ISO 22538-1:2007

Overview

ISO 22538-1:2007 - Space systems - Oxygen safety - Part 1: Design of oxygen systems and components provides a structured design process for oxygen systems and their components used in space applications. The standard applies equally to ground support equipment, launch vehicles and spacecraft, and focuses on managing the unique hazards of oxygen service (gaseous and cryogenic). It frames design activities-from specifications and materials selection to design reviews, testing and hazard analysis-to reduce ignition and combustion risks in oxygen-enriched environments.

Key topics and technical requirements

• Scope and terminology
  • Defines direct/indirect oxygen service, oxygen-enriched atmospheres, and roles such as qualified technical personnel.
• Design approach
  • Emphasizes starting designs with safety-focused specifications and avoiding unnecessary risk.
  • Requires integrated safety planning through the design lifecycle.
• Design reviews and analyses
  • Mandates staged reviews: Preliminary Design Review (PDR), Critical Design Review (CDR), and specialized reviews (FMECA, SSA/SR, TRR, EPR, ORI).
  • FMECA and hazards analyses must address single-point and single-barrier failures, ignition modes, contamination and secondary hazards (e.g., leakage to electrical systems).
• Materials and components
  • Highlights criticality of materials selection for high-pressure/high-temperature gaseous oxygen (GOX) and cryogenic liquid oxygen (LOX) systems and refers users to companion documents for material selection guidance.
  • Advises avoiding flammable materials where possible and mitigating ignition sources when their use is unavoidable.
• Testing and qualification
  • Recommends prototype testing with inert media initially, followed by acceptance tests with clean oxygen after a hazards analysis.
  • Includes pressure integrity, leak, life-cycle and functional tests; qualification and acceptance tests should be jointly developed by suppliers, test facilities and end-users.
• System-specific guidance
  • Contains dedicated guidance for high-pressure gaseous and cryogenic systems, piping, vessels, joints and components, plus electrical design considerations in oxygen service.

Applications and who uses this standard

ISO 22538-1 is directly applicable to:

• Aerospace systems designers and engineers working on oxygen delivery, life support and propulsion subsystems
• Safety and systems engineers performing oxygen hazards analysis, FMECA and system safety reviews
• Test facility managers and technicians responsible for component qualification and acceptance testing
• Manufacturers of oxygen-system components, ground support equipment and spacecraft subsystems
• Program managers and certification authorities ensuring compliance with oxygen safety practices

Practical uses include creating design specifications, selecting compatible materials, defining inspection/test plans, and documenting safety reviews to reduce ignition risk in oxygen-enriched environments.

Related standards

• ISO 22538-2: Selection of metallic materials for oxygen systems and components
• ISO 22538-3: Selection of non-metallic materials for oxygen systems and components
• ISO 22538-4: Hazards analyses for oxygen systems and components
• Parts under preparation: Part 5 (Operational and emergency procedures), Part 6 (Facility planning and implementation)

Keywords: ISO 22538-1, oxygen safety, space systems, design of oxygen systems, GOX, LOX, oxygen hazards analysis, FMECA, materials selection, oxygen-enriched atmosphere.