ISO 5 is an air cleanliness classification defined by the International Organization for Standardization (ISO) under ISO 14644-1 standards. It specifies the maximum concentration of airborne particles permitted in a controlled environment to be certified as an ISO 5 cleanroom or clean zone.
Cleanrooms are controlled environments with extremely low levels of pollutants such as dust, airborne microbes, aerosol particles, and chemical vapors. They are used extensively in industries like pharmaceuticals, medical devices, semiconductors, aerospace, and healthcare that require protection from contamination.
The purpose of ISO 5 cleanrooms is to provide a tightly controlled environment for handling sensitive materials and processes which cannot tolerate normal indoor levels of particulates and contaminants. The stringent air quality requirements in ISO 5 environments help eliminate risks of product defects or failures.
According to ISO Class 5 Cleanrooms | Fed-Std 209E, ISO 5 cleanrooms allow a maximum of 3,520 particles of 0.5 μm size per cubic meter of air, ensuring ultra clean air quality. They prevent contamination from pollutants like skin cells, cosmetics, dust, microbes etc.
ISO Standards Overview
ISO (International Organization for Standardization) standards aim to provide a globally unified set of principles and guidelines across various industries and activities. The organization began in 1926 as the International Federation of the National Standardizing Associations (ISA) with a focus on mechanical engineering. Over time, ISO expanded to cover wider technical and non-technical areas including healthcare, agriculture, and services (II. A Brief History of ISO).
Today, ISO has published over 23,000 international standards covering almost all aspects of technology and business. The standards are designed to be adopted and implemented consistently across countries and organizations. ISO standards aim to increase safety, reliability, and quality while reducing costs. The main classes of ISO standards include:
- ISO 9000 – Quality Management
- ISO 14000 – Environmental Management
- ISO 31000 – Risk Management
- ISO 50001 – Energy Management
The ISO 5 standard falls under the ISO 14644 family focused on cleanrooms and associated controlled environments. ISO 5 sets stringent specifications for particle counts and environmental control in cleanroom facilities used for aseptic manufacturing processes.
ISO 5 Specifications
ISO 5 classification is defined by the ISO 14644-1 standard. Here are the key specifications for an ISO 5 cleanroom:
- Temperature: 22°C ± 3°C 1
- Humidity: 45% ± 10% RH 2
- Particulate limits:
- ≥0.1 μm: 3,520 particles/m3
- ≥0.2 μm: 832 particles/ m3
- ≥0.3 μm: 353 particles/m3
- ≥0.5 μm: 83 particles/m3
- ≥1.0 μm: 29 particles/m3
- ≥5.0 μm: 7 particles/m3
- Air changes per hour: At least 30 air changes per hour 2
Applications of ISO 5 Environments
ISO 5 cleanrooms are used in a variety of industries that require extremely clean manufacturing environments. Some of the main applications include:
Electronics – Semiconductor and microchip fabrication facilities require ISO 5 cleanrooms for photolithography and other processes that are highly sensitive to particles. Even microscopic dust or skin flakes can ruin these precision components, so maintaining ISO 5 standards is critical. Duroair’s modular ISO clean rooms have been in use for many years in electronics production.
Pharmaceuticals – Medicines and injectables must be manufactured in sterile conditions to avoid contamination. ISO 5 cleanrooms provide the ultraclean environment needed for aseptic processing and packaging of pharmaceuticals. Airborne microbes are essentially eliminated in ISO 5 rooms.
Medical Devices – Many medical devices like implants and catheters also require ISO 5 cleanroom conditions during final clean and packaging stages. This prevents infections or other complications from contaminated devices. ISO 5 standards greatly reduce risks for patients.
Food Processing – Low moisture foods like spices, nuts, and dried fruits are processed in ISO 5 environments to avoid contamination from dust, insects, or bacteria. Maintaining extremely low particle counts is critical for food safety and purity.
Design and Construction
ISO 5 cleanrooms require very specialized design and construction to achieve the stringent particulate levels required. Some key considerations include:
HVAC Systems – ISO 5 environments require highly advanced HVAC systems including HEPA or ULPA filtration capable of removing >99.999% of particles ≥0.12 μm. Air changes typically range from 300-500 per hour. Systems maintain positive pressure, temperature, and humidity control. Equipment introduces minimal additional particulates. (AdvanceTECLLC)
Airlocks – Multi-stage airlocks are used to maintain air pressure differentials between cleanroom and non-clean areas. These create an air barrier and prevent unfiltered air entering. Staff may also pass through showers and change into cleanroom garments. (MeCart Cleanrooms)
Materials – All surfaces are made of smooth, non-shedding materials. Epoxy resin floors, polypropylene walls, and stainless steel worksurfaces are common. No exposed insulation, wood, cardboard, or cloth. (American Cleanrooms)
Cleaning – Strict protocols enforced. Surfaces wiped with alcohol or sterilizing agents multiple times per day. Only cleanroom-safe vacuums and mops used. Staff wear gloves, masks, hoods, boots, and coveralls. (MeCart Cleanrooms)
Personnel working in ISO 5 environments must follow strict garment requirements to minimize contamination. The main garments worn are coveralls, gloves, hoods, masks, and booties.
Coveralls are full-body suits made of fabrics like polyester or nylon that generate very little particle shedding. They often feature elastic cuffs and collars to minimize exposed skin. Common standards require coveralls to shed less than 5 particles ≥0.5μm per minute for an ISO 5 cleanroom .
