ISO 5 rated cleanroom air is widely adopted as a minimum requirement for air quality when processing, packaging, or manufacturing products that are sensitive to microbes and ultra-fine particulates. In ISO 5 environments, airborne particulates are closely measured and monitored to ensure appropriate cleanliness for ISO 5 certification under ISO-14644-1.
Particulate and contamination arise from many different hosts including operators, clothing, processes, equipment, cleaning procedures, raw materials, and the introduction of outside air.
Subpar air quality detrimentally influences throughput, reproducibility, and shelf life across a multitude of life science applications, encompassing but not limited to in vitro fertilization, cell culturing, genomics, and proteomics.
ISO 14644 cleanroom standards specify the requirements for cleanrooms and controlled environments, including ISO 5. Unlike cGMP, ISO 14644 focuses on quantifiable attributes like particle counts, air change rates, and room pressurization. cGMP and USP protocols lean on the framework of air cleanliness established by ISO 14644, thus providing the technical air quality specifications for specialized tasks.
ISO 5 cleanroom certification requires that each cubic meter of air must contain no more than 3,520 particles (0.5 microns or larger). By way of comparison, a typical indoor atmosphere may harbor millions, if not billions, of these particles, yet they largely remain invisible to the naked eye.
|Number of Particles per Cubic Meter by Micrometer Size|
|Class||0.1 micron||0.2 micron||0.3 micron||0.5 micron||1 micron||5 microns|
Terra manufactures several unique fan filter unit systems rated for ISO 4 - ISO 8 environments.
Smart Fan Filter Units with EC Motors provide annual energy savings of nearly $500 per fan filter unit. The control card features industry-standard MODBUS® networking, precision speed control (1-100%), and closed-loop control capability for air pressure, airflow, and particle count sensors.
Paired with a Smart Control Panel and an external pressure sensor, MODBUS® integrated fan filter units enable room-to-room pressure monitoring and high/low setpoints for automatic differential pressure control.
WhisperFlow® Reverse-Flow Fan Filter Units include a filtered exhaust system that contains dust that is generated during maintenance or construction. The unit's dust collector pan is designed for seamless compatibility with bag-in/bag-out (BIBO) systems and can be effortlessly disengaged for cleaning or maintenance activities.
Narrow WhisperFlow® Fan Filter Units are common for small-footprint labs or pharmacies with long corridors, narrow spans, and limited overhead clearance.
Terra offers room-side replaceable, explosion-proof, heated and low-profile configurations for cleanrooms, laminar flow hoods, and containment enclosures.
Fan filter units with integrated fan filter collector pans and bag-in-bag-out (BIBO Systems) collect dust particles that can dislodge from the HEPA filter, thus preventing contaminants from re-entering the cleanroom. Terra's Bag-in/Bag-out (BIBO) modules are suggested for applications involving toxic fumes, biohazards, or other harmful materials.
BIBO modules seamlessly integrate with the filter media system for safe filter disposal and replacement from the inside of the room for contact-free removal of filters with potentially hazardous airborne contaminants.
In ISO 5 cleanrooms, fan filter ceiling coverage can range between 35% and 70%. As required, the remaining bays will be furnished with LED light panels and cleanroom-compliant ceiling tiles. Expressed as a percentage, fan filter ceiling coverage indicates the percentage of bays in the ceiling grid that will require fan filter installations versus those that will not.
|ISO 14644-1 (Federal Standard 209E)||Average Airflow Velocity m/s (ft/min)||Ceiling Coverage|
|ISO 8 (Class 100,000)||0.005 – 0.041 (1 – 8)||5 – 15%|
|ISO 7 (Class 10,000)||0.051 – 0.076 (10 -15)||15 – 20%|
|ISO 6 (Class 1,000)||0.127 – 0.203 (25 – 40)||25 – 40%|
|ISO 5 (Class 100)||0.203 – 0.406 (40 – 80)||35 – 70%|
|ISO 4 (Class 10)||0.254 – 0.457 (50 – 90)||50 – 90%|
|ISO 3 (Class 1)||0.305 – 0.457 (60 – 90)||60 – 100%|
|ISO 1 – 2||0.305 – 0.508 (60 – 100)||80 – 100%|
A: As a general range, ISO 5 cleanrooms require anywhere from 35 – 70% of ceiling surface coverage in the ceiling grid to support adequate airflow and air exchange rates under ISO 14644-1
A: The formula to calculate the Number of Fan Filter Units (FFUs) is:
Air Change Rate (ACR) expresses the number of times that the entire volume of room air is replaced each hour. It can vary based on the application, and specific rates are often recommended for different settings (e.g., cleanrooms, hospitals, residential, manufacturing facilities).
