For part 2, the angle is measured from the point of view of the seated occupant. In other words, bare lamps and luminaire surfaces that are located above 53 degrees, when measured as a solid angle from a seated occupant's point of view at a workstation, desk or other seating area, must have luminance’s that are less than 8,000 cd/m2.
Light sources above 53 degrees above horizontal may contribute to "overhead glare", and as such should be limited to 8,000 cd/m2 or less. Note that this does not necessarily preclude a fixture with over 8,000 cd/m2 from being used, but shielding may be required to ensure that the surface that is directly emitting light (the bare lamp or the luminaire surface) cannot be seen from a seated occupants point of view. Project teams can obtain photometric data from the lamp manufacturer to confirm compliance.