My Experience Shaping Industry Guidelines

Outgoing chairman of the ISO/TC 209 shares accomplishments, challenges of standards development

By David S. Ensor

Before I started volunteering in the standard development process, I read a standard. I thought, this is so simple, it must have taken a few days to write.  

Now, reflecting on the last 30-plus years and thousands of hours in working group meetings and reviewing scores of documents, I know the immense commitment and collaboration required.

My nine-year term as chairman of ISO/Technical Committee (TC) 209 Cleanrooms and Associated Controlled Environments ends this year. The committee has 24 member countries and 21 observing countries. Volunteers including heads of delegation, delegations, and working group convenors and experts have brought experience and passion to the development process and I appreciate their collaborative efforts.  

During the last nine years the committee has been very productive. It has:

  • Published 11 standards, 8 first editions and 3 revisions.
  • Revised the scope of the technical committee.  The initial scope emphasized air cleanliness within the cleanroom. The new scope recognizes that the activities within the cleanroom and associated with the cleanroom need to be considered as well.
  • Revised its Strategic Busines Plan (a new version will be voted on early next year). 
  • Adapted to the virtual meeting format caused by COVID-19 travel restrictions and has continued its high level of productivity.
  • Developed an understanding among its membership that managing the process is critical to completing high quality documents within reasonable time.


Standardization for cleanrooms and associated controlled environments for controlling cleanliness, as well as other attributes and characteristics, relating to facilities, sustainability, equipment, processes and operations.

An ongoing challenge is continuous improvement of the application of the ISO Directives to the practices of the TC.

One of the challenges to the TC in the next few years will be developing modern biocontamination control standards with the revision of ISO 14698-1 and ISO 14698-2. A standard recently developed by CEN, EN 17141, will be used as a starting point for the revision.

For those interested in standards development, I have the following observations:

  • Know the rules.
  • Honor your commitments.
  • Act ethically and respectfully.
  • Understand that the existential value of a standards document is to establish the minimum requirements of a transaction and not to serve as a textbook.
  • The IEST Recommended Practices are invaluable to the field of contamination control. Often the content of a RP is used as the basis of an international standard. For that reason, IEST should consider evolving RPs into national standards.

I have been asked, who is ISO? The International Organization for Standardization (ISO) is a bottoms-up organization, each technical committee acts with a great deal of freedom. IEST contributes to ISO in many ways including financially with support of the Secretariat and members volunteering to serve as chairman, committee manager (Secretary), members of delegation, convenors and experts, and members of the U.S. Technical Advisory Group. ISO is us.

How can you get involved in shaping standards? Attend an IEST Working Group meeting in your area of expertise. IEST is always seeking expert participation. Contact IEST Technical Program Manager Jennifer Sklena at for further information on providing valuable volunteer service to your industry.

Dr. David S. Ensor retired from RTI international in 2014 as a Distinguished Fellow and Corporate Scientific Integrity Officer. At RTI International, he managed research programs in nanotechnology, cleanroom technology, instrumentation, filtration, and air pollution. Dr. Ensor is an expert of and mirror group convenor for the American National Standards Institute’s Delegation to ISO/TC 229 Nanotechnologies. Dr. Ensor served on the behalf of IEST as Convenor of ISO/TC 209 Working Group 7.  He is a founding editor-in-chief of Aerosol Science and Technology and a Technical Editor of the Journal of the IEST. Dr. Ensor has more than 200 published works and 26 patents. He is a fellow member of IEST, AAAR, and ASHRAE (Life Member). He received a bachelor’s degree in chemical engineering from Washington State University and his Ph.D. in civil engineering from the University of Washington.

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