Your Cleanroom Specialist
Competence from + 100 Cleanrooms and since 1992
Cleanroom 14644 ISO 1-9 FS209E EU GMP ABCD USP 797, 800, 825
Cleanroom Design, Construction, Operation
Limit Your Liability
Cleanroom End User
Limit Your Liability - I make sure that Your Cleanroom project meets Your demands, from Design to Operation.
Architects
Limit Your Liability- I make sure that Your Cleanroom Specification will meet the End Customer needs, and at the right budget/cost.
Contractors
Limit Your Liability- I make sure that all building processes are aligned, in line with the Cleanroom demand.
Consulting Engineers
Limit Your Liability- I offer extended Cleanroom competence
Alata
Alice
Open Sans
Noto Sans
Bebas Neue
Great Vibes
Rock Salt
Exo
Belgrano
Overlock
Cinzel
Indie Flower
Staatliches
Roboto Slab
Lato
Noto Serif
Open Sans
Montserrat
Ubuntu
Rubik
Delius
Amiri
Montserrat
Advanced Airflow Modelling: Applying CFD in Cleanroom Design 1. Introduction Computational Fluid Dynamics (CFD) has become an essential tool for engineering cleanrooms that meet stringent performance, contamination-control, and regulatory requirements. While ISO 14644 and GMP Annex 1 provide the performance criteria, CFD enables engineers to predict airflow behavior—velocity fields, turbulence, particle transport, and temperature distribution—before construction or modification of a cleanroom. When properly validated, CFD strengthens design decisions, reduces lifecycle risk, and improves operational reliability. This article provides a technically grounded, engineer-focused guide to using CFD in modern cleanroom design, from modelling strategy to validation and integration with qualification activities. 2. The Role of CFD in Cleanroom Engineering CFD supplements traditional engineering calculations by offering a detailed, three-dimensional understanding of airflow patterns. In cleanrooms where unidirectional flow, pressure cascades, and contamination pathways are critical, CFD offers insights that are not achievable through rule-of-thumb design alone. Primary uses of CFD in cleanroom design include: Predicting airflow velocity profiles and identifying turbulence zones. Visualizing unidirectional flow uniformity over process-critical areas. Simulating particle generation, transport, and deposition. Optimizing placement of HEPA filters, returns, and make-up air inlets. Assessing temperature, humidity, and buoyancy-driven effects in high-load areas. Supporting contamination-control risk assessments and the facility’s Contamination Control Strategy (CCS). CFD is not a substitute for compliance testing; rather, it improves the likelihood that the constructed facility will meet ISO 14644 performance criteria during OQ/PQ. 3. Modelling Objectives and Boundary Conditions Accurate CFD results depend on well-defined modelling goals and boundary conditions that reflect real operational expectations. Typical modelling objectives include: Achieving consistent unidirectional airflow ≥0.36–0.54 m/s over ISO 5 zones. Maintaining required pressure differentials (generally 10–15 Pa between grades). Minimizing recirculation zones above critical process locations. Verifying recovery time following simulated particle disturbances. Predicting environmental stability near heat-emitting equipment. Essential boundary conditions: Supply airflow: HEPA/ULPA face velocities, FFU performance curves, and uniformity assumptions. Exhaust/return flow: Locations, flow rates, and balance settings. Thermal loads: People, equipment, lighting, and process heat sources. Process barriers: Isolators, RABS, curtains, and equipment footprints. Contaminant sources: Personnel particle emission rates and process-specific generation assumptions. Boundary conditions must be based on engineering calculations, manufacturer data, and documented URS/Basis of Design (BOD) criteria. 4. Turbulence Models and Solver Selection Selecting an appropriate turbulence model is one of the most critical decisions in cleanroom CFD because the accuracy of particle transport and velocity uniformity predictions depends heavily on it. Commonly applied models: k–ε (standard or realizable): Robust for general room-scale modelling; good balance between accuracy and computation time. k–ω SST: Better near-wall resolution; useful for unidirectional flow uniformity and identifying micro-recirculation zones. RNG k–ε: Helpful where buoyancy and swirl effects are present. LES (Large Eddy Simulation): High accuracy but computationally intensive; typically reserved for research-level or high-risk applications. For most cleanroom design projects, a realizable k–ε or k–ω SST model achieves the necessary practical accuracy while maintaining reasonable simulation times. 