While the Americans with Disabilities Act (ADA) permits the installation of a single unisex toilet room in lieu of separate facilities, the 2014 NYC Building Code and Plumbing Code are more stringent.
Section 403.2 of the plumbing code requires separate facilities for each sex when the occupant load exceeds 30, and the number of facilities provided must comply with
Table 403.1. For most occupancy groups a minimum of one of each fixture type will be required for each sex. With the adoption of local law 79 of 2016 designers and building owners now have the option to utilize single-user gender neutral toilet rooms as an alternative to separate facilities, but the minimum number of fixtures must still be accounted for.
In example, a small office space with 35 occupants would be required to provide one toilet and one lavatory for both men and women. If the designer elected to utilize single-user gender neutral toilet rooms two must be installed and would account for the required fixtures by table 403.1. Section 1009.2 of the NYC building code requires all restrooms to be made accessible and a minimum of one fixture type in each restroom to be accessible.
in either example above, whether separate facilities or gender neutral toilet rooms, each restroom provided must be accessible. The only case in which a single unisex toilet would be permitted to be the only accessible restroom would be a space having an occupant load less than 15, and only when other facilities are not provided in addition to single toilet room.