Cleanroom Testing/Certification

Sterile Environment Technologies practices proper procedures to decontaminate and certify cleanrooms, labs, manufacturing areas or other controlled or sterile environments.

ISO 14644 Standards can be found through IEST, the Secretariat of ISO/TC209.

International Standards for Cleanrooms and Critical Environments

International Cleanroom Standards
ISO/TC209 has proposed ten (10) documents which will make up the cleanroom standards. These documents are in their final voting stages and can be legally used in trade. The tables and sections below outline the first seven of these documents in order.

ISO-14644-1 Classification of Air Cleanliness
Cleanliness class designations and quantity have changed from FS209E (see Table 1). Along with the obvious change to metric measure of air volume, ISO 14644-1 adds three additional classes.

(Table 1) Airborne Particulate Cleanliness Classes (same as table above)

Class Number of Particles per Cubic Meter by Micrometer Size
0.1 um 0.2 um 0.3 um 0.5 um 1 um 5 um
ISO 1 10 2
ISO 2 100 24 10 4
ISO 3 1,000 237 102 35 8
ISO 4 10,000 2,370 1,020 352 83
ISO 5 100,000 23,700 10,200 3,520 832 29
ISO 6 1,000,000 237,000 102,000 35,200 8,320 293
ISO 7 352,000 83,200 2,930
ISO 8 3,520,000 832,000 29,300
ISO 9 35,200,000 8,320,000 293,000

(Table 2) Comparing FED STD 209E to the new ISO 14644-1.

Airborne Particulate Cleanliness Class Comparison

ISO 14644-1


3 1 M1.5
4 10 M2.5
5 100 M3.5
6 1,000 M4.5
7 10,000 M5.5
8 100,000 M6.5
ISO-14644-2 Cleanroom Testing for Compliance
This document determines the type and frequency of testing required to conform with the standard.

Strategic Testing: (Table 1) Schedule of Tests to Demonstrate Continuing Compliance.

Test Parameter Class Maximum Time Interval Test Procedure
Particle Count Test < or = 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

Strategic Testing: (Table 2) Schedule of Additional Optional Tests.

Test Parameter Class Maximum Time Interval Test Procedure
Installed Filter Leakage All Classes 24 Months ISO 14644-3 Annex B6
Containment Leakage All Classes 24 Months ISO 14644-3 Annex B4
Recovery All Classes 24 Months ISO 14644-3 Annex B13
Airflow Visualization All Classes 24 Months ISO 14644-3 Annex B7


ISO-14644-4 Cleanroom Design & Construction
This document will be a primer on the design and construction of cleanrooms. It will cover all aspects of the process from design development to startup and commissioning.

ISO-14644-5 Cleanroom Operations
This document will be an introduction on cleanroom operation. It will cover all aspects of the operation of a cleanroom including entry and exit procedures for equipment and personnel, education and training, cleanroom apparel, and facility issues such as maintenance, housekeeping, monitoring, system failure, etc.

ISO-14644-6 Terms, Definitions & Units
This document will provide a consistent reference for all terms, definitions and units discussed across all ISO cleanroom standards.

ISO-14644-7 Minienvironments & Isolators
This document will focus on specialized stand-alone clean spaces including their design, construction, and operations.

Outmoded Cleanroom Standards

What is Federal Standard 209e?

The outmoded (replaced by ISO 14644) benchmark for optimum and safe operating levels is compared to Federal Standard 209e for at 100,000 particles at .5 microns per cubic foot of air space. Optimum levels for temperature should normally be 70 to 72 degrees Fahrenheit, with humidity levels at 50%.

Please note: equipment manufacturers have varying optimum operating levels.

Federal Standard 209E has been replaced with ISO Standard 14644. The first subsection in ISO 14644 (ISO STND. 14644-1) has some unique changes from the old Federal Standard – however they are very similar. This standard is now in effect for critical environments (Cleanrooms, Data Centers, etc.) worldwide. Some companies have been successful with the federal Standard 209E, and may not have switched over yet. It is important for these companies to know the main differences are easy to implement and may not be a costly or diificult change. If you need help we have expert consultants that can assist. Contact us today.


FS 209E ISO 14644-1
N/A 1
N/A 2
1 3
10 4
100 5
1,000 6
10,000 7
100,000 8
N/A 9


The main differences between Federal Standard 209E and ISO 14644-1 (Testing Standards) are:

  • ISO Establishes 0.1um as the “Standard” Diameter
  • ISO Creates 3 New Cleanliness Classes-
    • 2 “Cleaner” classes (ISO class 1 and ISO class 2) than Federal Standard 209E
    • 1 “Dirtier” Class (ISO Class 9) which is allows more particulate than Fed Standard 209E class 100,000
  • Allows for discarding of “Outliers” – Federal Standard 209E did not.