Overview
ISO 10648-2:1994, "Containment enclosures - Part 2: Classification according to leak tightness and associated checking methods," defines a uniform framework for classifying and testing the leak tightness of containment enclosures. The standard supports safe handling of radioactive/toxic substances and protection of personnel and the environment, and it sets out test regimes for factory manufacturing tests, laboratory acceptance tests, pre-commissioning checks, and periodical in-service tests.
Key topics and technical requirements
- Classification by leak tightness: Containment enclosures are categorized by their hourly leak rate (Tf). Classes range from the most stringent (for controlled inert atmospheres or high-purity needs) to less stringent classes for enclosures with potentially hazardous atmospheres. Leak rates are assessed at normal operating pressure and more stringent acceptance conditions.
- Test pressures: Operational checks are typically performed at around 250 Pa relative pressure; acceptance tests are commonly performed at about 1 000 Pa to provide a more stringent verification.
- Leak testing methods: Three primary methods are described:
- Oxygen method - measures the rise in oxygen concentration after purging an enclosure with inert gas. Recommended for the most stringent classes and for measuring very low leak rates. Requires an oxygen analyser, inert-gas purge and circulation, and calibrated instrumentation.
- Pressure change method - measures pressure rise or decay over time after isolating the enclosure at negative (or positive) pressure. Widely used; sensitive to temperature and atmospheric changes; requires thermometers, barometer and precision differential pressure gauge.
- Constant pressure method - used where appropriate for higher-leak-rate classes; maintains a set pressure and measures input or loss to infer leak rate.
- Measurement conditions and reporting: The standard specifies acceptable ranges for temperature and atmospheric variation during tests, instrumentation calibration, and required contents of test reports (measured values, test conditions, evaluation and incidents).
- Scope limits: ISO 10648-2 excludes pressurized process vessels, sealed radiation sources, transport packagings for radioactive materials and nuclear reactor primary circuits/vessels.
Practical applications
- Testing and certifying gloveboxes, hot cells, containment lines, sterile aseptic enclosures and other controlled-atmosphere systems used in:
- Nuclear and radiological laboratories (radiation protection applications)
- Pharmaceutical and sterile manufacturing environments
- Research facilities handling toxic or sensitive materials
- Use cases include acceptance testing at supplier sites, pre-commissioning verification, routine leak-tightness surveillance and regulatory compliance checks.
Who uses this standard
- Manufacturers and designers of containment enclosures
- Test laboratories and commissioning teams
- Facility operators and maintenance staff performing periodic testing
- Regulatory and licensing authorities overseeing safety and environmental protection
Related standards
- ISO 10648-1 - Design principles for containment enclosures
- ISO 6144 - Gas analysis and calibration methods referenced for oxygen-method calibration
Keywords: ISO 10648-2, containment enclosures, leak tightness, leak testing methods, oxygen method, pressure change method, constant pressure method, acceptance test, periodical tests, nuclear radiation protection.
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