Appendix D Ventilation - Hamworthy F175V Installation, Commissioning And Operating Instructions

APPENDIX D - VENTILATION
D1.1 Air Supply
Detailed recommendations for air supply are given in BS 6644 and BS5440 Pt 2. The following notes are intended
to give general guidance. In all cases there must be provision for an adequate supply of air for both combustion
and general ventilation, in addition to that required for any other appliance.
Note: For Open flue applications, combustion air for the boiler is drawn through the top of the boiler casing. The
air inlets must be kept open and free from blockage at all times.
D1.2.1 Air Supply by Natural Ventilation - Open Flue applications
The boiler room must have, or be provided with, permanent air vents directly to the outside air, at high level and at
low level. For an exposed boiler house, air vents should be fitted, preferably on all four sides, but at the least on
two 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 louvres must be so designed that high velocity air streams do not occur within the space
housing the boiler.
Boiler house ventilation
Low level (inlet) - 4cm² per kW of total rated input (Net)
High level (output) - 2cm² per kW of total rated input (Net)
Compartment ventilation
Where the boiler is to be installed in a cupboard or compartment, permanent high and low level ventilation is
required which must communicate direct to outside, for cooling purposes.
Low level (inlet) - 10cm² per kW of total rated input (Net)
High level (output) - 5cm² per kW of total rated input (Net)
D1.2.2 Air Supply by Natural Ventilation - Room Sealed Installations
Where the boiler(s) are to be installed in a boiler room or internal space, the room or internal space must have
permanent air vents directly to the outside air, at high level and at low level with the general requirements detailed
above on location and construction.
Boiler house ventilation
Low level (inlet) - 2cm² per kW of total rated input (Net)
High level (output) - 2cm² per kW of total rated input (Net)
Compartment ventilation
Where the boiler is to be installed in a cupboard or compartment, permanent high and low level ventilation is
required which may communicate to an adjoining room or outside, for cooling purposes.
Ventilation to a room or internal space - 10cm² per kW of total rated input (Net)
Ventilation direct to outside
D1.3 Air Supply by Mechanical Ventilation
Air supplied to the boiler room by Mechanical means should be as follows:
1) Mechanical ventilation must be interlocked with the boilers to prevent operation in
the event of ventilation fan failure
2) Mechanical inlet and mechanical extract can be utilised providing the design
extraction rate does not exceed one third of the design inlet rate.
3) Mechanical extract ventilation with natural inlet ventilation MUST NOT be used.
For Mechanical ventilation systems an automatic control should be provided to cut off the gas supply to the boiler,
in the event of failure of air flow in either inlet or extract fans.
HAMWORTHY HEATING LTD
- 5cm² per kW of total rated input (Net)
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FLEET V series 500001217/D