Pharmaceutical industries have strict cleanroom classifications to maintain product safety, quality, and regulatory compliance.
These classifications are based on the maximum allowable levels of airborne particles and microbial contamination, which vary depending on the pharmaceutical product produced.
They range from ISO Class 1 to ISO Class 9, with ISO Class 1 having the lowest allowable number of airborne particles (and therefore the cleanest) and ISO Class 9 having the highest.
This article covers cleanroom classification pharma guidelines, including the types of cleanrooms in pharmaceutical industries, cleanroom regulatory standards, and cleanroom requirements for pharmaceuticals.
What Is a Cleanroom?
A cleanroom is an enclosed, controlled environment that filters out microscopic pollutants such as dirt, dust, airborne microbes, and aerosol particles. It’s traditionally used in industries like pharmaceuticals, life sciences, biotechnology, food packaging, and microelectronics, all of which are highly susceptible to product contamination.
A cleanroom maintains tightly regulated environmental conditions, with temperatures ranging from 68°F to 72°F (20°C to 22°C) and humidity between 30% and 50%.
These conditions are supported by high-efficiency air filtration systems like High Efficiency Particulate Air (HEPA) or Ultra Low Particulate Air (ULPA) filters, which continuously purify the air to maintain the cleanroom’s classification.
Personnel who work in cleanrooms undergo extensive training in various aspects of contamination control. They wear special clothing before entering the room (coveralls, mask, gloves, cleanroom boots, etc.), and pass through air showers and airlocks to sterilize their garments and bodies.
What Is the Purpose Of A Cleanroom?
The purpose of a cleanroom is to minimize the risk of product contamination and damage to sensitive components due to air contamination and humidity.
In pharmaceutical industries, cleanrooms ensure that drugs, medical devices, and vaccines are produced under the strictest sterile conditions. Regulatory standards require zero microbial contamination in finished sterile products, and this can only be achieved in cleanrooms as even one colony-forming unit (CFU) of bacteria can make the entire batch unsafe.
Facilities that manufacture superconductors and other sensitive electronic products also rely on cleanrooms to produce fully functioning and reliable electronic devices.
The tiniest speck of dust or particle contamination can lead to thousands, if not millions, of dollars in damages as it may compromise circuit integrity or disrupt conductivity.
Because of this, manufacturers maintain ultra-clean environments—classified as ISO 5 or better—with precise control over air quality, temperature, and humidity.
Cleanroom in Pharmaceutical Industry
Pharmaceutical industries produce large batches of medications, vaccines, and biologics every day. These batches are distributed to thousands—or even millions—of patients, so any contamination during production can have serious public health implications and lead to costly recalls or regulatory penalties.
Cleanrooms prevent such contamination by filtering out airborne particles and maintaining optimal temperatures, humidity, and pressure during the manufacturing process.
Cleanrooms used in pharmaceutical industries are called medical industry cleanrooms. They comply with Good Manufacturing Practice (GMP) regulations enforced by agencies like the FDA (U.S.), EMA (Europe), and WHO, and are typically designed to meet EU GMP Annex 1 or ISO 14644-1 classifications.
Other cleanrooms, such as those in electronics or aerospace, follow ISO standards but aren’t subject to GMP unless working with medical devices or biotech components.
This is because pharmaceutical industries produce products directly used in or on the human body, such as medications, vaccines, and medical devices. Even the smallest microbial or particulate contamination can lead to serious health risks and sometimes even death in the worst cases.
One example of the severe consequences of cleanroom contamination is the New England Compounding Center (NECC) scandal, which led to over 800 cases of serious illness and 60 deaths. The contamination was caused by a fungus called Aspergillus fumigatus found in the medication, a result of the center’s failure to adhere to strict sterilization protocols.
Comparatively, industries that manufacture electronics and fail to adhere to cleanroom requirements face less deadly consequences. A contamination can ruin a batch of components or cause a malfunction that can result in millions of dollars lost, but it doesn’t pose a direct threat to individuals’ health or safety.
Types of Cleanrooms in the Pharmaceutical Industry
Cleanrooms come in various sizes and serve different functions. Some are designed with specific temperature regulations, while others focus on maintaining strict air quality or humidity levels. Below are some of the most common cleanrooms used in the pharmaceutical industry:
Pharmaceutical Cleanroom
Pharmaceutical cleanrooms are the standard cleanrooms found in pharmaceutical industries.
