TOWARDS GLOBAL CLEANROOM TECHNOLOGY STANDARDS

Introduction

Cleanroorn technology is eminently international: most of the leading suppliers of services and hardware as well as many users operate on an international, mostly global scale. Harmonised technical standards are thus of vital importance if uniform quality and performance goals are to be met everywhere in the world. To address this need, ISO - the International Organisation for Standardisation - established, in 1993, its Technical Committee ISO/TC 209 Cleanrooms and associated controlled environment. This committee enjoys broad support from all over the world as well as from CEN, the European Committee for standardisation.
Ten different standards covering a wide range of contamination and biocontamination control topics are presently being developed, and 5 of these documents have already been, or will soon be, circulated as Draft International Standards for the parallel ISO and CEN approval procedures. The most advanced is ISO/DIS 14644-1 devoted to the new ISO classification system for cleanrooms. This document is discussed in particular detail in this article.

International Cleanroom Technology Standards - Why?

Since the mother of all cleanroom technology standards - U.S. Federal Standard 209- was first published in 1963,more than 300 normative documents, guidelines or recommended practices on contamination control topics have been published all over the world.

Without any doubt they contain valuable advice on many important subjects. However, the sheer number of documents and the fact that they have been prepared on a national rather than an international level creates a very unsatisfactory situation in a field as international as cleanroom technology: microelectronics, the pharmaceutical and medical device industries, the emerging nanotechnologies and all the other leading application areas of contamination and biocontamination control technology act and operate globally. The same applies to many of their suppliers of design, testing and qualification services, of cleanroom components and systems as well as of cleanroom disposables - and to all the other industries serving the field of cleanroom technology.

International Standardisation: The Key Objectives

International technical standardisation is driven by two key objectives:

• to establish a common basis for understanding, agreed and accepted on a global scale;
• to eliminate technical barriers to trade.

In the field of cleanroom technology, international harmonisation of standards is driven by two entities:

• on a European level by CEN, the European Committee for Standardisation;
• on a truly global level by ISO, the International Organisation for Standardisation.

ISO, established in 1947, is a world-wide federation of national standards bodies - one per nation - and it comprises at present 127 members [3]. Of these, 85 are full members enjoying voting rights, the remaining member bodies being correspondent and subscriber members. ISO's work is carried out through 2 830 technical bodies grouped together into 214 technical committees. More than 30 000 experts from all parts of the world participate in the technical work which, to date, has resulted in the publication of 11 258 ISO standards. ISO is independent from the various political and economical blocks in existence throughout the world. Its objective is to promote standardisation on a world wide basis: it aims at facilitating international exchange of goods and services, and at developing co-operation in the spheres of intellectual, scientific, technological and economic activity.

CEN, on the other hand, has been established since 1975 as a common organ of the European Community (now European Union EO) and the European Free Trade Association EFTA. Its objective is the elimination of technical barriers to trade between the CEN member nations through harmonisation of the European technical standards. It embraces the 18 standardisation bodies of the EU and EFTA nations, and its scope of work is identical with that of ISO.

ISO and CEN aim at harmonising their standardisation activities to the widest possible extent. With this in mind, they have negotiated the Vienna Agreement on Technical Co-operation between ISO and CEN. It entered into force in 1991 and establishes procedures for the mutual recognition of standards developed within one or the other of the two organisations.

What is the impact of this agreement on the adoption of standards? If ISO and CEN agree on a given technical item of standardisation, the ISO and CEN approval procedures can be triggered in parallel. If through this procedure a draft standard is approved on ISO level, it will be published in the ISO collection of standards as International Standard. Each nation is then free to decide whether it wishes also to include it in its national collection of standards. If the draft has also been approved during the parallel CEN vote, then all CEN nations are bindingly obliged to include this standard into their national standards collections as European Standard. Furthermore, all national standards conflicting with the European Standard thus adopted must be withdrawn, and no new national standards on the same subject may be elaborated henceforth.

