---
title: "ISO 14644-1 Cleanroom Classes: Particle Limits | Aethair"
description: "ISO 14644-1 cleanroom class limits: maximum particles per cubic meter for ISO Class 5 to 8, who uses the standard, and a recommended configuration."
url: https://aethair.io/standards/iso_14644_1/
---

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.

[Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [Configure ISO 14644-1 Monitoring](https://aethair.io/build/?params=particle_count)

At a glance

**ISO** Indoor: cleanrooms and controlled environments

1 parameter · 4 limit values

[Particle Count (by size)](https://aethair.io/parameters/particle_count/)

1 device measures them all

- **Aethair PRO**

[Official text from ISO](https://www.iso.org/standard/53394.html)

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](https://aethair.io/standards/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.

[**Particle Count (by size)** Particulate Matter](https://aethair.io/parameters/particle_count/)

**3520 particles/m³** *ISO Class 5, ≥0.5 µm*

**35200 particles/m³** *ISO Class 6, ≥0.5 µm*

**352000 particles/m³** *ISO Class 7, ≥0.5 µm*

**3520000 particles/m³** *ISO Class 8, ≥0.5 µm*

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](https://aethair.io/standards/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.

[Customize this configuration](https://aethair.io/build/?params=particle_count)

### Who measures each parameter

| Parameter | Aethair PRO | Aethair IAQ | External |
| - | - | - | - |
| [Particle Count (by size)](https://aethair.io/parameters/particle_count/) | Built in | Built in | [1 instrument](https://aethair.io/parameters/particle_count/) 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

[**Aethair PRO** Built-in sensors Covers it](https://aethair.io/products/pro/) [**Aethair IAQ** Built-in sensors Covers it](https://aethair.io/products/iaq/)

Covers it on its own

[**Particles Plus** Particulate & Dust Monitors](https://aethair.io/sensors/particles-plus-particulate-dust-monitors/)

Solutions

## Solutions Judged Against ISO 14644-1

### [Cleanrooms, Labs & Manufacturing](https://aethair.io/solutions/cleanroom/)

Particle counting and controlled environments

### [Healthcare Air Monitoring](https://aethair.io/solutions/healthcare/)

Clinical air quality, pressurization, and patient safety

[All solutions](https://aethair.io/solutions/)

Article Library

## Articles on ISO 14644-1

### [Data Center Air Quality Monitoring, Inside and Out](https://aethair.io/resources/data-center-air-quality-monitoring/)

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](https://aethair.io/resources/healthcare-air-quality-monitoring/)

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](https://aethair.io/resources/ashrae-170-requirements/)

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.

[All articles](https://aethair.io/resources/)

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](https://aethair.io/standards/usp_797/) for sterile compounding, ASHRAE's data center guidance, and LEED v5.