There’s a lot to consider when planning new cleanrooms, which is why, right from the start, companies that are redesigning or converting their cleanroom ideally involve an experienced planner as a partner. At this early stage, it is particularly important to define the technical specifications, URS (User Requirement Specifications), standard operating procedures (SOPs) and other customer-specific documents that describe and define the project criteria. Current good manufacturing practice (cGMP) regulations and country specific requirements must also be acknowledged, so that engineering can take every requirement into consideration.
Once the “requirements catalog” for the project has been drawn up, the real challenge begins: the coordinated interaction of the various disciplines. Detailed consultations with cleanroom experts at regular and closely timed intervals are absolutely essential. After all, every element must meet strict requirements to comply with cleanroom conditions — from electrical installations and furniture to any fixture that directly touches or penetrates the wall, ceiling or floor.
In contrast, an uncoordinated approach quickly leads to costly rework and rescheduling. And, here, the devil really is in the details; for example, if installations are not cleanroom-compliant, they may have to be dismantled and reinstalled. These could be small elements, such as power outlets, monitors that were not properly integrated or process technologies in and around the cleanroom that do not comply with cGMP standards. In the worst case, compromises may have to be made that are not suitable for the cleanroom. By contrast, cross-discipline and interface-reduced planning minimizes the potential for conflict and reduces both time and costs.
Details in focus: from floors to walls and beyond
In the cleanroom, every installation needs to be well thought out. Take the cleanroom surfaces, for example; here, good cleanability is right at the top of the priority list, along with resistance to disinfectants, cleaning agents and input materials. Reason enough, certainly, to reduce the number of joints in the cleanroom to a minimum. If this is considered at the planning stage, wall elements can be planned to fit exactly to avoid gaps and process equipment can be inserted precisely. The number of joints can be further reduced by a clever choice of “wall against ceiling” or “ceiling against wall” system.
Fixtures such as fully surface welded and floor-flush washing stations with no maintenance joints — or customized stainless-steel furniture — that perfectly integrate into the cleanroom and its associated process conditions are prime examples of successful planning.
The floor covering must also be carefully selected. Whether that’s PVC, terrazzo or epoxy resin, each material has different properties. Therefore, the requirements of the specific project are critical. For example, if wet areas are involved, slip-resistance plays a key role. The degree of mechanical stress or conductivity are further criteria that must be considered during the selection process.
Which class of cleanroom is to be implemented, the number of employees that will pass through personnel airlocks and what the material flow plan between areas looks like are just a few of the issues that must be addressed in advance by the client and the project planner. For this purpose, cross-discipline planning is indispensable. At Glatt, all the required skillsets involved (HVAC, EI&C, process, black and clean media) are available in-house.
The right choice of wall elements is the first step. Among the multitude of different cleanroom walls available, double-shell cleanroom elements are recommended for interior walls (single-shell for exterior walls) or sandwich elements (so-called monoblock elements). Alternatively, for lower cleanroom classes, drywalls with a suitable two-component coating can be used. However, a higher dirt entry during the construction or conversion phase must be considered here.
Monoblock constructions with an insulating core and firmly bonded, surface-finished metal cover layers on both sides are recommended. Galvanized steel sheets with a polyethylene coating are mainly used as the top layer. Depending on the supplier, wall elements can be designed up to six meters high without horizontal joints or crossbars. On-site cutting should always be avoided as there is greater precision when cuts are done at the manufacturing site.
Meanwhile, media and electrical lines are integrated into the wall system as standard. To facilitate this, a wall thickness of at least 80 mm has become the norm. Doubling the wall thickness or even incorporating a separate technical area is also possible. Horizontal and vertical cable and media ducts with the possibility of revision — as well as empty conduits, flush-mounted boxes and other supply lines — can be integrated during the planning and production of the elements. The subsequent fitting of various media is thus possible (within limits).
Maintenance-free washing area: perfect for cleanrooms
Occasionally, elements must also be developed, designed and manufactured in-house. Cleanroom washing stations are a good example. They are best designed as a fully welded version and made of high-quality stainless steel. They should be free from silicone joints that might need to be replaced on a regular basis during continuous operation. As such, the washing area should be maintenance free, easy to clean and resistant to all common disinfectants and cleaning agents used in the pharmaceutical sector. Also flexible in terms of installation, the washing area can be integrated into almost all standard cleanroom constructions and is compatible with most ceiling systems. Media connections and columns can easily be fitted to map hose receptacles or water taps in the washing area. It is approved for high mobile loads and has impact-resistant ramming and collision protection. Cleanroom washing areas can be designed with or without slopes — and can be installed quickly.
Cleanroom doors: contaminants stay outside
Another important aspect in cleanroom planning is the doors or door systems. The three most common variants are swing doors, sliding doors and rolling doors. Single- or double-leaf swing doors usually consist of a tubular frame construction made of aluminum system profiles with a powder coating and should be installed flush with the partition wall. All-glass doors should not be used where material handling is particularly important (breaking glass is an accident risk). Sliding cleanroom doors are now of a high technical standard, including overall tightness, but they should only be used in particularly space-constrained situations as they are more difficult to clean than, for example, hinged doors. The cost of a sliding door, which should be automatically lockable, is also higher. Although cleanroom-compatible rolling doors are more expensive than hinged ones, they are a good alternative if they are to be used frequently and there is a lack of space: both the external material properties (enclosure of the mechanics) and the tightness of cleanroom-compatible designs meet all requirements and work reliably.
Keeping a clear view with glazed elements
Glazed elements are indispensable in a cleanroom: they serve to promote communication and the well-being of employees, provide an overview from outside and allow natural light to enter. Windows should therefore be a significant consideration in the layout from the very first planning phase, although the exact position and size can still be changed. Integration into cleanroom walls should follow the wall frames to avoid many different wall sizes. Material pass-throughs can have different sizes and designs depending on the intended use; they can be actively ventilated or purely passive. Their integration into cleanroom walls should always be flush with the clean side for better cleanability.
Design, plan, implement and succeed
An important point, after the engineering work has been completed, is making sure that the assembly process goes smoothly. If you work with an experienced partner who has already successfully implemented many small, medium and large-scale projects in different industries and cleanroom classes, and who can coordinate a wide range of disciplines on the construction site without exception, the chances of successful implementation are good. Glatt Ingenieurtechnik has implemented many cleanroom projects of all classes with areas ranging from a few hundred to several thousand square meters. No two projects are the same. Yet, thanks to the large number of completed projects — from small conversions in existing facilities to major builds in the pharmaceutical sector — the company’s team of experts can draw on an enormous wealth of experience and prevent errors or defects in advance through forward-looking planning.
Copyright: Wiley-VCH GmbH
Copyright: Vogel Communications Group
