Where the ductwork leaves the compartment from which it serves (demonstrated in blue) it need to retain integrity and insulation fire ratings for the same time frame as the compartment through which it passes. The structural design of grease ducts performs an important role in industrial kitchen area safety. A https://fireresistingductworkinsu88990.onzeblog.com/36911999/the-single-best-strategy-to-use-for-fire-resisting-ductwork-insulation