Door Clear Width, Thresholds, and Doors in Series (2010 ADA Standards 404.2)
32 in is the CLEAR OPENING, not the door. It is measured between the face of the door open 90 degrees and the stop, so the leaf loses its own thickness and the stop first -- which is why a 32 in door nets about 30 in and does not comply, and why 36 in is the smallest leaf that reliably works. Two rules ride along and get skipped: an opening more than 24 in DEEP owes 36 in rather than 32, so a thicker wall fails a door that would pass anywhere else, and the 5/8 in latch-side stop projection everyone quotes is an ALTERATIONS exception not available in new construction. Doors in series need 48 in PLUS the width of doors swinging in, which is the term people drop.
Formula and source
required clear width = 32 in, or 36 in where the opening is more than 24 in deep. Estimated clear opening from the leaf = leaf width - door thickness - 1/2 in stop. Effective clear width subtracts any latch-side stop projection beyond the allowance, which is 5/8 in in alterations and zero in new construction. Threshold limit 1/2 in, or 3/4 in for an existing or altered threshold beveled on each side at no steeper than 1:2. Doors in series: 48 in plus the width of doors swinging into the space.
2010 ADA Standards for Accessible Design, 404.2.3 and its exceptions, 404.2.5 and its exception, and 404.2.6. A US federal standard in the public domain, quoted directly.
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