Page 1 of 5
Posted: Tue Oct 03, 2017 5:24 pm
I received this particle counter
yesterday but it came with no user guide.
At the moment, I am unsure of the units of measure in the "USA" display. I made a few measurements in my clean chamber and on the desk beside it, and noticed that the values varied considerably over time, so I took measurements every minute for five minutes and got the following results.
Below is the USA Federal Standard 209-E regarding clean room classifications:
If the units of measure of my device are thousands of particles per cubic meter, the chamber is approximately Class 100. Class 100 is defined as having (a maximum?) of 10.6 thousand 0.3μm particles per cubic meter and 3.5 thousand 0.5μm particles per cubic meter. I observed averages of 10.2 and 2.0, respectively but the maximum counts during the five-minute test exceeded those prescribed by the standard for Class 100. Without a calibrated particle counter against which to compare under the same conditions, I have no idea how (in)accurate my counter is.
I’ve asked the seller of my meter to provide the units of measure and when I hear back, I’ll update this post.
Posted: Tue Oct 03, 2017 5:33 pm
The standard that included Class 100 is long obsolete. You should really be looking at the ISO 3 through ISO 5 standards now. Here's a PDF with the current rating standards: https://www.terrauniversal.com/file_lib ... 164241.pdf
Posted: Tue Oct 03, 2017 8:11 pm
Thanks, Jared. I had seen that standard discussed here
. I was more curious to just know where my clean chamber ranked and it ranks as an ISO 5, which has the same specs as Class 100. If I were rolling in the big bucks from DR like you and Luke, sure, I'd go for something cleaner.
Posted: Wed Oct 04, 2017 3:15 am
And have you checked the accuracy of that reader with a "professional" reader and compare values?
Posted: Wed Oct 04, 2017 9:28 am
Not yet, Nuno. I have to find a lab with one that's willing to test my unit or loan me their professional-grade counter. I believe there are local businesses that re-certify clean rooms, but they want an arm and a leg to do the calibration. I need to do some searching.
Posted: Wed Oct 04, 2017 12:24 pm
I suspect that it is accurate enough. It isn't like Larry's work is affected by the numbers. That said, it would be nice to get and IM-PARTICAL opinion, too.
Posted: Wed Oct 04, 2017 1:47 pm
LarrySabo wrote:I have to find a lab with one that's willing to test my unit or loan me their professional-grade counter. I believe there are local businesses that re-certify clean rooms, but they want an arm and a leg to do the calibration.
I've found it near impossible to find anyone who does this. I've called a few places listed online who advertise clean room certifications, but none ever seem to return a phone call. Maybe coming out to just run a meter in a clean hood is somehow beneath them.
That's why I just finally bought a decent laser particle counter and do constant monitoring whenever I'm working in it. I wait until the 0.5 micron count reaches 0, then I start work. Occasionally, while working, it might jump up to 1, but usually never higher than that. I do wish my meter went all the way down to 0.3 microns, since that's what they actually base the rating on, but I figure that if 0.5 count is at zero, there's no possible way that the 0.3 count is over 10,200. I doubt it's even at 10. My hood came factory tested out at ISO 5, but it's a hood that can actually meets ISO 3 testing, especially if you put a ULPA filter in instead of the HEPA. They just don't certify to that unless you opt for the $1000 ULPA filter to come installed in it.
Posted: Fri Oct 06, 2017 7:52 pm
I received a quote from one company today that wanted $115 CAD to test the meter, plus another $50 CAD if I wanted a written report, presumably plus 13% HST (harmonized sales tax). I've decided I'm not that interested, especially given the variability of the readings.
Posted: Tue Oct 10, 2017 5:58 am
I Am also Going To Order 1 Unit or Two For My Lab .Very Decently Priced .
Posted: Tue Oct 10, 2017 8:47 am
Amarbir, let us know what you think of it. My BIL (physicist) and family were over for Thanksgiving dinner last night and I showed him the meter. He suggests that with such low particle counts, one should expect a lot of variability. In my clean chamber, I was pointing the sensor into the air stream. Perhaps I'll run the chamber for a few minutes then turn it off and see what happens to the particle count.
Maybe I should send my unit to Jared to run alongside his Dylos meter for comparison. That should be cheaper than $165 CAD!