It is for multifamily. However, I understand CA Accessibility Code is more restrictive. I haven't done enough FHA covered work in CA to know exactly.
Is the detectable dropoff requirement in the CA code, it's not in ANSI.
The OP was about a patio restaurant, so we are not dealing with FHA.
ANSI is NOT the applicable accessibility code in CA. For restaurants, the code is CBC-11B, and the federal accessibility standard is ADA Standards (ADAS) Title III for a non-governmental public facility. Both 11B and ADAS share much of the same language and formatting as ANSI 117.1, but ANSI 117.1 was not adopted as a code to be enforced by local building departments.
It is true that if a slope is less than or equal to 1:20 (5%), it is not a ramp, it is a "walkway", and does not require handrails.
If it is steeper than 1:20 and less than 1:12, it is a ramp, and in CBC 11B -405.7 it requires a 60" long top landing, and a 72" bottom landing (note this is greater than required by ANSI and ADAS). In that scenario total length of a 1:12 ramp plus landings is 5'+6'+6'= 17' long.
If this is a new restaurant patio, then CBC-11B-405.8 requires you to provide handrails, with a couple of exceptions:
CBC-11B-405.8 exc. #3 does not require handrails at curb ramps.
CBC-11B-405.8 exc. #4 does not require handrails at door landings where the ramp run is less than 6" in rise or 72" in length.