“Please tell me how to map this chamber!” This is a plea we hear at every Vaisala current Good Manufacturing Practice (cGMP) seminar. The question deals with environmentally controlled chambers, everything from small refrigerators or freezers, to walk-in chambers or even large warehouses regulated under cGMP rules and guidelines. Attendees who ask the question are usually more interested in how to map a chamber for maximum reliability or effectiveness as opposed to meeting the U.S. Food and Drug Administration (FDA) regulations. Like many of our answers, the first two words of our response are, “It depends.” After the third seminar where this question kept cropping up, we formulated an eight-step guidance document to help answer the question from an effectiveness perspective. An overview is presented here.

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