I don't know of anywhere that allows "polyester fiber batts" as a component of insulation. You probably have fiberglass batts, which melt eventually but don't burn.
If the EPS (expanded polystyrene) is covered by fiberglass insulation and/or drywall, it will last sufficiently long for you to escape from a fire.
It's not glass wool. It's essentially the same stuff duvets are made from. Very comfortable actually! But maybe has some special fire retarding additive or something - I don't know.
Just looking up the product now, the brochure says "Please consult a fire engineer when specifying GreenStuf insulation ". That certainly didn't happen. Oops. But as another replyer said, it doesn't really matter for a normal house. It might burn down but you'd have escaped because of smoke alarms and just walking out the door.
The polystyrene is exposed to the outside with no covering.
You probably don't live in the same country as me so the rules are different.
... it really is polyester fiber. They say it's 100% polyester. Hope your wires are in conduit. And the EPS is just on the side of your house with no cladding? It'll get beat up just from wind-blown debris. Your construction ideas are very odd.
If the EPS (expanded polystyrene) is covered by fiberglass insulation and/or drywall, it will last sufficiently long for you to escape from a fire.