Described is an insulation module (1) for a vessel (2) used in a chemical plant. The module may take the form of a panel having an outer surface layer (3) and an insulation layer (5) secured to the outer surface layer (3). Mounting means (10) extends from the panel (1) and enables mounting of the insulation module (1) on an outer wall (2) of the vessel. An air gap (15) is provided between the insulation layer (3) and the outer vessel wall (2) when the insulation module is mounted (1) on the vessel (2).