5. Particle Transport and Contamination Modelling Simulating particle movement allows engineers to assess contamination risks early in design. Two principal approaches exist: Lagrangian (discrete particle) modelling: Tracks individual particles; useful for simulating personnel-generated contamination and verifying whether particles escape critical zones. Eulerian (scalar concentration) modelling: Treats particle concentration as a continuum; suitable for evaluating uniformity or dilution in larger volumes. Key considerations: Use iso-kinetic boundary conditions near HEPA inlets to avoid artificial deposition. Apply realistic particle size distributions (commonly 0.5–5 µm for viable and 0.3–5 µm for non-viable particles). Incorporate gravitational settling and turbulent dispersion when modelling deposition risk. Particle simulation results should be cross-checked with anticipated ISO 14644-1 class limits and expected PQ operational performance. 6. Modelling Common Cleanroom Configurations Different room layouts and process arrangements require tailored CFD approaches. Unidirectional (laminar) airflow zones: Evaluate face velocity uniformity and identify edge effects near walls and equipment. Examine the influence of obstructions such as robots, filling lines, or microscopes. Confirm downward flow continuity to low-wall returns. Turbulent-mixed airflow rooms: Model dilution effectiveness, especially in ISO 7–8 rooms with high heat loads. Verify that return locations do not create stagnant corners. Airlocks and transfer rooms: Simulate opening/closing cycles using transient models to predict pressure cascade stability. Assess air velocity through door gaps for contamination containment. RABS and isolator environments: Model internal recirculation patterns and assess glove port disturbances. Evaluate leakage paths between zones and HEPA supply interactions. 7. CFD Integration in the Cleanroom Design Workflow CFD should not be an isolated task; it must integrate with the broader engineering design and qualification lifecycle. Typical workflow alignment: URS & DQ: CFD supports design decisions for HEPA placement, supply air volume, and equipment layout. IQ: Ensures installation matches the design assumptions used in the model. OQ: CFD predictions are verified using airflow visualization, smoke studies, HEPA integrity tests, and velocity measurements. PQ: CFD results help interpret operational classification testing and particle behaviour under dynamic conditions. CFD findings should feed into the facility’s CCS, particularly around critical interventions, airflow protection strategies, and environmental monitoring locations. 8. Validation and Verification of CFD Models Regulatory expectations require that CFD models used for design or risk assessment be validated against real data. Core verification steps: Compare predicted velocities with measured values during OQ. Validate pressure gradients using HVAC commissioning data. Confirm predicted flow patterns with smoke visualization. Cross-check predicted contamination trends with PQ results. Documentation should include model setup, assumptions, solver settings, mesh strategy, convergence criteria, and deviations from standard practice. 9. Limitations and Engineering Considerations Although powerful, CFD is not infallible and must be applied with engineering judgement. Known limitations: Over-simplified boundary conditions can lead to false uniformity. Turbulence models vary in accuracy for low-velocity, cleanroom-specific flows. Mesh resolution significantly affects results; inadequate meshing may hide recirculation. CFD cannot replace ISO 14644 testing, HEPA integrity testing, or real PQ performance data. Well-designed CFD complements, but never substitutes, field testing. 10. Conclusion CFD has become a cornerstone of advanced cleanroom design, enabling engineers to visualize airflow behaviour, predict contamination risks, and optimize HVAC performance before construction. When grounded in accurate boundary conditions, suitable turbulence models, and validated assumptions, CFD provides actionable insights that significantly improve the reliability and regulatory robustness of cleanroom design. By integrating CFD throughout the DQ–IQ–OQ–PQ lifecycle, cleanroom designers and operators can achieve systems that meet ISO 14644 and GMP Annex 1 requirements with greater confidence, efficiency, and long-term performance stability. Read more here: About Cleanrooms: The ultimate Guide
Cleanroom expertise: design, construction, and compliance from 14644 Cleanroom At 14644 Cleanroom, we understand that a successful cleanroom is much more than just a sterile environment. It’s a meticulously designed and controlled space, critical for protecting sensitive processes, products, and personnel. Since 1992, we’ve been at the forefront of cleanroom technology, helping businesses like yours navigate the complexities of cleanroom design, construction, operation, and certification. With over 100 cleanroom projects under our belt, our goal is to provide impartial guidance that helps you limit your liability and ensure unwavering compliance with international standards. Whether you're developing a new facility, upgrading an existing one, or simply seeking expert advice, our team is equipped with the knowledge and experience to guide you every step of the way. We partner with end-users, architects, contractors, and consulting engineers, offering comprehensive services tailored to your