Given their role in public health, the United States Food and Drug Administration (FDA) regularly updates the stringent standards of these cleanrooms. These standards are designed to control factors such as air pressure, humidity, microorganisms, and temperature to ensure the highest quality and safety of pharmaceutical products.
Pharmaceutical cleanrooms typically require a cleanroom environment with ISO 8 to 5 classification.
Medical Device Cleanroom
Medical device cleanrooms are specialized environments used for the manufacturing and assembly of medical devices, such as implants, surgical instruments, diagnostic equipment, and disposable products like syringes or catheters.
These cleanrooms maintain stringent levels of cleanliness and environmental control in accordance with FDA-approved validations and Current Good Manufacturing Practice (CGMP) regulations.
To meet rigorous hygiene requirements, medical device cleanrooms are designed with pre-engineered, prefabricated components, which are assembled on-site.
They often feature Fiberglass Reinforced Plastic (FRP) wall panels, which are resistant to chemical exposure, as well as HEPA or ULPA filtration systems and corrosion-resistant anodized aluminum frame components.
Depending on the type of device being manufactured, medical device cleanroom classifications can range from ISO Class 7 to Class 5.
Softwall Cleanroom
Softwall cleanrooms feature clear or opaque vinyl curtains hung on aluminum frames to create walls.
They’re used for weighing and dispensing raw materials, the production of non-sterile medication (creams, ointments, oral pills, etc.), and the preparation of formulations where ISO Class 7 or 8 conditions are sufficient.
They also offer a controlled area for material sampling or microbiological testing.
Mask Manufacturing Cleanroom
Mask Manufacturing Cleanrooms are specifically designed for the production of K95 and surgical masks.
Unlike other cleanrooms used in pharmaceutical industries, mask cleanrooms can host a large number of personnel due to the multi-step processes involved in mask production (fabric cutting, layering, sealing, and quality control).
Personnel working in these cleanrooms follow strict gowning procedures to minimize the risk of contamination. Among these are protective clothing, gloves, face shields, and hair covers.
Mask manufacturing cleanrooms are typically classified as ISO Class 7 or Class 8, depending on the specific processes being performed.
USP 797/800 Cleanrooms
USP 797/800 Cleanrooms specifically cater to compounding pharmacies.
For the uninitiated, compounding pharmacies sell custom-made medicines tailored to a patient’s unique medical requirements.
USP 797/800 Cleanrooms comply with USP <797> and USP <800> regulations, which outline the standards for preparation of sterile medications and handling hazardous drugs, respectively.
Compounding cleanrooms come in two forms: sterile or negative pressure cleanrooms.
Sterile compounding cleanrooms produce sterile medications like injectables, eye drugs, or intravenous (IV) solutions, while negative pressure cleanrooms handle hazardous or cytotoxic drugs like chemotherapy drugs that require extra precautions for both patient and pharmacy staff due to their toxicity.
Pharmaceutical Cleanroom Classification
The cleanliness of a cleanroom is determined by its ISO classification. There are nine ISO classifications, with a class corresponding to a maximum allowable number of particles per cubic meter of air.
These standards are set by the ISO 14644-1, an international guideline that replaced the older Federal Standard 209E used in the U.S. The lower the class, the cleaner the cleanroom and the more stringent the qualifications.
Here’s a breakdown of each classification:
ISO Class 1
Class 1 is the cleanest level of cleanroom, allowing a maximum of just 10 particles per cubic meter of air that are 0.1 micrometers or larger.
ISO Class 1 is rare and hard to achieve, often requiring air filtration systems, unidirectional airflow, and tight environmental controls.
They’re mainly used in nanotechnology, quantum computing, semiconductor manufacturing, and other fields where even the smallest particles can disrupt delicate processes.
ISO Class 2
Class 2 cleanrooms permit 100 particles per cubic meter at 0.1 microns or larger. Class 2 cleanrooms are used to manufacture microelectromechanical systems (MEMS) or aerospace components.
ISO Class 3
Class 3 allows a maximum of 1,000 particles per cubic meter at 0.1 microns or larger. It’s commonly used in photonics, microelectronics, and biotech research that requires stringent cleanliness but can tolerate slightly higher particle counts.