The parallel ISO and CEN voting procedure gives tremendous weight to the standards thus approved, as the inclusion into 18 national collections of standards is guaranteed right from the beginning.

International Cleanroom Standards: The First Steps

The first step towards international harmonisation of standards in the field of contamination control technology took place in 1990: the establishment of the European Technical Committee CEN/TC 243 Cleanroom Technology. Without delay, it embarked upon a dynamic work programme addressing the topics of air cleanliness classification; design, construction and operation of Cleanrooms; terms and definitions; plus a wide range of biocontamination control subjects. The only drawback to these efforts was the limitation to Europe: the other driving regions in microcontamination control technology - North America and the Far East - were left out. However, the European initiative paved the way, and not much time was wasted until a proposal was submitted to ISO by the United States of America to launch an international standardisation effort in this field. This initiative was enthusiastically supported and promoted by the world-wide contamination control community including the European nations. Duly, the International Technical Committee ISO/TC 209 Cleanrooms and associated controlled environments was launched in 1993 - a mere three years after CEN/TC 243 had been created.

Presently, ISO/TC 209 membership stands as follows:

• 19 nations which, as P-members (participating members) pronounced their intention to actively participate in the elaboration of the forthcoming family of standards: Australia, Belgium, China, Denmark, Finland, France, Germany, Italy, Jamaica, Japan, the Republic of Korea, the Netherlands, Norway, Portugal, the Russian Federation, Sweden, Switzerland, the United Kingdom and the USA;
• 15 nations which, as O-members (observing members) keep themselves informed on the progress of the standardisation work: Bulgaria, the Czech Republic, Egypt, India, Ireland, Malaysia, New Zealand, the Philippines, Poland, Saudi Arabia, South Africa, Thailand, Turkey, the Ukraine and Yugoslavia.

In addition, the International Confederation of Contamination Control Societies ICCCS - the roof organisation of the various national professional societies promoting cleanroom and contamination control technology - also lends its support to ISO/ TC 209: as a Category A liaison organisation to said Technical Committee, it is entitled to participate in its deliberations and is expected to give the standardisation work items in development its explicit backing.

ISO/TC 209: Scope and Guidance Principles for Work

The scope of work established for ISO/TC 209 is ample and reads as follows: Standardisation of equipment, facilities, and operational methods for Cleanrooms and associated controlled environments. This includes procedural limits, operational limits and testing procedures to achieve desired attributes to minimise microcontamination. Topics of interest are non-viable particles, viable particles, surface cleanliness, room temperature and humidity profiles, airflow patterns and velocities, room vibration profiles, room light levels, room infiltration leakage, personnel procedures, personnel cleanroom clothing, equipment preparation, and any other topics related to optimising cleanroom operations.

Indeed, a spirit of total contamination control was to reign!

The general guidance principles to be observed in the development of the forthcoming family of standards are:

• The family of standards to be developed shall address only subjects of general applicability to all cleanroom technology usage areas.
• Applicationspecific standardisation remains outside the brief of ISO/TC 209.
• The standards to be prepared should be target oriented and establish objectives to be met.
• As much freedom as possible should be granted regarding the path leading to the goal.
• The standards should promote and encourage progress, rather than impeding it.
• The standards should contribute to the elimination of technical barriers to trade, and promote understanding between nations.
• The standards should neither favour nor prejudice individual nations.

ISO/TC 209: Structure, Projects, and Priorities

A total of 15 work items have been approved by the P-members for being addressed by l SO/TC 209, and a total of 7 Working Groups have been established for their development into standards (the nations entrusted with convenorship are given in brackets):

• WG 1: Air cleanliness classification (United Kingdom);
• WG 2: Biocontamination and biocontamination control (France);
• WG 3: Metrology and testing methods (Japan);
• WG 4: Design and construction (Germany);
• WG 5: Cleanroom operation (USA);
• WG 6: Terms, definitions and units (Switzerland);
• WG 7: Mini-environments and isolators (USA).

