Recently searched
      • Published 24 Jun 2024
      • Last Modified 24 Jun 2024
    • 7 min

    A Guide to Cleanrooms

    Cleanrooms are widely used in industries where a very low level of airborne particles is needed, enabling manufacturers to precisely control the production environment. This guide explains what cleanrooms are and why they are used.


    Reviewed by David Carmichael, Solution Engineer (May 2024)

    Manufacturers looking to maintain the highest standards of cleanliness use cleanrooms to minimise contamination from airborne particles and prevent product defects. Cleanrooms are used in industries from aerospace, defence, and electronics to medicine, product manufacturing, and research and development.

    Want to know more about cleanrooms, the industries in which they are used, and the benefits they provide? Read on.

    What is a Cleanroom?

    What is a cleanroom? A cleanroom is a special type of room where the level of airborne particles is carefully controlled. Cleanrooms are classified on an ISO scale. (There are also some alternative classification systems in use in the United States.) The ISO 14644-1:2015 standard runs from one to nine and dictates the level of particles that are permitted. ISO 1 represents the highest standard.

    A sample from an ISO 1 cleanroom should contain 10 or fewer particles measuring 0.1 microns (micrometres, µm) and two or fewer particles at 0.2 microns per cubic metre of air. Contrast that with ISO 9 (regarded as typical of an ordinary room), where the standard allows for 35,000,200 particles measuring 0.5 microns, 8,320,000 or fewer particles measuring one micron, and 293,000 or fewer particles measuring five microns, and you can see how carefully a top cleanroom is controlled.

    Small amounts of airborne contamination can adversely affect production in certain industries. These sectors include semiconductor production and pharmaceuticals, but cleanrooms are also used in aerospace, defence, and energy to provide a contaminant-free environment. Cleanrooms can also be designed to have precise levels of temperature, pressure, or humidity. Some cleanrooms are designed to be completely sterile.

    Cleanroom Benefits

    The use of a cleanroom may be determined by industry standards, so cleanrooms help enable manufacturers to comply. For example, in the life sciences, manufacturing drugs for treating cancer has to take place at a specific cleanroom level. In semiconductor manufacturing, a single unwanted particle can damage a chip. Semiconductor foundries therefore control airborne particles very precisely (typically to ISO 5 or better), along with other factors including humidity, temperature, light level, noise, and vibration.

    There are other cleanroom benefits. Investing in a cleanroom environment may improve brand reputation in the market by indicating that a manufacturer is working to the highest possible standards of cleanliness. In terms of research and development, the pure environment of a cleanroom is also useful for experimenting without the results being distorted by contaminants.

    Cleanroom Standards

    The International Organization for Standardization (ISO) dictates the maximum number of particles in microns permitted per cubic metre of air in a cleanroom. See ISO 14644-1:2015. This chart illustrates the different ISO cleanroom standards:


    ≥0.1 μm

    ≥0.2 μm

    ≥0.3 μm

    ≥0.5 μm

    ≥1 μm

    ≥5 μm

    ISO 1



    ISO 2





    ISO 3






    ISO 4






    ISO 5







    ISO 6







    ISO 7




    ISO 8




    ISO 9




    Cleanroom Technology

    Cleanroom technology consists of a range of equipment that helps create a very low level of particles in the room. It includes:

    • High-efficiency particulate absorbing filters (HEPA filters). Cleanroom air filters must filter out a defined level of particulate matter. For example, the ISO dictates that HEPA filters must filter out 99.95% of airborne particles greater than 0.3 microns in size
    • Ultra-low particulate air (ULPA) filters. ULPA filters remove ultrafine particulates: at least 99.999% of airborne particles larger than 0.12 µm
    • Laminar airflow systems. These systems direct air horizontally or vertically across the cleanroom in one direction. The air is then filtered by filters on the walls or floor
    • Air ionisers. Static electricity can be an issue in cleanrooms with low humidity, so air ionisers are used to create a flow of positive and negative ions to prevent surface static charges from damaging microchips and other sensitive electronic components. A range of ESD control cleanroom equipment such as anti-static mats may also be used
    • Air showers. Air showers reduce contamination from employees or objects by using high-pressure air to remove particles. They are used at cleanroom entrances
    • Ultraviolet air filters. These filters are designed to eliminate bacteria and viruses in the cleanroom. The HVAC system sucks contaminated air in, the UV system neutralises it, and the clean air flows into the cleanroom environment
    disposable coveralls
    • Cleanroom suits. Personnel working in cleanroom settings may wear cleanroom suits to help reduce contamination. For example, in semiconductor manufacturing, one-piece coveralls are often used by production line workers. (Check out our range of disposable workwear)

    Shop Disposable Coveralls

    Cleanroom Environments

    Cleanroom environments help manufacturers produce goods without defects. They are used in several industries. What are cleanrooms used for? Let’s look at cleanroom types and cleanroom uses:

    Manufacturing Cleanrooms

    Cleanrooms are used in a range of manufacturing sectors, from aerospace and defence to semiconductor, electronics, and food manufacturing. Cleanroom environments are also used to produce nanotechnology and optical devices such as camera lenses.

    Medical Cleanrooms

    Medical device manufacturing requires the cleanliness of cleanrooms and is subject to very strict standards from regulators and the government. For similar reasons, the pharmaceutical industry also needs cleanrooms for making drugs. Meanwhile, hospitals create isolation rooms which separate patients with unusual symptoms using cleanroom technology. These separate patients with unusual symptoms from the rest of the hospital.

    R&D Cleanrooms

    Cleanroom uses also include research and development across several industries. For example, in pharmaceuticals and biotechnology, the sterile environment a cleanroom can provide helps to create new drugs and vaccines. In aerospace and defence, cleanrooms are used to develop new types of satellite and space technology and new types of missiles and other weapons.

    Cleanroom Challenges

    Cleanroom challenges include meeting the strict requirements of ISO standards and industry regulators. Cleanrooms can also be expensive to construct. They present a challenge in a working environment: personnel must be thoroughly trained to work safely in a cleanroom and understand the importance of contamination control. Even then, the presence of people poses a hurdle to maintaining the cleanliness of the environment.

    Cleanrooms and Quality

    One of the most important functions of cleanrooms for manufacturing applications is ensuring that products are created to high-quality standards. These standards are maintained thanks to minimal contamination from particles, microbes, or chemicals during the production process. In some industries such as semiconductor manufacturing, where dust or static electricity can easily damage sensitive electronic components, the sanctity of the cleanroom environment is essential to upholding quality. Manufacturers that use high-quality, well-designed cleanrooms benefit from not having to rework products due to quality issues.

    Future of Cleanrooms

    Much as they are playing a more and more important role in manufacturing, robots are also making an impact on cleanrooms, where they have some advantages over people. Robots may be more accurate than people for precision jobs, and they are less prone to contaminating the environment. The filtration technology used in cleanrooms also continues to develop and will in the future remove even smaller particulate matter from the air, making these environments even cleaner. For example, filtration systems that work at a molecular level or nanoscale are being developed. The integration of the Internet of Things with cleanroom technology, meanwhile, is allowing some of the benefits manufacturers are already experiencing from the IoT (like the ability to predict maintenance requirements and precisely monitor parameters and generate data) to move into the cleanroom.

    As well as developments of this type, there is considerable effort going into making cleanroom technology more sustainable. This principally involves reducing the energy consumption of HVAC systems, lighting, and filtration technologies – all without compromising the stringent standards that have made cleanrooms such an essential part of the manufacturing and medical landscape.

    Need equipment to maintain your cleanroom, such as cleanroom wipes? RS has you covered.

    Related Articles

    Related links