During such a fire, the temperature within the duct can be as much as 800°C and past. This large temperature raise demands higher-end, specialised insulation options to protect the people within these structures. ROCKWOOL fire rated duct products can help minimise the chance this poses, and guard lives. Related resources https://simontujyn.blogunteer.com/35328398/caswell-group-things-to-know-before-you-buy