Gas turbines-ATEX compliance case study

ATEX compliance model


Business Need
To verify the safety and conformance to regulations of gas turbine enclosures on offshore platforms.



The considerable power demands of offshore production and processing platforms are usually met by the use of gas turbine power generators that provide reliable and cheap energy. However, these units are encased within acoustic enclosures, which create the risk of explosion as the hot surfaces and natural gas combine. The design of these enclosures is governed by the pan-European ATEX directives and UK-specific DSEAR regulations, which require assurances that the largest undetectable gas leak will not lead to an uncontained explosion.


Frazer-Nash worked under a joint industry project with the Health & Safety Executive to develop a process that would provide this assurance. Using a mathematical modelling technique called Computational Fluid Dynamics (CFD); we simulated the ventilating airflow throughout the turbine enclosure.

The CFD model highlighted poorly ventilated areas inside the acoustic enclosure where escaped fuel gas could pool. This identified a series of possible gas leak scenarios which could potentially lead to an explosion. The model also established whether a cloud of sufficient size could develop without tripping the gas detectors in the ventilation exhaust.

Using this data, we then proposed a number of modifications to the enclosures, including:

  • Using baffles and turning vanes to control the ventilation flow and remove dead zones
  • Modifying the ventilation flow volume
  • Modifying the number, location, and setpoints of gas detectors

The Health & Safety Executive was satisfied that once the acoustic enclosures had been amended, they would fully comply with the DSEAR and ATEX Regulations.


Advanced CFD is just one of the tools Frazer-Nash utilise to calculate the probability and impacts of overpressure explosion. We also use FLACS (FLame ACceleration Simulator)

which is an advanced tool for the modelling of ventilation, gas dispersion, vapour cloud explosions and blast in complex process areas.