The manufacturer must give evidence of the production process to be carried out inside the Clean Room, at least for the main lines.
At least the following information must be available:
- product to be manufactured (e.g. circuit boards, medical devices, etc.);
- flow of materials and operators;
- layout of the production process.
Cleanliness Class ISO 14644
The Cleanliness Class is one of the leading elements to define the project, as it determines the performance of ventilation systems. It is therefore important to determine precisely:
- the cleanliness class required by the production process
- for which operating status the cleanliness class defined is required: as build; at rest, in operation.
It is important to define the status because the desired status determines a difference in Clean Room performance within the same class.
Clean Room size
A Clean Room must suitably fit the production lines, auxiliary equipment, plants and anything necessary for the good functioning of the production process: in addition, spaces for material passageways, dressing and equipment maintenance must be envisaged. Stressing the size too much does not bring about considerable economic benefit, it actually makes it difficult to manage the Clean Room, therefore increasing the risk of uncontrolled contamination. It’s a good thing to submit an approximate layout to the manufacturer. The basic information to find are:
- dimensions of the environment that will house the Clean Room;
- approximate dimensions of the Clean Room;
- heights available and useful for the process.
As a general rule, it is important to guarantee thermo-hygrometric conditions inside the Clean Room, compatible with the well-being of operators and that, at the same time, prevent the forming of condensation and/or electrostatic charges that may compromise the degree of environmental cleanliness (heavy particles loaded with water are hard to direct to air-cleaning filters, while those charged electrostatically tend to stick to Clean Room surfaces, production lines and processed products). For this reason, temperatures between 20/24°C are favoured as well as a relative humidity between 40/60%: nonetheless, some processes need different conditions, which is why manufacturers need to be informed in order to adopt alternative solutions.
Thermal loads dissipated in the environment
It is of essential importance to know the thermal load generated by the production process to suitably dimension air conditioning systems respecting the well-being of operators. In-depth analyses of this topic are available on the page dedicated to Comfort Rate in Clean Rooms.
Just like for thermal loads, process fumes/vapour extraction affect the dimensioning of the systems for the pressurization of Clean Rooms: it is therefore recommended to have these data available for each machine.
Operators are the main source of contamination inside Clean Rooms: it is therefore important to establish dressing procedures suitable for the process analysed to determine compatible dressing areas (i.e. changing rooms). The size and furnishing of changing rooms are defined by the manufacturer based on the number of operators, number of shifts and cleanliness class.
Other useful information to set up a Clean Room
The following additional parameters must also be kept into consideration when designing a Clean Room:
- average lighting at the required worktop;
- system noise level;
- any limits on vibration and electromagnetic fields that may affect the process.
Clean Rooms must be considered as the suits of the production process, i.e. they must be made to measure according to the activity that will be carried out inside it.
To facilitate the collection of the above information useful to design a Clean Room, we have prepared a practical questionnaire you can fill in and send to us.