This International Standard specifies requirements and gives recommendations for the mechanical design, material selection, fabrication, inspection, testing and preparation for shipment of shell-and-tube heat exchangers for the petroleum, petrochemical and natural gas industries. This International Standard is applicable to the following types of shell-and-tube heat exchangers: heaters, condensers, coolers and reboilers. This International Standard is not applicable to vacuum-operated steam surface condensers and feed-water heaters.