ISO Class 4
Class 4 permits a maximum of 10,000 particles per cubic meter at 0.1 microns or larger. It’s used for biotechnology, pharmaceutical products, and electronics assembly.
ISO Class 5
ISO Class 5 is one of the most commonly used classifications in the pharmaceutical and biotechnology industry, especially for aseptic processing. It allows a maximum of 100,000 particles per cubic meter at 0.1 microns or larger.
ISO Class 5 is the standard class for DNA/RNA amplification, cell culture, microbiology research, and sterile/non-sterile pharmaceutical compounding. It’s also used for IVF therapies, where it has become the preferred standard due to observed improvements in embryo quality compared to Class 6 environments.
ISO Class 6
ISO Class 6 allows up to 1,000,000 0.1 microns per cubic meter. It’s used for the production of medical devices, sensitive products, and non-sterile or terminally sterilized products.
ISO Class 6 is often connected to ISO 7 and ISO 8 rooms, which are used for gowning and preparing materials.
ISO Class 7
Class 7 allows a maximum of 10,000,000 particles at 0.5 microns per cubic meter or later. It’s widely used across multiple industries.
In the pharmaceutical sector, it’s mostly used as prep rooms (gowning areas), formulation suites, and non-sterile manufacturing zones.
Outside pharmaceuticals, it’s used for PCB/SMT manufacturing, microelectronic assembly, and the manufacturing of medical devices.
ISO Class 8
Class 8 allows up to 35,200,000 particles at 0.5 microns or larger per cubic meter. It’s commonly used for gowning rooms and airlocks, and manufacturing processes like powder handling, packaging, storage of packaged goods, and localized process containment or isolation.
ISO Class 9
ISO Class 9 is the least clean of all cleanroom classifications, allowing up to 352,000,000 particles at 0.5 microns or larger per cubic meter.
ISO Class 9 only appears in standard industrial or office settings. It’s used as warehouses, general storage, and buffer zones before entering cleaner areas.
This class doesn’t require HEPA filtration or extensive gowning.
What Is the Difference Between Class-Based vs. ISO-Based Cleanroom Ratings?
When an industry describes a cleanroom as class 1, 10, 100, etc., it uses terms from the older US Federal Standard 209E.
The US Federal Standard 209E was officially replaced in 2001 by the ISO 14644-1 standard to provide a more comprehensive and internationally applicable system for cleanroom classification, using particle counts based on cubic meters instead of cubic feet.
Here’s how they compare:
| Federal Standard 209E (Outdated) | ISO 14644-1 (Current) |
| N/A | ISO Class 1 |
| N/A | ISO Class 2 |
| Class 1 | ISO Class 3 |
| Class 10 | ISO Class 4 |
| Class 100 | ISO Class 5 |
| Class 1,000 | ISO Class 6 |
| Class 10,000 | ISO Class 7 |
| Class 100,000 | ISO Class 8 |
If you’re wondering why the older classification starts at ISO Class 3, it’s because ISO Classes 1 and 2 represent cleanliness levels that exceed the scope covered in Federal Standard 209E. There were no direct equivalents in the older system.
Cleanroom Regulatory Standards
Cleanrooms must adhere to stringent regulatory standards to ensure product safety and contamination control.
These standards vary by region and industry, with some following stricter standards than others. Generally, though, the most widely followed standards include the EU GMP Annex 1, ISO 14644-1, and US FDA Guidance.
EU GMP Annex 1
EU GMP Annex 1 is a section of the European Union’s Good Manufacturing Practices (GMP) that focuses on the manufacture of sterile medicinal products.
It covers topics like air cleanliness levels, pressure differentials, gowning procedures, and environmental monitoring. It also lists the differences among cleanroom grades A to D, as follows:
- Grade A: Requires the highest level of environmental control, equivalent to ISO Class 5. Often used for high-risk operations, like filling open ampoules, vials, and stopper bowls.
- Grade B: Equivalent to ISO Class 5 at rest and ISO Class 7 in operation. Used for aseptic filling, preparation, and compounding, as a background zone for Grade A. Features a particle monitoring system that triggers an alarm if limits are exceeded.
- Grade C: Equivalent to ISO Class 7 at rest and ISO Class 8 in operation. Used for filtration, solution preparation, weighing, and filling products intended for terminal sterilization.
