Overview
ISO 16726:2018 - Space systems - Techno‑medical requirements for space vehicle human habitation environments - Requirements for the air quality affected by harmful chemical contaminants - defines environmental and techno‑medical requirements for spacecraft air quality. It establishes limits, monitoring and control measures for harmful chemical contaminants in manned spacecraft and habitable modules, and specifies requirements for contaminant removal systems that support crew life‑support. The standard applies to continuous in‑flight stays up to three years and includes provisions for nominal and emergency exposure durations.
Key topics and technical requirements
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Scope and applicability
- Integration with life‑support systems across all flight phases, including ground processing and emergency scenarios.
- Applicability to manned spacecraft (MSC), habitable modules and missions up to 3 years.
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Contaminant classification and limits
- Toxicological grouping (very toxic, toxic, low‑toxicity, slightly toxic) with associated limiting permissible concentration (LPC) and maximum allowable concentration (MAC) concepts.
- Definitions for maximum permissible concentration for single dose (MPC SD) for emergency exposures.
- Example contaminants listed (from the standard’s tables): formaldehyde, methanol, benzene, toluene, ammonia, carbon monoxide, various hydrocarbons and solvents.
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Air quality control and measurement
- Requirements for measurement methods, monitoring frequency and data verification.
- Annexed daily excretion rates for human‑derived gaseous contaminants to support source estimation.
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Contaminant removal systems
- Requirements for design, integration, verification and operation of systems that remove harmful chemical contaminants (part of the life support system).
- Material selection guidance for non‑metallic materials to reduce off‑gassing.
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Program governance
- Verification, monitoring and traceability requirements for flight programs to demonstrate compliance.
Practical applications and users
ISO 16726:2018 is used by:
- Spacecraft and life‑support system designers and integrators for specifying air‑quality requirements and designing contaminant control systems.
- Mission planners and systems engineers to set exposure limits and verification plans for long‑duration missions.
- Aerospace medical officers and flight surgeons for health risk assessment and monitoring protocols.
- Materials engineers and payload planners to select low‑offgassing materials and to estimate contaminant loads.
- Test laboratories and certification bodies for compliance testing and air quality validation.
Applications include design and verification of adsorption/scrubbing systems, preflight processing controls, emergency response procedures for contaminant release, and long‑duration habitat environmental planning.
Related standards
- ISO 17763 - higher‑level standard on human‑life activity support systems and equipment integration.
- ISO 16157 - related second‑level standard for crew habitation environments; ISO 16726:2018 is positioned as a third‑level standard relative to ISO 17763 and second‑level relative to ISO 16157.
Keywords: ISO 16726:2018, spacecraft air quality, harmful chemical contaminants, life support systems, LPC, MAC, MPC, human habitation environment, contaminant removal systems.