The following exemptions are offered for certain interior light fixtures in certain situations for LEED for Existing Buildings: O&M project buildings. The language below is written to apply with respect to a wall opening, but with the proper orientation shift it can be used to exempt fixtures with respect to skylights as well. 1) Distance exemption 1 (rule 1): project teams may exempt any fixtures mounted above the top of the wall opening (e.g., recessed troffers) if and only if all parts of the fixture are located more than the exemption distance from the opening, measured along a perpendicular to the opening. The exemption distance for Rule 1 is 150% of the distance from the floor to the top of the wall opening, i.e. if the top edge or point of the window glass is 6 feet from the floor, the exemption distance is 9 feet inward from the window. 2) Distance exemption 2 (rule 2): project teams may exempt any fixtures mounted below the top of the wall opening (e.g., wall sconces) if and only if all parts of the fixture are located more than the exemption distance from the opening, measured along a perpendicular to the opening. The exemption distance for Rule 2 is 250% of the distance from the floor to the top of the wall opening. 3) Angle exemption (rule 3): project teams may exempt any fixtures mostly shielded by exterior walls as follows: Draw a perpendicular to the wall opening. Then draw a line from the fixture corner or edge nearest the wall opening to the portion of the wall opening nearest the fixture (i.e., the fixture line of sight forming the shallowest angle from the perpendicular). Form the angle between this fixture line of sight and the perpendicular, with the vertex located at the window glass. Exempt the fixture if and only if this angle is 75 degrees or higher. Applicable Internationally.