KI-Discus testing should be carried out at intervals appropriate to the cabinet, its application, the manufacturer’s recommendations, the laboratory’s risk assessment and the applicable standards or procedures. Annual testing is commonly used for microbiological safety cabinets, although more frequent testing may be appropriate for higher-risk applications or where cabinet performance could be affected by intensive use.

Testing should also be considered following significant maintenance, repairs, relocation or modifications that could affect containment performance.

Impact Technical Services can advise on an appropriate testing programme based on your cabinet and laboratory requirements.

KI-Discus testing is an established method for assessing operator and aperture protection performance in open-fronted microbiological safety cabinets and is associated with the EN 12469 testing framework. BS EN 12469:2000 includes the potassium iodide method for assessing operator protection, while the standard has now been restructured into a series of standards, including BS EN 12469-5:2025, which covers the installation, commissioning and routine testing of biological safety cabinets.

The appropriate testing requirements depend on the cabinet type, application and stage of testing. Impact Technical Services can advise on the relevant testing requirements for your microbiological safety cabinet and provide the appropriate performance testing and reporting.

Microbiological safety cabinet testing is the process of assessing whether a safety cabinet is operating correctly and providing the intended level of protection for laboratory personnel, the environment and, where applicable, the work being carried out inside the cabinet.

Testing can include airflow measurements, containment testing, HEPA filter integrity testing, alarm checks and other performance checks, depending on the cabinet and its application.

KI-Discus testing specifically assesses containment and operator protection. DOP testing, by comparison, assesses the integrity of HEPA filtration, meaning the two tests provide different information and can form complementary parts of a cabinet’s overall testing programme.

BS EN 12469 covers performance requirements and testing of microbiological safety cabinets, with the 2025 series now providing more specific requirements for different cabinet classes and routine testing.

KI-Discus and DOP testing assess different aspects of microbiological safety cabinet performance.

KI-Discus testing assesses containment and operator protection by introducing a potassium iodide aerosol and measuring whether particles escape through the cabinet’s working aperture.

DOP testing assesses HEPA filter integrity by challenging the filter with an aerosol and measuring whether any aerosol penetrates through the filter or escapes through leaks in the filter installation.

In simple terms:

KI-Discus – Cabinet containment and operator protection

DOP – HEPA filter integrity and leakage

Airflow testing – Air velocity and airflow performance

KI-Discus and DOP testing are therefore not interchangeable. Depending on the cabinet and application, both may be required as part of a comprehensive testing and maintenance programme.

A failed KI-Discus test indicates that the cabinet has not demonstrated the required containment or operator protection performance under the test conditions. The cause should be investigated before the cabinet is returned to work where effective containment is required.

Potential causes can include incorrect or unstable airflow, cabinet damage, mechanical faults, problems with filters or seals, unsuitable installation conditions, or disturbances around the cabinet’s working aperture.

Impact Technical Services can investigate the cause of a failed test, recommend or undertake remedial work where appropriate, and retest the cabinet to verify that containment performance has been restored. A clear test report provides a record of the results and any actions required.

KI-Discus testing can be used to assess the operator and aperture protection performance of open-fronted microbiological safety cabinets, including Class I and Class II cabinets. The KI-DISCUS system is also designed for certain hybrid and specialist containment applications.

The appropriate test method depends on the cabinet design, intended use and applicable testing requirements. Impact Technical Services can advise on whether KI-Discus testing is appropriate for your cabinet.

A KI-Discus test report records the testing undertaken, the results obtained and the cabinet’s Operator Protection Factor, together with any relevant observations or recommendations. This provides laboratories with documented evidence of the cabinet’s containment performance and a useful record for maintenance, quality and compliance purposes.

Where issues are identified, Impact Technical Services can explain the findings and advise on appropriate remedial action and retesting.