Understanding Cleanroom Classifications

For any research lab, establishing the cleanroom is an important aspect of the manufacturing and developing process. Cleanrooms need to have a maintained and controlled environment to ensure the purity of research subjects. Based on this factor, there are different levels of cleanroom classification. Airborne particles and pollutants in this room are kept at a minimum and at a specified level. Once you understand cleanroom classifications and how they impact your research lab, you will be better able to choose the right laboratory products and implement industry best practices


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Description: Scientist working in a Cleanroom environment

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                        To keep the air clean and free of particles, cleanrooms function on a positive air pressure method. High power HEPA filters pump air to remove contaminants from it. The air is pushed through the room and down towards the floor into the vents. This creates an air flow, which constantly cleans the contaminated air, pushes it away, and also constantly cleans the room. Apart from this, the cleanroom classification is another aspect which makes a pronounced difference on the end product. This classification hinges on different factors; the most important relates to the nature of your industry. To help you understand more about cleanroom classifications and their impact on your research lab, we have taken the time to outline the following:

                        Does The Nature of the Cleanroom Matter?

                        Cleanroom classification hinges a lot around the application of the room itself. This also affects how it works. To keep the air clean and free of particles, cleanrooms function on a positive air pressure method. High power HEPA filters pump air to remove contaminants from it. Positive pressure cleanrooms are common for many industries but not for all of them. In some industries such as in the medical field where they’re dealing with infectious diseases or hazardous substances, negative pressure cleanrooms might be used. Some industries are also stricter in the enforcement and application of cleanroom classifications and specifications. Being negligent here is dangerous as it increases the risk of product contamination. You can also face heavy fines or penalties for any oversight. 

                        How to read Cleanroom Classifications:

                        Cleanroom standards are classified according to the number and size of particles permitted per volume of air in a specific amount of time.Clean room industry requirements are classified according to ISO 14644-5:2004 which specifies basic requirements for cleanroom operations. Federal Standard 209E is still also used (see Table 1).ISO cleanroom classifications are rated according to how much particulate of specific sizes exist per cubic meter (see second chart). The "cleanest" cleanroom is a class 1 and the "dirtiest" a class 9. Each clean room is rated by ISO class. This cleanroom standard rating system provides the necessary information to make an informed decision based on your product needs. Most clean rooms fall into the class 6,7, or 8 categories. Based on the number of contaminants which exist in the room, the contamination is measured. This is usually done on a per cubic meter ratio. Suppose you have a cleanroom classification of ISO Class 6 level and a rating of 35,200 per cubic meter. This means that you’re not allowed to exceed 35,200 and 0.5 microns in the cleanroom. 

                        Why is the ISO Standard Preferred over the Federal Standard?

                        The ISO 14664-1 applies different classes, starting from class 1 as the cleanest and going up to class 9. As a rule of thumb, the lower the rating is on the ISO scale, the cleaner the room. Some businesses still make use of the Federal Standard 209E, but the ISO 14664-1 adds more classes to accommodate major areas, which were left out previously.

                        Here’s a table which sheds more light on the difference in their ratings:

