The tube bundle comprises of the heat exchanger tubes, tube sheets, baffles and tie rods which hold the bundle together. The tubes can be welded and/or expanded into the tubesheets. The baffles are located on the shell side to control the heat-transfer rate by increasing the flow rate accross the tubes and to support the tubes. Over time, tubes can be damaged by vibration, corrosion, erosion or thermal stress fatigue. Replacement tube bundles including tubesheets can be custom manufactured to replace existing units that require replacement. Replacement bundles can be certified to the ASME Code (/TEMA) and Canadian CRN regulations and requirements.