4.1.5 Accessible Buildings: Additions. Each addition to an existing building or facility shall be regarded as an alteration. Each space or element added to the existing building or facility shall comply with the applicable provisions of 4.1.1 to 4.1.3, Minimum Requirements (for New Construction) and the applicable technical specifications of section 4 and the special application sections. Each addition that affects or could affect the usability of an area containing a primary function shall comply with 4.1.6(2).