This Practice includes two standard details (internals) applicable to the fabrication and installation of vessels and shell-and-tube heat exchangers. Each detail is also assigned a PIP document number (VEFV1124 and VEFV1125) for ease of reference. These details are mandatory when referenced in other PIP Practices. Those not referenced may be used at the discretion of the Designer (when specified on the Data Sheet) or at the Manufacturer's option. The details cover the more common accessories attached to vessels and heat exchangers.