This major work specifies requirements for the material, design, manufacture, inspection, testing and verification of compliance for unfired fusion welded pressure vessels manufactured from carbon, ferritic alloy and austenitic steels, aluminium, copper and nickel used in a wide range of process and energy industry applications.The term 'pressure vessel' as used in this specification includes branches up to the point of connection to the connecting piping by bolting, screwing or welding, and supports, brackets or other attachments directly welded to the pressure-containing shell.PD 5500 is applicable to vessels subject to electrical heating or heated process streams. It excludes, however, those that are subject to direct generated heat or flame impingement from a fired process.Key amendments for 2013:

The clarification of the use of design strength based on actual material properties
Corrections to Table 3.6-2
Requirements for pressure relief for vessels contained in casings
A correction to Table 5.7-2
Revisions to Figures D.1 and D.2
Clarifications regarding the calculations in Annex G.2
Recommendations for stress checks for local loads applied to reinforced nozzle walls
Revisions to Enquiry Cases 5500/133 (Flat unstayed ends of non-circular shape and associated flanges) and 5500/134 (Superseded referenced standards).

Additionally various internal and external references have been updated.