unique requirements. What exactly is a cleanroom? A cleanroom is an engineered space where the concentration of airborne particles is rigorously controlled to specific limits. This control extends beyond just dust particles; it includes airborne microbes, aerosol particles, and chemical vapors. Achieving and maintaining these conditions requires precise management of factors such as temperature, humidity, and pressure. The fundamental purpose of a cleanroom is to minimize contamination, which can be critical for a wide range of industries, including pharmaceuticals, biotechnology, microelectronics, and medical device manufacturing. The level of cleanliness required in a cleanroom varies significantly depending on the application. This is why cleanrooms are classified according to strict international standards such as ISO 14644, which we specialize in. Each classification dictates the maximum number of particles of a specific size allowed per cubic meter of air. Understanding these classifications and ensuring your facility meets them is paramount for product integrity and regulatory compliance. Our holistic approach to cleanroom solutions We believe in a holistic approach to cleanroom solutions, focusing on minimizing risks, optimizing efficiency, and providing future-proof facilities. Our involvement starts at the conceptual stage and extends throughout the operational life of your cleanroom. This comprehensive support ensures that every aspect, from initial planning to ongoing maintenance, aligns with your strategic objectives and regulatory obligations. Cleanroom design: foundational excellence The success of any cleanroom project hinges on its initial design. Our expert consulting services begin with developing robust User Requirement Specifications (URS) . This crucial step ensures that all functional, operational, and regulatory needs are clearly defined from the outset. We work closely with your team to translate your specific requirements into a detailed design brief, forming the bedrock for a compliant and efficient cleanroom. Our experience gained from over 100 cleanroom projects allows us to anticipate challenges and implement optimal solutions during this critical phase. Good design isn't just about meeting current standards; it's about anticipating future needs and technological advancements. We consider factors like workflow, energy efficiency, cleanroom classification, and material selection to create a design that is not only effective but also sustainable and scalable. Cleanroom construction: quality and precision Once the design is finalized, meticulous construction is essential. We provide expert guidance during the construction phase, including validating supplier quotations and overseeing the build. Our impartial advice helps ensure that construction adheres to the highest standards of quality, materials, and processes, preventing costly errors and delays. We act as your advocate, ensuring that contractors deliver on their promises and that the cleanroom is built exactly to specifications. Our project management services further ensure that the cleanroom construction stays on track, within budget, and meets all regulatory milestones. We understand the specific challenges associated with cleanroom builds and leverage our extensive experience to mitigate risks effectively. For more on how we manage projects, visit our project management page. Cleanroom operation: maintaining peak performance A cleanroom’s effectiveness is only as good as its ongoing operation and maintenance. We offer extensive support for cleanroom operations, including advice on essential cleanroom accessories , garments, and cleaning protocols. Proper operational procedures are vital to sustain the integrity of your controlled environment. We help you develop and implement best practices for personnel gowning, material transfer, and environmental monitoring. Understanding and controlling potential sources of contamination, such as human presence and equipment, is a continuous process. We guide you in establishing robust standard operating procedures (SOPs) that ensure consistent performance and compliance. Our aim is to empower your team with the knowledge and tools to operate your cleanroom efficiently and safely. Cleanroom validation & certification: ensuring compliance Validation and certification are non-negotiable for any cleanroom. We specialize in navigating complex regulatory frameworks, including ISO 14644, FS209E, EU GMP ABCD, and USP 797, 800, 825. Our services include comprehensive cleanroom validation and cleanroom certification , ensuring your facility meets all required international standards. Compliance is not a one-time event; it's an ongoing commitment. We help you establish robust validation master plans and conduct routine certifications to demonstrate continuous adherence to regulatory requirements. This proactive approach helps you limit your liability and build trust with regulatory bodies and clients. Our expertise in these diverse global standards provides you with a competitive edge, ensuring your cleanroom