Clean Spaces
ASHRAE Technical Committee 9.11

Scope of TC 9.11

TC 9.11 is concerned with air conditioning systems for cleanrooms and spaces, including process, product and facility air conditioning and related process ventilation for Research and Development, manufacturing, assembly, test and clean medical areas. This includes electronic, microelectronic, pharmaceutical and aerospace facilities and operating rooms.


The ASHRAE Handbook is published in a series of four volumes, one of which is revised each year, ensuring that no volume is older than four years. The Handbook can be purchased at the ASHRAE Bookstore by clicking on this link.

This TC is responsible for the following chapter in the HVAC Applications Volume:

Clean spaces are defined as areas in which particle concentration and environmental conditions are controlled at or within specified limits. Design of clean spaces (or cleanrooms) covers much more than traditional control of air temperature and humidity. Additional factors may include control of particle, microbial, electrostatic discharge (ESD), molecular, and gaseous contamination; airflow patterns; air pressurization; sound and vibration; environmental health; life safety; industrial engineering aspects; and manufacturing equipment layouts. The objective of good cleanroom design is to maintain effective contamination control while ensuring required levels of reliability, productivity, installation, and operating costs.

The ASHRAE HVAC APPLICATIONS HANDBOOK may be purchased from the on-line bookstore by clicking on the highlighted text.

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Technical committees develop and sponsor technical sessions at the winter and annual conferences. Information about their future technical program is discussed at each TC meeting and at the TC’s Program Subcommittee meeting

ASHRAE publishes papers and transactions from presentations at its conference events. In addition, ASHRAE records most of the seminar sessions from its conferences on DVD. These DVDs are ideal for use at chapter meetings, in university courses, or company lunch and learns. Products available from the most recent conference may be found here.


Technical Committees are responsible for identifying research topics, proposing research projects, selecting bidders, and monitoring research projects funded by ASHRAE. Information about their specific research program is discussed at each TC meeting and at the TC’s Research Subcommittee meeting.

Research Strategy
TC 9.11’s focus on Clean Rooms overlaps several technical areas supported by ASHRAE, including fundamental issues, such as load calculations, system sizing, and modeling; systems issues ranging from air filtration to air side systems and hydronics; and applications issues, such as controls. The sensitivity of these spaces to airborne contaminants places a heavy emphasis on filtration and air system sizing. With air volumes that are typically much higher than comparably sized commercial spaces, these facilities force owners to exhaust all opportunities to optimize their design. As a result, TC 9.11’s focus relative to research has been the development of tools to aid engineers in design optimization. Currently, most of the emphasis of the research plan for TC 9.11 is related to developing modeling tools which will assist design professionals in validating their assumptions and stretching the state of the art in the design of clean spaces.

This TC has the following active research projects:

The intent of this research project is to gather empirical data on particulate generation rates for various cleanroom processes.  That empirical data, correlated to the surveyed activities and operations will then be used to develop a design guideline which will show a range of particulate generation rates for different cleanroom operations.

The main objective of this project is to establish a scientific approach to implement demand controlled filtration (ventilation rate) for cleanrooms for the two cleanroom classes (ISO, 7 and 8, (10 000 and 100 000) that have the broadest application.


ASHRAE writes standards for the purpose of establishing consensus for: 1) methods of test for use in commerce and 2) performance criteria for use as facilitators with which to guide the industry. ASHRAE publishes the following three types of voluntary consensus standards: Method of Measurement or Test (MOT), Standard Design and Standard Practice. ASHRAE does not write rating standards unless a suitable rating standard will not otherwise be available. ASHRAE is accredited by the American National Standards Institute (ANSI) and follows ANSI's requirements for due process and standards development. Standards may be purchased at the ASHRAE Bookstore.

TC 9.11 has no standards responsibilities at this time.

Design Guide

TC 9.11, Clean Spaces, has begun the process of creating a "Design Guide" for clean spaces. Its intention is to provide guidance beyond the Applications Handbook to assist professionals involved in clean space design in developing a correct design basis. Based on feedback from the society the the most desirable “design guide” style is an 8”x11” paper format with quality photos, charts and tables, with 120,000-150,000 words, about 300-350 pages.  An outline of the content has been developed.

Participation and Recognition
Several categories of recognitions will be provided to participants as “authors”, “contributors” or “reviewers”. All these participants will be automatically included as this subcomittee's "members”. Each participant will be listed by name with affiliation inside the book in a category based on the level of his/her contribution before publishing
   - Authors – Potentially 10-12 persons from both TC9.11 members and outside experts through application and 
     selection process. Each of the selected authors will be assigned to the Sections/Chapters based on their expertise.
     Authors will be responsible for major contribution of the book in writing, editing and response to reviewers’ comments,
     one Section or Chapter could be contributed by multiple authors for the best result.
   - Contributors – Partially contribute in adding or modifying of paragraphs of the book, no pre-assigned Section/Chapter
     limitation and no limitation on participant numbers.
   - Reviewers – Provide review comments in writing and/or editing on the draft manuscript of the book, not necessary to
     provide substantial writing, no limitation on participant numbers.

Since our subcommittee has limited members, a person who serves as an author or a contributor can also provide review comments to the Sections/Chapters written by others.

Please refer all questions and ideas to the Chair.


ASHRAE Technical FAQs are provided as a service to ASHRAE members, users of ASHRAE publications, and the general public. While every effort has been made to ensure their accuracy and reliability, they are advisory and provided for informational purposes only, and in many cases represent only one person’s view. They are not intended and should not be relied on as an official statement of ASHRAE. Technical questions not addressed may be submitted to the ASHRAE Technical Services department at