The ISO-14698-1,2 in the Annex A (Guidance on Measuring Airborne Bio-contamination), point A.3.2. specifies that “disturbance of unidirectional airflow by the sampling apparatus should be limited”; “exhaust air from the sampling apparatus should not contaminate the environment being sampled or be re-aspirated by the sampling device.” To address this guideline, a specialized stainless steel low speed wind tunnel (LSWT) was developed for the SAS Air Sampler to ensure constancy of airflow, temperature and particulate distribution for biological efficiency testing of the SAS. The LSWT certifies the three parameters of ISO- 14698-1,2: (A) air turbulence test, (B) exhaust air test and (C) environmental test.
The purpose of the air turbulence test is to verify that the unidirectional air flow (air laminar flow) is not disturbed by the air exiting the outlet of the SAS. The SAS is considered suitable if the air disturbance is less than 10-12 cm from the instrument outlet. The test is performed using a smoke tracer. The average distortion of the smoke is 10.15 cm and confirms the air flow deviation is insignificant for the Clean Room application.
The purpose of the exhaust air test is to verify that the exhaust air from the sampling apparatus is not contaminating and re-aspirated by the sampling device. The photo shows that the air exiting the sampler outlet is not re-aspirated but follows the unidirectional air flow.
The purpose of the environmental contamination test is to verify that the exhaust air from the SAS is not contaminating the environment being sampled. The test, performed with a particle counter positioned in a laminar flow bench at the back of the SAS outlet with a SAS Super 100 programmed and working with 1000 liters of air, confirms that there is no particle emission.
For the complete text of this study, please contact Bioscience International and request Application Note 99/53.
From Bioscience World, Autumn 2017
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