is recognized globally for its high standards. Essential elements for every cleanroom A functional cleanroom relies on more than just its walls and air filtration system. The right accessories, garments, and cleaning protocols are crucial for maintaining the controlled environment. We provide expert recommendations and guidance on these vital components: Cleanroom Accessories: From specialized workstations to pass-through boxes, we advise on the accessories that enhance efficiency and maintain sterility. Cleanroom Storage and Furniture: Proper storage solutions and furniture are designed to minimize particle generation and facilitate easy cleaning. See our solutions at cleanroom storage and furniture. Cleanroom Garments: The choice and use of specific cleanroom garments are critical for preventing personnel-borne contamination. Cleanroom Cleaning Protocols: Meticulous and documented cleaning procedures are fundamental to sustaining the cleanroom classification. Learn more about effective cleanroom cleaning . Each of these elements plays a pivotal role in the overall integrity of your cleanroom. By integrating them correctly, you ensure a consistent and compliant operational environment. Why choose 14644 Cleanroom? Choosing the right partner for your cleanroom needs is crucial. Since 1992, we have provided impartial, expert advice that empowers our clients. Our extensive experience, spanning over 100 cleanroom projects , means we bring unparalleled knowledge to every challenge. We actively contribute to shaping industry best practices and upholding the highest standards of cleanroom integrity. Our commitment is simple: to help you achieve and maintain optimal cleanroom performance while minimizing risks and ensuring full compliance. We speak your language and understand the specific demands of your industry, whether you operate under ISO 14644, FS209E, EU GMP ABCD, or USP 797, 800, 825 requirements. Our services are designed to protect your investments and enhance your operational excellence. Ready to discuss your cleanroom project? Contact us today to learn how our expertise can benefit you. We are located at Strandvejen 23, DK 6000 Kolding. You can reach us by phone at +45 5160 6457 or email us at kl@14644.dk. Let's build a cleaner future together. Optimizing your cleanroom for efficiency and future growth Beyond basic compliance, we focus on helping you optimize your cleanroom for long-term efficiency and adaptability. This includes advising on advanced filtration technologies for enhanced air quality, energy-efficient designs, and modular cleanroom solutions that can scale with your business. Our goal is to provide a cleanroom solution that is not only compliant today but also future proof for tomorrow's challenges. Consider the impact of your cleanroom on global manufacturing . A well-designed and operated cleanroom contributes significantly to product quality, reducing waste, and increasing overall productivity. We're here to help you achieve these benefits. Frequently asked questions about cleanrooms What are the primary functions of a cleanroom? The primary functions of a cleanroom are to control airborne particulate contamination, maintain specified environmental parameters (temperature, humidity, pressure), and protect sensitive processes, products, and personnel from environmental contaminants. This control is critical for industries requiring high levels of sterility and precision. How is a cleanroom classified? Cleanrooms are primarily classified according to the ISO 14644-1 standard, based on the maximum allowable concentration of airborne particles of a specified size per cubic meter of air. Other standards like FS 209E, EU GMP, and USP are also used depending on the industry and region. We have expertise in all these standards. Why is ongoing validation important for a cleanroom? Ongoing validation and certification are crucial for a cleanroom to demonstrate continuous compliance with regulatory standards and maintain its specified performance. This includes regular testing of particulate levels, airflow, pressure differentials, and environmental conditions. It helps identify potential issues early and ensures the cleanroom remains fit for purpose, helping you to limit your liability . What types of industries utilize cleanrooms? A wide range of industries rely on cleanrooms, including pharmaceuticals, biotechnology, medical device manufacturing, microelectronics, aerospace, optics, nanotechnology, and even some food and beverage production facilities. Any industry where contamination can compromise product quality or safety will likely utilize a cleanroom. What role do cleanroom garments play in contamination control? Cleanroom garments are essential for preventing human-generated contamination, such as skin flakes, hair, and clothing fibers, from entering the controlled environment. They are made from low-shedding fabrics, designed to prevent particle release, and must be donned and doffed according to strict protocols. Proper garment selection and use are critical for maintaining cleanroom integrity. Read more here: The ultimate Cleanroom Guide
