Appendix D: Example calculation of the ventilation requirements of an oil-fired appliance

(SEE DIAGRAM 40)

D1 An open-flued appliance is installed in an appliance compartment such as a cupboard, which is ventilated via an adjoining room. The air permeability of the dwelling is 6.0 m³/(h.m²) at 50Pa. The appliance has a rated output of 11kW, i.e. 6kW more than the rating at which permanent ventilation openings become necessary for the adjoining room.

D2      Air for combustion and the safe operation of the flue enters the adjoining room partially through infiltration, with the balance entering via vent A, whose area is calculated as follows:

Equation D2

Equation D2

D3      The cooling air for the appliance compartment is exhausted through vent B, which has an area:

Equation D3

Equation D3

D4      All of the air for combustion and the safe operation of the flue as well as cooling air enters the appliance compartment through vent C, which has an area:

Equation D4

Equation D4

D5      The ventilation areas in cm² can be found by dividing the results given above in mm² by 100.