Grease or kitchen extract ductwork is generally made from metal, commonly galvanised sheet steel in an oblong or spiral-wound circular structure, but can be made from all-welded ‘black iron’ or stainless steel. This grease and oil can Create up if left unchecked, bringing about a fireplace hazard inside the ductwork. https://basement-extract-systems56677.bluxeblog.com/61069916/the-greatest-guide-to-kitchen-extract-systems