A cleanroom is a controlled environment with low levels of pollutants such as dust, airborne microbes, aerosol particles, and chemical vapors. Cleanrooms are designed to maintain strict control over environmental parameters such as temperature, humidity, air pressure, and particulate matter.
ISO 14644-1 is an international standard that defines cleanroom classifications based on the concentration of airborne particles. ISO classifications range from ISO Class 1 (the cleanest) to ISO Class 9 (the least clean). ISO Class 5 cleanrooms have strict particle count requirements.
ISO Class 5 cleanrooms allow no more than 3,520 particles per cubic meter that are 0.5 microns or larger in size. They also allow no more than 20 particles per cubic meter that are 5 microns or larger. This makes ISO Class 5 cleanrooms suitable for work requiring high levels of cleanliness such as pharmaceutical manufacturing, medical device assembly, and microelectronics fabrication.
Compared to lower ISO classes, ISO Class 5 cleanrooms allow fewer airborne particles. However, they are not as stringent as higher ISO classes like ISO Class 4 or ISO Class 3 cleanrooms which allow even lower concentrations of particles.
Purpose and Applications
ISO Class 5 cleanrooms are designed to maintain extremely low levels of particles, making them suitable environments for work requiring high levels of cleanliness and sterility. Here are some of the key industries and applications that utilize ISO Class 5 cleanrooms:
Healthcare – Pharmaceutical manufacturing, medical device assembly, tissue and cell culturing, and sterile preparations all require ISO Class 5 cleanrooms. These spaces allow the safe handling of sterile pharmaceuticals and reduced risk of contamination.
Microelectronics – Sensitive electronics manufacturing for semiconductors, flat panel displays, and other devices needs contamination-controlled environments. ISO Class 5 cleanrooms provide the ultraclean conditions needed.
Food and beverage – Low-particle environments are essential for manufacturing sterile food products, supplements, and more. ISO Class 5 cleanrooms maintain sterility when handling these consumables.
Aerospace – Precision manufacturing and assembly of aircraft components calls for exceptionally clean spaces. ISO Class 5 cleanrooms reduce defects and minimize contamination risks.
In general, ISO Class 5 cleanrooms facilitate scientific research, product development, and advanced manufacturing processes requiring sterility. The high air filtration and rigorous cleaning protocols maintain ultraclean environments for mission-critical operations.
Design and Construction
ISO Class 5 cleanrooms are carefully designed and constructed to achieve the extremely low levels of particles required for this classification. Some key design elements include:
Materials used – Wall, floor and ceiling panels are typically made of smooth non-shedding materials such as stainless steel or FRP. Joints are sealed to minimize particle generation. All furniture, tools and equipment must also be made of cleanroom-compatible materials (Source 1).
Ventilation – Sophisticated air handling systems provide a high rate of filtered air exchanges per hour, removing contaminant particles from the cleanroom. Fan filter units with HEPA or ULPA filters provide laminar flow throughout the space (Source 2).
Room pressure – Positive pressure is maintained so any leaks push air out of the cleanroom rather than allow unfiltered air to enter. Airlocks prevent pressure differentials when doors are opened.
Gowning requirements – Strict protocols require personnel to gown in full coveralls, boots, gloves, hair/beard nets and face masks. Extensive washing and garment sanitization maintains cleanliness.
Particle Counts
ISO 14644-1 specifies maximum concentrations of airborne particles per cubic meter for different ISO classes. For ISO Class 5, the maximum particles/m3 allowed are (ISO 14644-1:2015):
- ≥0.1 μm: 3,520 particles/m3
- ≥0.2 μm: 1,020 particles/m3
- ≥0.3 μm: 352 particles/m3
- ≥0.5 μm: 83 particles/m3
- ≥1 μm: 29 particles/m3
- ≥5 μm: 7 particles/m3
To monitor particulate counts, calibrated particle counters are used as specified in ISO 14644-1. Testing is conducted at representative locations throughout the cleanroom during operation. Counts are taken at the 1 ft level for vertical laminar flow cleanrooms. For turbulent flow rooms, additional sampling locations may be needed near the ceiling and corners (Understanding Cleanliness Classifications for Life Science Facilities).
Routine particle counting is necessary to validate that the cleanroom continues meeting ISO 14644-1 particle concentration limits. Any excursions above the maximum levels require investigation and corrective actions to bring particulate counts back within specifications.
Temperature and Humidity
ISO Class 5 cleanrooms require tightly controlled temperature and humidity ranges to maintain proper conditions. The guidelines state that temperature should be maintained between 15-22°C (59-72°F), with an optimal range of 18-21°C (64-70°F) [1]. Relative humidity levels are recommended between 30-45% year-round, with a target of 35-40% [2].
Temperature is controlled through the use of heating, ventilation and air conditioning (HVAC) systems. Air handling units filter and supply clean air into the room at a constant temperature. Humidity is regulated through the use of humidifiers or dehumidifiers as part of the HVAC system. The air management system monitors conditions and adjusts to maintain the required parameters at all times.
Keeping temperature and humidity within the specified ranges helps minimize particle generation, electrostatic discharge, and contamination risks. This ensures optimal conditions for the processes and products within the cleanroom environment.
