GMP is short for Good Manufacturing Practice, and it is a regulation to ensure that concentrations of airborne particulate and microbial contamination should remain within specified limits, thereby minimizing the risk of product contamination.
A GMP cleanroom is a controlled environment where the design, construction, operation, and monitoring strictly adhere to the mandatory requirements of Good Manufacturing Practice regulations, and it is widely used in many industries like pharmaceuticals, medical devices manufacturing, cosmetics manufacturing, food and beverages, biotechnology, etc.
GMP Cleanroom Classification
Like the ISO 14644 standard, GMP cleanrooms are classified into grade A, B, C, D, and each grade specifies the level of cleanliness by the limits on the number of particles per square meter, and the critical control parameters are summarized below.
| Cleanliness Grade | Maximum Permitted Particles per m³ (at rest) | Maximum Permitted Particles per m³ (in operation) | Primary Function & Risk Level | ISO Equivalent (At Rest / In Operation) | ||
|---|---|---|---|---|---|---|
| ≥0.5 μm | ≥5.0 μm | ≥0.5 μm | ≥5.0 μm | |||
| Grade A | 3,520 | 20 | 3,520 | 20 | Local zone for highest-risk aseptic operations (e.g., fill-point, open vial manipulation). | ISO 5 / ISO 5 |
| Grade B | 3,520 | 29 | 352,000 | 2,900 | Background environment for a Grade A zone. Acts as a fortified buffer. | ISO 5 / ISO 7 |
| Grade C | 352,000 | 2,900 | 3,520,000 | 29,000 | Zone for less critical aseptic steps or high-risk non-sterile processing (e.g., solution preparation, staging). | ISO 7 / ISO 8 |
| Grade D | 3,520,000 | 29,000 | Not defined | Not defined | Controlled area for entry/exit (airlock) or low-risk non-sterile manufacturing. Serves as a contamination control barrier. | ISO 8 / Not formally defined by ISO |
Grade A: Grade A provides the highest level of environmental control for local, high-risk aseptic operations, such as sterile filling and open-container manipulations. It is equivalent to ISO 5 both at rest and during dynamic operations. This grade is mandated for the most critical points in a process where the product is directly exposed. It is typically achieved within an ISO 5 unidirectional airflow hood or isolator located inside a Grade B background environment.
Grade B: Grade B serves as the background cleanroom environment for Grade A zones, providing a protective buffer. It is classified as ISO 5 at rest but operates at ISO 7 during production activities. This grade is essential for supporting high-risk processes like aseptic preparation and filling. It surrounds and protects the critical Grade A core from the larger facility.
Grade C: Grade C is designated for less critical cleanroom operations that still require a controlled environment, such as the preparation of solutions to be sterile-filtered. This zone is classified as ISO 7 at rest and ISO 8 in operation. It is commonly used for staging components and handling products with a lower risk profile. Its controls are effectively managed through quality risk assessment principles.
Grade D: Grade D represents the basic level of contamination control for support areas in pharmaceutical manufacturing. It is classified as ISO 8 at rest, with no formal ISO class specified for its in-operation state. This grade is typically applied for material airlocks, gowning rooms, and the production of non-sterile oral dosage forms. It acts as the foundational controlled transition zone into cleaner environments.
Typical Applications for GMP Cleanrooms
1. Production of Sterile Injectables
Sterile injectables are filled and sealed in environments where the product is directly exposed. Any microbial or particulate contamination here poses a direct, life-threatening risk to patients upon injection. A GMP cleanroom provides an ISO 5 (Grade A) unidirectional airflow zone at the critical point, actively preventing contamination. This controlled environment is a regulatory mandate from agencies like the FDA and EMA for market approval. It ensures product safety through validated processes and continuous monitoring.
2. Manufacturing of Cell & Gene Therapies (CGT)
CGT products involve the manipulation of live cells, which are vulnerable and cannot be terminally sterilized. The process must prevent both microbial contamination and cross-contamination between batches. GMP cleanrooms provide an aseptic, tightly controlled environment for these fragile living drugs. They enable process consistency and full traceability, which are essential for personalized therapies.
3. Assembly of Implantable Medical Devices (Class III)
Devices like pacemakers or artificial joints are often assembled in cleanrooms, as they may be sensitive to terminal sterilization. The goal is to minimize bioburden and particulate matter before packaging and final sterilization. A GMP cleanroom controls the level of contaminants to ensure the subsequent sterilization process is reliably effective. This control directly impacts the long-term performance and safety of the device inside the body.
