A cleanroom is a defined area of space in which the air must be so pure that even invisible particles (twenty times smaller than the eye can see) are filtered out. This purity is achieved by creating a shell consisting of a floor, ceiling, walls and egress which are completely sealed off from the rest of any other environment. The air in this shell -- or cleanroom -- is then regulated by high powered, advanced design Heating Ventilation Air Conditioning (HVAC) systems. Air is exchanged as often as sixty times an hour in cleanrooms compared to six times exchanged in regular office spaces. Everything in a cleanroom, including humidity, temperature, air flow and balance are continuously monitored and work together to create and maintain this cleanliness level. Cleanrooms are pressurized to insure that any leakage shall be outward.

Equipment is constructed of non-shedding components and lends to the overall cleanliness of the room. All people who work in cleanrooms wear special clothing designed to prevent particulation (shedding of any kind) and, in many instances, workers first pass through an air shower to further remove any microscopic particles before entering a cleanroom. Think about this:

Semiconductor manufacturing is moving into the SUBHALF MICRON era. That means ONE HALF OF ONE MILLIONTH of a meter! Particles of a few hundredths of a micron in size are like meteors in this environment and might cause circuit faults and product failure. In other words, how clean is clean? The average surgical operating room is three times dirtier than the "dirtiest" cleanroom.

The need for this level of cleanliness arose over thirty years ago when NASA created "white rooms" which were designed to screen out dust during process of communication systems for aerospace. Since then, nearly all areas of high tech manufacturing, biotechnological research, animal containment, and overall fields of medicine and pharmaceuticals have begun to realize the benefit of cleanroom environments.

Objectives of using a cleanroom:

• To maximize productivity. If the environment is not clean, maximum production is not achieved.
• To reduce rejection. When product failure begins, the room leaks and contamination enters from an undiagnosed source.
• To achieve unbiased experimentation. Airborne contamination hampers test findings in laboratory settings.
• To prevent contamination. In micro settings, biological contamination promotes infections or worse.
• To increase product shelf life. Food and beverage production.

Who monitors the cleanliness levels in a cleanroom? The owners do. Product failure, biased test results, faulty research findings, shortened shelf life, and biocontamination can cost owners millions of dollars and adverse publicity -- problems they must work very hard to prevent. As owners spend millions of dollars to create these high-tech cleanroom environments they know that their investments will pay for themselves in product yield, increased shelf life, reduced contamination risks and accurate research findings. When these standards of operation decline, so do profits.

So, who decides how clean a room must be? The Federal Standards Bureau determined a classification system (Federal Standard 209) for NASA. It basically determined that in order to achieve the goals of cleanroom operation, the number and size of potentially damaging particles would have to be regulated.

Cleanrooms are designed to provide a CONTAMINANT FREE environment because any form of particulate matter -- dust, spore, virus, bacteria, fungi, or mold can destroy the productivity of the cleanroom. Cleanrooms are classified according to the number and size of particles found in a given cubic foot of space once the room becomes operational. The number of particles will determine the class of the room; thus, a Class 1 room will allow ONE, micron sized particle (a micronmeter is equivalent to one millionth of a meter) per cubic foot; a Class 10 will allow ten, a Class 100 will allow one hundred, and so on, to Class 100,000.

In order to achieve a Class 1 or Class 10 level, laminar air flow design is incorporated into the cleanroom. Laminar flow moves all air in a vertical or horizontal pattern. With vertical laminar flow, the entire ceiling system consists of high efficiency particulate air (HEPA) filters or Ultra Low Penetration Air (ULPA) filters which screen out 99.995% and 99.999% of the particles. All incoming purified air moves in a vertical pattern through the ceiling, down to a raised, ducted floor, and back up through the outer walls. In a horizontal laminar flow, the same principle works in a horizontal pattern with filtered walls. Laminar flow is highly used in the semiconductor and electronics industries where wafer chips and circuit boards are so tiny that one micron of dust can destroy production. As the process in the cleanroom grows less critical, greater quantities of these invisible particles may be present without the risk; hence, the class of cleanroom is higher.

The major governing factor to designing a cleanroom is awareness of the activity in it. All materials, type of air flow requirements, component materials, and temperature, etc. will be determined by the process conducted in the cleanroom. For example, the presence of toxic fumes or food and beverage handling will necessitate the use of at least 304 stainless steel on all exposed areas of contact. Working in a photosensitive processing room may require the screening out of certain nanometers of light. Cleaning techniques might require that components be able to withstand high impingement hosedown spray. Each cleanroom process involves different design parameters based on the activity to be performed in the clean space. And, even more challenging for the designer is that many times the activity remains undisclosable.

