9. Cleanroom Testing and Monitoring

Purposes for initial test: Fulfill the design –working correctly and achieving the contamination standards Bench-mark: –establish the initial performance of the room to compare the results of routine check or contamination problem in the future. Training the staff: (most important) –initial testing is to familiarize and train the staff. –Only opportunity to understand how their cleanroom works and learn the methods used to test.

initial test Time – been built/ going to hand over/ reopen Tested standards – ISO Monitoring – to regularly check the room at the time intervals set by ISO

Principles of Cleanroom Testing Quantity: –Turbulently: dilute--air volume (supply and extract) –Unidirectional: remove –air velocity Direction (flow direction): –from clean area  less-clean areas to minimise the movement of contaminated air. Quality: –the air will not add significantly to the contamination within the room Distribution inside cleanroom – the air movement has no areas with high concentrations of contamination.

Cleanroom Tests

Air supply and extract quantities –turbulently ventilated cleanrooms  the air supply and extract volumes –unidirectional airflow  air velocity. Air movement control between areas: direction –The pressure differences between areas are correct. –The air direction through doorways, hatches, etc. is from clean to less-clean.

Filter installation leak test –a damaged filter –between the filter and its housing or –any other part of the filter installation. Containment leak testing –Contamination is not entering the cleanroom through its construction materials.

Air movement control within the room –turbulently ventilated : check that there are no areas within the room with insufficient air movement. –unidirectional airflow : check that the air velocity and direction throughout the room is that specified in the design. Airborne particles and microbial concentrations –final measurements of the concentration of particles and micro-organisms

Additional tests –temperature –relative humidity –heating and cooling capabilities of the room –sound levels –lighting levels –vibration levels.

requirements Guides provided by – the American Society Heating Refrigeration and Airconditioning Engineers (ASHRAE) in the USA, and –the Chartered Institute of Building Services Engineers (CIBSE) in the UK.

Testing in Relation to Room Type and Occupation State The type of tests to be carried out in a cleanroom depends on whether the room is unidirectional, turbulent or mixed airflow: –‘as-built’ ---in the empty room, –‘at rest’ --- the room fitted with machinery but no personnel present or –‘fully operational’---these occupancy states are discussed more fully in Section 3.4 of this book.

Re-testing to Demonstrate Compliance The cleanroom checked intervals, these intervals being more frequent in higher specified rooms: ISO

Monitoring of Cleanrooms Use risk assessment to decide what monitoring tests should be done and how often. The variables that are most likely to be monitored are: –air pressure difference This might be necessary in high quality cleanrooms such as ISO Class 4, and better. –airborne particle count This might be necessary in high quality cleanrooms such as ISO Class 4, and better. –where appropriate, microbiological counts.