Particle Counters

LarrySabo

Member
I received this particle counter yesterday but it came with no user guide.
PM2.5 Particle Counter Screens.jpg

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.
Particle counts, by diameter (µm) and time (min.).jpg

Below is the USA Federal Standard 209-E regarding clean room classifications:
Particle Counts, per USA Std 209E.jpg

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.
 

LarrySabo

Member
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. :lol:
 

pclab

Moderator
Hi Larry

And have you checked the accuracy of that reader with a "professional" reader and compare values?
Thanks
 

LarrySabo

Member
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.
 

lcoughey

Moderator
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.
 

Jared

Administrator
Staff member
LarrySabo":1exjx348 said:
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.
 

LarrySabo

Member
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.
 

LarrySabo

Member
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! :lol:
 
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