Insulation @ fire prevention within a passive, zero energy, passive house.
They check how well it holds pressure. That’s partly true. Read the 30.30.30 rule Would you climb the Everest in a north face jacket made out of feather or with a “balloon” on your skin? Why do they want us to live in a pink balloon? Seriously. Sorry but I can’t help myself. Birds are not insulated because they are not wearing a condom? Ok, done with the cheap jokes.
They say: if it holds air then the insulation is pretty good. That’s just partially true. Insulation should be perfect at doors, windows. The fitting should be perfect. However in case of the wall is different. A straw bale, hempcrete works like a charm. Papercrete is like God level of insulation. You can’t even compare with polystyrene. If polystyrene catches fire your family could die easily because of the toxins in the air. In case of residential homes you can escape the house within seconds.
Jump threw fire like a Lion? You can even jump threw fire with a blanket on yourself. In a few days, weeks you’ll be fine. However with polystyrene insulation your children could die from the toxins while they are sleeping. I’m not exaggerating and being negative or rude here. Unfortunately that’s the truth. All the materials mentioned above insulate way better and are SAFE. Yes even straw bale.