You buy a powerful dust collector, install it according to spec, and expect the air to clear. But at a few workstations, dust still escapes the hood, and your team keeps dealing with buildup in the duct runs. It’s frustrating, especially when the equipment itself seems “right on paper.”
In many facilities, the dust collector isn’t the real issue. The problem is the dust collector ducting that connects your pickup points to the collector. Even a well-sized fan and brand-new filters can’t overcome a duct system that’s too restrictive, too long, or laid out in a way that slows the air down.
Ducting doesn’t just “move air.” It decides how much air actually reaches each pickup, how fast that air travels, and whether dust keeps moving or settles in the line. When your dust collector ducting is laid out well, the whole system feels smooth and predictable. When it’s not, you see weak capture, clogs, and unnecessary wear on the fan and filters.
This guide keeps the technical language simple. You’ll learn what ducting does, why layout and size matter, and practical steps you can take to improve performance or plan your next system with fewer surprises.
In plain terms, dust collector ducting is the pipework that carries dirty air from where dust is created to the dust collector, and then (in some systems) returns clean air back into the building.
It usually includes:
Most people first think of ductwork in the context of heating and cooling. In ductwork for dust collection systems, the goal is different. Instead of simply moving air for comfort, you’re moving air in a way that reliably carries dust, fumes, and in some cases combustible dust, safely out of the workspace and into the collector for filtration.
When the duct network is planned well, airflow feels “even” across the system and dust doesn’t have a chance to settle in the pipework. When it’s an afterthought, you often see dusty corners, certain hoods that don’t capture dust well, and more time spent on cleanouts than you’d like.
It’s easy to treat duct as an accessory: run a line from each machine, tie everything into a main, and hook it to the collector. In reality, duct design has a major influence on how well your system performs day to day.
The design affects:
Every choice adds a little bit of resistance to airflow - duct length, number of elbows, how many branches you have, and what size pipe you use. Resistance is simply how hard the fan has to pull to move air through the system. As resistance goes up, airflow tends to go down, especially at the farthest or most restrictive pickup points.
When ductwork is laid out with smooth routes and sensible sizes, the fan can move air efficiently. When the system is full of tight elbows, abrupt size changes, very long runs, and lots of flexible hose, the fan spends more effort pushing against resistance instead of delivering the airflow you expect. Static pressure goes up, CFM at the hoods goes down.
If you're troubleshooting, it can be helpful to remember: duct problems often look like collector problems. Low capture, uneven performance, and frequent clogs can all trace back to duct layout and sizing choices rather than the collector itself.
If you’ve ever wondered why a brand-new collector doesn’t “feel” as strong as its label suggests, duct design is often the missing piece. And you don’t need to be an engineer to talk about airflow. Three simple ideas explain most of what you see in the field.
CFM stands for “cubic feet per minute” and simply describes how much air is moving through your system. Each pickup point needs a certain amount of CFM to grab dust and fumes before they drift into the room.
Your total system CFM is based on:
Duct sizing and layout affect whether the collector can actually deliver that airflow. If ducts are too small or too restrictive, the system may never reach the CFM you planned for on paper.
Static pressure is a way of talking about resistance inside the system. As air moves through the duct, it rubs against the walls, turns corners, and passes through fittings. All of that creates resistance the fan must overcome.
If you add up the effects of straight duct runs, elbows and transitions, branches and take-offs, and hoods and filters, you get the total static pressure the fan sees. If that total is higher than what the fan was chosen for, the system will move less air than expected. The result is weak capture at some hoods, especially those farthest from the collector or at the end of complex runs.
Transport velocity is the speed of air inside the duct. It needs to be fast enough to keep dust suspended and moving toward the collector.
If the air slows down too much - often in oversized ducts, low spots, or long horizontal runs - dust can drop out of the airstream and settle in the line. Over time, that buildup:
What matters most in day-to-day operation is that your system keeps dust moving and doesn’t let it collect inside the duct - especially if you’re handling combustible dusts, where internal buildup is also a safety concern.
The physics behind duct design can be complicated, but the basic principles are straightforward.
Put together, effective duct design is about finding a balance: duct sizes and layouts that keep the air moving, carry dust all the way to the collector, and stay within what the fan can handle.
Here are some frequent duct design issues that hurt performance:
The goal isn’t for your team to become full-time duct designers. Instead, you want a simple process that leads to a system that works.
If you already have a system and keep seeing the same problems such as weak capture, uneven performance, or recurring clogs, it’s worth having your existing duct layout reviewed instead of just replacing equipment.
There is no single “standard” duct size that fits every plant. The right diameter depends on how much airflow you need at each pickup and what speed you need to keep dust moving. Sizing charts, design guides, and manufacturer input can help you choose diameters that fit your layout and process.
Longer duct runs add more resistance. The more length and fittings you have between the pickup and the fan, the harder it is to deliver strong airflow. Keeping runs as short and direct as practical usually improves performance.
Instead of starting from a duct size and asking how much CFM it can handle, it’s better to start with how much airflow your process needs. From there, you select duct sizes that can carry that airflow at a suitable conveying speed, using a CFM-versus-duct-size chart as a guide.
There is no strict limit, but every elbow adds resistance. Runs with many tight elbows in a row are far more likely to have performance issues than runs with just a few gentle turns. When in doubt, simplify the path if you can.
In most industrial systems, smooth metal duct performs more predictably and with less resistance than long runs of flex hose. A flexible duct is best kept short and used where movement or vibration makes rigid connections difficult.
Even the best duct design needs a dust collector and fan that can support it. When you choose or review a collector, it helps to look at the whole picture:
When your fan, collector, and dust collector ducting are designed together, you get more reliable capture, fewer surprises, and a system that’s easier to maintain over time.
If you’re planning a new system or trying to improve an existing one, it’s a good time to review the duct side of the equation. Talk to the A.C.T. team about your processes, layout, and challenges, and get help turning your ductwork and collector into a system that works as a whole.