ISO 15859-13:2004

Overview - ISO 15859-13:2004 (Breathing air for space systems)

ISO 15859-13:2004 defines composition limits, sampling and test requirements for breathing air used in space systems. It applies to breathing air intended for purging and pressurization of launch vehicles, spacecraft, flight hardware, ground support equipment and facilities. The standard ensures that fluid entering the spacecraft or launch vehicle meets agreed purity and safety limits and can be applied to influent breathing air as well.

Key topics and technical requirements

• Composition limits: Specifies volume fraction ranges for major gases (e.g., oxygen and nitrogen) and maximum concentrations for contaminants such as carbon monoxide, carbon dioxide, water, total hydrocarbons, halogenated/chlorinated hydrocarbons, nitrous oxide and aromatic hydrocarbons.
• Sampling plan: Requires a documented plan covering sampling points, procedures, frequency, sample size, number of samples, test methods and responsibilities.
• Sampling responsibility and points: Unless otherwise specified, the supplier must sample and verify breathing air; sampling is normally done at the storage site or the flight vehicle interface.
• Sampling frequency: At minimum annually or per agreement between supplier and customer.
• Sample handling: Guidance on sample containers, simultaneous filling, direct withdrawal and direct connection to analyzers; sample containers should not be refilled after sampling.
• Rejection: Any sample failing to meet limits must be rejected and disposition specified by the customer.
• Test methods: Accepts multiple analytical techniques for verification, including gas chromatography, mass spectrometry, electrochemical and paramagnetic oxygen analyzers, infrared analyzers for CO/CO2, dew-point and hygrometer methods for water, flame-ionization for hydrocarbons, and human sniff testing for odour. Calibration and traceability provisions are required.

Applications - who uses ISO 15859-13

• Launch operators and spacecraft integrators for qualification of purge and pressurization systems.
• Breathing air suppliers and ground support service providers to demonstrate compliance.
• Test laboratories and quality assurance teams performing verification tests.
• Safety and life-support engineers specifying air quality for crewed systems.
• Procurement specialists referencing standard composition limits in supplier contracts.

Practical benefits include consistent supplier–customer interfaces, reduced contamination risk to flight hardware and crewed environments, and traceable test procedures for acceptance.

Related standards

• Other parts of ISO 15859 (Parts 1–12, e.g., Oxygen, Nitrogen, Water) cover additional fluids and test methods relevant to space systems.
• ISO 9000 is referenced for quality management and terminology.

Keywords: ISO 15859-13:2004, breathing air standard, space systems, sampling and test methods, breathing air composition, purge and pressurization, gas analysis, launch vehicle.