ISO/DIS 14644-12 covers the monitoring of air cleanliness by particles in terms of concentration of airborne nanoscale particles
ISO Draft International Standard (DIS) 14644-12 – Specifications for monitoring air cleanliness by nanoscale particle concentration is now available from the Institute of Environmental Sciences and Technology (IEST).
Airborne ultrafine particles have been measured in cleanrooms since the 1980s. At the time, particles smaller than 100nm were called ultrafine particles rather than the more recent term nanoparticles.
Within ISO/DIS 14644-12, reference made to a nanoparticle signifies a nano-object with all external dimensions in the nanoscale, where the lengths of the longest and the shortest axes of the nano-object do not differ significantly.
While most sub-micron and macro particles in cleanrooms can be related to human activity, nanoparticles are generated by electrostatic discharge, chemical reactions such as oxidation, and gas phase nucleation. Therefore, the majority of the nanoparticles in cleanrooms are process-related.
While the composition of sub-micron and macro particles is generally comparable, each cleanroom will have nanoparticles corresponding to the specific process.
Measurement of the nanoparticle concentration is only suitable when the cleanroom is in an operational state (using occupancy states as defined in ISO 14644-1:2015). In the as built or at rest state, the lack of process related particles will lead to data that does not correlate to realistic conditions.
The protocol in ISO/DIS 14644-12 was developed to monitor the cleanroom air near the process equipment under operating conditions.
ISO/DIS 14644-12 will have immediate application for organisations that currently monitor nanoparticles for process evaluation and should prove quite useful to process engineers.
While aerospace and electronics have had interest in this area for decades, new applications are developing in the fields of biotechnology and pharmaceuticals.
It is anticipated ISO 14644-12 will also have a long-term impact as 1. instrumentation for cleanroom measurement improves and 2. the number of nanotechnology-based products requiring manufacture in a cleanroom environment increases.
The expert group responsible for creation of the standard – ISO Technical Committee (ISO/TC) 209 Working Group 10 Nanotechnology – is convened under IEST leadership through United States Convenor Anne Marie Dixon.
While nanotechnology is a new endeavour for ISO/TC 209, IEST offers several Nanotechnology Recommended Practices with a focus on facility design.
In July, IEST released IEST-RP-NANO205.1: Nanotechnology Safety: Application of Prevention through Design Principles to Nanotechnology Facilities.
The Recommended Practice (RP) provides facility design information intended to help minimise risks for personnel associated with nanotechnology research and production.
IEST has served as the Secretariat for ISO/TC 209 for nearly 25 years. ISO/TC 209 is circulating ISO/DIS 14644-12 for comment and approval to move to Final Draft International Standard (FDIS) stage and eventual publication as an International Standard.