ISO 5371:2025

Overview

ISO 5371:2025 - Containment high efficiency filtration unit (CHEFU) in ventilation system of biosafety facilities - defines basic performance requirements and corresponding test methods for CHEFUs used to remove harmful bio-aerosols in biosafety and other controlled environments. The standard covers design, construction, testing and verification (including decontamination and leakage identification) of containment filtration units. It is explicitly not applicable to filtration units for removing radioactive aerosols.

Key topics and technical requirements

• Scope & applicability: Performance and test methods for filtration units intended to remove biological aerosols in biosafety labs, vaccine manufacturing and similar controlled facilities.
• Design and construction: Materials must be resistant to disinfectant corrosion; inner surfaces should inhibit microbial growth and be accessible for cleaning and decontamination.
• Visual and mechanical requirements: Appearance (smooth, free of defects), resistance to air flow, and provisions for pressure-differential monitoring during service.
• Structural integrity tests: Vacuum deformation and air tightness tests to verify enclosure integrity under operational conditions.
• Leakage and filtration performance:
  • Leakage test of installed HEPA filter, including scanning leak tests and total penetration leakage tests.
  • Specified aerosol generation and measurement approaches (references to Laskin nozzles and thermal generators for test aerosols).
• Decontamination: Requirements and verification methods, including use of biological indicators (BIs) and defining decontamination effect level (DEL).
• Leakage identification: Methods and test apparatus to detect and locate leaks.
• Test program guidance: Recommended timelines for design verification, factory testing and in‑situ testing; procedures for evaluation of test results.
• Annexes: Normative test methods for air tightness and aerosol concentration uniformity; informative guidance on CHEFU decontamination verification.

Practical applications and users

ISO 5371:2025 is intended for:

• Filter and CHEFU manufacturers - to design and certify containment filtration units.
• HVAC and ventilation system designers - to size and specify CHEFUs for biosafety facilities.
• Biosafety laboratory managers and facility operators - to validate installation, maintenance and decontamination procedures.
• Validation and testing laboratories - to perform leakage, aerosol and decontamination verification tests.
• Regulatory and procurement teams - to specify performance criteria in contracts and compliance documentation.

Use cases include terminal HEPA/CHEFU installations in high‑containment labs, duct‑mounted containment filters with in‑situ service strategies, vaccine production cleanrooms, and animal laboratory ventilation systems.

Related standards (normative references)

• ISO 29463 series (HEPA filter classification and test methods)
• ISO 14644‑3 (test methods for cleanrooms)
• ISO 21501‑1 / 21501‑4 (particle sizing / airborne particle counters)
• Other referenced ISO documents for materials and test equipment

Keywords: ISO 5371:2025, CHEFU, containment high efficiency filtration unit, biosafety facilities, HEPA, air tightness, leakage test, decontamination, bioaerosol.