Exhaust Systems WG

ETN Exhaust Systems Working Group

The Exhaust Systems Project was initiated in 2009, and initially chaired by Statoil, as they experienced problems with their exhaust systems. The goal was to bring together operators facing similar problems with their exhaust systems, as well as exhaust system designers and external expertise and support, who could address the problems by developing a common standard for the design of gas turbine (GT) exhaust systems.

In the first phase of the project, the group carried out a gap analysis, uploaded an index to facilitate the creation of the standard, and collected valuable material. Both Shell and Statoil shared their internal standard. In the autumn of 2010 Total took over the lead of the project group. The shared standards were then merged as well as supplemented by additional internal documents, which had been provided by exhaust system designers, such as Mjørud and BIHL.

During various meetings it was decided to focus on the creation of the Waste Heat Recovery Unit (WHRU) standard and later amend the existing API standard on Heat Recovery Steam Generators (HRSG). The different organisations have reviewed their section of the standard which will be rewritten to fit ISO standard regulations.

Moreover, it has been decided that the standard should highlight the possibilities and importance of Computational fluid dynamics (CFD) simulation. The group agreed that the best way to validate the CFD code is to use a benchmark case which can be included in the appendix of the standard. ETN, Total and Frazer-Nash have written the Description of Work (DoW) for the benchmark test, explaining the benefits of the study and including a clear timeline and financial overview.

The ETN standard was issued in 2015 (see “Documentation” tab). In February 2016 the ISO TC 192 initiated a new work item aiming at drafting an ISO standard on the WHRU based on the ETN standard. As liaison member of the ISO TC192, ETN followed the development of the ISO standard.

In October 2019 the final draft of the “ISO 21905 – Gas turbine applications – Requirements for exhaust and heat recovery unit” was submitted for formal approval to the ISO/TC 192 WG 16. The ISO standard was published in March 2020. Work has yet to start on the HRSG based version of the standard.


Interested to join this Working Group? Please send an email to info[at]etn.global


Not a member yet? Find out more about the ETN membership here.



Ugo Simeoni (ETN)


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