The open space, lot coverage and yard modifications of this Section shall apply as follows.

1. Permitted obstructions
   1. Easement volumes in all zoning districts
      
      Any portion of an easement volume shall be considered a permitted obstruction within a required open space, yards, rear yard equivalent, or court pursuant to the regulations of this Resolution. Any easement volume, including any use or structure therein, shall be located at least 20 feet from any legally required window at the same level on the zoning lot.
   2. Non-residential uses in Commercial or Manufacturing Districts
      
      Any building or portion of a building used for any permitted commercial or community facility uses, up to two stories, excluding basements, or 30 feet above curb level, whichever is less, shall be considered a permitted obstruction in any rear yard or rear yard equivalent of a zoning lot with an easement volume serving an above-grade mass transit station. Any portion of a building containing residences or rooms used for living or sleeping purposes (other than a room in a hospital used for the care or treatment of patients, or joint living-work quarters for artists) shall not be a permitted obstruction.
2. Special lot coverage modifications in certain districts
   
   The underlying lot coverage provisions shall apply except any easement volume, or portion thereof, that is open to the sky shall not be included in lot coverage.