ASHRAE 55 80% of acceptability

[charlie.brooker]

Hi @Tiago_Pereira, see this discussion

Difference between PMV and ADP

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 …