4. Production of Potent Compounds & Cytotoxins
Manufacturing highly active pharmaceutical ingredients (HPAPIs) requires containment to protect both the product and the operators. The primary concern is preventing cross-contamination with other products and limiting operator exposure to hazardous substances. GMP cleanrooms for these applications are specifically designed with containment technologies and negative pressure zones. They ensure operator’s safety while maintaining the integrity and purity of the potent compound.
GMP Cleanroom Monitoring and Control
The GMP cleanroom serves as the critical core of pharmaceutical production. Its role extends far beyond simply maintaining low levels of particulate and microbial contamination, it must precisely regulate a suite of environmental parameters to prevent product compromise. Based on our team’s extensive analysis of international regulations and project experience, we have consolidated the following six key areas of regulatory focus. This summary is designed to help manufacturers deeply understand and implement these essential requirements to establish an environment that is both compliant and operationally effective.
1. Microbial Contamination Control
Microbial monitoring is a cornerstone of GMP compliance. While core regulations like the US FDA’s sterile processing guidelines primarily mandate monitoring during dynamic (in-operation) conditions, the EU GMP Annex 1 explicitly requires microbial data collection during both performance qualification (static, at-rest) and routine environmental monitoring (dynamic). This dual requirement underscores the principle of proving inherent system capability and its consistent performance during actual production. From our perspective, a robust program integrates both phases, providing a complete validation of the cleanroom’s aseptic control.
| Cleanliness Grade | Airborne Viable(cfu/m³) | Settling Plates(cfu/4 hours) | Contact Plates(cfu/plate) | Glove Print(cfu/glove) |
|---|---|---|---|---|
| Grade A | <1 | <1 | <1 | <1 |
| Grade B | 10 | 5 | 5 | 5 |
| Grade C | 100 | 50 | 25 | — |
| Grade D | 200 | 100 | 50 | — |
2. Temperature and Humidity Management
Current GMP regulations do not prescribe absolute, universally mandatory values for temperature and humidity. Instead, parameters should be set based on product and process needs. In the absence of specific requirements, industry-standard guidance suggests maintaining Grade A, B, and C areas between 20°C – 24°C with 45% – 60% relative humidity. For Grade D areas, a common range is 18°C – 26°C with 45% – 65% relative humidity. The primary goals are to ensure operator comfort in full gowning, prevent microbial proliferation, and safeguard product stability.
3. Pressure Differential Cascade
Maintaining a defined pressure cascade is a fundamental engineering control to protect cleaner areas from contamination. A positive pressure differential (e.g., 10-15 Pa as a typical minimum) must be sustained between adjacent areas of different cleanliness grades, ensuring airflow from cleaner to less-clean spaces. Furthermore, maintaining a slight gradient (e.g., ~5 Pa) between rooms of the same grade but with different functions (e.g., a corridor and a processing room) can prevent cross-contamination. We consistently emphasize that this cascade must be monitored continuously with alarm capabilities.
4. Illumination and Noise Levels
Similar to temperature, GMP does not enforce specific numeric limits for illumination (lux) and noise (dB). However, standards must be established based on process risk, operator safety, and comfort. Common practice, often informed by technical guidelines like ISO standards, sets general illumination at approximately 300 lux for main work areas and 200 lux for auxiliary spaces. For noise, a common limit is ≤60 dB(A) for non-unidirectional flow rooms and ≤65 dB(A) for unidirectional flow (e.g., Grade A) zones under as-built conditions. The rationale is to prevent distraction, facilitate precise work, and support a controlled environment.
5. Air Change Rates and Recovery
While not a direct substitute for particle classification, Air Change Rates (ACH) are a critical design and operational parameter. EU GMP Annex 1 provides a guideline of ≥20 ACH for typical cleanrooms, which directly influences the recovery time—the period required for a room to return from a contaminated state to its specified cleanliness level. A standard recovery time target is 15-20 minutes. In our engineering practice at KINROM, we calculate and validate ACH specifically to achieve the required recovery performance for each unique room layout and operational profile.
6. Personnel Control and Access
Personnel are the most significant variable contamination sources. GMP principles mandate strict control over the number and movement of individuals within clean zones. Implementing access control systems (e.g., card readers) is a standard practice to restrict and log entry. The maximum number of personnel in each room should be determined scientifically, taking the lower value from two calculations: one based on the supply of fresh air per person (e.g., 40 m³/h), and another based on the area of the room and its air cleanliness grade. This calculated limit must be enforced and documented in procedures.
Build Your GMP Cleanroom With KINROM
Have questions about GMP cleanrooms design and construction? Get in touch with our team at KINROM. As cleanroom design and installation experts, we are pleased to guide you through the GMP qualification and validation process and to ensure your cleanroom is built for safe, controlled operations.
