Defining and calculating the number of active cleanrooms worldwide poses a challenge.

By Robert McIlvaine, The McIlvaine Co.

The cleanroom business is unique in that it is not structured around one industry or one product. It is structured around a result. However, this result is even subject to various definitions. Historically the definition has been based on enclosed space that contained recirculating air with fewer particles than found in the normal environment.

Typically this space utilized at least partial filtration with high efficiency (HEPA) filters. However, providers of gloves, garments, and other supplies have found that there is a significant market for space that strives to be cleaner than the typical office but would not meet the conventional cleanroom class limitations.

In November 2001 the U.S. Federal Standard 209E was canceled by the General Services Administration and replaced by ISO standards. This older standard defined the cleanest cleanroom as having no more than 1 particle per cubic foot, which was larger than 0.5 μm. The ISO standards set up three classes of very clean rooms to replace the Class 1 rooms under FED-STD-209E. They are based on the numbers of particles larger than 0.1 μm.

One micrometer (micron) equals 1,000 nanometers. The measurement of 0.1 μm, which is now the new criterion for measuring the cleanliness of space, is equal to 100 nm. Let’s assume that you start up a business to produce nanoparticles 50 nm in diameter. Lots of these particles may escape into the room. But since the cleanliness definition is based on a minimum particle size that is twice as large as particles you are manufacturing, you could theoretically meet the ultimate cleanliness criterion of ISO Class 1.

This inability to measure very small particles is of concern to the medical community. There is the realization that these nanoparticles can easily penetrate the lungs and reach the bloodstream. Therefore this progress in technology will put pressure on the cleanroom industry to once again revise its basis for classification.

The old Class 100,000 room (now ISO Class 8) was based on not exceeding 100,000 particles larger than 0.5 μm. There was no “less clean” classification. Now we have ISO Class 9, which allows 1 million particles/ft³ that are larger than 0.5 μm and even some particles at 1- and 5-μm sizes.

The average office building has a cleanliness level somewhere close to the ISO Class 9 limit. There are substantial purchases of garments and gloves by operators who want to maintain a space as clean as or cleaner than the typical office. In terms of floor space and numbers of workers, this is a very significant segment for the cleanroom industry.

It is not a significant segment for manufacturers of filters and air handling equipment. Most of these ISO Class 9 rooms achieve their cleanliness with little or no HEPA filtered air. But as a result of the large amount of space and number of employees, it has potential for garment and glove suppliers.

These ISO Class 9 rooms are just as often found in combination with cleaner space than as isolated operations. Many pharmaceutical companies surround their cleaner space with the relatively clean space. One of the reasons is that with movement in and out of the cleaner space, it is less likely to become contaminated if the entry space is relatively clean.

People frequently want to know how many cleanrooms there are in a particular country or a particular industry. This is another tricky question. If an operator has two ISO Class 4 cleanrooms inside an ISO Class 8 cleanroom, does this count as three cleanrooms or one?

Another factor is the number of shifts. One client needed help when his $100,000 survey did not match his knowledge of the industry. It turned out that the people doing the survey had assumed one-shift operation at all rooms. In fact, some operate three shifts and others two.

In the last several decades, concern about molecular contamination has entered the picture. Molecules of gases such as volatile organic compounds (VOCs) cause damage to computer chips and can impact health. This interest adds another complexity to the cleanroom rating system.

Numbers of cleanrooms

Despite the previous explanation as to why numbers of cleanrooms are of little value we will now attempt to calculate these numbers. The reason to do this is that the questions keep coming even when it is explained that there are lots of caveats in the statistics.

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We have calculated the number of cleanrooms in the world at approximately 121,000 (see Table 1).

This calculation does not include minienvironments or biological safety cabinets as rooms. But it does include rooms as small as 100 ft². The average size of rooms varies greatly by industry. Aerospace has some vast cleanrooms where space shuttles are assembled. Flat-panel display rooms can be very large as well. At the other end of the spectrum are the biolab rooms that can include animal research and similar applications.

Asia boasts nearly half the cleanrooms in operation worldwide while Africa has few. Asia will continue to gain share as the electronic industry expands in this region.

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The Asian market share in terms of annual investment in new rooms is greater than 50 percent. This is an indicator of a similar trend in numbers of rooms.

Asian cleanrooms employ more than 1 million people compared to 400 million in the Americas. There are some individual cleanrooms in Asia with 9,000 workers in garments and other cleanroom clothing. There are no comparable sites in the rest of the world.

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Asia will continue to add employees and build more cleanrooms at a rate greater than the other regions. The flat-panel industry is almost exclusively located in Asia. The pharmaceutical industry is one of the few that manufactures in Europe and the United States at a greater rate than in Asia. Quality control is one of the issues that has kept the bulk of production elsewhere.

It is recommended that cleanroom space and numbers of employees be utilized in assessing markets. The number of rooms is a weaker statistic because of definition problems. The same is true of revenues. Prices in China are much lower than in the U.S., so equal revenues do not translate to an equal numbers of units. It is better to start with the number of employees and the number of garments per employee, then units can be calculated. Revenues can then be forecasted using the different prices in different regions.

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Robert McIlvaine is president and founder of The McIlvaine Co. in Northfield, IL. The company first published Cleanrooms: World Markets in 1984 and has since continued to publish market and technical information for the cleanroom industry. He can be reached at [email protected].