Metallurgical processing installation comprising a metallurgical vessel lined internally with water cooled panels. A vessel access tower (61) fits around vessel (11) and supports a coolant flow system (62) to provide for flow of cooling water to and from the cooling panels within the vessel through water inlet and outlet connections (42,43) distributed around the exterior of the vessel. Coolant flow system (62) includes large diameter water supply and return pipes (66,67) mounted on an upper part of the tower (61) to extend around the upper end of vessel (11), a first series of vertical dropper pipes (68) of relatively small diameter connected to the main water supply pipe 66 and extending downwardly to connections with the water inlet connectors for respecting cooling panels of the vessel and a second series of smaller diameter vertical pipes (69) connected at their upper ends to the main return pipe (67) and at their lower ends to undivided outlet connectors for the cooling panels in the vessel.