Taking samples for Air change per hour (ACPH)


How many samples need to be taken for ACPH? For instance, our granulation room has a volume of 200m^3 and the spec is NMT 20 times/hour, how can we calculate the average ACPH?

Thank you.

The formula for calculating cleanroom ACH:
Air changes / hr = CFM X 60min / Volume of Room
The rate of cubic feet per minute is recalculated into cubic feet per hour, which is then divided by the volume of the room (height X width X length).

Also you can refer ISO14644-4 and USP <797> and USP <800> for further reading and clarity.

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