Compliance · ISO
ISO 14644-1: cleanroom classification by particle concentration
Indoor: cleanrooms and controlled environments
ISO 14644-1, Cleanrooms and associated controlled environments — Classification of air cleanliness by particle concentration, defines cleanroom classes by the maximum number of particles per cubic meter at given sizes. At ≥0.5 µm, the limits are 3,520 particles/m³ for ISO Class 5, 35,200 for Class 6, 352,000 for Class 7, and 3,520,000 for Class 8: each class allows ten times the particles of the one below. The current edition is from 2015.
The standard
What ISO 14644-1 Is
Other standards build on it: USP <797> for sterile compounding (ISO Class 5 and 7), ASHRAE's data center guidance (ISO Class 8), EU GMP grades for pharmaceutical manufacturing, and LEED v5, which accepts ISO Class 8 as an alternative particulate result.
Limit values
ISO 14644-1 Limit Values
Every value ISO publishes for the parameter below, with its averaging period, as the standard states it.
Who it applies to
Who Uses It
Anyone who has to show a space meets a cleanliness class: pharmaceutical and biotechnology manufacturing, semiconductor and electronics fabrication, medical device production, hospital pharmacies, laboratories, and data centers.
Monitoring
How Monitoring Demonstrates Compliance
Classifying a room means counting particles at defined sampling locations with an optical particle counter calibrated to ISO 21501-4, following the sampling plan in the standard. Ongoing monitoring against the class follows ISO 14644-2. Continuous particle trends between classifications show when a room drifts, alongside the pressure cascade, temperature, and humidity that keep it in class.
Recommended
best match-
Industrial monitor for indoor and outdoor sites. Built-in sensors cover the essentials, and hot-swappable gas sensor cartridges and a differential-pressure option add more.
Built-inParticle Count (by size)Gas 1
Free: one more gas sensor cartridge
Gas 2
Free: one more gas sensor cartridge
MultiSense
Free: a MultiSense, stock or built to order
Expansion
Free: differential pressure
Also measures 12 more
Dew PointHeat IndexRelative HumidityIlluminance / LightPM1PM10PM2.5Total PM / Mass Conc.Barometric PressureEquivalent Continuous Level (Leq)Sound Pressure Level (SPL)Air Temperature
Alternative
Aethair IAQ-
Aethair IAQ built-in sensors
Compact plug-in monitor with every sensor built in, nothing to add. Ideal for straightforward indoor air quality monitoring.
Built-inParticle Count (by size)Also measures 12 more
Formaldehyde (CH₂O)Carbon Dioxide (CO₂)Dew PointHeat IndexRelative HumidityPM1PM10PM2.5Total PM / Mass Conc.Barometric PressureAir TemperatureVOC (Total)
Who measures each parameter
| Parameter | Aethair PRO | Aethair IAQ |  External |
|---|---|---|---|
| Particle Count (by size) | Built in | Built in | 1 instrument via Thiamis |
Devices
Devices That Cover ISO 14644-1
How much of this standard one Aethair monitor covers, followed by the third-party instruments in the sensor catalog that measure its parameters. Each connects to Environet through a Thiamis gateway, which adds whatever the monitor leaves out.
Aethair monitors
Covers it on its own
Solutions
Solutions Judged Against ISO 14644-1
Cleanrooms, Labs & Manufacturing
Particle counting and controlled environments
Healthcare Air Monitoring
Clinical air quality, pressurization, and patient safety
Article Library
Articles on ISO 14644-1
Data Center Air Quality Monitoring, Inside and Out
Data center air quality monitoring for operators: ISO 14644 cleanliness in the white space, construction dust, generator emissions, and perimeter noise.
Hospital Air Quality Monitoring: Standards by Space
Hospital air quality standards from ASHRAE 170 and The Joint Commission explained, plus what to measure in operating rooms, isolation rooms, and labs.
ASHRAE 170 Requirements and Which Edition Applies to You
ASHRAE 170 requirements explained: what the standard sets, which edition your facility is held to, what changed in 2025, and how each value gets verified.
Questions
ISO 14644-1 FAQ
What are the ISO 14644-1 cleanroom class limits?
At ≥0.5 µm: 3,520 particles/m³ for ISO Class 5, 35,200 for Class 6, 352,000 for Class 7, and 3,520,000 for Class 8.
What instrument classifies a cleanroom?
An optical particle counter calibrated to ISO 21501-4, used at the sampling locations and volumes the standard sets.
Which standards refer to ISO 14644-1 classes?
Among others, USP 797 for sterile compounding, ASHRAE's data center guidance, and LEED v5.
Monitor Against ISO 14644-1
Schedule a callBuild a Configuration All standards
A 30-minute call: you tell us about your application, then we demo the solution for it.