Difference between NAS Class and SAE AS4059

Udaya
I have only just picked this up, so If anyone has replied I hope that we are consistent, because it can get a tad confusing!!

Please note that ISO4406 is the Solid Contamination Code but I assume that you meant ISO4402 which is the 'old' calibration method. Also AS4059 is now at issue E!!

Yes you can use ISO4402 calibration as both Issue D & E allow this (look at the dual size scale on the tables) but I recommend that you use to ISO11171 calibration as it is better, gives greater precision and the level of traceability that modern Quality systems demand. You will see from my article that we at ISO have selected the 'new' size labels (6µm(c) etc) so that they give very similar particle counts as APCs calibrated to ISO4402.

Also, Issue E now gives the option of using two systems, Table 1 which is the same as the 'old' NAS 1638 (thge uUS aircraft industry demanded the change!!) and Table 2 which is the same as AS4059 IssueD. The Off Shore industry is standardising on AS4059 so you should use Table 2.

If you have any queries please contact me on mike_day@europe.pall.com

quote:

Originally posted by Mike Day:
...
Also, Issue E now gives the option of using two systems, Table 1 which is the same as the 'old' NAS 1638 (thge uUS aircraft industry demanded the change!!) and Table 2 which is the same as AS4059 IssueD. The Off Shore industry is standardising on AS4059 so you should use Table 2.

If you have any queries please contact me on mike_day@europe.pall.com

Mike

I have both tables in front of me (AS4059 Table 1 from Rev. D and Table 2 from rev. E) and they have changed. Not much, but enough for us to have to re-wright some software. The particlie limits has gone from nice round figures to more accurate. Why has this been done?

Also I wonder if the method ISO4407 is accepted for microscopy counts (cumulative counts) for the AS4059E? The rev. E contains: 4.2.2 "Method B. Optical Microscope: Optical microscopic counts shall be conducted in accordance with ARP598."

.. Hope you can comment.
Brgs

Kevin Hughes