N. The installation, alteration or replacement of a flue, forming part of a microgeneration biomass heating system, on a building other than—
(a)a dwellinghouse or a block of flats; or
(b)a building situated within the curtilage of a dwellinghouse or a block of flats.
N.1 Development is not permitted by Class N if—
(a)the capacity of the system that the flue would serve exceeds 45 kilowatts thermal;
(b)the height of the flue would exceed either—
(i)the highest part of the roof by 1 metre or more, or
(ii)the height of an existing flue which is being replaced,
whichever is the highest;
(c)the installation of the flue would result in the installation on the same building of more than 1 flue forming part of either a biomass heating system or a combined heat and power system;
(d)the flue would be installed on a listed building, within the curtilage of a listed building or on a site designated as a scheduled monument; or
(e)in the case of a building on article 2(3) land, the flue would be installed on a wall or roof slope which fronts a highway.