CLEAN ROOMS IN MANUFACTURING

Technological requirements in some industries result in certain production stages being carried out in controlled environments. Often, industry regulations, standards or individual agreements specify, for example, maximum levels for airborne particles, including pollutants (e.g. dust, bacteria, chemical vapours, etc.) and enforce the highest possible control of temperature, humidity, differential pressure and static levels. An example of this can be found in high-technology production, where the reasons behind such stringent requirements relate to the desire to achieve the highest possible quality and sophistication of products. Clean rooms are a solution for maintaining sterility in, for example, the laboratory, food and technology industries. i. Due to this broad spectrum of industries in which they are used, the demand for clean rooms and their equipment is growing.

What are cleanrooms?

A clean room (such as a clean room or clean box) is a room in which the level of contaminants (such as dust and chemical vapours), pressure, temperature, humidity and lighting are strictly controlled so as not to exceed certain values imposed by accepted standards, ensuring a clean and sterile workplace. All activities and processes carried out on their premises take place in safe and contamination-free conditions.

The installations are designed and constructed in a special way, including appropriate equipment (HEPA ventilation systems, showers and airlocks, etc.). Only authorised personnel should have access to clean rooms. This prevents products from being exposed and exposed to factors that could lead to contamination.

Clean room applications

The idea of clean rooms originates from medicine, more specifically from operating theatres in hospitals. This is because the correct temperature and ventilation of the room, sterilisation of the instruments used and adherence to strict hygiene requirements are essential for surgical intervention. This concept has also been implemented in industry to ensure the safety of products manufactured in certain industries, while controlling the level of contamination. The presence of contaminants in the environment can adversely affect the properties of certain products. This is particularly true in the food, medical, pharmaceutical and technology sectors.

All in accordance with the standard

Controlling and minimising contamination levels in cleanrooms is not an easy task and requires very precise design of such spaces. Many aspects need to be considered, from the technical specifications governing the correct operation (HEPA filters play a key role here), to the regulations governing the construction process or the equipment needed, to the expected flow of personnel and load rotation. During the design and implementation phase of a project, two criteria are used to determine cleanroom characteristics:

– GMP (Good Manufacturing Practice). These are international regulations governing the production of pharmaceuticals, cosmetics or foodstuffs under optimal environmental conditions. In Europe, their application is regulated by Regulation (EC) No. 1223/2009 of the European Parliament and of the Council. In addition to maintaining air purity, it is important that clean rooms have adequate temperature control, adequate lighting and fire protection in accordance with the regulations. At the same time, the sterility of the materials used and the surfaces on which the various activities take place must be guaranteed.

– ISO 14644. This is an international standard developed by the International Organisation for Standardisation (ISO) for air hygiene in clean rooms. The standard divides rooms into nine categories and sets maximum limits for the number of particles inside. This division can be more or less restrictive depending on the industry. The main objective of cleanroom construction is to minimise the formation, retention and penetration of contaminants.

From design to construction

When designing a clean room, it is necessary to work out the layout of the available space by enclosing it and then designing doors, windows, flooring, as well as providing filtration and access points. The main factors influencing the different uses of the room will be its purpose. The materials used to create a clean room should be of a higher quality than those used for any other building. This is because a number of criteria must be met: durability, physical and chemical resistance, ease of cleaning and fire behaviour. The materials used for construction should be of a higher quality than those used for any other building. The reason is that the room has to meet a number of criteria, such as durability, physical and chemical resistance, ease of cleaning and behaviour in contact with fire. The ISO 14644 standard specifies several requirements for cleanroom construction:

– Wall cladding and ceilings. They should be made of sandwich panels, i.e. panels composed of two external surfaces usually made of galvanised steel sheet and an infill that provides rigidity to the whole structure (and additional properties such as fire resistance and adequate levels of thermal insulation). With the right combination of panels, microbial penetration and dust accumulation can be blocked and cleaning can be facilitated.

