ISO 14644-1 Class 7 for medical devices

ISO 14644-1 classifies cleanrooms by airborne particle concentration. Class 7 permits at most 352,000 particles of 0.5 micrometres and above per cubic metre in operation — roughly ten times class 6 and a tenth of class 8. In medical technology it is the most common level for assembly, packaging and cleanroom injection moulding of products that are subsequently sterilised.

The state the figure refers to is decisive. Measurement takes place at rest, in operation or as built — and the values differ considerably. A statement of "class 7" without the state says little; only "class 7 in operation" describes the environment in which work actually happens. Added to this are air change rate, the pressure cascade towards adjacent rooms, and qualification to ISO 14644-3.

For buyers, the most common error is to confuse the room with the process. A cleanroom provides conditions; whether the product stays clean depends on what happens inside — personnel airlocks, garments, material transfer, cleaning schedules, monitoring. Asking about those is more revealing than asking about the class.