ISO 18888:2017 specifies standard rules for preparing, conducting, evaluating and reporting thermal performance tests on combined cycle and cogeneration power plants driven by gas turbines for base and part load operation with or without supplementary firing.

ISO 18888:2017 is applicable to

- thermal performance tests for general information,

- thermal acceptance tests for determining the performance of the combined cycle plant in relation to a contractual guarantee, and

- comparative tests designed to check the performance differentials of the combined cycle and cogeneration power plants, for testing before and after modifications, upgrades or overhauls.

It can be used to determine the following thermal performance test goals and expected values, under specific operating and reference conditions within defined test boundaries:

- electrical power output;

- heat rate or thermal efficiency;

- process steam and/or district heat w/o generation of electrical power output by means of a steam turbine.

ISO 18888:2017 does not apply to individual equipment component testing, which is covered by corresponding standards.

It is not intended to be applied to the following test goals:

- environmental testing for example emissions, noise;

- vibration testing;

- operational testing;

- absolute or comparative performance of specific components of the combined cycle covered by dedicated standards (e.g. gas turbines).