Hi!

I am in the process of preparing the recovery study protocol for AHUs in our clean room.

Your inputs will help me in creating the good protocol without missing any important points.

Thanks in advance.

Regards / Raghu

Hi!

I am in the process of preparing the recovery study protocol for AHUs in our clean room.

Your inputs will help me in creating the good protocol without missing any important points.

Thanks in advance.

Regards / Raghu

Refer ISO 14644 Annex B.13 for details on Recovery test

Thanks.

Regards / Raghu

I have referred ISO 14644-3 (First edition 2005-12-15).

Section B.12.1 states that “Recovery test is not recommended for ISO classes 8 and 9”.

Is there any reason for why it has not been recommended?

Ours is ISO class 8 area and there is a possibility that occupancy of clean room is less (i.e) some times AHU is in running mode even though there is no activities are performed in clean room.

By considering the above we have recommended for the recovery study.

Is it possible to manage the above situation without recovery study? If so how it shall be justified?

Or

whether we need to go for recovery study even though guideline is not recommending for the test.

Regards / Raghu

I have referred ISO 14644-3 (First edition 2005-12-15).

Section B.12.1 states that “Recovery test is not recommended for ISO classes 8 and 9”.

Is there any reason for why it has not been recommended?

Ours is ISO class 8 area and there is a possibility that occupancy of clean room is less (i.e) some times AHU is in running mode even though there is no activities are performed in clean room.

By considering the above we have recommended for the recovery study.

Is it possible to manage the above situation without recovery study? If so how it shall be justified?

Or

whether we need to go for recovery study even though guideline is not recommending for the test.

Regards / Raghu

Hi Raghu,

If you refer ISO 14644-3, it states that Particle Count Test, Air Pressure Difference and Airflow are mandatory tests to show continuing compliance while the other tests like Installed Filter Leakage, Containment Leakage, Recovery and Airflow Visualization are additional optional test.

Hope that will give justification.

It is not recommended for ISO class 8 or 9 due to the nature of the test: if you increase the concentration of particles to 10 times the normal concentration then you go beyond the capabilities of the particle counters available. Even at lower concs (higher Grade areas) you still may have problems working at those high particle levels and may damage your particle counter- the ISO recomends using a graph to predict the recovery rate rather than actually testing in this case also.
Recovery Rate determination as per ISO is best for a Grade A, highest cleanliness class room.

Thanks.

Regards / Raghu