(1) Where the performance level of an existing building is reduced under Subsection 11.4.2., compensating construction shall be carried out in accordance with this Subsection.
(2) Except as provided in Sentence (3), compensating construction required under this Subsection applies to the part of the building being altered and shall include,
(a) fire separations, with the required fire-resistance ratings, separating the part being altered from the floor areas immediately above and below and from the immediate adjacent areas, and
(b) access to exits and exits from the building, where the alteration adversely affects the exit system of the building.
(3) Compensating construction required under this Subsection applies to the existing building systems that are adversely affected by the proposed construction.