What Size Particles Do Big Brute Filters Stop?

April 19, 2021

We’re often asked: “What’s the smallest size particles the filters in a Big Brute can stop?”

The answer is, well, not as straightforward as you might think.

Fabric Filters

Standard Dry Only Big Brute models use 2 separate fabric filters to capture dust from the air passing through. The Wet & Dry Big Brute models also use these same filters when operating in dry mode.

These fabric filters are made from an interwoven mesh of fibres and end up with some pretty random arrangements. If you were to look at them under a microscope, you’d see a wide range in the size of the microscopic holes between the fibres. Some holes are much smaller, where the fibres are tightly interwoven, and some are much larger holes, where the fibres are more loosely intertwined.

This random nature of the interwoven fibres produces a very wide variety in the size of the microscopic holes in between. This means that some holes will stop smaller particles, and others will let them pass through.

So with Big Brutes that use fabric filters only, it’s not possible to specify the minimum particle size the Big Brute will filter out.

The Muckier, The Better

To add further complications to the way the fabric filters work, they actually work better the more you use them. When you first start cleaning up with a Big Brute, dust and particles start to get trapped on the filters. Which is perfect, because this is their job. However, as more particles get trapped, the holes between the fibres start to get blocked. Which is also great as the filters then start trapping smaller and smaller particles leading to better filtration.

However, you’ll eventually reach a point where the filters are so caked in dirt that they start to obstruct the airflow. And if there’s nowhere for the air to get through the Big Brute, your suction performance will start to drop off. This is know as “filter blinding” and it’s at this point when you’ll need to take a few seconds to stop vacuuming and shake the filters clean.

Having said all this, there is a Big Brute where we can confidently state the smallest particle size the filters will trap – enter the Big Brute HEPA.

HEPA Filters

The Big Brute HEPA uses 2 stages of fabric filters, as described above, but has an additional, final stage of filtration – a dedicated HEPA filter cartridge.

Because the HEPA filters are made from paper, not fabric, it is possible to precisely engineer the size of the microscopic holes that the air passes through, and therefore the smallest possible particle size that the HEPA filter will trap. And each HEPA cartridge undergoes testing at manufacture to certify this.

We’ll talk more about the HEPA filtration in another article, but for now, if you have a cleaning application where you need to guarantee the efficiency of the filtration, have a look at the Big Brute HEPA.

Fabric Fibres under a Microscope