CEN/TC 243 has harmonised its list of work items with that of ISO/TC 209, and has transferred its earlier activities in the development of standards fully into said ISO Technical Committee. Thus, the determinations of the Vienna Agreement will apply and all standards developed by ISOITC 209 - without a single exception - will be submitted to the parallel approval procedure under ISO and CEN auspices.

The 15 internationally approved work items will be developed into a family of 10 international standards. Table 1 shows the ISO number allocated to them, their provisional title and the date when they have been approved by ISO/TC 209 - or are scheduled for approval by this body - prior to forwarding them to the ISO Central Secretariat. This body will subsequently launch them into the formal approval procedure by circulating them to the 85 voting members of ISO for the ISO enquiry as Draft International Standards (DIS). In parallel, CEN will circulate them to their 18 member bodies for the CEN enquiry.

Table 1:Standards being developed by ISO/TC 209 and the date of approval for subsequent international circulation as draft international standards(DIS)

The document in pole position - ISO/DIS 14644-1 [4] - has already successfully passed the ISO and CEN enquiry stage, with not a single negative vote having been cast! It is now being readied for the final and formal ISO and CEN vote of approval as Final Draft International Standard (FYIS), Another four documents have been liberated by ISO/TC 209 into the DIS stage, and the remaining ones are to follow in quick succession.

The approval procedure of international standards is tedious - even more so if they are submitted to the parallel ISO and CEN approval procedures which requires them to be circulated in three languages: English, French and German. In order to bridge this gap in time, CEN has decided to publish an interim document prepared under the auspices of CEN/TC 243 prior to the integration of its activities into ISO/TC 209: the European Prestandard ENV 1631 Cleanroom technology - Design, construction and operation of cleanrooms and clean air devices [5]. One of the highlights of this prestandard is the orientation given in respect to the various qualification steps of a cleanroom system, i.e. design, installation, operational and performance qualification. This is - as far as this author is aware - the first time that this issue is addressed exhaustively in any cleanroom and contamination control technology standard. ENV 1631 will automatically be withdrawn as soon as the corresponding ISO documents - ISO 14644-4 and ISO 14644-5 - are approved and published.

Some of the forthcoming ISO cleanroom technology standards have been developed from earlier national standards. Others, such as the biocontamination control documents, are pioneering efforts without national precedents. Will not quality suffer if documents of this complexity are developed by international teams of experts, with cultural differences and language problems,-and obeying a very tough schedule of deadlines? The opposite is the case: a high degree of perfection is striven for and is being achieved. Where comparison can be made, the documents are perceived by professionals to be clear improvements in substance and clarity in comparison with their national predecessors.

Editor: In the next issue Hans will look at air cleanliness classes.

REFERENCES

[1] A.L. Moller, "International standards for the design of cleanrooms" in W.Whyte (editor), Cleanroom Design, John Wiley & Sons, Chichester, 1991, pp. 121-162.

[2] Document IES-RD-CC009.2 "Compendium of standards, practices, methods, and similar documents relating to contamination control", Institute of Environmental Sciences and Technology IEST, Mount Prospect, IL/USA, 1993.

[3] Anon., ISO Memento 1998, International Organisation for Standardisation, Geneva , 1998.

[4] Draft International Standard ISO/DIS 14644-1, "Cleanrooms and associated controlled environments - Part 1: Classification of air cleanliness". International Organisation for Standardisation, Geneva, December 1996.

[5] European Prestandard ENV 1631:1996, "Cleanroom technology - Design, construction and operation of cleanrooms and clean air devices". European Committee for Standardisation, Brussels, July 1996.

[6] U.S. Federal Standard 209E "Airborne particulate cleanliness classes for cleanrooms and clean zones". Washington, DC/USA, 11 September 1992.

[7] Draft International Standard ISO/DIS 14644-2 "Cleanrooms and associated controlled environments - Part 2: Specifications for testing and monitoring cleanrooms and clean zones to prove continued compliance with ISO 14644-1 ", International Organisation for Standardisation, Geneva, approved for circulation 14 April 1997.