Federal Standard 209E will determine the class of room needed for the required activity to be performed. The design and purchase of a cleanroom is conducted in a number of ways. Most Fortune 500 companies are exploring the use of cleanrooms in their businesses. As outlined in the accompanying chart, most areas of technology already employ these rooms in their daily operations. Many of the larger companies will employ architectural and engineering firms to design and specify the cleanroom and all of its components.

Other companies purchase soft wall and hardwall, portable cleanrooms which can be transported from one sight to another. When designed by architectural and engineering firms, sales forces who represent the component manufacturers will call on the architect and engineer to have their products specified. In many instances, owners are large enough to have their own design staff who will specify everything, then will hire a cleanroom contractor for construction. Additionally, cleanroom manufacturers are companies who will design, purchase O.E.M. components, and fabricate everything from portable, soft wall, hard wall, and stick built to permanent, fixed cleanrooms. There are a number of players in this arena: Manufacturer's representatives will sell everything from garments to lighting fixtures. Others will specialize in an area of the cleanroom, such as the ceiling system which would typically consist of a "T" grid system (1/2" to 2" in width). HEPA or ULPA filters, blowers and lighting fixtures in a 2'x4' grid configuration. Most often, room class is Federal Standard driven and owner enforced.

Who Uses Cleanrooms?

Generally, any company who wishes to achieve the previously outlined objectives uses a cleanroom; and specifically, those companies who cannot afford product failure or biased research because of airborne contamination cannot do without cleanrooms. These are but a few of the industries that utilize cleanrooms: Kodak, Mitsubishi, BASF, Campbell Soup, AT&T, Searle, Eli Lilly, Fluor Daniel, Allied Signal, Boeing, Texas Instrument, Kellogg, Baxter Travenol, Abbott Laboratories, hospitals, universities, research facilities, Anheuser-Busch, Delco, Genetech, dairies, Beatrice Foods, Motorola, Sony, Sandia Laboratories. The list is endless. The point is that cleanrooms and the need for contamination control have entered nearly every segment of the market. It is the future. And it's here to stay. And get even cleaner.

Once a room has passed its Class rating and becomes active, the owner will contract with outside certifying agencies to periodically test the cleanroom to make sure it meets its original rating. Ideally, a corporation will not have to call in one of these organizations because of a problem. Usually when trouble arises -- products fail, test results are biased --microcontamination has entered the clean space, a violation of the cleanroom shell has allowed outside air into the cleanroom. Two of the biggest culprits of this violation are lighting fixtures and HEPA filters.

LIGHTING THE CLEANROOM:

In a non-laminar flow cleanroom, recessed lighting fixtures -- in a grid or flange configuration -- penetrate the ceiling shell. Even surface mounted fixtures, while substantially reducing the size of the opening, still require conduit entry ports. When installed, they must re-seal the shell. This means that the housing, which is exposed to the plenum, must be sealed to prevent contamination during re-lamping and fixture maintenance. During operation, the fixture's door frame must seal to the housing, and the lens medium must seal to the door frame, thus, providing a three-way seal. Seams, penetrations, and gaps between parts even if sealed, provide potential storage areas for contamination and also must be reduced to as few as possible. Thus, cleanroom lighting fixtures have to be designed and constructed for cleanroom use -- to forbid air passage and prevent contamination. Adequate illumination (100fc on the work surface) from a totally sealed fixture is a must.

In a laminar flow setting, the entire ceiling system is comprised of HEPA filters. In order to achieve and maintain a Class 10 or cleaner rating (so necessary for success in the semiconductor industry) the HEPA filtered air cannot be interrupted with turbulence (objects which will interrupt the vertical or horizontal air flow). In these rooms, lighting fixtures come in two varieties: The first is called a teardrop and mounts to the "T" grid. Its lens is shaped like an airfoil and contributes to the laminar flow in the room. The second, called a flowthru, mounts under the HEPA filter and allows the clean air to pass through it. Design preferences will determine which of these laminar flow fixtures works best in the setting.

