Jonathan Newell reviews the latest updates to the ISO standard covering cleanrooms and associated controlled environments.
The International Organisation for Standardisation (ISO) has released 2016 updates to Parts 1 and 2 of ISO 14644 – Cleanrooms and associated controlled environments. Part 1 concerns the classification of air cleanliness by particle concentration; Part 2 covers monitoring for the provision of evidence of cleanroom performance related to air cleanliness by particle concentration and a framework for classifying and monitoring the cleanliness of cleanroom air.
Generally, changes over the years have reflected increasing precision in manufacturing, particularly in the automotive, electronics and aerospace sectors, as well as more stringent demands on controlled environments in healthcare, pharmaceuticals and food processing. Such changes are likely to continue as contaminants become more of a challenge and cleanroom technology evolves.
Members of the cleanroom community have requested that certain parts of ISO 14644-1:1999 be reviewed, especially selecting the number of sampling locations in a cleanroom and the analysis of data at each sampling point.
ISO standards are systematically reviewed every five years by members of the Technical Committee, led by ANSI, the ISO member for the USA, under the administration of the Institute of Environmental Sciences and Technology (IEST). The latest revisions have now been in circulation for a few months.
“In the 1999 standard, the error in the test data for each point was estimated statistically using the student’s test, whereas now a statistical procedure is used to determine the number of sampling points as a function of cleanroom area and a simple average is used for the results of each test location,” Ensor explained. “And ISO 14644-2 has been revised to include requirements for the development and implementation of a monitoring plan.”
The need to consider progressively finer particles and reduced concentrations is likely to result in a new family of so-called Super Cleanrooms for use in nano-manufacturing plants. Ensor asserts that specific cleanroom classes may be specified and this depends on the application. ISO 14644-1:1999 included a section on “ultrafine particles”, but material covering particles smaller than 100nm has now been removed from ISO 14644-1. “This is being developed as a new standard, ISO 14644-12 Cleanrooms and associated controlled environments: Monitoring of air cleanliness by nanoscale particle concentration,” Ensor added.
Another important change is the progression to improved energy management in cleanroom operations. Work is currently underway on ISO 14644-16 – Cleanrooms and associated controlled environments: Cleanroom energy – a code of practice for improving energy efficiency in cleanrooms and clean-air devices.