Gloves must also be made of cleanroom-approved materials, typically nitrile or latex. They should have long cuffs to overlap with coverall sleeves. Frequent glove changes are recommended to reduce particle shedding .
Hoods protect the head and neck area and are typically integrated into the coverall. Face masks provide additional protection for critical environments. Masks also help protect the product from particles expelled during talking.
Proper gowning procedures should be followed before entering an ISO 5 space. This includes sequenced steps for hand washing, suiting up in garments, and sanitizing all materials .
All garments should be certified and regularly tested to meet ISO 5 particle count requirements. Garments must be replaced frequently to sustain cleanliness.
Maintaining ISO 5 Standards
Maintaining an ISO 5 cleanroom environment requires constant monitoring and control of contamination sources to meet the strict particulate limits. Facilities must implement rigorous cleaning procedures and ensure proper gowning protocols are followed.
Airborne particle counters should be installed to continuously monitor particulate levels and ensure they remain below 3,520 particles per cubic meter greater than or equal to 0.5 μm. If counts rise above the limit, the source of contamination must be identified and addressed immediately.
Potential sources of contamination include people, processes, equipment, and materials brought into the cleanroom. HEPA filters on the air handling system should be checked and replaced regularly to filter particles from the air supply. Staff must be properly gowned with coveralls, gloves, masks and booties to minimize shedding of skin and fibers.
Cleanroom surfaces should be wiped down frequently using cleaning agents like isopropyl alcohol to remove any deposited particles. Daily and weekly deep cleaning schedules help maintain cleanliness between production runs. All materials brought into the cleanroom must be thoroughly cleaned ahead of time.
Facilities are re-certified annually to confirm the space continuously meets ISO 5 standards. Unscheduled testing may also be performed after any major changes to the cleanroom.
Testing and Certification
To obtain ISO 5 certification, a cleanroom must undergo rigorous particle counting and testing procedures. Particle counters are used to measure the concentration of airborne particles per cubic meter at set locations throughout the cleanroom. Testing must be conducted in accordance with ISO 14644-1 standards.
Airborne particle testing involves sampling air at multiple locations and heights within the cleanroom to generate a particle count map. Sampling durations and volumes must adhere to ISO 21501-4 requirements. Testing firms use particle counters capable of detecting particles ≥0.1 μm for viable and non-viable particles. Results are reported in particle concentration levels per cubic meter for particle sizes of ≥0.1 μm, ≥0.2 μm, ≥0.3 μm, ≥0.5 μm, ≥1 μm, and ≥5 μm.
In addition to air sampling, surface particle counts are conducted via swab sampling of critical surfaces. Surface samples are analyzed and reported similar to air samples. All testing data must be recorded and reported according to ISO 14644-1 annex B.
To maintain certification, ISO 5 cleanrooms require recertification testing at minimum every 6 months. Any modification to the cleanroom requires re-testing to confirm it still meets ISO 5 specifications. Surprise audits may also be conducted by the certifying body.
For more details on ISO 5 certification, see the article on ISO Certification Requirements.
Constructing and operating an ISO 5 cleanroom environment involves significant costs. The main expenses include:
Building a traditional ISO 5 cleanroom with rigid walls and ceilings costs approximately $500-1500 per square foot, with lower classrooms on the less expensive end (according to Cleanroom cost estimator). Portable and modular designs can reduce initial construction investments.
Maintaining strict air filtration and ventilation 24/7 leads to high energy costs. ISO 5 cleanrooms require approximately 10 air changes per hour. The air handling system must continuously filter airborne particles down to 0.5 microns in size (according to Cost of a Modular Cleanroom per Square Foot).
Garments and Supplies
Workers in ISO 5 cleanrooms must wear specialized gowns, gloves, masks, hairnets, and shoes. These protective garments prevent contamination but add recurring expenses for replacements. Sticky mats, cleaning agents, and other consumables also require regular replenishment.
Testing and Certification
Mandatory testing at least twice per year verifies that airborne particulates remain below ISO 5 limits. Each certification can cost thousands of dollars from third-party testing agencies (according to Traditional Vs Portable Clean Room Cost).
Advantages of ISO 5 Environments
ISO 5 environments offer several key advantages for industries requiring high levels of cleanliness and environmental control.
Product quality is greatly improved in an ISO 5 cleanroom. By limiting airborne particles to specified low concentrations, defects and contaminants in products are significantly reduced. This results in higher manufacturing yields and less waste. Pharmaceuticals, microelectronics, and medical devices all benefit from the enhanced quality control of an ISO 5 environment. As noted by American Cleanrooms, “ISO 5 cleanrooms provide significant particle protection for applications requiring moderately low particle concentrations.” (1)
Process control is also improved with ISO 5 cleanrooms. By carefully regulating temperature, humidity, air changes, and other parameters, processes can be standardized and variability is decreased. This leads to more consistent results. Cleanroom operators have greater control and can detect any deviations from norms. Improved process control also allows for more automation and robotics within an ISO 5 space.
The reduced defects and enhanced process control result in far fewer rejected products and materials. This lowers costs and improves efficiency for manufacturers. As explained by Isocleanroom, using a cleanroom can “increase the efficiency, accuracy and life cycle of a product by eliminating defects caused by airborne contaminants.” (2) The controlled environment makes it far less likely issues will arise during critical production steps.