Lifecycle Qualification Strategies for Modern Cleanrooms (DQ–IQ–OQ–PQ) 1. Introduction Lifecycle qualification is a foundational framework for ensuring that modern cleanrooms consistently meet the performance, compliance, and product-protection requirements defined by ISO 14644 , GMP Annex 1 , and related regulatory expectations. The DQ–IQ–OQ–PQ sequence provides a structured, evidence-driven method to verify that a cleanroom is designed correctly, installed correctly, operating correctly, and performing consistently under real process conditions. This article outlines practical, engineering-grounded lifecycle qualification strategies suitable for new cleanroom facilities, major retrofits, and ongoing performance lifecycle management. 2. Design Qualification (DQ) Design Qualification establishes that the cleanroom design—down to the HVAC architecture, building envelope, process layout, and control strategies—meets the intended functional, regulatory, and risk-reduction requirements. DQ must be fully documented and approved prior to procurement or construction. Key Objectives Demonstrate alignment with user requirements (URS), regulatory standards, and contamination-control risk assessments. Validate the design basis for airflow volume, pressure regime, filtration efficiency, heat loads, and classification goals. Confirm that materials, finishes, and mechanical/electrical systems support cleanability, durability, and cleanroom compatibility. Core Activities URS Development: Defines required cleanliness class (e.g., ISO 7/8 rooms leading to ISO 5 zones), environmental parameters, process flows, and gowning strategy. Basis of Design (BOD) Review: Verifies engineering assumptions including supply air volume, terminal HEPA load, air change rate targets, and pressure cascade. Design Risk Assessment: Evaluates contamination pathways, personnel/material movement, and failure modes (e.g., loss of differential pressure). Drawings and Specification Review: Architectural drawings, HVAC schematics, control diagrams, and finish schedules are checked against URS and applicable standards. DQ Acceptance Criteria All functional requirements traceable to the URS. Design conforms to ISO 14644 requirements, GMP zoning concepts, and classified-area pressure cascade norms. Design risks identified and mitigated with engineering or procedural controls. 3. Installation Qualification (IQ) Installation Qualification verifies that the cleanroom and its systems were installed according to approved design documentation and equipment specifications. IQ is typically executed after construction is complete but prior to HVAC balancing and environmental verification. Key Objectives Confirm correct installation of architectural elements, HVAC components, filtration assemblies, electrical systems, and monitoring devices. Verify that materials and finishes meet certification requirements (e.g., low-VOC, non-shedding, GMP-compatible). Document all utilities, equipment IDs, calibration statuses, and as-built conditions. Core Activities Component Verification: HEPA/ULPA filters, fan filter units (FFUs), terminal housings, ductwork, dampers, valves, and sensors must match approved specifications. Material and Finish Inspection: Wall panels, flooring, doors, pass-throughs, and sealants are checked for fit, compatibility, cleanability, and integrity. As-Built Documentation: Includes redlined drawings, HVAC equipment lists, control sequences, and wiring diagrams. Calibration and Utilities Check: Differential pressure sensors, temperature/humidity probes, and airflow measurement devices are installed, tagged, and calibrated. IQ Acceptance Criteria All equipment installed per manufacturer recommendations and design documents. All sensors and instruments calibrated with traceability. As-built documentation complete and approved. 4. Operational Qualification (OQ) Operational Qualification demonstrates that the cleanroom and its supporting HVAC/control systems operate as designed across the full range of expected environmental and operating conditions. OQ is executed after HVAC commissioning and initial balancing but before introducing process equipment or personnel workflows. Key Objectives Confirm the HVAC system achieves and maintains the required environmental conditions (classification, pressure, temperature, humidity). Demonstrate correct operation of interlocks, alarms, monitoring systems, and control loops. Verify that control logic supports contamination-control requirements, including recovery and cascade stability. Core Activities Airflow and Pressure Verification: Measurement of supply volume, extract volume, and differential pressures between adjacent zones under at-rest conditions. HEPA Integrity Testing: Leak testing using ISO 14644-3 compliant methods (e.g., PAO/DEHS aerosol challenge). Particle Classification Testing: Conduct at-rest classification tests per ISO 14644-1 to confirm compliance with specified cleanroom class. Recovery Testing: Demonstrate the room’s ability to return to classification levels after a particle challenge or simulated disturbance. Alarm and Interlock Testing: Validation of door interlocks, pressure-loss alarms, temperature/humidity deviations, and exhaust/supply failures. Environmental Stability Study: Trending temperature, humidity, and pressure over time to ensure steady-state performance. OQ Acceptance Criteria All environmental parameters meet specified limits under at-rest conditions. All alarms/interlocks operate predictably and within defined tolerances. HEPA filters pass integrity tests with no leaks above allowed limits. Particle counts comply with the ISO class designation. 