- Grade D: Equivalent to ISO Class 8, both at rest and in operation. Considered the “dirtiest” area of GMP guidelines, and are often used as general production and packaging areas.
Annex 1 was originally published in 1989 and has since undergone several revisions. The most recent revision occurred in August 2022 and came into effect in August 2023. The latest revision addresses advancements made in technology and removes ambiguities and inconsistencies in the manufacture of sterile products.
ISO 14644-1
The ISO 14644-1 is the cleanroom standard developed by the International Organization for Standardization (ISO), specifically by the Technical Committee ISO/TC 209. It was published in 1999 and has undergone multiple updates since.
ISO 14644-1 replaced the old U.S. Federal Standard 209E in 2001 and introduced nine ISO Classes (1 to 9) according to the maximum allowable particles per cubic meter of air at various particle sizes (commonly ≥0.1 µm, ≥0.5 µm).
US FDA Guidance
The FDA (Food and Drug Administration) has published several documents that highlight the importance of facility design, personnel training, and monitoring to prevent contamination of food and drug products.
Among these documents is Sterile Drug Products Produced by Aseptic Processing: Current Good Manufacturing Practice, which was published in October 2004.
The 63-page PDF file goes into detail about what’s required when manufacturing sterile drugs and biological products using aseptic processing.
It covers topics like personnel training, qualification, and monitoring, time limitations, endotoxin control, sterility testing, among others.
It also discusses requirements for HEPA filtration, airflow patterns, cleanroom behavior, and environmental monitoring.
Clean Room Requirements for Pharmaceuticals
Cleanroom requirements for pharmaceuticals differ depending on the product being manufactured or tested within.
For example, sterile products like vaccines or IV medications must be prepared in ISO Class 5 environments, while non-sterile products like tablets and capsules can be prepared in ISO Class 7 environments.
Generally, though, most pharmaceutical cleanrooms have the following requirements:
Personnel Practices
All personnel entering a cleanroom must undergo training in hygiene, aseptic techniques, and contamination control.
They’re required to wear specialized garments, including coveralls, hoods, face masks, goggles, gloves, and boot covers, and follow strict gowning procedures in designated gowning rooms or airlocks to minimize the risk of contamination during the manufacturing process.
Higher-grade areas such as ISO Class 5 or GMP Grade A/B have even stricter requirements, often demanding the use of sterile, single-use garments.
Other common protocols include:
- Personal items should be left outside the controlled environment.
- Don’t touch the face or hair with gloved hands.
- Don’t enter the cleanroom if feeling unwell.
- Avoid running or unnecessary movement, as rapid motions can stir up particles and increase the risk of contamination.
- Maintain good personal hygiene at all times.
- Don’t wear makeup, perfume, or other personal care products inside the cleanroom.
- Don’t use non-compliant supplies and equipment.
- Don’t sit or lean on equipment or work surfaces, as this can transfer contaminants between your garments and work surfaces.
Cleanroom Design and Materials
Cleanrooms must be constructed from materials that are non-shedding, easy to clean, and resistant to disinfectants and chemicals. Common choices include FRP (Fiberglass Reinforced Plastic) walls, seamless flooring, and anodized aluminum framing.
Additionally, surfaces must be smooth and free of cracks to minimize particle buildup. If a cleanroom develops cracks, sterile operations must be halted to prevent product contamination.
Equipment must also be compatible with the controlled environment, like cleanroom-approved disinfectants (e.g., sporicidal agents, IPA 70%), Sterile buckets with double-wipe systems, and sterile wipes and mops.
Environmental Control
Given that most medications are temperature sensitive, pharmaceutical cleanrooms must be equipped with a dedicated HVAC system with HEPA filters to remove airborne particles from the environment. Temperature must also be regulated and maintained at around 70°F (21°C) to prevent microbial growth and product degradation. The same is said for humidity levels, which must fall between 30-40% Relative Humidity (RH).
Cleanrooms must be regularly checked for temperature, humidity, pressure, and airborne particle count to ensure they meet the required standards at all times.
Compliance and Documentation
All cleanroom operations must be documented in accordance with cGMP. Personnel are required to maintain records of Standard Operating Procedures (SOPs), cleaning logs, and environmental monitoring data.