If I understand correctly, the mechanism to inflate an emergency slide relies on a tank of inert gas and on an "aspirator" that sucks ambient air. This aspirator works thanks to depression causes by the stored inert gas velocity (Venturi effect) while it inflate the slide.
This implies that the slide requires enough outside air to inflate correctly. I'm confident such mechanism are certified to work at high altitude international airport (I'm thinking of Lima but there may be other international airport at high altitude), but an aircraft can still crash in high altitude mountains, higher than any airport.
I wonder what is the minimal outside pressure required to inflate an emergency slide. Maybe air density is more relevant than pressure. Given the standard atmosphere model, both can be converted in altitude (either using pressure-altitude or density-altitude).
What is the maximal altitude at which the mechanism to inflate an emergency slide can work as expected (i.e. suck enough outside air to inflate the slide)?