The most obvious difference between the 2010 ADA Standards and A117.1-2009 is Chapter 2. Chapter 2 of the ADA Standards provides complete scoping for determining when and where accessibility is required. Chapter 2 of A117.1 does not include scoping but instead defers to the administrative authority that adopted the standard. Typically, the scoping comes from Chapter 11 of the IBC.
Aside from this bureaucratic difference, there are some major differences between the scoping and technical requirements of the ADA Standards and the IBC/ICC A117.1.
For example: Multiple Single-User Toilet and Bathing Rooms
Both standards start with the requirement that each toilet room and bathing room must be accessible.
ADA 213.2 Toilet Rooms and Bathing Rooms. Where toilet rooms are provided, each toilet room shall comply with 603. Where bathing rooms are provided, each bathing room shall comply with 603.
IBC 1109.2 Toilet and bathing facilities. Each toilet room and bathing room shall be accessible.
Then, exceptions are offered for existing conditions, private offices, transient lodging and medical facilities.
The exceptions for multiple single-use toilet rooms have one not-so-obvious difference:
ADA 213.2 Exception 4. Where multiple single user toilet rooms are clustered at a single location, no more than 50 percent of the single user toilet rooms for each use at each cluster shall be required to comply with 603.
IBC 1109.2 Exception 3. Where multiple single-user toilet rooms or bathing rooms are clustered at a single location, at least 50% but not less than one room for each use at each cluster shall be accessible.
The exception in the ADA Standards leaves out bathing rooms and only allows the exception for toilet rooms. It is unclear why bathing rooms were not included in the exception.
The result is that if you have multiple single user bathrooms in facility such as a truck stop, 100% of the bathing rooms must be accessible. A clinic that has 4 unisex toilet rooms would only require 2 accessible toilet rooms.
This interpretation has been confirmed by the Texas Department of Licensing and Regulation and addressed in Technical Memorandum 2013-10.