Once again, the activity in the cleanroom will determine component parts of the lighting fixtures, too. In food process areas, for example, stainless steel on all exposed parts might be a requirement. In an animal containment facility where cleaning is a daily occurrence, a lighting fixture may have to withstand high impingement hosedown. In photosensitive areas, amber lens may be needed to screen out certain nanometers of light. In addition to designing a lighting fixture for the cleanroom environment where particulation and outside air passage cannot take place, manufacturers have to be ready and willing to make modifications to existing fixture designs to accommodate the special requirements of this demanding environment.

It seems, at this time, that there are as many ways to sell cleanroom lighting as there are ways to sell the rooms themselves. Most of the large cleanroom users -- cleanrooms vary in size from a 4'x6' portable structure to hundreds of thousands of square feet -- work with project managers and design firms for the architecture and engineering of their rooms. The role, however, of the manufacturer's representative changes.

Traditionally, lighting has been sold through a lighting representative who handles only lighting and maybe some switching. In the cleanroom industry, however, there are many more players vying for the specifier's time. Therefore, many representatives have put together packages of cleanroom components -- from garments to filters, ceiling grids, work benches, portable walls, shatterproof windows, etc., and many of these representatives also have lighting fixtures on their line cards.

When a cleanroom is designed by an architectural or design firm, components will be specified by manufacturer and catalog number. Cleanrooms are demanding enough environments that most engineers will not tolerate substitutions and will do a thorough process of choosing what they want during the specification process.

The next time you look at the expiration date on the cream at your local grocery store, you might notice one or more brands with dates longer than two months from now. It's called "ultra pasteurized" and because it was processed in a cleanroom environment, the shelf life extended from two weeks to two months. As you pop a compact disc into your player, remember that it was probably made in a cleanroom. When you hear headlines of genetic research's latest advancement and the suffering it will eliminate, know that the discovery was made in a cleanroom. If you wonder whether these rooms are just a passing fad, think again: No area of advancement will take place without facilities for the research, testing and manufacture of the future, facilities called CLEANROOMS.

For a fixture to have NSF Certification indicates that the fixture and the manufacturing facility that manufactured the fixture have passed a battery of tests that pertain to the stringent requirements of the FDA and USDA. Guth Lighting Clean Room Product Line

What is the National Sanitation Foundation (NSF)?

• A not-for-profit, independent, third party certifier of products and systems for conformity with consensus and official regulations and specifications, industry standards, and product specific test protocols.

How do I know that the NSF is a viable independent third party certification organization?

The NSF is itself certified by: 1. The American National Standards Institute (ANSI);
• a federation of more than 250 technical organizations, 30 government agencies, and 1,200 companies;
• the recognized accreditor of third party certifiers and quality system registrars in the United States;
• the recognized accreditor of consensus standards in the United States; standards adopted by ANSI are American National Standards; 2. The Dutch Council for Certification (RvC);
• the official accreditation body for third party certification bodies and registrars in the Netherlands;
• the only accreditor for third party certification bodies and registrars active worldwide;
• NSF is recognized internationally for its services to clients in over 30 countries outside the United States;
• NSF is active in United States - European Community private sector standards and conformity assessment negotiations.

Why should NSF listing of product be meaningful to me?

• NSF requires all materials, which could come in contact with food products, to meet the stringent requirements of the Federal Food, Drug, and Cosmetic Act (FDA) as amended.
• In order to ascertain its suitability for use in food processing and food handling areas, the equipment and the manufacturer must pass a rigorous battery of tests. Additionally, NSF performs unannounced inspections and audits to ensure on going conformance.
• This is your safeguard against unfit products, and/or negligent manufacturing practice.

Who performs the testing, and where is the testing done?

• All testing and analysis is performed by NSF staff scientists which include, but are not limited to, toxicologists, chemists, micro-biologists, mechanical engineers, and other industry experts.
• NSF maintains its own modern and current testing laboratories in several locations in the U.S. and abroad.

How can I tell if a product is NSF listed?

• Look for the NSF mark on the label affixed to the fixture.

What are the listings that apply to lighting products?

• Lighting equipment falls under the NSF C-2 listing procedure, Special Equipment and/or Devices.
• The C-2 procedure has protocols which analyze the physical design of, the specific properties of each substance used in the manufacture of, and the fabrication of the fixture. Additionally, NSF investigates the reliability of the manufacturer and the manufacturing process as it relates to the listed product.
• These are three certifiable locations for equipment used in food processing, the first two of which apply to lighting fixtures: NON-FOOD ZONE, SPLASH ZONE, and FOOD ZONE.