Hi @mkdg,
Interesting, the wording here is wrong as far as I can tell so worth @chris being aware - rather than PPD it should be “acceptability limit”. I thought an acceptability limit of 80% equates to a PPD of 20% but looking through ASHRAE 55 2020 I can’t see that stated anywhere, which makes me think ASHRAE are trying to separate PPD from the adaptive comfort approach.
Looking in ASHRAE 55 the default should be an acceptability limit of 80%, not 90%. 80% equates to a temperature band of 7 (21.3-14.3 = 7), so 3.5degC above or below the “comfort temperature” (I might be using the wrong term there).
For EN15251 there are comfort classes defined. Normal expectation is ±3degC.(Note the image below is from CIBSE TM52, but it’s supposed to be implementing the same comfort classes and EN15251 and it’s a nicer image)
Looking at the Adaptive Comfort Parameter component the way to control this is through the neutral offset. ASHRAE 55 2.5degC would be 90% acceptability, 3.5degC would be 80% acceptability.
Hope that helps!