top occupied floor height
The vertical distance from base level to the highest floorplate available for regular occupant usage.
The top occupied floor height is the elevation from a building's base to the top of the floor slab of the highest interior level containing usable space for building tenants. In the event that the floorplate is not of uniform level, then its height is the median height taken across its entire area.
Mechanical floors and mechanical penthouses are not considered occupied floors; the highest full mechanical floor level is represented by the top mechanical floor height, and the mechanical penthouse is usually at the main roof height.
The measurement runs from the base of the structure, the level of the lowest significant open-air pedestrian entrance. A building on a slope therefore has one height rather than one per side, and a figure taken from the low side of the same building is a different number.
Two sources giving different heights for one building have usually measured from different levels rather than measured badly.