Installation guide

SECTION XX • XXXXXXXXX
30
AIR SUPPLY AND VENTILATION
CONVENTIONAL FLUE SYSTEMS
The minimum effective areas of the permanent air vents
require in the compartment are as follows:
IMPORTANT!
1. The effective area requirements specified in the table
are related to the maximum heat input of the heater(s)
and are equivalent to those specified in BS6644 and
IGE/UP/10, Pt 1.
2. The free area of the grilles should not be less than the
size of the recommended ventilation opening.
3. The supply of air to a space housing the heater(s) by
mechanical means should be:
(a) Mechanical inlet with natural extraction
(b) Mechanical inlet with mechanical extraction
NOTE! Natural inlet with mechanical extraction
must not be used.
Where a mechanical inlet and mechanical extraction
system is used, the design extraction rate must not
exceed one third of the design inlet rate.
All mechanical ventilation systems must be fitted with
automatic gas shut off safety systems which cut off the
supply of gas to the heater(s) in the event of failure of
either the inlet or extract fans.
The requirements for air supply by mechanical ventilation
are given in BS6644, Clause 19.3 & IGE/UP/10 Pt 1.
The permanent air vents shall be sited away from any
extract fans. Where an extract fan is fitted, check for
spillage at the draught diverter as detailed in BS5440,
Pt 1, Appendix B.
It may be necessary to increase the ventilation are to
compensate for the extract fan.
The vapours emitted by halogen based compounds can,
if drawn into the combustion air, cause corrosion of the
gas burner, thermocouple and storage vessel. Therefore,
if heaters are to be installed in locations where halogens
are likely to be present, they should be isolated from such
compounds and ventilated from and to outside
uncontaminated atmosphere.
Some of the vulnerable areas are:
(a) Hairdressing salons and adjoining rooms and
basements
(b) Establishments where dry cleaning solutions are used
or stored
(c) Degreasing plants using hydrocarbon solvents
(d) Premises where refrigerant gases are used or stored
SECTION 3 • INSTALLATION
30
Air Vents Areas
Position of Air Vents Air from Room or Internal Space Air Direct from Outside
High Level 10cm
2
per kW Net input 5cm
2
per kW Net input
Low Level 20cm
2
per kW Net input 10cm
2
per kW Net input
Note: Both air vents must communicate with the same room or internal space or must both be on the same wall
to outside air.