The Storage and Distribution must be maintained in a recirculating hot mode. This is the normal operating mode. The WFI Distribution loop is maintained at 85±5oC. The system is considered self-sanitizing and there is no need to do a sanitization of the main distribution loop. Those portions of the piping system, Point of Use heat exchangers and piping downstream of the Loop Valve must be routinely sanitization the scheduled outlined in this SOP.