In the early 2000s, studies by Rajan Jaisinghani and others brought forth several challenges to air change rate (ACR) standards developed in the 1990s. Arguing for more practical and energy-efficient cleanroom air change benchmarks, they found that previous ACH benchmarks for cleanrooms did not adequately reflect modern advancements in fan filter media, blower design, baffling, and impeller technology.
|FS209E Class||ISO Class Equivalent||Suggested ACR|
Q: What Is the Ideal Air Change Rate (ACH) for ISO 5 clean rooms?
A: With adjusted values shown in the table below, new ISO 5 cleanroom builds should consider starting ACH values toward the lower end of the ACR range for ISO 5 filtration design (240 - 480 ACH). This research derived the following air change rates, which more closely reflect ACH values that would be required under actual operating conditions.
A: For cleanrooms rated ISO 5 or cleaner, retest particle counts, air pressure differentials, and total airflow every 6 months. As a best practice, extended testing is optional, but advisable every 24 months.
|Schedule of Tests to Demonstrate Continuing Compliance|
|Test Parameter||Class||Maximum Time Interval||Test Procedure|
|Particle Count Test||<= ISO 5||6 Months||ISO 14644-1 Annex A|
|> ISO 5||12 Months|
|Air Pressure Difference||All Classes||12 Months||ISO 14644-1 Annex B5|
|Airflow||All Classes||12 Months||ISO 14644-1 Annex B4|
|Schedule of Additional Optional Tests|
|Test Parameter||Class||Maximum Time Interval||Test Procedure|
|Installed Filter Leakage||All Classes||24 Months||ISO 14644-1 Annex B6|
|Containment Leakage||All Classes||24 Months||ISO 14644-1 Annex B4|
|Recovery||All Classes||24 Months||ISO 14644-1 Annex B13|
|Airflow Visualization||All Classes||24 Months||ISO 14644-1 Annex B7|
Filter leakage testing involves the systematic evaluation of High-Efficiency Particulate Air (HEPA) or Ultra Low Penetration Air (ULPA) filters to detect the presence of any leaks that could allow particles to bypass the filtration system.
Terra's fan filter units with challenge ports provide a simple and efficient mechanism for conducting localized leak tests of each filter. For critical applications, the USP <797> framework requires that fan filter units undergo leak testing during initial installation, and semi annually throughout the life of the filter.
Containment leakage tests evaluate the effectiveness of the cleanroom's structural barriers. Excessive leakage can lead to reduced control over room pressure, and will require increased airflow to overcome air leaks. Leakage can disrupt the laminar flow of air throughout the cleanroom and increase the minimum fan speed that is needed to achieve the same room pressure. Increased fan filter speeds require more energy, thus drawing more power, and incurring added operating costs.
Filter Replacement Alarms provide automatic replacement alerts to avoid costly and unexpected operational interruptions. Simply adjust the pressure set-point to adjust the frequency of filter alerts for replacement.
Air Recovery Testing assesses how quickly a cleanroom or controlled environment can return to its specified particle concentration levels after an event that disrupts these conditions, such as operational procedures, the opening or doors during entry and exit, or the speed of recovery to the intended particulate levels after maintenance or shutdown procedures.
Airflow visualization testing provides visual indicators of disruptive airflow patterns such as zones of turbulence or stagnation where contaminants may accumulate. This test provides actionable insights into how to improve airflow design, contributing to better contamination control.