Windows are an important component of cleanrooms. One of the most important things in a cleanroom environment is to allow personnel to see inside the cleanroom, without making unnecessary trips inside, since you want to limit the amount of people entering the environment.
Cleanroom door selection is an interesting topic because from a cleanliness standpoint, the decisions are somewhat easy. In a pharmaceutical environment you’re concerned about cracks or crevices in the door and how microbial growth can result from that. But the decision process for a cleanroom door is more influenced by what you need from the entry and exit of people, personnel and materials, than on how a door relates to the cleanliness level.
The type of cleanroom wall surface used is dictated by a lot of things, including the cleanliness required of the cleanroom, whether static electricity is an issue, or the type of cleaners that will be used to clean your cleanroom.
There are basically three different air flow systems in cleanrooms: pressurized plenum, ducted supply and ducted return, and ducted supply and open return. Pressurized plenum essentially means you pump the air into the plenum, push it through the filters and down on into the cleanroom. With a ducted supply and ducted return, you’re doing just that; you’re ducting the air delivered to the cleanroom and you’re ducting the air back out of the cleanroom.
There’s really not an enormous difference between a single pass and a recirculating cleanroom, it just has to do with the preciseness of how you control the return. In any cleanroom you’re taking the air and you’re pushing it down through the room, and then you’re transferring it out of the room. Now the difference between a single pass and a recirculating cleanroom is what you do with that air once it’s purged out of the room. For instance, are you just going to control the return back to the plenum, or are you going to let that air wash into the surrounding areas? The decision based on which design you use has to deal with the preciseness of your control.
While there are discrete steps in the design and construction of a cleanroom, those projects deemed successful incorporate certain practices that promote flow of the construction process toward completion on time and within budget. Proper front end planning is not completed until it results in appropriate values for design parameters; "buy-in" at all levels of management, and clear direction for the design phase. Engineering the cleanroom in accordance with recognized industry practice would produce construction documents that facilitate clear procurement and construction planning as well as a focused, efficient, construction effort. A full return on the energy expended through the construction phase cannot be realized without a well-executed start-up and certification process that provides baseline data for effective operation and maintenance. This paper describes the steps in the cleanroom design/construction undertaking and offers practical suggestions on how to avoid pitfalls along the way.
Modular clean room construction can offer a number of important advantages over conventional (stick-build) approaches. For example, modular walls are an inherently dry construction material with little or no modification required for installation, thus minimizing dust generation. Modular systems can also be manufactured from materials that are non-shedding and non-particulating.
Any construction project, whether cleanroom-related or not, is subject to building codes. Regardless of construction technique, the overall objective of a building project is the same. The components of the clean room facility must satisfy local and national building regulations for fire protection and structural design. Materials are required to meet minimal flame and smoke development requirements (Class A non-combustible) or have fire separation walls (1- or 2-hour fire-rated for hazardous areas).
The question of modular versus conventional clean room construction is increasingly common in high-tech industries, and one that may have a different answer depending on each individual project. Speed to market, however, is critical for almost all manufacturing companies, and it’s particularly important for the pharmaceutical and biopharmaceutical industries, which need to maximize the patent protection period after what is usually a long and expensive product development cycle. It’s also crucial for the microelectronics industry where technology changes on a near-daily basis.
There are a lot of determining factors involved in choosing a cleanroom classification and every industry has a default standard to start with. In medical device packaging for instance, the default classification is ISO 7 (or a class 10,000) cleanroom.
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