(a) General Rule. Alterations to a qualified historic building or facility shall comply with 4.1.6 (Accessible Buildings: Alterations), the applicable technical specifications of section 4 and the applicable special application sections unless it is determined in accordance with the procedures in 4.1.7(2) that compliance with the requirements for accessible routes (exterior and interior), ramps, entrances, or toilets would threaten or destroy the historic significance of the building or facility in which case the alternative requirements in 4.1.7(3) may be used for the feature. Appendix Note
(b) Definition. A qualified historic building or facility is a building or facility that is:
(i) Listed in or eligible for listing in the National Register of Historic Places; or
(ii) Designated as historic under an appropriate State or local law.