Cleanroom Requirements & Classifications
01 March 2023

Cleanroom Requirements & Classifications

ISO classifications are based on international standards that regulate acceptable cleanliness standards in a cleanroom. International Organization for Standardization ISO 14644-1 provides guidance for acceptable air quality levels within the specific clean room ISO classes. A cleanroom’s class is determined by the level of cleanliness the room complies with, according to the quantity and size of particles per volume of air.

What is an ISO Cleanroom?

A cleanroom is a specially engineered enclosed area within a manufacturing or research facility. These rooms allow for precise control, monitoring, and maintenance of an internal environment. ISO classifications are specifically designed to regulate:

  • Temperature
  • Humidity
  • Airflow
  • Filtration
  • Pressure

Clean Air Products is Your Source for Cleanroom ISO Classification Information

At Clean Air Products, we manufacture softwall cleanrooms and hardwall cleanrooms that comply with various ISO classifications, fs209e, and ISO cleanroom standards. From Class 4 cleanrooms that maintain meticulous cleaning standards to less strict Class 7 cleanrooms, Clean Air Products manufactures cleanrooms that will meet your application’s specifications.

Cleanroom Industry Requirements & Classifications

Cleanroom requirements are classified according to the number and size of particles permitted per volume of air in a specific amount of time. Our engineers can provide guidelines and ISO class code descriptions for the class of cleanroom required for your specific application. The government requires many industrial businesses to maintain specific cleanroom standards. For example, government regulation USP 797 outlines the requirements for pharmaceutical product manufacturing.

Cleanroom industry requirements are classified according to ISO 14644-1 cleanroom standards, which specify basic requirements for cleanroom operations. Federal Standard 209E is still also used.
ISO cleanroom classifications are rated according to how much of a particulate of a specific size exists per cubic meter within a given enclosure (see second chart). Cleanroom classifications are based on an eight-class rating system, with an ISO class 1 cleanroom being rated the most particle-free and ISO class 8 allowing the most particles. Most cleanrooms fall into the class 6,7 or 8 categories.

Cleanroom ISO Class Code Descriptions

Multiple factors should be considered when determining the correct cleanroom standards for a new product or business, including process requirements, cost, performance, and construction. Clean Air Products staff members work with you to review selection basics and all applicable cleanroom industry requirements. Clean Air Products provides cleanrooms by ISO class and additional cleanroom accessories to guarantee superior air quality and particle filtering.

The following cleanroom classifications provide the recommended air changes per hour, per class of cleanroom:

  • ISO Class 1 - The “cleanest” cleanroom is ISO 1, used in industries such as life sciences and electronics that require nanotechnology or ultra-fine particulate processing. The recommended air changes per hour for an ISO class 1 clean room is 500-750, and the ceiling coverage should be 80–100%.
  • ISO Class 2 - 500-750 air changes per hour, with a ceiling coverage of 80-100%
  • ISO Class 3 - 500-750 air changes per hour, with a ceiling coverage of 60-100%
  • ISO Class 4 - 400-750 air changes per hour, with a ceiling coverage of 50-90%
  • ISO Class 5 - 240-600 air changes per hour, with a ceiling coverage of 35-70%
  • ISO Class 6 - 150-240 air changes per hour, with a ceiling coverage of 25-40%
  • ISO Class 7 - 60-150 air changes per hour, with a ceiling coverage of 15-25%
  • ISO Class 8 - 5-60 air changes per hour, with a ceiling coverage of 5-15%

ISO Cleanroom Standards & Requirements

A cleanroom’s performance requirements identify the cleanroom class level required at a given state or condition. There are three levels of condition (states) for testing and characterizing the performance of cleanrooms: as-built, at rest, and operational. Specific test methods for these three classifications are outlined in 14644-3:2005.

Cleanroom Classifications for As-Built Systems

Most cleanrooms are rated and sold in the as-built category, categorized as an empty room with the filter system running, but without workers and production equipment. However, adding workers and equipment will introduce contamination and affect the room rating. A clean room may be rated ISO 6 at rest but at ISO 7 during operation.

To comply with performance requirements, the as-built empty room should be tested and benchmarked, followed by testing and documentation of the at-rest and operational states. Corrective steps must be taken if contamination in the at-rest or operating conditions is not in compliance. These steps can range from examining the production process and the number of workers in the cleanroom to testing the room’s air flow performance.

In addition, cleanroom airflow performance can be cost-effectively upgraded by adding fan filter modules (FFM). For example, FFMs cover approximately 5-15% of an ISO class 8 cleanroom requirement for ceilings. Upgrading to an ISO 7 cleanroom requires 15-25% ceiling coverage, and covering 25-40% of the ceiling changes the room to an ISO 6 Class.