Andy Pye examines the latest contamination control standards which incorporate the best practices in the use of cleanrooms.
Controlling contamination is essential in many manufacturing and research activities. The use of cleanrooms, along with strict and stringent processes, makes this possible. The recently revised ISO standards for cleanrooms can help.
Food production, pharmaceuticals, aerospace and automotive manufacturing are just some of the many areas where controlled and classified cleanrooms – where contaminants in the air are highly controlled – are essential. Without effective control, contamination can wreak havoc on products and processes.
ISO has a series of standards dedicated to cleanrooms, outlining the practices and procedures required to manage the risk of contamination. The first two in the series have just been updated to take into account the latest technological developments and market requirements.
ISO 14644-1:2015, Cleanrooms and associated controlled environments – Part 1: Classification of air cleanliness by particle concentration, specifies the classification of air cleanliness in terms of concentration of airborne particles in cleanrooms and clean zones; and separative devices as defined in ISO 14644-7.
Only particle populations having cumulative distributions based on threshold (lower limit) particle sizes ranging from 0.1 to 5µm are considered for classification purposes.
The use of light scattering (discrete) airborne particle counters (LSAPC) is the basis for determination of the concentration of airborne particles, equal to and greater than the specified sizes, at designated sampling locations.
ISO 14644-1:2015 does not provide for classification of particle populations that are outside the specified lower threshold particle-size range, 0.1 to 5 µm. Concentrations of ultrafine particles (particles smaller than 0.1µm) will be addressed in a separate standard to specify air cleanliness by nano-scale particles. An M descriptor may be used to quantify populations of macroparticles (particles larger than 5µm).
ISO 14644-1:2015 cannot be used to characterize the physical, chemical, radiological, viable or other nature of airborne particles.
ISO 14644-2:2015, Cleanrooms and associated controlled environments – Part 2 specifies minimum requirements for a monitoring plan for cleanroom or clean zone performance related to air cleanliness by particle concentration, based upon parameters that measure or affect airborne particle concentration.
ISO 14644-2:2015 does not address condition monitoring of aspects such as vibration or general maintenance of the engineering systems. It also does not provide for monitoring of particle populations that are outside the specified lower threshold particle-size range.
David Ensor, Chair of ISO/TC 209, the technical committee that developed the standards, which is led by ANSI, ISO member for the USA, under the administration of the Institute of Environmental Sciences and Technology (IEST), comments: “Cleanrooms enable a large number of modern high-technology industries; therefore, the work of the technical committee will have widespread impact. The two revised ISO standards will improve the ability to quantify and manage airborne particle contamination worldwide.”
The ISO 14644 series is available from national ISO members or from the ISO Store. ISO members form a network of national standards bodies. They are often the foremost standards organisations in their countries and there is only one member per country. Each member represents ISO in its country. Full members (or member bodies) influence ISO standards development and strategy by participating and voting in ISO technical and policy meetings.