What Is A Cleanroom?
A cleanroom is an environment that is designed, built and operated to provide cleanliness, control and/or isolation for certain processes. Cleanrooms are commonly used in manufacturing and research and development in fields such as Nanotechnology, Defense, Microelectronics, Pharmaceuticals, Biotechnology, Medical Device Industries, as well as many others. Many industries have recently discovered the benefit and need for cleanrooms for their specific processes.
The purpose of a cleanroom is to protect the product or the process from contamination, to restrict access to the product or process and to contain any hazards located in the cleanroom. Cleanrooms have little to no contamination, which is anything that could corrupt the process or make the product impure. Contamination in a cleanroom is defined by a specified number of certain size particles per cubic foot of air. The particle size measured in cleanrooms are typically 0.5 microns (µm) or larger in diameter. For perspective, a human hair is 60 -80 microns wide and outside air has about 35,000,000 0.5µm and larger sized particles sized per cubic foot of air.
How Do Cleanrooms Work?
Cleanroom classification is based on cleanliness level, which are:
- Class 1 (ISO 3)
- Class10 (ISO 4)
- Class 100 (ISO5)
- Class 1000 (ISO 6)
- Class 10,000 (ISO 7)
- Class 100,000 (ISO 8)
What these cleanroom classifications represent is the level of measured contamination from 1 particle at .5µm per cubic foot of air to 100,000 particles at .5µm per cubic foot of air.
Cleanrooms are built with smooth, hard and easily cleanable surfaces to minimize contamination. Materials such as walls, ceilings and floor systems are all designed to minimize internal particulate. Temperature control, humidity control, static control, sound and light levels are all critical factors when creating a cleanroom. The way air enters, is filtered, circulates and leaves a cleanroom is most important. Outside air is filtered to exclude particulates, and the air inside is constantly circulated through High Efficiency Particulate Arrestors (HEPA) and/or Ultra Low Particulate Arrestors (ULPA), to remove internally generated contaminants. People are the largest particle producer in a cleanroom and many precautions are made to protect the product. Personnel enter and leave cleanrooms first through gowning rooms, then often through airlocks. They wear protective clothing such as coveralls, hairnets, facemasks, booties and gloves. Materials and equipment are next in line as generators of contamination, which limits what they can be made out of when used in a cleanroom.
Hodess Cleanrooms
Hodess Construction Corp. is a general contractor with the expertise and know-how for cleanroom design and engineering. When you need a cleanroom, you need to hire an expert who understands design, construction and protocol. We at Hodess are cleanroom standards specialists who can provide both design/build (Turnkey) and plan and specification cleanrooms. We are also able to provide other cleanroom solutions, including modular cleanrooms, stick-built cleanrooms, stick-built modular cleanrooms and ISO Class 2 through ISO Class 8 cleanrooms. We are also experienced with pharmaceutical cleanrooms, as well as dryrooms, clean dryrooms and battery rooms. Hodess can provide white rooms, environmentally controlled spaces including BSL 1, BSL 2, BSL 3 and BSL 4 labs. We have built cleanrooms for General Electric, Millipore Corporation, Amgen, National Semiconductor, R.F. Micro Devices, Digital Equipment Corporation and many more.
Cleanroom Levels
Cleanrooms are defined by their level of cleanliness, more specifically the amount of particles found in the air. A class 1 cleanroom or ISO class 3, which is today’s standard, typically has one .5 micron sized particle per cubic foot of air, for which a typical HEPA is rated. Cleanrooms range up to class 100,000 or ISO class 8 which include up to 100,000 particles at .5 microns. A micron (denoted as µm) is one millionth of a meter. A typical human hair is about 80 µm wide. The types of filters used can also affect cleanliness. The HEPA filter (high efficiency particular arrestor) can give you class 1 through 100,000 at .5 microns depending on the quantities and the air flows used in the design. To meet a higher cleanliness level and smaller particulate level ULPA filters (ultra low particulate arrestors) are used to reduce particles sized down to .3 microns or less.
The cleanliness level of a cleanroom is typically set at the beginning through the cleanroom design analysis and depends on the product to be made. In some cases, particulate can have a crucial impact on the performance of the product. In other cases it can contaminate the product. The various cleanroom types, cleanroom air delivery systems, and analysis of the process and the design help determine the level of cleanliness to be accomplished.
With today’s cleanroom technology, they are tending to certify at least one class cleaner at rest than specified. However, the amount of air used to certify a cleanroom as specified in the ISO standards can vary. A facility’s energy savings, which helps the competitive nature of businesses, depends on the type of process used and the protocol maintained. These savings can be accomplished by specifying different levels of cleanliness or operating systems in such a manner that the level of cleanliness maintained meets the qualifications, but uses control systems such as particulate counters, to maintain but not exceed the cleanliness level.
Cleanrooms are typically energy inefficient compared to standard building systems. This is because pressure, temperature, humidity, particulate levels, light levels, static levels, sound levels, vibration levels and other criteria can critically impact the performance of the product being made in the cleanroom. Controls are employed through the mechanical, electrical and process systems to ensure that systems do not impact the product and in fact in many cases enhance the product. As a result, the tighter control means more energy expended to control these variables.