                        Table #1 - ISO 14644-1 Cleanroom Classifications and Standards


                        maximum particles / m3

                        FED STD 209E Equivalent

                        ≥0.1 µm

                        ≥0.2 µm

                        ≥0.3 µm

                        ≥0.5 µm

                        ≥1 µm

                        ≥5 µm

                        ISO 1







                        ISO 2







                        ISO 3







                        Class 1 Cleanroom

                        ISO 4







                        Class 10 Cleanroom

                        ISO 5







                        Class 100 Cleanroom

                        ISO 6







                        Class 1,000 Cleanroom

                        ISO 7







                        Class 10,000 Cleanroom

                        ISO 8







                        Class 100,000 Cleanroom

                        ISO 9







                        Room air

                        (µm denotes micron particle size)
                        ISO Class 1
                        The “cleanest” cleanroom is ISO 1, used in industries such as life sciences and electronics that require nanotechnology or ultra-fine particulate processing. The recommended air changes per hour for an ISO class 1 clean room is 500-750, and the ceiling coverage should be 80–100%.
                        ISO Class 2
                        The recommended clean room air changes per hour for an ISO class 2 rated cleanroom is 500-700, with a ceiling coverage of 80-100%.
                        ISO Class 3
                        The recommended clean room air changes per hour for an ISO class 2 rated cleanroom is 500-750, with a ceiling coverage of 60-100%.
                        ISO Class 4
                        The recommended clean room air changes per hour for an ISO class 2 rated cleanroom is 400-750, with a ceiling coverage of 50-90%.
                        ISO Class 5
                        The recommended clean room air changes per hour for an ISO class 2 rated cleanroom is 240-600, with a ceiling coverage of 35-70%.
                        ISO Class 6
                        The recommended clean room air changes per hour for an ISO class 2 rated cleanroom is 150-240, with a ceiling coverage of 25-40%.
                        ISO Class 7
                        The recommended clean room air changes per hour for an ISO class 2 rated cleanroom is 60-150, with a ceiling coverage of 15-25%.
                        ISO Class 8
                        The recommended clean room air changes per hour for an ISO class 2 rated cleanroom is 5-60, with a ceiling coverage of 5-15%.

                        What are the Three States of a Cleanroom?
                          1. Cleanroom State #1: As Built – This refers to the cleanroom’s performance when it is newly built. It usually does not have any machinery, furniture, equipment or even employees in it. 

                          2. Cleanroom State #2: At Rest  This is the second stage when the machinery, furniture, equipment and supplies have been moved in here. The room is still not used by employees as yet, but the furniture and supplies might introduce some contamination. 

                          3. Cleanroom State #3: Operational –This is the third and final state. Here you let the employees work in the cleanroom. Monitoring of contamination is done round the clock because numerous adjustments have to be made. 

                        Based on these three states, your cleanroom classification can be deduced.You will have to make adjustments as needed to improve the classification in accordance with the room’s purpose. 

                        Specific Cleanroom Industry Requirements:

                        There are numerous industries throughout the world that utilize cleanrooms for their specific product purposes. The following industries regularly use cleanrooms for their product needs, they include:

                        Medical Devices
                        The main objective of a medical device cleanroom is to eliminate surface contamination (viable particulate) on their products. Medical Device Cleanrooms are typically built under the cleanroom classifications ISO Class 7 and ISO Class 8 range. The manufacturing process of these products ensures that the surface of the product does not have particulate contamination when completed. It is important that cleanliness level be maintained both from a cleanroom stand point and a personnel protocol standpoint. Important elements to consider, include:
                        • Contaminant Levels

                        • Temperature

                        • Humidity

                        • Pressure

                        • Pressurization Control

                        • Elimination of Cross Contamination

                        • Filtration of Outdoor & Indoor Air

                        A cleanroom is often necessary during the manufacturing and building process of electronic components and parts, due to their extremely high sensitivity to outside influences. Important elements to consider: 

                        • HEPA filtration

                        • Positive/negative air pressure

                        • Monitoring systems

                        • Temperature control

                        Pharmaceutical Cleanrooms are usually specified at ISO Class 5 to ISO Class 8 and apply to many cleanroom standards. Particulate is a concern however, specifically, viable particulate contamination, the ability to keep the room clean typically using modular or stick built components with integral cove bases, cove corners, and coved ceilings to maintain a cleanable surface condition is crucial under cleanroom standards. Biotech and Pharmaceutical cleanrooms tend to be sanitized in different ways, and different products are applicable depending on the sanitization methods employed. Concealed areas for bacterial growth are unacceptable. These rooms typically use cleanroom technology that keeps the seal unbroken during sanitation and filter changes. Biotechnology and Pharmaceutical cleanrooms typically focus heavily on the following:
                        • Filtration of Outdoor & Indoor Air

                        • Elimination of Cross Contamination

                        • Pressurization Control

                        Food Industry
                        Cleanrooms for the food industry are used to prevent any particulate contamination during food processing, and to ensure the highest level of quality and safety in all food products. Food industry clean rooms are essential to providing a secure environment in which food is processed. They control air filtration, which in turn decreases the risk of any contamination or interference with the processing of foods. Other considerations that pertain to food industry cleanroom industry requirements, include:

                        • Temperature

                        • Humidity

                        • Pressure

                        • Contaminant Levels

                        Do You Need Special Lab Equipment or Supplies for a Cleanroom?
                        The cleanroom equipment you use does make a difference. Make sure that your staff has sterile cleanroom clothing and more. It is also important to get this equipment from the right suppliers. 

                        For over 40 years, Lab Pro has been committed to delivering a complete laboratory solution by offering the highest quality cleanroom supplies, chemicals, reagents, microscopes and imaging equipment for our customers worldwide. Come visit the biggest Lab Supply showroom in the Bay Area, or contact us online or at 888-4-LABPRO (888-452-2776).