Abstract: A method of setting a set point pressure of a back-up supply to supply gaseous product to the pipeline should pipeline pressure fall below the set point pressure. The pipeline and the back-up supply are part of a gas distribution network also having a production facility for supplying the pipeline with the gaseous product at the target pressure for distribution to customers connected to the pipeline. The set point pressure for the back-up gas supply is continuously calculated by calculating a series of pressure drops for each of the customers being fed by the pipeline and then determining required customer site pressures by adding the minimum contracted supply pressure for each of the customers to their respective pressure drops. The maximum required customer site pressure is utilized as the set point pressure for the back-up supply.