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Simplifying Complexity. Delivering Safety.
Simplifying Complexity.
Delivering Safety.

Hydrogen analysis for zero carbon transport

H2 refuelling station


Working with a leading gas analyser manufacturer on hazardous area protection for a hydrogen system



As the hydrogen distribution network for fuel cell powered vehicles grows, so does the need to guarantee the quality of the hydrogen, especially as fuel cells are sensitive to contamination. A leading measurement and analytical instrument manufacturer wished to develop a hazardous area version of their standard H2 analyser. They came to Expo because of our expertise in hazardous area solutions for safe area equipment, as well as our experience with flammable gas analysers. 


Project Brief

Work with the customer to develop a hazardous area enclosure solution for an existing H2 quality analyser that could be certified for zone 2 areas, such as H2 dispensing installations.


  • If possible the client wished to avoid excessive modification of the analyser for the hazardous area application.
  • Although the analyser requires only a small sample flow of H2, the enclosure would still be classed as having an internal source of release (ISOR - the potential for a release of hazardous gas inside the protected enclosure itself). This requires additional safety features and a more complex certification process under standard 60079-2.


  • Expo's engineers worked with the client to design a bespoke Ex p enclosure with a continuous flow (CF) X purge system, plus a purge interface unit for power & signal control. After the initial enclosure purge, the CF system provides a constant air flow through the enclosure at a sufficient rate to dilute any leak of the incoming H2 sample gas to below 25% of the lower explosive limit (LEL) as required by the standard 60079-2.
  • As an additional safety feature, Expo installed a certified H2 leak detector inside the enclosure, interlocked to the incoming power.
  • Expo's consultancy team developed the certification plan along with a Notified Body to deliver the required certification. This was necessary as systems with ISOR fall outside of Expo's standard populated certificate.


Expo Products and Services
  • Custom enclosure service
  • Expo Minipurge Type X
  • Minipurge interface unit (MIU)
  • Design services
  • Certification consultancy

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For more information contact your local partner to speak to one of our purge and pressurization experts or contact us.