||All Sizes of Particles Counted with Cleanroom-Wiper Standard;
Round Robin Participants Sought
The ability to count unwanted particles is of prime importance
in cleanrooms controlled environments where electronic, aerospace,
pharmaceutical, and other products are tested or assembled. Cleanroom
wipers, manufactured for these environments, must be carefully
tested for particle count and fiber contamination. They are used
to clean surfaces, apply liquids, and handle components.
As opposed to existing test methods that examine limited sizes,
a new ASTM standard counts all sizes of wiper-particulates released,
from <5mm to >100 mm. Now available,
E 2090, Standard Test Method for Size-Differentiated Counting of Particles
and Fibers Released From Cleanroom Wipers Using Optical and Scanning
Electron Microscopy, has been issued by ASTM Committee E21 on Space Simulation and Applications of Space Technology.
The test method was initially developed by wiper manufacturers
technologists and submitted to ASTM to promote uniform methodologies
and consistent data. After review and validation by space-industry
scientists working on ASTM Subcommittee E21.05 on Contamination,
it was balloted by the Society and approved in May.
According to the subcommittee, E 2090 provides a credible evaluation
of the amount of particle and fiber contamination in wipers used
in cleanrooms, and allows users of the wipers to reliably compare
products in order to determine the risk factor when using such
products in critical environments.
Over 20 pages of documentation are provided on test method procedures,
apparatus, and materials used, etc. When performed correctly,
this counting method is sensitive enough to quantify very low
levels of total particle and fiber burden, the subcommittee stated
in the document. [The results] are not influenced by artifact
or particle-size limitations. A further advantage to this technique
is that it allows for morphological as well as X-ray analysis
of individual particles.
Robert Moss, the subcommittee chair, is organizing a round robin
to garner valid interlaboratory comparisons and statistical analysis.
We recommend that anybody who is interested in particle counts
on fabrics take a look at this, said Moss, principal engineer,
Space Systems/Loral, Palo Alto, Calif. We think its worth at
least trying on your products, and seeing how it works. Wiper
manufacturers, representatives of the electronics, aerospace,
pharmaceutical industries, and other interested parties are invited.
To participate in the round robin, or for further technical information,
contact Robert Moss, Space Systems/Loral, 3825 Fabian Way, Palo Alto, Calif. 94303-4604
(650/852-6018; fax: 650/852-6441). Committee E21 and Subcommittee
E21.05 meet Oct. 24-25 during the IEST Space Simulation Conference
Oct. 23-27 at the Radisson Hotel in Annapolis, Md. Conference
registration is not needed to attend the ASTM meetings, which
are free and open to the public. For meeting or membership information,
contact Staff Manager Nancy McAvey, ASTM (610/832-9736). For IEST conference registration contact IEST (847/255-1561; or fax: (847/255-1699).
Copyright 2000, ASTM