Cleaning and Sanitation
Maintaining a clean, contaminant-free environment is critical in an ISO Class 5 cleanroom. Cleaning and sanitation procedures must be thorough and rigorous. According to Bluethunder Technologies’ Cleanroom Cleaning Product Guide, daily cleaning should focus on the following:
Floors should be vacuumed and wet mopped with cleanroom-approved disinfectants at least once per day. Common disinfectants include hydrogen peroxide, quaternary ammonium, and alcohol solutions [1]. Walls, doors, and ceilings should also be carefully wiped down to remove any contaminants.
All equipment, tools, carts, and work surfaces need to be thoroughly cleaned and disinfected between each use. 70% isopropyl alcohol is commonly used for rapid disinfection of surfaces.
To prevent recontamination, separate mop heads and wipes should be used for the cleanroom and support areas. All cleaning tools and disinfectants must be approved for cleanroom use and properly cleaned themselves after each use. Cleanroom garments need to be regularly laundered as well.
In addition to daily cleaning, complete disinfection of the entire cleanroom using cleaning agents like peroxide is recommended weekly or biweekly. Regular cleaning validations should also be conducted [2].
Gowning Protocols
Gowning protocols in ISO Class 5 cleanrooms ensure personnel do not introduce contamination while entering or exiting the cleanroom. Garment requirements help protect the cleanroom environment.
ISO Class 5 cleanrooms, being the highest classification other than ISO Class 1, have stringent gowning requirements as outlined in ISO 14644-1 standards. Personnel must wear coveralls, hoods, gloves, masks, and shoe covers [1] [2]. This protective gear minimizes shedding of particles and hair within the cleanroom.
For entry, personnel pass through an air shower to dislodge particles before donning cleanroom garments in a gowning room. Proper gowning procedures are followed, with hands and body covered first before head coverings. Upon exit, a reverse process occurs, removing headgear first before garments to avoid contaminating the cleanroom [3].
Maintaining ISO Class 5 Standards
To maintain ISO Class 5 certification, cleanrooms must follow strict testing and monitoring procedures on a routine basis. According to the ISO 14644-1 standard, airborne particle testing must be conducted at least every 6 months in ISO Class 5 environments to ensure ongoing compliance 1. Testing involves taking air samples at designated locations and measuring the concentration of particles ≥0.5 μm and ≥5.0 μm. If concentrations exceed the maximum levels, the cleanroom has failed its certification.
In addition to periodic testing, continuous monitoring of differential pressure, temperature, and humidity is critical. Alarm systems should be in place to notify personnel if critical parameters move outside specified ranges. Thorough disinfection procedures must be followed regularly as well.
When it’s time for recertification, an accredited third-party testing organization performs a comprehensive evaluation following the ISO 14644-1 standard. All criteria are re-verified, including air filtration performance, particle counts, microbial counts, air flow patterns, pressure differentials, and more. Operators are required to demonstrate proper gowning techniques and knowledge of standard operating procedures.
Common issues that can impact ISO Class 5 compliance include gowning procedure violations, insufficient preventative maintenance, calibration drift in sensors, containment breaches, and inadequate staff training. Solutions include re-training personnel, replacing worn filters, calibrating sensors, repairing pressure leaks, and performing deep cleans after events like containment breaches. With vigilant monitoring and routine testing, ISO Class 5 certification can be maintained long-term.
Cost Considerations
Constructing and operating an ISO Class 5 cleanroom requires significant investment. According to Cleanroom cost estimator, building a new rigid wall ISO Class 5 cleanroom costs approximately $215 per square foot. For a 1000 square foot cleanroom, construction costs alone would total $215,000.
Ongoing operation expenses must also be accounted for. These include energy costs for heating, cooling, ventilation and lighting, as well as expenses for cleaning supplies, gowns, masks, gloves, continuous monitoring, certification and maintenance. According to Traditional Vs Portable Clean Room Cost, operating costs for a traditional ISO Class 5 cleanroom can range from $25-$50 per square foot annually.
For manufacturers producing pharmaceuticals, medical devices or electronics, constructing an in-house ISO Class 5 cleanroom allows complete control over the production environment. This can lead to improved quality control and faster speed to market. The significant upfront investment is justified by increased revenues over the long-term. Careful planning and cost analysis is recommended to maximize return on investment.
Conclusion
In summary, ISO Class 5 cleanrooms are highly controlled environments designed to minimize particles, contaminants, and defects. They have strict standards for air filtration, pressure differentials, airflow patterns, surface cleanliness, personnel gowning, and operating procedures. The goal is to maintain extremely low levels of particles to protect sensitive processes and products from contamination.
These cleanrooms play a critical role across industries like pharmaceuticals, medical devices, aerospace, microelectronics, and optics. Maintaining proper ISO Class 5 standards helps ensure quality, safety, and reliability. Even minute defects can cause failures in complex manufacturing or research. That’s why strict protocols and vigilant monitoring are essential.
Overall, ISO Class 5 cleanrooms provide the ultraclean environment necessary for today’s advanced technologies and products. Their unique design, operation, and control offer contamination-free spaces vital for critical processes and sensitive materials.
