I found this on the Building Code Discussion Group of NAFFA International Inc website. It was "translated" by ADA_Guy
see below for inclusion of some California appropriate considerations.
10 Accessibility Considerations When Beginning a Project
1. CODE RESEARCH
Before you begin your design, make sure you are aware which code you are required to follow based on the City/state you are designing in. (for example, some Municipalities require ( ANSI vs. ADA vs. CBC) .
2. HAVE A CHECKLIST
It is smart to have a checklist so you don't forget some part of the puzzle. The ADA and DSA have checklists that you can follow for assessments, scoping and design process.
3. HAVE TOLERANCES
When given a range, don’t use the lowest or tallest number. Give yourself some tolerances for construction imperfections. For example, a handrail can be between 34” and 38”, so a 36” tall handrail is acceptable.
4. GIVE YOURSELF WIGGLE ROOM
When designing toilet rooms, keep in mind what finishes will be on the wall. If the water closet must be 18” away from the finished wall, ceramic tile is sometimes 3/8” thick which can throw off the required clearances.
5. CHECK DOOR SWINGS
Remember that in a toilet room, a door cannot swing into the clear floor space of an accessible fixture, but clear floor spaces of fixtures can overlap each other. And the door swing can overlap the required turning space.
6. KEEP IN MIND THE USERS
When designing storage rooms, keep in mind that if a person in a wheel chair can enter the room and close the door behind them, then they must be able to turn around and go back out.
In cases where the storage room is 48” deep (allowing a wheel chair front access), try to either swing the door in so they can’t close it once they are inside; or create shelving that will make the room shallower and therefore will not create the ability to stay stuck inside.
7. UNDERSTAND COMMON USES
Most places in a facility that are used by more than one employee at a time, or by patrons or visitors to the facility are required to be accessible and meet the requirements of the Guidelines. This includes employee non-work areas like storage closets, restrooms, and break rooms. The mistake I see often is that most people believe that the ADA is only for non-employees. In reality, common use spaces that are also accessed by employees must comply.
8. DEFINE WORK AREAS
Employee work areas only have the requirement to be able to be approached, entered and exited. Everything else within the work area is exempted. For example sinks that are in work areas (per ADA 4.1.3) are not required to have knee clearances for wheel chairs. Though Break Rooms are not considered work areas, they are common use areas therefore do require the knee clearance. Sinks and Lavatories have different requirements for knee clearances. Be aware that the knee clearance below sinks is 27” and below lavatories is 29” below their respective aprons.
9. WATCH OUT FOR HAZARDS
In California, CBC prefers that disabled persons not have to wheel behind their cars. When possible, allow for an accessible route in front of the cars. A person in a wheelchair is lower than the driver's visual range and if they are wheeling behind a parked car, the driver may not see them if they are backing up.
Also, if there are any objects that are along the circulation path that are placed higher than 27" above the ground, they must not project more than 4" from the wall into the circulation path. Visually impaired people will not detect the object and could hurt themselves.
10. MAKE SURE EXISTING CONDITIONS COMPLY
In an alteration of an area containing a primary function the existing parking, accessible route, restrooms, drinking fountains and telephones must be brought up to compliance with ADA. This is not always part of the scope of work of the remodel, but nevertheless must become part of the total scope if it's not already compliant
Note: CBC has a 20% rule, which allows an exception for disproportionate cost if the amount of money required to fix the non-compliance items exceeds the total cost of the project by 20%, up to a threshold value based on ENR US20 Cities Average Construction Cost Index.