Views: 0 Author: Shanghai Marya R&D Team Publish Time: 2026-10-08 Origin: Site
ISO and GMP cleanroom classifications are both used to control contamination, but they serve different purposes. ISO 14644-1 classifies cleanrooms according to airborne particle concentration, while GMP establishes broader contamination control requirements for pharmaceutical manufacturing.
For example, an ISO Class 5 environment may meet the non-viable particle limits associated with GMP Grade A, but that alone does not demonstrate GMP compliance. Sterile pharmaceutical production also requires microbial monitoring, qualified equipment, personnel controls, documented procedures, and a comprehensive contamination control strategy.
Understanding the difference between ISO and GMP cleanroom classifications helps pharmaceutical manufacturers select appropriate cleanliness levels, design controlled production environments, and prepare for regulatory inspections.
Table of Contents
The main difference is that ISO measures a specific aspect of air cleanliness, whereas GMP addresses contamination risks throughout the pharmaceutical manufacturing process.
Comparison | ISO 14644-1 | Pharmaceutical GMP |
|---|---|---|
Primary purpose | Classify air cleanliness by airborne particle concentration | Control contamination and ensure consistent pharmaceutical quality |
Classification system | ISO Classes 1–9 | Grades A, B, C, and D under EU GMP Annex 1 |
Particle limits | Defined according to ISO class and particle size | Defined according to grade and operational state |
Microbial contamination | Not assessed by ISO 14644-1 | Controlled through microbiological qualification and monitoring |
Application | Cleanrooms across multiple industries | Pharmaceutical production, particularly sterile manufacturing |
Operational requirements | Not established comprehensively by ISO 14644-1 alone | Includes personnel, cleaning, monitoring, documentation, and contamination control |
Compliance | Technical classification against a defined standard | Compliance with applicable pharmaceutical regulatory requirements |
The key takeaway: ISO classification is one component of pharmaceutical cleanroom qualification, but GMP compliance requires an integrated contamination control system.
ISO 14644-1 is an international standard used to classify the cleanliness of air in cleanrooms and controlled environments.
It establishes cleanliness classes based on the maximum permitted concentration of airborne particles at specified particle sizes. The classification is determined through measurements using calibrated airborne particle counters.
ISO classes range from ISO 1 to ISO 9, with ISO 1 representing the most stringent particle cleanliness level.
For pharmaceutical cleanroom design, ISO Classes 5, 7, and 8 are particularly relevant because their particle concentration limits are commonly used when comparing ISO classifications with GMP grades.
ISO Class | Maximum Particles ≥0.5 µm/m³ | General Cleanliness Level |
|---|---|---|
ISO 5 | 3,520 | Highly controlled clean zones |
ISO 6 | 35,200 | Intermediate particle cleanliness |
ISO 7 | 352,000 | Controlled cleanrooms |
ISO 8 | 3,520,000 | Less stringent controlled environments |
These values represent ISO 14644-1 classification limits at the specified particle size. Actual requirements depend on the production process and the applicable regulatory framework.
Importantly, ISO 14644-1 does not establish microbial contamination limits or determine whether a pharmaceutical process is GMP compliant.
Source: ISO 14644-1:2015 – International Organization for Standardization
ISO cleanroom classification involves measuring airborne particle concentrations at designated sampling locations.
The assessment generally includes:
Defining the required ISO class and particle sizes.
Identifying the cleanroom occupancy state.
Establishing sampling locations and sample volumes.
Measuring airborne particles using calibrated counters.
Comparing the results with the applicable ISO classification limits.
A cleanroom can be classified in an as-built, at-rest, or operational state, depending on the assessment requirements.
However, passing an ISO particle classification test does not independently verify microbiological control, aseptic processing performance, or the broader operational controls required for pharmaceutical manufacturing.
Good Manufacturing Practice (GMP) establishes quality and contamination control requirements for pharmaceutical production.
For sterile medicinal products manufactured under the European framework, EU GMP Annex 1 defines four cleanroom grades: A, B, C, and D.
These grades reflect the contamination control requirements associated with different manufacturing operations.
Grade A provides the highest level of environmental control for critical operations where sterile products or sterile components are exposed.
Typical applications include aseptic filling points, open sterile containers, and certain stopper feeding operations.
Grade A zones require effective protection through appropriately designed airflow or barrier technologies. Critical operations must be supported by validated processes, suitable environmental monitoring, and contamination prevention measures.
Grade B is generally the background environment for Grade A zones used in conventional aseptic preparation and filling operations.
It helps control contamination risks associated with personnel, equipment, and surrounding activities.
Where isolator technology is used, an alternative background classification may be appropriate based on the system design, qualification, and contamination control strategy.
Grade C supports manufacturing operations that require environmental control but are less critical than direct aseptic exposure in Grade A.
Depending on the process and sterilization strategy, Grade C may be used for certain preparation steps, component handling, and supporting production operations.
