Installation guide

INSTALLATIONSSECTION 3
AIR SUPPLY
AND
VENTILATION
CONCENTRIC
FLUE SYSTEMS
30
IMPORTANT:
1. The effective area requirements specified in the table are related to the maximum heat
input of of the heater(s), and are equivalent to those specified in BS6644.
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.
NB!! 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.
and in IGE/UP/10 Pt.1.
The permanent air vents shall be sited away from the extract fans. It may be necessary to
increase the ventilation area to compensate for the extractor fan.