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, Classification of air cleanliness
(U.S. Title: ANSI/IEST/ISO 14644-1:1999)
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
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
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), Classification of air cleanliness by particle concentration
(not yet adopted as an American National Standard)
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.
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.
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)
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
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.
part of ISO 14644 cannot be used to characterize the physical, chemical,
radiological or viable nature of airborne particles.
The actual distribution of particle concentrations within incremental
size ranges is normally not predictable and is typically variable over
View list of ISO 14644 Standards