Grade D is commonly associated with less critical stages of sterile manufacturing, including certain equipment preparation and component handling activities.
Although Grade D has less stringent particle requirements than Grades A–C, appropriate cleaning, environmental controls, and documented procedures remain necessary.
The required grade should always be selected according to the specific operation, product contamination risks, and applicable GMP requirements.
EU GMP Annex 1 distinguishes between non-viable particle classification and microbiological contamination control.
The following table summarizes the maximum airborne particle concentrations for cleanroom classification.
GMP Grade | ≥0.5 µm At Rest | ≥0.5 µm In Operation | ≥5 µm At Rest | ≥5 µm In Operation |
|---|---|---|---|---|
A | 3,520 | 3,520 | Not specified | Not specified |
B | 3,520 | 352,000 | Not specified | 2,930 |
C | 352,000 | 3,520,000 | 2,930 | 29,300 |
D | 3,520,000 | Risk-based | 29,300 | Risk-based |
Values are particles per cubic meter, based on EU GMP Annex 1, Table 1, for cleanroom classification. Separate particle limits apply to routine environmental monitoring under Table 5. For Grades A and B, classification involving ≥5 µm particles may be considered when justified by the contamination control strategy or historical trends.
GMP also establishes microbiological limits during cleanroom qualification.
GMP Grade | Active Air Sample (CFU/m³) | Settle Plate (CFU/4 Hours) | Contact Plate (CFU/Plate) |
|---|---|---|---|
A | No growth | No growth | No growth |
B | 10 | 5 | 5 |
C | 100 | 50 | 25 |
D | 200 | 100 | 50 |
These are qualification limits from Annex 1, Table 2. Microbiological monitoring during routine production is governed separately. Grade A microbial growth requires investigation.
This demonstrates an important difference between ISO and GMP: pharmaceutical cleanroom performance cannot be evaluated using airborne particle counts alone.
GMP cleanroom classification considers two important operating states.
At rest: The cleanroom installation is complete, utilities and HVAC are operational, and the main manufacturing equipment is installed but not operating. Personnel are absent.
In operation: The facility operates under defined manufacturing conditions, with equipment functioning and personnel performing or simulating routine activities.
Particle concentrations may increase during operations because of personnel movement, material transfer, and equipment activities.
For this reason, cleanrooms must be evaluated under the conditions specified by the applicable GMP requirements rather than relying only on measurements taken in an empty room.
ISO classes and GMP grades share certain airborne particle concentration limits, but they are not directly interchangeable.
The following comparison illustrates their general relationship at the ≥0.5 µm particle size.
GMP Grade | Approximate ISO Class at Rest | Approximate ISO Class in Operation |
|---|---|---|
Grade A | ISO 5 | ISO 5 |
Grade B | ISO 5 | ISO 7 |
Grade C | ISO 7 | ISO 8 |
Grade D | ISO 8 | Not predetermined |
This table compares particle limits only. It does not establish equivalence between ISO classification and GMP compliance. GMP also requires microbiological control, qualification, monitoring, and operational procedures.
ISO 5 and GMP Grade A share the same maximum airborne particle concentration of 3,520 particles/m³ at ≥0.5 µm.
However, ISO 5 classification alone does not confirm that the environment is suitable for aseptic pharmaceutical manufacturing.
Grade A requires additional controls, including appropriate airflow protection, microbiological monitoring, qualified processing conditions, and documented contamination prevention measures.
Therefore, ISO 5 particle classification is not the same as full GMP Grade A compliance.
Selecting a cleanroom grade requires understanding the manufacturing process rather than assigning a grade based solely on the type of equipment installed.
Important considerations include whether the product is sterile, whether it is exposed to the surrounding environment, the sterilization strategy, personnel interventions, and the use of barrier technology.
Aseptic pharmaceutical filling is a critical process because sterile products or components may be exposed during manufacturing.
For conventional aseptic filling operations, critical exposure points typically require Grade A protection with an appropriate Grade B background.
These requirements may apply to operations involving vials, ampoules, syringes, and other sterile containers, depending on the process design.
For example, a Vial Filling Sealing Line intended for aseptic operation must be integrated with suitable contamination control measures and qualified environmental conditions.
Modern facilities may also use Sterile Isolator Systems to separate critical processing areas from direct operator exposure.
Where an isolator is used, the surrounding background classification should be determined through risk assessment and the applicable Annex 1 requirements.
Grades C and D are used for operations with different contamination control needs, depending on the product and manufacturing process.
Examples may include certain preparation activities, component handling, and supporting manufacturing steps.
A process involving terminal sterilization may have different environmental requirements from a conventional aseptic filling process.
As a result, manufacturers should evaluate their production workflow, contamination risks, and regulatory obligations before selecting the appropriate cleanroom grade.
A well-designed pharmaceutical facility should provide sufficient environmental protection without unnecessarily over-specifying every room.
Selecting the correct cleanroom grade is only one part of pharmaceutical facility planning.
