Choosing the right particle counter for your application
Finding the right fit
Scenario #1: You’ve been tasked with finding a particle monitoring solution for a construction site. You mainly need to measure particles generated from cutting wood and similar materials. What kind of instrument do you need?
Scenario #2: You work in a cleanroom and need to measure aerosol particles. What type of counter best meets this application?
There are four main factors that will influence a choice of particle counter:
- The first consideration is the particle size(s) that must be monitored. This is partially determined by the ISO class of the testing/monitoring environment. There are ISO classes that correspond with cleanrooms, workplaces, manufacturing facilities, and more.
- Another factor is the customer’s needs. Typically a customer will chose one or two particles for the certification test (if you need help choosing which particle sizes to monitor please refer to the ISO standard). When purchasing your particle counter you will need to check the specifications to ensure the instrument can measure particles of the appropriate size(s). Make sure you choose a particle counter that can measure all the particle sizes that need to be monitored.
- The third factor is measuring location. Will the instrument be monitoring a specific area at all times? Will you need to take it with you to spot check different areas?
- The last factor that you’ll want to consider is the flow rate capability of the particle counter. In order to do that we need to consider one of the formulas from the ISO standard.
Getting into the Math
This formula will calculate how many litres of air need to be sampled at each location in a cleanroom: Formula: Vs = (20/Cnm) x 1000
Vs = the minimum single sample volume per location, expressed in litres
Cnm = is the class limit (number of particles per cubic metre) for the largest considered particle size specified for the relevant class.
20 = the defined number of particles that could be counted the particle concentration were at the class limit.
To learn more about how to use ISO standards to select the right particle counter for your needs please refer to the following PDF document.