Area qualification

Dear validation engineers,
I hope you are doing well
my question for re-new areas (corridor and production area) the corridor has class (D) and the production area is a class (A over B) so, Is the requalification must be done for the corridor? and if needed what is the requirements for requalification?
best regards

all areas under classification must be requalified, class A and B more frequent than class C and D. Requalification is performed based on particle count, pressure differential, at rest monitoring. Refer to ISO14644 1-4, these will tell you all you need to know.

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