A monitoring system for a multiple-walled fluid system with a first walled region including a flowing or stagnant fluid and at least one second walled region at least partially surrounding the first walled region. The first walled region and the at least one second walled region forming the multiple-walled fluid system, the first walled region being in fluid communication with the at least one second walled region, the at least one second walled region also being in fluid communication with the ambient environment. A data processing device for monitoring at least one pressure difference between a pressure in at least one a control volume and at least one second pressure in the at least one second walled region, a first control volume in fluid connection with the first walled region and the ambient environment. The at least one pressure difference indicating the status of the multiple-walled fluid system.