The Versatile World of Modular Cleanrooms

A cleanroom is a room in which the concentration of airborne particles is controlled and which is constructed and used in a manner to minimise the introduction, generation and retention of particles inside the room.

Modular cleanroom constructions are typically built as freestanding, solid and robust structures suitable for use for injection moulding, extrusion and thermoforming environments. They are designed to be an alternative to static cleanrooms.

A modular cleanroom will use standard off the shelf proprietary components that when combined with the customer’s requirements will create a 100% bespoke room, thus reducing cost and lead time. Examples of customer requirements include specific ISO classification, lighting and whether they want a hard or soft wall.

Modular cleanrooms use air filtration technology to reach the required cleanroom classification. The two main types are high efficiency particulate air (HEPA) or ultra-low penetration air (ULPA) filtration. Filtration creates an exceptionally clean environment. HEPA filtration is able to remove particles as small as 0.3 µm while ULPA can handle those as small as 0.1 µm. Variable speed adjustments means that air changes in the room can be changed as required—maintaining quality but giving the flexibility to benefit from reduced energy costs during off peak times.

Cleanroom ISO Classification

A cleanroom can be designed to achieve various ISO 14644-1 classifications of air cleanliness. ISO 14644-1 is the international standard for air cleanliness for cleanrooms and associated controlled environments.

Often, the type of product being manufactured will dictate the ISO classification required. Long term implantable products need to be manufactured in a cleanroom with a higher standard of air cleanliness than non-sterile products which are used outside the body. The main rule of thumb is to consider your process, determine the quality that you need to achieve using industry regulatory guidelines and if in doubt, speak to a reputable cleanroom company to gain professional advice.

Selected Airborne Particulate Cleanliness Classes

The standard ISO 14644-1 defines the various classifications for cleanrooms. The main criterion for classification is the maximum concentration of airborne particles up to a certain size per cubic metre of air. In medical plastics, typically the most stringent cleanroom class found is up to ISO class 5 while typically the least stringent is class 8. In a class 5 cleanroom, the maximum number of particles permitted per cubic metre of air is as follows: 100,000 of a size which is greater or equal to 0.1 µm, 23,700 of a size which is greater or equal to 0.2 µm, up to just 29 of a size which is greater than equal to 5 µm. A class 8 cleanroom, by contrast, doesn’t identify particles smaller than 0.5 µm and allows up to 29,300 particles greater than 5.0 µm in size.

Benefits of Modular Cleanrooms: Lean Manufacturing

Demand for modular cleanrooms is on the increase as more processes, particularly in the medical plastics sector, are benefiting from a cleanroom environment. With this demand comes a cost and companies are obviously going to look for the best solution to fit their needs and budget. Due to recent years of cut backs that many industries have witnessed, small, medium and large organisations have had to re-think their company strategies and become leaner in the way they manage processes. Modular cleanrooms are part of that leaner way of thinking, as contract manufacturers are finding they can dramatically increase their scope of work by introducing cleanroom facilities.

With traditional build cleanrooms, retrospective modifications are often a lengthy and costly process, so future demands must be accounted for in the initial specification. Modular solutions are more flexible as expansions and relocations can be accommodated much more easily. In these uncertain times companies are seeing the fact that they can stagger their investment to grow with contract wins or developments as a real benefit.

Dramatic design improvements have also led to an increased demand for modular cleanrooms. The use of clear, solid wall panels has led to an improved perception of the modular design of cleanrooms. They are no longer seen as the temporary, low budget option and now offer a reliable and robust alternative to the traditional build cleanrooms.

Hard or Soft Wall and Entrance Control

Modular cleanrooms are available as hard and soft wall options. Hard wall modular cleanroom options are manufactured from clear polyethylene terephthalate. This material is aesthetically pleasing yet limits access to the cleanrooms while allowing in light and ensuring that processes can be overseen.

Softwall options are also aesthetically pleasing, ensure minimum opening only when entering or exiting the cleanroom, maintain the integrity of the room and are a low cost investment. A modular cleanroom can be housed within a dirtier area, for example a warehouse, and still maintain their ISO integrity.

Tacky mats outside the cleanroom remove dust particles from footwear and changing rooms can be built within the modular cleanroom to ensure that the user can change into cleanroom apparel in a controlled environment prior to entering the cleanroom.

By including a mid-height rail to a softwall cleanroom enclosure, you can direct people to a dedicated entrance and prevent people from entering the cleanroom at any point thereby maintaining full control of access. Mid height rails also offer extra strength to soft wall cleanrooms.

Bespoke Design

Various cleanroom solutions can be offered to fit the many different processes offered within the medical plastics sector. The modular design creates a localised clean area which offers a solution that can be tailored to suit each organisation’s specific machinery.

A fixed ballroom design with no internal supports, allows cleanrooms to be designed to house large machinery with access panels located in the ceiling. These panels can be removed to allow a crane travelling above the cleanroom access to the machinery in the cleanroom.

Localised or part coverage of a machine by a cleanroom is often used when a specific area of the process needs to achieve a cleanroom standard. This can be, for example, at the packaging end of a machine where the product would have to be transferred and packed in an environment where particle reduction would be imperative.

Whole coverage of a machine by a cleanroom is also a common prospect which can unearth interesting variables such as the height of a robotic arm housed on top of an injection moulding machine. The advantage of a modular cleanroom is that it can be designed in such a bespoke manner that all variables are more often than not catered for.

High performance cleanroom solutions can be designed to be integral to the machine in the form of air conditioned laminar flow hoods that can feed cool, particulate-free air onto the machines. The airflow over the injection moulding tool can be kept at a predetermined cool temperature to ensure that condensation does not harm the processes.

Summary

Whatever cleanroom solution is chosen, an investment is being made which will have to be looked after. Regular validations of a cleanroom are recommended to ensure that it is achieving the correct ISO classification. Correct processes and procedures should be carried out, and cleanroom apparel should be worn, cleanliness should be maintained with appropriate lint-free cleanroom wipes and cleaning solutions. Stainless steel furniture is also available for cleanrooms to reduce particle output. A cleanroom should become an integral part of production and with the correct maintenance, care and attention it can open new opportunities, diversifying offerings.

Image: Modular cleanroom installation over an Arburg moulding machine in the UK.

Sean Fryers is marketing manager at UK-based cleanroom supplier Connect2Cleanrooms.