Finalising my building warrant drgs and my architect has a duct going from Island to external for the Hob. This would need to pass through my insulated slab and I don't fancy it.    I assumed it would recycle below the hob and then vent below the island to the room. I'm sure this is the case, but can someone confirm this is ok and that it works well that way?    Bora, Neff, Siemens, Nikola Tesla etc.    It's probably quite important as I have high levels of airtight