So you’re going to classify your cleanroom. But what cleanroom classifying tools can you use that will make the process painful and easy?
First things first, let’s define cleanroom classification.
The International Standards for Organization (ISO) is one organization that sets cleanroom classifications. ISO is a non-governmental agency that sets standards in a number of industries. These standards are widely respected throughout the world.
In the US, there is another set of classifications. The Federal Standard 209 (FS 209) was established in 1963 by the Institute of Environmental Sciences and Technology (IEST). This set of classifications also has a range of options. Their classifications range from FS209A to FS209E.
ISO classifications are defined by ISO 14644-1, which matches the requirements for FS209. We often see these classifications as a requirement, but in the world market, we tend to refer to ISO standards.
The ISO standards classify rooms in 9 categories. ISO 1 defines the cleanest of cleanrooms, in relation to the number and size of particles, whereas ISO 9 defines normal room air.
So when it comes to cleanroom classifying, it is important you do it right. You need the right tools to count your particles in different areas to get the numbers you need. After you classify your cleanroom, you need the right tools to keep it at your classification level. Both classification and ongoing monitoring are fundamental to a cleanroom contamination control strategy. 
Airborne particle counters are instruments that count the number and size of particles in a given space. There are three primary types of particle counters: remote, handheld, and portable. Remote particle counters are small and semi-permanent. They work well as a part of the infrastructure. Handheld particle counters are small and portable with a low flow rate, so they are often slow. Lastly, portable particle counters are the larger (but ergodynamic) and fast option that can be moved around the cleanroom. They are the most popular option.
Your selection criteria for your particle counter should consider the exact specifications of the instrument based on your needs. This includes how small of a particle it can detect, flow rate, ease of use, and more.
Because this is a major investment, we recommend examining your supplier. Take a look at their track record and service abilities. While the instrument really matters, the support behind it makes or breaks your successful classification.
Classifying your cleanroom requires using a calibrated instrument. Particle counters require annual calibration. The proper calibration for airborne particle counters follows ISO 21501:2018 according to ISO 14644-1:2015. Your instrument might also need sensor cleaning, optic parts replacement, occasional laser replacements, and other general maintenance for regular wear and tear.
With that in mind, what questions exactly should you ask when considering a particle counter? We have a few in mind!