All commercial functions must have some method of canopy extraction or ventilated ceiling mounted. Ample air flow is needed for virtually any products that generates warmth, fumes, smells, or steam. In all instances the joints and seams are going to be welded, the only exception are People manufacturing unit manufactured https://grease-tight-extract-duct12334.blognody.com/41298917/commercial-kitchen-extract-systems-for-dummies