Approved Document J: Combustion appliances and fuel storage systems
 
 
Requirement: Air supply
J1: Combustion appliances shall be so installed that there is an adequate supply of air to them for combustion, to prevent overheating and for the efficient working of any flue.
Section 1: Provisions which apply generally to combustion installations
1.10: Permanently open air vents should be non-adjustable, sized to admit sufficient air for the purpose intended and positioned where they are unlikely to become blocked.  Ventilators should be installed so that building occupants are not provoked into sealing them against draughts or noise.  Air vents should not be located within a fireplace recess except on the basis of specialist advice.
1.16: In noisy areas it may be necessary to install noise-attenuated ventilators to limit the entry of noise into the building.
Section 2: Additional provisions for appliances burning solid fuel (including solid biofuel) with a rated output up to 50kW
2.2: Any room or space containing an appliance should have a permanent air vent opening of at least the size shown in Table 1.  For appliances designed to burn a range of different solid fuels the air supply should be designed to accommodate burning the fuel that produces the highest heating output.