A. General

(a) Introduction

PD 5500 as is usual with national pressure vessel is “updated” regularly. The version covered here is the third revision of PD 5500: 2000, September 2001 (British Standards Institution, 1997). It will continue to change, possibly prompted by reference here to some of its shortcomings. PD (Published Document) 5500 replaces BS 5500 which has now been withdrawn because its status as a national standard would be incompatible with BSI’s obligations to CEN when the European standard for unfired pressure vessels, EN 13445 (European Committee for Standardisation 1999), is published. PD 5500 has the same scope and content as had BS 5500 and differs only in so far as it does not retain the latter’s status as a national standard. This brings the UK into line with several other major European countries whose existing national pressure vessel codes are not national standards.

References in Section 419 to PD 5500 begin with “PD”, to distinguish them from references to HEDH.

The general method adopted herein for each topic is to indicate where it is dealt with in PD 5500, followed by such comments and explanation as are thought to be helpful. Attention is drawn to important bits that may easily be missed. The British Standards committee responsible for this code has tried over the years to make it clear and has provided explanatory material (either as notes in the text or separate documents) that it is not our task to duplicate here.