Industrial gases carry hazards that behave unlike anything else in process manufacturing. Oxygen enrichment turns ordinary materials into fire hazards. Inert gas displacement kills without warning or smell. Cryogenic temperatures embrittle steels that are entirely suitable at ambient. And most of the plant operates at pressures that place it firmly within the scope of the Pressure Systems Safety Regulations.

Projex Solutions provides engineering design, process safety support and project delivery for industrial gas production, compression, cryogenic storage and distribution, including gas systems installed on customer sites.

What makes this work different

Asphyxiation is the most under-assessed hazard on these sites. Nitrogen, argon and carbon dioxide give no warning at all. Confined and semi-confined spaces, pits, and areas beneath cryogenic vessels require ventilation design and oxygen depletion monitoring based on credible release scenarios rather than a generic risk assessment.

Oxygen service is a materials and cleanliness discipline. Oxygen-enriched atmospheres dramatically lower ignition energy and raise flame temperature. Material selection, velocity limits, valve selection and cleanliness to oxygen service standards are design requirements, not good practice.

Cryogenic design constrains materials. Low temperature embrittlement, thermal contraction at pipe supports and expansion relief on trapped liquid sections are recurring design issues on cryogenic systems.

Pressure systems duties are extensive. PSSR 2000 with guidance L122 (2014) requires a written scheme of examination, and on gas plant the number of systems in scope is high.

Industry codes carry the practical detail. BCGA Codes of Practice and EIGA documents provide the working guidance for bulk storage, cryogenic tanks and installations at user premises. Revisions are issued frequently, so we work from the current revision at the time of design rather than an office copy.

Hydrogen is a distinct case. Wide flammability range, very low ignition energy and buoyant dispersion mean hydrogen cannot be area-classified by analogy with other fuel gases.

Where we help

  • Asphyxiation risk assessment, ventilation design and oxygen depletion monitoring strategy
  • Oxygen service design, covering materials, velocity, cleanliness and valve selection
  • Cryogenic system design, including materials selection, supports, insulation and trapped-liquid relief
  • Pressure systems design developed with the written scheme of examination under PSSR 2000
  • DSEAR assessment and hazardous area classification to BS EN IEC 60079-10-1:2021 and EI 15 (5th edition), including hydrogen service
  • HAZOP facilitation, LOPA and SIL determination to BS EN 61511
  • Bulk storage installation design to current BCGA and EIGA guidance
  • Customer-site installation design, where the gas supplier’s plant sits within someone else’s operation
  • Feasibility, FEED, detailed design and EPCM delivery under ISO 9001:2015

Typical reasons clients get in touch

  • Asphyxiation risk in pits, basements or plant rooms has not been properly assessed
  • An oxygen system needs designing or reviewing for materials and cleanliness compliance
  • A cryogenic installation requires modification, relocation or capacity change
  • Written schemes of examination need to be reflected in the design rather than retrofitted
  • Hydrogen is being introduced and existing area classification does not cover it
  • An installation is being placed on a customer’s site and both parties’ duties need resolving

Related

Part of our work across the chemical sector and the energy sector.

Standards and regulations we work to

  • PSSR 2000, with guidance L122 (2014), including written schemes of examination
  • DSEAR 2002, with ACOP L138 (second edition, 2013)
  • BS EN IEC 60079-10-1:2021 and EI 15 (5th edition, October 2024), including hydrogen service
  • COMAH 2015 where thresholds are crossed
  • BCGA Codes of Practice and EIGA guidance for bulk storage, cryogenic vessels and installations at user premises, worked to the revision current at time of design
  • Confined Spaces Regulations 1997 where entry is foreseeable
  • PUWER 1998, with ACOP L22 (fourth edition, 2014, amended 2018)
  • CDM 2015 and ISO 9001:2015

Frequently asked questions

Why do you treat asphyxiation as the priority hazard?
Because it kills people who had no warning. Nitrogen, argon and carbon dioxide are colourless and odourless, and oxygen depletion produces no useful physiological alarm before incapacitation. Pits, basements, vessel interiors and areas beneath cryogenic tanks need ventilation and monitoring designed against credible release scenarios, not a generic assessment.

What is different about designing for oxygen service?
Oxygen enrichment dramatically reduces ignition energy and raises flame temperature, so materials, velocities, valve selection and cleanliness all become design requirements rather than good practice. Components suitable for air service are not automatically suitable for oxygen.

Can we area-classify hydrogen the same way as natural gas?
No. Hydrogen has a very wide flammability range, extremely low minimum ignition energy and strongly buoyant dispersion behaviour. Classification by analogy with other fuel gases produces the wrong answer, and this is an increasingly common error as hydrogen projects proliferate.

We are installing a bulk vessel on a customer’s site. Whose duties are whose?
That needs establishing in writing early. Both parties hold duties, and the interface between the gas supplier’s equipment and the customer’s operation is where they are most often left ambiguous.

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