Breaking Down Cleanroom Grades

A Breakdown of Cleanroom Grades & Standards

Europe, Australia, and some Asian countries have a set of standards that cleanrooms used for the manufacture of sterile medicinal products should adhere to. The standards dictate that sterile products should be manufactured in clean areas with entry into the areas by personnel and materials through airlocks. Filters should efficiently clean the air passing into the area.

Still, it’s impossible to completely eliminate contamination in a cleanroom; these measures only mean it’s controlled to acceptable levels. That is done in the following ways:

• The internal surface: Every surface in the cleanroom should be smooth and impenetrable so that it doesn’t generate its own contaminants such as dust or corrosion. That also makes it easier to clean the surface when surfaces aren’t prone to cracking, shattering, or creasing.
• Cleanroom air control: Cleanrooms need a lot of air to stay clean. Air systems circulate air through the cleanroom, keeping the temperature and humidity stable while removing contaminants. The air system recirculates the air after the contaminants have been filtered out. The more air a cleanroom has, the faster the cleaning is. Cleanrooms are usually pressurized by allowing in more air than the amount that goes out.
• Operating a cleanroom: Operating a cleanroom properly helps to maintain its air quality. The amount of contamination from manufacturing operations should be minimal and the cleanroom should be regularly cleaned through the proper laid-down guidelines. Maintenance of the equipment and air control systems should also be regularly undertaken. Most importantly, only trained personnel should have access to the cleanroom.

Manufacturing operations are usually divided into those that are aseptically conducted and those that require the product to be sterilized. Sterile production requires certain characteristics to minimize the risk of contamination of the materials or products. For a cleanroom to meet in-operation conditions, it must first achieve specific levels of cleanliness in at-rest occupancy rates.

Cleanrooms are usually graded depending on the level of manufacturing for sterile products. The grades are as below:

• Grade A: These are cleanrooms used for high-risk operations such as stopper bowls, filling zone, open ampoules and vials, and creating aseptic connections. Laminar airflow workstations provide these conditions in normal situations by providing a homogeneous airspeed of around 0.45 m/s at the working position. Grade A is the cleanest and is used for sterile operations.
• Grade B: This grade provides a background environment to enable aseptic preparation and filling for some grade A zone items.
• Grade C: Grade C cleanrooms are used to perform less critical activities needed for the non-critical manufacturing stages. They are mostly used for support and packing operations.
• Grade D: Similar to Grade C and used for the less critical operations.

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The grades can be related to ISO classes. ISO classes are basically the level of cleanliness of a cleanroom based on the number of particles of a given size per cubic meter. ISO 8 is usually the base level. Cleanrooms used for sterile manufacturing processes need to achieve ISO 5 level of cleanliness. Only electronics manufacturing requires classes above ISO 5.