In my view there is no need to have sampling booth in Class A or Class B areas.
GMP and regulatory guidance tells us to “Sample the product under Laminar flow benches and also to have various sampling booths for Excipients, Active Ingredients and Preservatives/Vitamins”.
The reason is simple. You should not have an intermixing with other substances during sampling.
Secondly if 1 or 2 products to be sampled at same time they can be sampled in different booths as per their nature.
After every sampling procedure we have to clean the sampling booth properly.So it takes time to the next sample to be sampled.
If you observe the sampling booth design it has a HEPA at the top and a return at the bottom of the booth (One return at the bottom side behindthe weighing balance Or you have 2 returns either sides of the walls of the sampling booth.
First of all we have to know how it works and why it is put there. The reason is that product dust that comes out during sampling will go into the return rather than the guy who is sampling or dispensing.
Every API is a drug and certainly have effects on humans who have no etiology of disease.
To prevent such risks sampling booths are arranged in Warehouses.In no guideline it says it should be housed in class C or ClassB back ground areas.
There are speacial provisions added only to Cytotoxic sampling and Immunosupressent sampling.
One need to read the guideline and know the place and purpose of such guideline.
Sampling will be done in Oral solid or Liquid and Ointment facilities too. It is rather unnecessary and waste of money to place such sampling booths in Class B areas. One needs to go by logic of what products they are manufacturing rather than sticking to singile guideline.
In case of Gigastorm it is allowed and as per GMP or any regulatory document and no need to worry about that.
There is Place for everything in GMP and Everything has a place too.