Properties of Deluge Water Spray in Offshore Installations

The Norwegian petroleum industry has developed a standard for the technical safety of offshore installations. When dimensioning accidental load with this standard, the deluge or fire water spray may be considered as a risk reducing measure for equipment and pipes, but not for the structural elements or fire partition. In risk evaluation, proper documentation of the suppression effect and reliability has to be provided when water is used as a fire risk reduction measure. The standard states that the deluge system shall be automatically activated upon confirmed gas detection when it is used for explosion mitigation. This work presents results from an image-based method for characterizing the flow properties of the spray from a medium velocity nozzle. The measurements are performed at different locations in the spray to fully characterize the flow pattern of the nozzle. This will result in a large amount of data and needs to be simplified to fit the input of CFD codes. This can be done in different ways and one method is given here.