5. Performance Qualification (PQ) Performance Qualification confirms that the cleanroom performs as required under normal operational conditions, including personnel activity, equipment operation, and process workflows. PQ represents the final verification stage before routine production or regulated use. Key Objectives Validate real-world performance including personnel-generated loads, process equipment heat loads, and operational contamination sources. Demonstrate environmental control and consistency during typical and peak operational states. Establish baseline performance data for future ongoing monitoring. Core Activities Dynamic Classification Testing: Particle sampling during typical operations with personnel, processes, and equipment running. Microbial Monitoring: Viable air and surface sampling following GMP Annex 1 expectations. Temperature/Humidity/Pressure Trending: Confirmation that environmental parameters remain stable during active operations. Process Simulation (Media Fill or Surrogate Operations): For aseptic processes, PQ may include media fills or other simulation protocols. Workflow Verification: Assessment of gowning, personnel behavior, and material transfer methods to ensure contamination control integrity. PQ Acceptance Criteria Cleanroom meets required ISO class under operational conditions (where required by process). Microbial contamination levels remain within specified action and alert limits. Operational conditions do not compromise the pressure cascade or airflow patterns. All critical process simulations meet acceptance criteria. 6. Documentation Structure and Traceability A robust documentation package ensures regulatory compliance and facilitates future audits and requalification. Each lifecycle stage must include: Qualification protocols (DQ/IQ/OQ/PQ) with clearly defined acceptance criteria. Traceability matrices linking URS → DQ → IQ/OQ/PQ tests. Calibration records, commissioning reports, and as-built drawings. Deviations, corrective actions, and risk assessments. A final qualification summary report consolidating results and confirming readiness. 7. Integration With ISO 14644 and GMP Annex 1 Modern cleanroom qualification strategies must continuously reflect international standards and regulatory updates. ISO 14644 Part 1: Air cleanliness classification by particle concentration. Part 2: Monitoring requirements for demonstrating continued compliance. Part 3: Test methods for cleanroom performance (airflow, recovery, HEPA integrity). Part 4: Design, construction, and start-up best practices. Part 16: Energy efficiency considerations. GMP Annex 1 adds requirements for: Contamination Control Strategy (CCS). Formal risk management throughout the cleanroom lifecycle. Demonstrable environmental control during sterile operations. Expected performance and monitoring frequencies for classified areas. Qualification strategies must ensure that the DQ–IQ–OQ–PQ lifecycle aligns with every relevant element of the CCS, including airflow design, cleaning effectiveness, gowning, and monitoring programs. 8. Requalification and Ongoing Lifecycle Management Qualification does not end with PQ. Cleanrooms require periodic requalification, especially HEPA integrity, airflow verification, and environmental monitoring performance assessments. Typical requalification intervals: HEPA integrity: annually (or more often for high-risk areas). Airflow/pressure/temperature/humidity: semiannual to annual, depending on risk. ISO classification tests: typically annual for high-grade areas; up to biennial for lower-risk rooms, based on documented risk justification. Changes in configuration, HVAC equipment, control logic, or process flows should trigger change control and potentially partial requalification. 9. Conclusion Effective lifecycle qualification using the DQ–IQ–OQ–PQ framework is fundamental for ensuring that modern cleanrooms are engineered, constructed, and operated to meet rigorous contamination-control requirements. A disciplined approach grounded in ISO 14644, GMP Annex 1, and established engineering practice produces cleanrooms that operate with reliability, safety, and regulatory confidence. By maintaining robust documentation, integrating risk management, and committing to ongoing monitoring and requalification, facility owners and operators can ensure long-term cleanroom performance and compliance. Read more here: About Cleanrooms: The ultimate Guide
Cleanroom Consulting Services from Design to Operation
