Methods for carry out airflow pattern for clean room grade B,C,D

Validation
1

Pl. let me know the SOP to carry out Air flow study for Grade B,C & D .

Is it required to carry out smoke study at regular intervals or during re-validation of HVAC system ?

2

Yes, it’s mandatory

3

It is required during re validation of HVAC system.

4

You can refer ISO guideline ISO-14644 for complete info.