There’s no official definition of “passive survivability hours” that I know of but I usually try to assess this by running an energy simulation for the extreme_hot_week or the extreme_cold_week from the LB Import STAT component. I’ll create a thermostat setpoint schedule such that the space is conditioned on Sunday (the first day of the simulation) but not any other days of the week. Then, I’ll look at what happens to the interior operative temperature as the week progresses to get a sense of how long the conditions in the building are tolerable. Of course, “tolerable” has a bit of a subjective meaning and it isn’t nearly as well defined as “comfortable” but, if I want to assess whether the space is occupiable at all, I might use the “heat stress” or “cold stress” categories of the UTCI model.
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