ISO 14644 Part 1 has been revised as a Draft International Standard (DIS): ISO/DIS 14644-1, Cleanrooms and controlled environments, Part 1: Classification of air cleanliness by particle concentration. This document is under review by ISO member bodies for voting and comment by May 2, 2011, for approval for submission as a Final Draft International Standard (FDIS). This page describes the current 1999 Standard as well as the 2010 DIS, both of which may be used as trade reference per agreement between customers and suppliers and are available from IEST.

ISO 14644-1, Cleanrooms and associated controlled environments—Part 1: Classification of air cleanliness

The first official internationally approved Standard in the ISO 14644 series, Part 1: Classification of air cleanliness may be ordered directly through IEST. ISO Standard 14644-1 was the first ISO International Standard prepared by ISO Technical Committee 209 (ISO/TC 209). IEST serves as the official Secretariat for ISO/TC 209, which developed the document as part of a series of 11 documents to serve the needs of the global contamination control community. The document was submitted as an American National Standard and adopted as ANSI/IEST/ISO 14644-1:1999 in the United States, following the cancellation of FED-STD-209.

Introduction to ISO 14644-1
ISO 14644-1 is one part of a series of documents, being developed as International Standards, concerned with cleanrooms and associated subjects. Many factors besides airborne particulate cleanliness must be considered in the design, specifications, operations, and control of cleanrooms and other controlled environments. These are covered in some detail in other parts of the International Standards prepared by ISO/TC 209. Cleanrooms and associated controlled environments provide for the control of airborne particulate contamination to levels appropriate for accomplishing contamination-sensitive activities. Products and processes that benefit from the control of airborne contamination include aerospace, microelectronics, pharmaceuticals, medical devices, healthcare, food, and others.

Scope of ISO 14644-1
ISO 14644-1 covers the classification of air cleanliness in cleanrooms and associated controlled environments. Classification in accordance with this standard is specified and accomplished exclusively in terms of concentration of airborne particles. Furthermore, the only particle population's consideration for classification purposes are those that have cumulative distributions based on threshold (lower limit) sizes ranging from 0.1 µm to 5 µm.

The United Kingdom is the convenor for the Working Group that produced ISO 14644-1. Over 1,000 professionals from the 34 nations of ISO/TC 209 have united to create a family of true international standards, governing all aspects of the cleanroom community — from design inception to daily operations.

ISO/DIS 14644-1 (2010), Cleanrooms and associated controlled environments—Part 1: Classification of air cleanliness by particle concentration

The new Draft International Standard (DIS) edition of ISO 14644-1, which may be ordered directly through IEST, is the result of a systematic review and includes changes in response to user and expert feedback validated by international enquiry. The title has been revised to “Classification of air cleanliness by particle concentration” to be consistent with other parts of the standard. The nine ISO cleanliness classes are retained unchanged, but Table 1 defines the particle concentration at various particle sizes for the nine integer classes. The use of Table 1 ensures better definition of the appropriate particle-size ranges for the different classes. A formula is retained to allow definition of intermediate decimal classes. The standard retains the concept of ultrafine and macroparticle descriptors for particle sizes outside the range appropriate for measurement using airborne particle counters.

The most significant change is the adoption of a more consistent statistical approach to the selection of number of sample locations and the evaluation of the data collected. The number of sample locations compared with the 1999 version of the standard have been changed. The approach allows each location to be treated independently with a 95% level of confidence that at least 90% of the cleanroom or clean zone will comply with the maximum particle concentration limit for the target class of air cleanliness. A reference table is provided to define the number of sample locations required. Because a degree of randomness is required, the cleanroom or clean zone is then divided into equal sectors and the sample location placed randomly within each sector.

Finally, the annexes have been reordered to improve the logic of the Standard.

Please note: In addition to the new DIS version of 14644-1, IEST will continue to sell the 1999 version of the Standard until the new version is adopted as an International Standard (thus replacing the previous Standard). Until then, either the 1999 Standard or the new Draft International Standard can be referenced in a contract. It is up to the customer and supplier to mutually agree on the reference.

Scope of ISO/DIS 14644-1 (2010)

This part of ISO 14644 covers the classification of air cleanliness in cleanrooms and associated controlled environments exclusively in terms of concentration of airborne particles. Only particle populations having cumulative distributions based on threshold (lower limit) particle sizes ranging from 0.1 µm to 5 µm are considered for classification purposes.

The use of discrete-particle airborne counting and sizing instruments is the basis for determination of the concentration of airborne particles, equal to and greater than the specified sizes, at designated sampling locations.

This part of ISO 14644 does not provide for classification of particle populations that are outside of the specified particle-size range, 0.1 µm to 5 µm. Concentrations of ultrafine particles (particles smaller than 0.1 µm) and macroparticles (particles larger than 5 µm) may be used to quantify these populations in terms of U descriptors and M descriptors, respectively.

This part of ISO 14644 cannot be used to characterize the physical, chemical, radiological or viable nature of airborne particles.

Note: The actual distribution of particle concentrations within incremental size ranges is normally not predictable and is typically variable over time.

View list of ISO 14644 Standards