A. Introduction

Pressure vessel codes or standards, which cover much of the mechanical design of shell-and-tube heat exchangers, are usually used voluntarily or under the terms of a contract. In some countries they also fulfil statutory or regulatory functions; indeed in several countries the national code is legally enforced, and compliance with the code is mandatory for items supplied to that country, whether built there or imported. Table 1 shows the principal codes covering heat exchanger design, the approving organisations, regulations and other acceptable codes applicable in a range of countries. A more complete list covering 117 countries is given in British Standards Institution (2006).

In order to ensure the integrity of the equipment and thus public safety, some of the above regulations require as part of the process of allowing a vessel or heat exchanger to be used in the country, that the design and construction are vetted by an independent inspector. The use of approved QA systems or of independent inspections are also embodied into some codes and standards to provide the assurance of compliance with the code and thus the provision of the integrity demanded by the risks associated with certain industrial processes.