Facilities, Equipment, and Environmental Monitoring
Rooms, air, and evidence
The physical hierarchy is ISO 5 at the primary engineering control (PEC - LAFW, BSC, CAI, CACI), ISO 7 in the buffer area, and ISO 8 in the ante-area where garbing occurs. A segregated compounding area (SCA) is a permitted alternative for lower-category work but carries restricted BUDs and no buffer/ante separation. HEPA-filtered air is delivered at defined air-change rates, and the buffer must be positive to the ante-area, which is positive to the corridor - at least 0.02 in. w.c. - so contamination moves outward, never inward. The PEC must be certified by a qualified certifier at least every 6 months, and after relocation or significant repair.
Environmental monitoring supplies evidence that the controls work: nonviable particle counts, viable air sampling, surface sampling, and gloved fingertip/thumb sampling. Know the difference between certification (scheduled, performed by a qualified certifier) and routine monitoring (performed by staff on a defined frequency), and which sample type answers which question - air and surfaces describe the room; gloved fingertips describe the person.
Traps in questions: mixing up ISO classes (ISO 5 is cleanest, ISO 8 the least clean of the three); assuming a certified hood guarantees sterility; forgetting that particle counts are nonviable and cannot substitute for microbial sampling; ignoring pressure alarms.
Rule of thumb: the PEC protects the product; the room protects the PEC. If a required pressure relationship is lost, stop compounding, notify, and document.