A GMP cleanroom must also be designed, qualified, and operated to maintain the required level of contamination control.
Heating, ventilation, and air conditioning (HVAC) systems are essential for maintaining controlled pharmaceutical environments.
A suitable cleanroom HVAC design may include:
HEPA filtration to control airborne particle contamination.
Airflow patterns that protect critical manufacturing zones.
Appropriate pressure differentials between adjacent areas.
Temperature and humidity control based on process requirements.
Airflow visualization studies to verify environmental protection.
For unidirectional airflow systems, EU GMP Annex 1 provides a guidance range of 0.36–0.54 m/s at the working position unless an alternative is scientifically justified through the contamination control strategy.
Airflow performance must be established through qualification and supported by appropriate testing.
Pharmaceutical manufacturers planning new facilities or upgrades can evaluate integrated Cleanroom Projects that combine controlled environments with pharmaceutical production requirements.
GMP requires ongoing evidence that cleanroom conditions remain suitable for manufacturing.
A pharmaceutical contamination control program may include non-viable particle monitoring, viable microbial monitoring, personnel monitoring, cleaning verification, and investigation of environmental trends.
Cleanroom qualification may involve:
Airborne particle classification.
Final filter integrity testing.
Airflow volume and velocity measurements.
Pressure differential verification.
Airflow visualization.
Microbiological assessments.
Recovery and other relevant performance tests.
Under EU GMP Annex 1, the maximum periodic requalification interval is six months for Grades A and B and twelve months for Grades C and D. Additional requalification may be necessary following significant changes or events.
Qualification is not the same as routine environmental monitoring. Both are important elements of maintaining a controlled pharmaceutical manufacturing environment.
EU GMP Annex 1 emphasizes the need for a comprehensive Contamination Control Strategy.
A CCS evaluates how contamination risks are prevented, detected, and controlled throughout manufacturing.
It should consider facility design, equipment, personnel, utilities, materials, cleaning, environmental monitoring, and process controls.
For pharmaceutical manufacturers, integrating cleanroom design with the overall CCS helps ensure that facilities are developed around actual production risks rather than particle classification alone.
Shanghai Marya provides pharmaceutical cleanroom engineering and integrated manufacturing solutions for different production requirements.
Our Cleanroom Solutions support pharmaceutical facility planning, controlled environment design, equipment integration, and related project requirements.
By considering cleanroom classification, production equipment, HVAC systems, operational workflow, and project qualification requirements together, we help manufacturers develop cleanroom environments suited to their intended pharmaceutical applications.
Whether you are planning a new pharmaceutical facility or upgrading an existing production area, understanding the relationship between ISO classification and GMP requirements is an important first step.
Contact Marya to discuss your pharmaceutical cleanroom requirements and explore a suitable engineering solution for your production process.
No. ISO 14644-1 classifies cleanrooms based on airborne particle concentration. Pharmaceutical GMP establishes broader requirements involving contamination control, microbiological monitoring, personnel practices, qualification, and manufacturing procedures. ISO classification may support GMP compliance, but it does not replace GMP requirements.
ISO 5 and GMP Grade A share a particle concentration limit of 3,520 particles/m³ at ≥0.5 µm. However, Grade A also requires appropriate microbial control, airflow protection, qualification, monitoring, and operational controls. Therefore, ISO 5 classification alone is insufficient to establish GMP Grade A compliance.
Grade B generally serves as the background environment for Grade A critical zones in conventional aseptic operations. Grade C supports less critical manufacturing operations under suitable process conditions. Grade B has more stringent operational and microbiological requirements than Grade C.
In conventional aseptic filling, critical exposure zones generally require Grade A conditions with an appropriate Grade B background. Isolators and other barrier technologies may permit different surrounding background classifications when supported by design, qualification, contamination control measures, and regulatory requirements.
Yes, an ISO-classified cleanroom can form part of a GMP-compliant pharmaceutical facility. However, the facility must also satisfy applicable requirements for microbial control, qualification, monitoring, documentation, personnel practices, and contamination prevention. ISO classification alone does not establish GMP compliance.
Depending on the cleanroom grade and intended use, qualification may include particle classification, filter integrity testing, airflow measurements, pressure differential testing, airflow visualization, microbial qualification, and recovery testing. The test program should follow applicable GMP requirements and documented risk assessments.
ISO and GMP cleanroom classifications are closely related, but they are not interchangeable.
ISO 14644-1 defines airborne particle cleanliness, while pharmaceutical GMP establishes the broader controls required to protect product quality and prevent contamination.
For pharmaceutical manufacturers, selecting the correct cleanroom grade requires considering product exposure, manufacturing processes, environmental monitoring, and the overall contamination control strategy.
By integrating ISO classification principles with GMP requirements, manufacturers can develop controlled environments suited to their specific production needs.
Explore Marya's pharmaceutical cleanroom solutions to learn more about planning and integrating cleanroom systems for pharmaceutical manufacturing.
