ISO 25457:2008 specifies requirements and provides guidance for the selection, design, specification, operation and maintenance of flares and related combustion and mechanical components used in pressure relieving and vapour-depressurizing systems for petroleum, petrochemical and natural gas industries. Although ISO 25457:2008 is primarily intended for new flares and related equipment, it can also be used in the evaluation of existing flare facilities. Further guidance and best practices are provided for the selection, specification and mechanical details for flares and on the design, operation and maintenance of flare combustion and related equipment. ISO 25457:2008 also includes a set of data sheets, together with instructions and guidelines, for use in communicating and recording design information.