Sorry been long few weeks everyone taking advantage of the nice weather. In the wild west of Kansas by the way. Trained in Oregon this place is too laxed compared to there.
Architects response:
The east vestibule doors currently have thresholds that comply with ADA, but I am understanding that your concern is regarding the change in height between the concrete floor and the tile floor finish in the vestibule itself, which is approximately 5/8 to 3/4” There will be an epoxy floor coating added to the hallway concrete will reduce the difference a bit, but also the transition between the two surfaces will effectively be a "threshold ramp” consistent with ADA Table 405.2, wherein the height change is accomplished at a 1:8 slope. Section 404.2.5 refers to changes in levels at doorways needing to comply with ADA Sections 302 and 303. Section 303.4 is the applicable reference, which says that changes in level greater than 1/2” high shall be ramped, referring you back to Section 405 (and table 405.2).So to make a long story shorter, the change in floor elevation between the vestibule and hall is permitted as long as the transition meets the definition of a ramp, or in this case, occurs over a slope of 1:8 or about 5” for a 5/8” rise, which is the case at these doors.
1008.1.7 Thresholds at doorways shall not exceed 3/4" in dwelling units and 1/2" on all other doors. So I guess who get precedent ADA or IBC (2012) I will see what the thickness of the epoxy floor is (was 5/8" when I measured) it may get pretty close to 1/2" But I still have an issue seeing this as a "ramp".