Table 6.1 – Alterations to Primary Function Areas
Current Guidelines:  4.1.6  Accessible Buildings: Alterations.

(3)  Where substantial alteration occurs to a building or facility, then each element or space that is altered or added shall comply with the applicable provisions of 4.1.1 to 4.1.4 of 4.1, Minimum Requirements, except to the extent where it is structurally impracticable.  The altered building or facility shall contain:

(a)  At least one accessible route complying with 4.3, Accessible Route, and 4.1.6(a);

(b)  At least one accessible entrance complying with 4.14, Entrances.  If additional entrances are altered then they shall comply with 4.1.6(a); and

(c)  The following toilet facilities, whichever is greater:

(i)  At least one toilet facility for each sex in the altered building complying with 4.22, Toilet Rooms; and 4.23, Bathrooms, Bathing Facilities, and Shower Rooms.

(ii)  At least one toilet facility for each sex on each substantially altered floor, where such facilities are provided, complying with 4.22, Toilet Rooms; and 4.23, Bathrooms, Bathing Facilities, and Shower Rooms.

(d) In making the determination as to what constitutes “substantial alteration,” the agency issuing standards for the facility shall consider the total cost of all alterations (including but not limited to electrical, plumbing, and structural changes) for a building or facility within any twelve (12) month period.  For guidance in implementing this provision, an alteration to any building or facility is to be considered substantial if the total cost for this twelve month period amounts to 50 percent or more of the full and fair cash value of the building as defined in 3.5

Final Revised Guidelines:  202.4  Alterations Affecting Primary Function Areas.  In addition to the requirements of 202.3, an alteration that affects or could affect the usability of or access to an area containing a primary function shall be made so as to ensure that, to the maximum extent feasible, the path of travel to the altered area, including the rest rooms, telephones, and drinking fountains serving the altered area, are readily accessible to and usable by individuals with disabilities, unless such alterations are disproportionate to the overall alterations in terms of cost and scope as determined under criteria established  by the Attorney General. . . .

[Note:  The Department of Justice defines a “primary function” and “disproportionate” in its regulations at 28 C.F.R. § 36.403.  A “primary function” is “a major activity for which a facility is intended.”  Alterations to provide an accessible path of travel to the altered area are “deemed disproportionate to the overall alteration when the cost exceeds 20 percent of the cost of the alteration to the primary function area.”]

Model Codes & Standards
IBC 2000:  Section 3408.6 has an equivalent requirement for alterations to primary function areas.

IBC 2003:  Sections 3409.6 has an equivalent requirement for alterations to primary function areas.