– The cladding of walls and ceilings must be made of sandwich panels, i.e. panels consisting of two external surfaces, usually steel sheets, and an infill to ensure the rigidity of the whole structure (and additional properties such as fire resistance or thermal insulation) The correct connection of the panels helps to prevent the ingress of micro-organisms and the accumulation of dust in the premises and makes it easier to clean.

– Doors must also be made of multi-layered panels to provide insulation, and windows should have double glazing for security.

– Different floor finishes can be used depending on the permeability of the room. Optimal floors should be smooth thus providing the best protection against dirt, making cleaning easier and preventing the growth of germs.

– Lighting. Lamps with a neutral white colour should be used.

The next step in designing a clean room is to choose the right filter. This is one of the most important factors in the design of such a room. The air supplied to the sealed chamber is filtered to reduce the amount of particles in the air. Glass fibre HEPA filters, which capture and retain airborne particles and micro-organisms, contribute to air exchange and quality. Indoor air conditioning is also an important aspect to ensure that the production process runs properly, that working conditions are good and that the risk of cross-contamination is reduced. It is recommended to create an airlock, i.e. a chamber with two entrance curtains (one in and one out) that never open at the same time. This system prevents sudden changes in temperature and pressure during access to the clean room.

Cleanliness and sterility

Keeping the cleanroom clean is very important to maintain its essential functions. Staff hygiene and the cleanliness of materials brought into the room must be controlled. This requires that operators are properly trained and informed of the importance of cleanliness. Staff must wear special clothing that absorbs natural contaminants from human skin and body, and they should use hair nets, gloves and masks.

Access points are another important aspect, as these are areas where there is an increased risk of particles and other contaminants entering the premises. Air showers are used for workers to minimise the risk. This is because it is an area designed to remove germs from body surfaces before entering the cleanroom.

Clean Box – the compact solution

The construction of clean rooms is a very serious investment which, for obvious reasons, is most often feasible for large companies and corporations. For these reasons, an increasingly popular alternative to this type of construction is the so-called clean box. This is a modular and movable structure that allows the creation of a clean area of a few to several square metres.

Using this type of smaller solution requires users to analyse their production process and identify the stages in the process where the use of controlled conditions is absolutely necessary. An obvious advantage of this type of solution is its cost. A mobile installation means lower maintenance costs associated with specialised cleaning.

There are also no maintenance costs for the supply and ventilation equipment. Smaller rooms – including clean boxes – are often equipped with filter fans that, even when running continuously, do not generate high electricity costs.

The clean box also has the advantage of being mobile. It is a lightweight structure that can be adapted to others and relocated in the event of changes in production. In the case of a classic clean room – for example, in the case of increased production volumes – expansion involves demolition of walls, construction work, building permits; and of course there are high financial, time and labour costs.

With a clean box, these costs are significantly lower, the process takes less time and no construction projects are required. These types of rooms can also be expanded without losing the clean layer – by adding another clean box module, a corresponding number of filter fans are also added.

CLEANROOM on offer from Renex

The RENEX Group, one of Poland’s largest electronics companies, has been rapidly developing its product range in the CLEANROOM sphere for the past 10 years. Amongst other things, the Group, through its REECO brand, provides the equipment, finished infrastructure elements and services necessary to create new and maintain the proper functioning of existing cleanrooms.

The product range includes, among other things, a wide range of specialised furniture, sluice rooms, serving windows and garments made of dust-free materials, as well as ready-made clean box rooms. Production in Poland allows for the rapid realisation of non-standard, customised orders.

As part of the activities of the RENEX TECHNOLOGY AND TRAINING CENTRE, the Group also conducts extensive consultancy, training and research and development activities. This allows not only the selection and development of appropriate technologies and solutions for a given type of activity, but also the appropriate training of employees.

The spectrum of RENEX’s CLEANROOM offer is further complemented by services for the maintenance of premises and equipment infrastructure, audits and comprehensive project implementation.