. The vent must be
either direct to outside air or to an adjacent room or internal space which must itself have
a permanent vent of at least the same size direct to outside air. The minimum effective
area of the permanent air vent(s) required is as follows:
Air supply requirements for appliances up to 44kW
Where the appliance is to be installed in a room.
High level 550mm
2
per kW of appliance rating over 5kW.
Where the appliance is to be installed in a compartment. Air supply direct to outside.
High level 550mm
2
per kW of appliance rating over 5kW.
Low level 1100mm
2
per kW of appliance rating over 5kW.
Where the appliance is to be installed in a compartment. Air supply into a room.
High level 1100mm
2
per kW of appliance rating over 5kW.
Low level 1650mm
2
per kW of appliance rating over 5kW.
The room itself must have permanent ventilation direct to outside.
High level 550mm
2
per kW of appliance rating over 5kW.
Draught Stabilisers
When an appliance with draught stabiliser is fitted in a room, add 550mm
2
per kW to the
free air of the combustion air inlet. When an appliance with a draught stabiliser is fitted
in a compartment which is vented as above, no additional allowance is required.
Air supply requirements for appliances of 44kW and above.
High level 0.1m
2
per 300kW of appliance rating.
Low level 0.2m
2
per 300kW of appliance rating.
Typical example for heater model OFS63
Heat input 71.8kW/300kW = 0.24kW
High level 0.24kW x 0.1m
2
= 0.024m
2
Low level 0.24kW x 0.2m
2
= 0.048m
2
Some halogen containing compounds can cause rapid corrosion of the Burner
and Storage Vessel if drawn into the combustion air.
Therefore, if heaters are to be installed in any of the following locations or in any
applications where the above compounds are present they should be sealed off from
atmospheres which may contain these compounds, and all ventilation air must be taken
completely from outside.
i) Hairdressing salons and adjoining rooms or basement.
ii) Establishments where dry-cleaning solutions are used.
iii) Industrial use near chemical de-greasing processes or where solvents are used or
stored.
iv) Installations where refrigerant gases are used or stored.
v) Environments with dust laden atmosphere.
