Technical Booklet F2 Conservation of Fuel and Power in Buildings Other Than Dwellings·Page 9
Definitions - Total Useful Floor Area
Defines total useful floor area as the gross floor area measured to the inside face of external walls, with specific provisions for sloping surfaces and exclusions for open areas.
"Total useful floor area" means the total area of all enclosed spaces measured to the inside face of the external walls, that is, the gross floor area, and in the case of sloping surfaces such as staircases, galleries, raked auditoria and tiered terraces shall be taken as their area on plan but shall exclude areas that are not enclosed such as open floors, covered ways and balconies.
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