VPC300 particle counter

[joniengr081]

I am wondering what is the unit of particle counts in VPC300. Are these numbers (counts per particle size) are measured in per cubic meter ?

[thm_w]

ug/m³ is the standard measurement unit yes.

But it looks like it depends on what mode you are in:
"Particle Count Modes Cumulative, Differential, and Concentration modes"

https://www.fondriest.com/pdf/extech_vpc300_manual.pdf

[joniengr081]

ug/m3 look like a unit of density but the measurements should be in terms of count per m3 or count per cm3, maybe ft3. I am not getting how it related to density.

[joniengr081]

The user manual says "If a room is classified as an ISO clean room or clean zone, the counts of particle sizes for that
class cannot be exceeded when tested. Refer to the ISO Clean Room Class chart (ISO 14644-1:1999) for values." I have looked at the maximum particle count limit for ISO 5 to ISO 8 and found that these numbers are per m3. But the unit in which VPC 300 is displaying is not clear to me.

[thm_w]

ug/m3 look like a unit of density but the measurements should be in terms of count per m3 or count per cm3, maybe ft3. I am not getting how it related to density.

If you have it set to cumulative, then its just counting the total number of particles. Does anything change if you set it to concentration mode?

But seems you are right, its counts per m³. Then if needed use some equations to convert it to ug https://www.researchgate.net/post/How_to_convert_mass_concentrations_ug_m3_to_particle_number_concentrations_particles_cm3

[joniengr081]

I understand the cumulative mode and differential mode but don't understand the concentration mode. How it differs then the other two modes ?

If it shows the numbers in the unit of per m3 than it's fine but it is not clearly written in the user manual. Where can I see the measurement unit documented ?