Do you monitor both 0.5 and 5 micron in ISO Class 8 cleanrooms?

[Ajit Basrur]

I have a question on the nonviable particle monitoring for ISO Class 8 cleanrooms. The particle monitoring is done for both 0.5 and 5 microns but the new ISO 14644-1:2015 recommends using one channel, and heard that most companies are planning to monitor the cleanrooms at 0.5 microns only.

I still prefer the old way of monitoring at both 0.5 and 5 microns to have a good distribution of the particulate contaminants.

Can I know what is your practice - do you monitor only at 0.5 or 5 micron or both?

 

[Ajit Basrur]

Any thoughts?

 

[Ninja]

I operate a 100K (ISO8-ish) and a 10K (ISO7-ish) room.
We monitor only 0.5um...though I scan the other sizes since they are right there on the standard report anyway.

It is pretty difficult to "fix" one size channel without improving the others anyway...so monitoring one channel makes sense to me unless there is a specific outside influence like a particularly specific customer requirement.

We tend to 'pass' by such a large margin on every test that we have not gone into the nitty gritty of the test details.

 

[AgnieszkaSz]

We monitor 0,5, 1 and 5 micron particles for ISO-8 and ISO-7 cleanrooms. But I doubt there is any reason for this other than "it has always been so".

 

[somashekar]

Is there not another condition that the cumulative of all particle count should not exceed a certain number for each class ... ?

 

[Ninja]

Each particle size is "this size or larger"...so in effect each of the particle size measurements in themselves is cumulative.

The 0.5um particle size count will always be larger than the 1um particle count since all of the 1um particles are included in the 0.5um particle count.

 

[RCH2016]

Out of curiosity, what instrument are you using to measure particle size? In the industry I am in, the Sedigraph is the standard, but I have had reason in the distant past to explore other instruments and test methods and have found the results from the various approaches to vary to an eye popping degree.

 

[Ninja]

Howdy,

I use Sedigraph too...but for wildly different things.

Air sampling and Sedigraph particle size measurement are like apples and warm. Nothing at all to do with each other.
Air sampling typically uses a suction port running through a laser PS measurement grid whereas Sedigraph typically has discrete particles in fluid suspension.

Do an image search for "cleanroom air sampling machine" and the difference will jump right out at you (I can't figure out how to put a pic in here).

 

[Morlock]

But what particle size is the specification actually for (which I feel is a different question than "what micron size is being monitored"? 0.5 micron? 1 micron? 5 micron? Any of them? All of them? I've reviewed the reference table for maximum values of each particle size for each rating, but the table I reviewed was unclear regarding my question.

For example, say a clean room passes the 0.5 micron specification, but fails the 5 micron specification? Is the clean room certified? What about the reverse?

I found one reference that says "Class 6, 7, and 8 are based on the number 0.5 micron particles. " and "Federal 209B Standards: Class 10,000: Particle count not to exceed a total or 10,000 particles per cubic foot of a size 0.5 micron and larger or 65 particles per cubic foot of a size 5.0 micron and larger." (I added the emphasis). (Source: Cleanroom Classification Comparison Specifications Defined )

Thanks all.

 

[Tata347]

have any of you "validated" the room for medical devices? there seems to be some discussion here about exactly needs to be monitored on a daily basis. taking 30 readings a day is going to be too time consuming and not cost effective.. your thought?