5.1 HP and HTHP corrosion tests are commonly used to evaluate the corrosion performance of metallic materials under conditions that attempt to simulate service conditions that involve HP or HTHP in combination with service environments. Examples of service environments where HP and HTHP corrosion tests have been utilized include chemical processing, petroleum production and refining, food processing, pressurized cooling water, electric power systems and aerospace propulsion.

5.2 For the applications of corrosion testing listed in 5.1, the service involves handling corrosive and potentially hazardous media under conditions of high pressure or high temperature, or both. The temperature and pressure usually enter directly into the severity of the corrosion process. Consequently, the laboratory evaluation of corrosion severity cannot be performed in conventional low pressure glassware without making potentially invalid assumptions as to the potential effects of high temperature and pressure on corrosion severity.

5.3 Therefore, there is a substantial need to provide standardized methods by which corrosion testing can be performed under HP and HTHP. In many cases, however, the standards used for exposure of specimens in conventional low pressure glassware experiments cannot be followed due to the limitations of access, volume and visibility arising from the construction of high pressure test cells. This guide refers to existing corrosion standards and practices as applicable and then goes further in areas where specific guidelines for performing HP and HTHP corrosion testing are needed.