Thursday, 18 April 2013

Basics of cleanroom design



The aim of the cleanroom contractor must be to provide a complete facility with minimum participation by the customer or end user. The cleanroom contractor has the responsibility to design and construct the cleanroom facility in a timely manner and to come in at or below budget. To do so the contractor must consider the following points:
  • At what cleanliness level and in what locations are cleanliness levels required? This is highly dependent on the type of process which will be conducted in the cleanroom.
  • What floor plan works best for the process being conducted? Does the process require multiple rooms and of what cleanliness level? Is a gowning room or ante room required?Where are the critical work areas located, and how will they be affected by the location of the HEPA or ULPA filters and the airflow pattern in the room?
  • What environmental conditions, such as temperature and humidity, are required in the clean space and will those requirements vary in the future?
  • What are the temperature, humidity, and pressure specifications of the cleanroom? There must be a full understanding of the complexity of HVAC design.
  • What are the heat loads due to number of people and equipment loads in the space?
  • Are pass thru units or air showers required to isolate various areas from cleanroom to cleanroom or noncleanroom to cleanroom?
  • Construction materials for walls, ceilings, and floors and their compatibility with the process requirements must be evaluated. The output from your cleanroom could easily be directly related to the amount the materials out-gas or how well the materials dissipate static electricity.
  • Design the wall system, taking into consideration material required and location and size of doors, windows, and other openings such as return grilles.
  • Is there sufficient space above the proposed ceiling for light troffers and HEPA or ULPA filter units and the required mechanical distribution system?
  • Fire protection and any process requirements from electrical requirements to gas or liquid requirements must be designed and coordinated.
  • Correctly identify the size and location of the filters, the air supply, and the air return to properly distribute clean air throughout the space.
  • Light level must meet customer specific light level needs within the space while meeting OSHA requirements.
  • What are the requirements for process piping or electronic communications with the cleanroom?
  • What temperature, humidity, pressure controls, monitors, and network connections are required?
This useful advice comes from an article by George Pollick, which can be found on the Controlled Environments website.

Posted by Tim Sandle